FIELD OF THE INVENTION

The present invention relates to a process for producing gasoline having a reduced alkene content and a reduced organosulfur content. The process is particularly suitable for reducing the alkene and organosulfur contents of gasoline from fluid catalytic cracking (FCC).

BACKGROUND OF THE INVENTION

Global demand for transportation fuels continues to grow, and this demand will continue to be met largely by gasoline and diesel fuels. The fluid catalytic cracking (FCC) process plays a key role in modern petroleum and petrochemical integrated refinery as the primary process for conversion of crude oil to lighter products. Moreover, as a major product which is produced from the FCC process, FCC gasoline is a significant fuel used in internal combustion engines (ICE). It is a volatile, inflammable mixture composed of paraffinic, olefinic, naphthenic, and aromatic hydrocarbons (C ₄ -C ₁₂ ). In FCC gasoline and other refined fuels the contents of olefins and organosulfur compounds (OSCs) are required to meet stringent modern product specifications.

One of the primary reasons for such specifications is that, during storage, olefins react with atmosphere oxygen and with other components. Thus, due to polymerization reactions and formation of gums, changes in FCC gasoline's physiochemical characteristics are promoted. Because the materials formed have polymeric character, they invariably cause deposition in a vehicle's oil filters and distribution lines. These limitations have led to the stability of FCC gasoline being defined as low.

In addition, OSCs are converted to SO _x during the engine combustion process, and the exhaust gases from motor vehicles contribute to a large extent to acid rain and air pollution through their NO _x and SO _x content. Moreover, OSCs may be present in varying

concentrations in refined fuels and additional contamination may take place as a consequence of transporting the refined fuel through pipelines containing sulfur contaminants. Sulfur has a particularly corrosive effect on equipment such as brass valves, gauges, and in-tank fuel pump copper commutators. Importantly, fuels containing impurities such as sulfur are also lightly effective poisons for a vehicle's catalytic converters. Therefore, OSCs are also a significant undesirable component in fuels, and this has led the governments of numerous countries to adopt new regulations which target at a drastic reduction of sulfur emissions by imposing a very low concentration of this element in fuels (50 ppm or less by 2005; 10 ppm or less by 2009).

It has been found that commercial gasoline is made up of different fractions coming from reforming, isomerization and FCC units (Brunet, S.; Mey, D.; Perot, G.; Bouchy, C; Diehl, F. Applied Catalysis A: General 2005, 278, 143). Those coming from the reforming and isomerization units are produced from so-called "distillation cuts", and consequently contain little or no sulfur because the OSCs in crude petroleum have generally high boiling point. However, the atmospheric residues or the vacuum distillates which constitute FCC feedstocks contain significant amounts of sulfur: 0.5-5% by weight generally. Consequently, FCC gasoline, which represents 30-40% of the world's total gasoline pool, is by far the most important sulfur contributor in gasoline, up to 85-95%). A lower sulfur content in the FCC gasoline will not only mean higher fuel quality, but also will reduce the pollution from motor vehicles' exhausted gases. To improve the stability and quality of FCC gasoline and reduce the pollution from motor vehicles' exhaust gases, it is critical to reduce olefin and OSCs content.

The prior literature for reducing olefin content shows that there are two major directions of research: (i) to separate the olefins through various physical approaches; and (ii) to use specific chemical reactions to convert the olefins into other compounds. The most typical and conventional physical separation of olefins uses cryogenic distillation, which is very costly and energy-intensive due to the similar relative volatilities of every components. A large portion of the capital cost of a modern olefin plant is devoted to the large distillation columns used in the separation process (Song, F.; Yu, Y.; Chen, J. Tsinghua Science & Technology 2008, 13, 730). In the field of chemical conversion, various catalysts such as SAPO-11, Ηβ, HMOR, HZSM- 5, HZSM-5 with Ga ₂ 0 ₃ , Co-Mo/ A1 ₂ 0 ₃ , Ni-Mo/Al ₂ 0 ₃ and Mesoporous Zeolite L (M-L) have been introduced into the FCC process (Fan, Y., Bao, X., Lei, D., Shi, G., Wei, W., Xu, J. Fuel 2005, 84, 435; Fan, Y., Lin, X., Shi, G., Liu, H., Bao, X. Microporous and Mesoporous Materials 2007, 98, 174; Viswanadham, N., Negi, B., Garg, M., Sundaram, M., Sairam, B., Agarwal, A. Fuel 2007, 86, 1290; Zhang, P., Guo, X., Guo, H., Wang, X. Journal of

Molecular Catalysis A: Chemical 2007, 261, 139; and Huo, Q., Dou, T., Zhao, Z., Pan, H. Applied Catalysis A: General 2010, 381, 101). Through hydroisomerization and aromatization treatment, olefins can be selectively converted into paraffin and aromatic hydrocarbons which are more stable and desirable. This measure reduces the olefin content in the FCC gasoline efficiently. However, this process not only has high cost, but also requires catalysts and complex reaction conditions.

To reduce OSC content, refiners worldwide are urgently developing technologies and strategies for economically and reliably meeting new, demanding clean fuel regulation as reviewed by Krishnaiah and Cartwright (Krishnaiah, G.; Cartwright, T. 2004 PRA Annual Meeting, San Antonio, TX, 2004). As the result, technical development for so-called "deep desulfurization" of FCC gasoline has attracted increasing attention. In the past various methods have been used to remove unwanted sulfur-compounds, both by chemical treatment and by hydrodesulfurization.

The hydrodesulfurization (FIDS) process, also known as a hydrotreating process, involves the reaction of OSCs with H ₂ to yield H ₂ S. This is one of the most common and conventional desulfurization methods that have been used in refinery processes around world since the 1950s. While HDS allows the sulfur content in gasoline to be reduced to any desired level, these processes require severe conditions, such as high temperatures up to 300 or 450°C and high-pressure which may be up to 207 bar. The HDS process therefore consumes a considerable amount of energy during operation. Of course, large volumes of hydrogen are also needed for this process. In addition, installing or adding the necessary hydrotreating capacity requires a substantial capital expenditure and increased operating costs.

Furthermore, alkenes and cyclic alkenes are susceptible to hydrogenation during

hydrotreating. This leads to a significant loss in octane number since alkenes and cyclic alkenes have a higher octane number than paraffin. In recent decades, novel technologies with better desulfurization performance than general methods have also developed quickly. For instance, a biodesulfurization (BDS) process based on the application of microorganisms can selectively remove sulfur atoms from OSCs. Oxidative desulfurization (ODS) processes are considered as the latest unconventional desulfurization process which involves chemical oxidation of divalent organic sulfur compounds to the corresponding hexavalent sulfur, also known as sulfone. In adsorptive desulfurization (ADS), OSCs are absorbed into a specified solid adsorbent so as to produce low-sulfur fuel. Another approach is extractive desulfurization (EDS), which is based on liquid-liquid extraction to remove sulfur-compounds, and has approximate 80% sulfur content reduction rate (Ibrahim, A.; Xian, S. B.; Wei, Z. Petroleum Science and Technology 2003, 27, 1555). Other sufur reduction processes include pervaporation desulfurization (PV) process, which is achieved by the application of specific membrane. Olefinic alkylation desulfurization (OATS) consists of weighing down the sulfur compounds by catalytic alkylation with olefins present in the feed followed by distillation, and its levels of desulfurization of 99.5% with a minimal octane loss (less than two points) have been reported. Photochemical or photocatalytic desulfurization processes can remove the sulfur compounds through photochemical reaction, and is activated by photons instead of high temperature, high pressure or other chemicals. Although these novel technologies have better desulfurization performance and energy efficiency than HDS, they may require severe conditions, complex procedures and specific chemicals or materials.

To overcome the disadvantages found in both the current olefin and sulfur reduction processes, and to achieve high olefin and sulfur removal efficiency, a unique and novel extractive refining technology has been developed by the inventors.

SUMMARY OF THE INVENTION

In view of the problems associated with the prior art alkene and OSC reduction processes, the inventors have developed an effective extractive alkene and organosulfur reduction which does not require a catalyst or high pressure or high temperature conditions. The present inventors have unexpectedly found that a solvent extraction process may be used to remove both organosulfur compounds and alkene compounds. The removal of both of these compounds from FCC gasoline by a single process has not been demonstrated before.

Thus, the invention provides a process for producing gasoline having a reduced alkene content and a reduced organosulfur content,

which process comprises contacting gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound, with an extraction solvent suitable for extracting alkenes and organosulfur compounds, which extraction solvent comprises a polar organic solvent,

and thereby forming

i) a first phase comprising said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound, and ii) a second phase comprising gasoline having a reduced alkene content and a reduced organosulfur content compared to said gasoline obtainable by a fluid catalytic cracking process.

The process typically further comprises recovering said gasoline having a reduced alkene content and a reduced organosulfur content.

There is also growing interest in the catalytic conversion of small organic molecules into useful organic feedstock compounds. The small organic molecules can be those of a solvent, such as an alcohol. For instance, methanol to gasoline (MTG), methanol to olefins (MTO) and methanol to aromatics (MTA) are increasingly useful techniques for producing chemical feedstock. Catalytic processes for the production of chemical feedstock compounds can also benefit from the presence of alkenes or other hydrocarbon compounds in the starting material. For example, the presence of alkenes in methanol used in MTG, MTO and MTA processes can result in an improved yield. The inventors have found that the extraction solvent ultimately recovered from the process of the invention for producing gasoline having a reduced alkene content and a reduced organosulfur content may be used in the production of other organic compounds.

The invention therefore also provides a process for producing one or more organic

compounds, which process comprises:

a) providing a recovered first phase, which recovered first phase is obtainable by: contacting gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound, with an extraction solvent suitable for extracting alkenes and organosulfur compounds, which extraction solvent comprises a polar organic solvent,

and thereby forming

i) a first phase comprising said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound, and

ii) a second phase comprising gasoline having a reduced alkene content and a reduced organosulfur content compared to said gasoline obtainable by a fluid catalytic cracking process,

and recovering at least part of the first phase; and

b) performing a reaction on at least part of the recovered first phase to produce one or more further organic compounds. In the process according to the invention for producing gasoline having a reduced alkene content and a reduced organosulfur content, the extraction solvent extracts alkenes and organosulfur compounds from FCC gasoline. The gasoline and extraction solvent may separate into phases, one of which comprises gasoline having a reduced alkene content and a reduced organosulfur content, and another of which comprises alkenes and OSCs extracted from the FCC gasoline.

Accordingly, the invention provides a composition comprising:

a) a first phase which comprises an extraction solvent suitable for extracting alkenes and organosulfur compounds, which extraction solvent comprises a polar organic solvent, at least one extracted alkene, and at least one extracted organosulfur compound; and b) a second phase, which second phase comprises gasoline having a reduced alkene content and a reduced organosulfur content compared to gasoline obtainable by a fluid catalytic cracking process.

The invention also provides an apparatus for carrying out the process of the invention. Thus, the invention provides an apparatus for producing gasoline having a reduced alkene content and a reduced organosulfur content, wherein the apparatus comprises:

a) a first reservoir comprising gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound;

b) a second reservoir comprising an extraction solvent, which extraction solvent is suitable for extracting alkenes and organosulfur compounds, and which extraction solvent comprises a polar organic solvent; and

c) a reactor which is connected in fluid communication with the first and second reservoirs. The extraction solvent used in the process of the invention for producing gasoline having a reduced alkene content and a reduced organosulfur content extracts an alkene and an organosulfur compound from FCC gasoline. Thus, the invention also provides the use of an extraction solvent for extracting at least one alkene and at least one organosulfur compound from gasoline obtainable by a fluid catalytic cracking process, which extraction solvent comprises a polar organic solvent. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows weight gain of the methanol phase against methanol:MFGM (model FCC gasoline mixture) ratio for a methanol extraction carried out on MFGM in Example 1.

Figure 2 shows GCMS chromatograms of the upper (MFGM) phase of samples (i) to (v) obtained in Example 1.

Figure 3 shows the composition of the upper (MFGM) phase of each sample in Example 1 after the extraction with methanol, compared with the original composition of the MFGM.

Figure 4 shows photographs of the mixture of the extraction solvent and commercial gasoline before and after extraction in Example 2. Figure 5 shows the weight of the lower (methanol/ethylene glycol) phase after extraction in Example 2.

Figure 6 shows the composition of the upper (gasoline) phase of each sample after extraction with ethylene glycol in Example 2.

Figure 7 shows the composition of the upper (gasoline) phase of each sample after the extraction with a methanol/ethylene glycol binary solvent in Example 2.

Figure 8 shows lower (solvent) phase weight after extraction with different mixing ratio samples of solvents.

Figure 9 shows upper (oil) phase olefin mass fraction before and after extraction. Figure 10 shows upper (oil) phase aromatics mass fraction before and after extraction. Figure 11 shows upper (oil) phase OSCs concentration before and after extraction. DETAILED DESCRIPTION OF THE INVENTION

Definitions

The term "gasoline", as used herein, refers to composition comprising hydrocarbons that may be used as fuel, for instance in an internal combustion engine. Typically, gasoline comprises alkanes, alkenes, cyloalkanes and aromatic compounds (also known as paraffinic, olefinic, naphthenic and aromatic hydrocarbons respectively). Gasoline typically comprises hydrocarbon compounds containing from 4 to 12 carbon atoms. Gasoline may comprise one or more C _4-12 alkane compounds, one or more C _4-12 alkene compounds, one or more C _4-10 cycloalkane compounds, or one or more C _6-12 aromatic hydrocarbon compounds. The components of gasoline typically have boiling points of less than or equal to 200°C.

Typically, gasoline comprises hydrocarbons having a boiling point of from 30°C to 200°C. Gasoline is typically derived from a fraction of crude oil, either directly by fractional distillation to obtain a gasoline fraction or indirectly via the treatment of a heavier fraction obtained from crude oil. Gasoline may also be produced by other methods, such as the combination of a mixture of hydrocarbon compounds. Any reference to "boiling point" or "melting point" made herein is a reference to the boiling point or melting point at standard pressure, unless otherwise stated.

The term "fluid catalytic cracking process", as used herein, refers to any process whereby high molecular weight hydrocarbons are converted to lower molecular weight hydrocarbons. The term is well known in the art. Typically, this involves a process whereby hydrocarbons having a boiling point of greater than 340°C are converted to lower boiling point (less that or equal to 340°C, or typically less than or equal to 200°C) hydrocarbons by a catalytic process. A variety of catalysts may be used in an FCC process. Typically, a solid acid catalyst such as a zeolite catalyst is used, for instance a faujasite or zeolite Y catalyst. An FCC process may convert long chain alkanes (for instance, Cn-20 alkanes) to shorter chain hydrocarbons including alkanes, cycloalkanes and alkenes (for instance C3-10 alkanes, C3-10 alkenes, C4-10 cycloalkanes). Gasoline produced by an FFC process typically has a greater alkene content than gasoline obtained by fractional distillation of crude oil.

The term "alkane", as used herein, refers to a linear or branched chain saturated hydrocarbon compound. An alkane may be a C2-18 alkane, a C _4-14 alkane, a C4-12 alkane, or a C5-10 alkane. Examples of a C _4-14 alkane are butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane and tetradecane. Examples of a C4-12 alkane are butane, isobutane, pentane, isopentane, hexane, methylpentane, dimethylbutane, heptane,

methylhexane, dimethylpentane, octane, methylheptane, dimethylhexane, trimethylpentane, nonane, decane, undecane and dodecane. The terms "alkane" and "paraffin" may be used interchangeably. The term "n-alkane" ( or "n-paraffin"), as used herein, refers to a straight chain alkane. The term "i-alkane" (or "i-paraffin"), as used herein, refers to a branched chain alkane. Alkanes such as dimethylbutane may be one or more of the possible isomers of this compound. Thus, dimethylbutane includes 2,3-dimethybutane and 2,2-dimethylbutane. This also applies for all organic compounds referred to herein including cycloalkane, alkene, cylcoalkene and alcohol compounds. The term "cycloalkane", as used herein, refers to a saturated cyclic hydrocarbon compound. A cycloalkane may be a C3-10 cycloalkane, a C4-8 cycloalkane, or a C5-8 cycloalkane.

Examples of a C4-8 cycloalkane include cyclobutane, cyclopentane, cyclohexane,

methylcyclopentane, cycloheptane, methylcyclohexane, dimethylcyclopentane and cyclooctane. Examples of a C5-8 cycloalkane include cyclopentane, cyclohexane,

methylcyclopentane, cycloheptane, methylcyclohexane, dimethylcyclopentane and cyclooctane. The terms "cycloalkane" and "naphthene" may be used interchangeably.

The term "alkene", as used herein, refers to a linear or branched chain hydrocarbon compound comprising one or more double bonds. An alkene may be a C2-18 alkene, a C4-14 alkene, a C4-12 alkene, or a C4-10 alkene. Examples of a C4-14 alkene are butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene and tetradecene. Examples of a C4-12 alkene are butene, pentene, methylbutene, hexene, methylpentene, dimethylbutene, heptene, methylhexene, dimethylpentene, octene, methylheptene, nonene, decene, undecene and dodecene. Alkenes typically comprise one or two double bonds. The terms "alkene" and "olefin" may be used interchangeably. The one or more double bonds may be at any position in the hydrocarbon chain. The alkenes may be cis- or trans-alkenes (or as defined using E- and Z- nomenclature). An alkene comprising a terminal double bond may be referred to as an "alk-l-ene" (e.g. hex-l-ene), a "terminal alkene" (or a "terminal olefin"), or an "alpha-alkene" (or an "alpha-olefin"). The term "alkene", as used herein also often includes cycloalkenes. The term "cylcoalkene", as used herein, refers to partially unsaturated cyclic hydrocarbon compound. A cycloalkene may be a C4-10 cycloalkene, or a C5-8 cycloalkene. Examples of a C4-8 cycloalkene include cyclobutene, cyclopentene, cyclohexene, cyclohexa-l,3-diene, methylcyclopentene, cycloheptene, methylcyclohexene, dimethylcyclopentene and cyclooctene. A cycloalkene may comprise one or two double bonds. The term "aromatic compound", "aromatic hydrocarbon" or "aromatic hydrocarbon compound", as used herein, refers to a hydrocarbon compound comprising one or more aromatic rings. The aromatic rings may be monocyclic or polycylic. Typically, an aromatic compound comprises a benzene ring. An aromatic compound is typically a C _6-14 aromatic compound, a C _6-12 aromatic compound or a C ₆ -io aromatic compound. Examples of C _6-12 aromatic compounds are benzene, toluene, xylene, ethylbenzene, methylethylbenzene, diethylbenzene, naphthalene, methylnaphthalene and ethylnaphthalene. The terms "aromatic compounds", "aromatics" and "arenes" may be used interchangeably.

The term "alkene content", as used herein, refers to the total amount of all alkene compounds in a composition. The alkene content of a composition is typically measured as a weight percentage of total alkene compounds present in the composition, relative to the weight of the composition. If a composition comprises a single alkene compound, the alkene content is the percentage by weight of the single alkene compound relative to the weight of the

composition. If a composition comprises two or more alkene compounds, the alkene content is the percentage by weight of the sum of the weights of all alkene compounds present relative to the weight of the composition. If a composition comprises a cylcoalkene compound, this also contributes to the alkene content.

The term "organic compound" takes its normal meaning in the art. As the skilled person would understand, an organic compound generally comprises at least one carbon atom.

Often, an organic compound comprises a carbon atom which is covalently bonded to another carbon atom, or to a hydrogen atom, or to a halogen atom, or to a chalcogen atom (for instance an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom). Organic compounds usually comprise at least one hydrogen atom in addition to the at least one carbon atom, typically bonded to a carbon atom. However, as the skilled person would understand, some organic compounds do not contain hydrogen atoms bonded to a carbon atom, for instance perhalogenated organic compounds and compounds such as oxalic acid, urea and thiourea. As the skilled person will also understand, the term "organic compound" does not typically include compounds that are predominantly ionic such as, for instance, carbides.

The term "organosulfur compound", as used herein, refers to an organic compound comprising one or more sulfur atoms. An organosulfur compound may comprise only C, H and S atoms. The term "organosulfur content", as used herein, refers to the total amount of all organosulfur compounds in a composition. The organosulfur content of a composition is typically measured as a weight percentage of total organosulfur compounds present in the composition, relative to the weight of the composition. If a composition comprises a single organosulfur compound, the organosulfur content is the percentage by weight of the single organosulfur compound relative to the weight of the composition. If a composition comprises two or more organosulfur compounds, the organosulfur content is the percentage by weight of the sum of the weights of all organosulfur compounds present relative to the weight of the composition.

The term "reduced alkene content" or "reduced organosulfur content", as used herein, refers to a reduction of the alkene or organosulfur content relative to the untreated gasoline obtainable by an FCC process. The term "solvent" , as used herein, refers to any liquid composition in which other compounds may dissolve. Solvents typically have a melting point of less than or equal to 15°C and a boiling point of greater than or equal to 40°C. A solvent may consist essentially of a single compound.

The term "binary solvent", as used herein, refers to a solvent which consists essentially of two compounds, each of which are solvents. Thus, a binary solvent may consist essentially of compounds A and B, where A and B are both solvents.

The term "multinary solvent", as used herein, refers to a solvent which consists essentially of three or more compounds, each or which are solvents. Thus, a multinary solvent may consist essentially of A, B, C and D, where A, B, C and D are all solvents. The terms "consist essentially of, "consists essentially of and "consisting essentially of, as used herein, refer to a composition which comprises greater than or equal to 95 % by weight of the given component or components. In some contexts, these terms may refer to a composition comprising greater than or equal to 97 % by weight or greater than or equal to 99 % by weight of the given components or components. The term "polar organic solvent", as used herein, refers to an organic compound which is a solvent, and which organic solvent is polar. Polar organic solvents typically have a dielectric constant (ε _Γ ) of greater than or equal to 10 at room temperature (21°C). In some instances, polar organic solvents may be considered to be those organic solvents have a dielectric constant of greater than or equal to 15. For instance, acetone has a dielectric constant of 20.7 and methanol has a dielectric constant of 32.7. Tables of dielectric constants are readily available.

The term "polar protic organic solvent", as used herein, refers to an organic compound which is a polar solvent, and which comprises a hydrogen atom bonded to a heteroatom. Thus, polar protic organic solvents typically comprise a hydroxy group, a carboxylic acid group, a primary amine group or a secondary amine group.

The term "alcohol", as used herein, refers to an organic compound which comprises one or more hydroxy (-OH) groups. Typically, an alcohol is an alkane substituted with one or more hydroxy groups. Examples of alcohols include methanol, ethanol, isopropanol, propane- 1,2- diol (propylene glycol) and sorbitol.

The term "monohydric alcohol" as used herein, takes its normal meaning in the art, i.e. an alcohol with a single -OH group. Examples of monohydric alcohols are methanol, ethanol, propanol, butanol and pentanol.

The term "dihydric alcohol", as used herein, takes its normal meaning in the art, i.e. an alcohol with two -OH groups. Examples of dihydric alcohols are ethane- 1,2-diol (ethylene glycol) and propane- 1,2-diol (propylene glycol).

The term "polyhydric alcohol", as used herein, takes its normal meaning in the art, i.e. an alcohol with two or more -OH groups. Examples of polyhydric alcohols are ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol) and sorbitol. The term "miscible", as used herein, refers to two or more liquids that form a homogeneous liquid when they are mixed. A homogeneous liquid is a liquid that does not comprise two or more separate phases. For instance, ethanol and water are miscible.

The term "immiscible", as used herein, refers to two or more liquids that do not form a homogeneous liquid when they are mixed. Thus, immiscible liquids will form two or more separate phases when mixed. For instance, water and oil are immiscible. Immiscible liquids may have some degree of miscibility. Thus any separate phases formed may comprise part of each of the two or more liquids mixed. The term "reservoir", as used herein, refers to any receptacle capable of holding a reserve of a material, typically wherein the material is a liquid. This, "reservoir", includes receptacles such as tanks and containers.

The term "container", as used herein, takes its normal meaning in the art. Thus, the term "container" refers to any physical means capable of containing a material.

The term "in fluid communication", as used herein, refers to the ability for fluids to be passed between two areas. For instance, for a reservoir and a reactor in fluid communication, it will be able to transfer one or more fluids in either or both directions between the reservoir and the reactor. A reservoir and a reactor are in fluid communication if they are, for example, connected by a pipe or a supply line.

The term "alkyl", as used herein, refers to a linear or branched chain saturated hydrocarbon radical. An alkyl group may be a C _{1 -18} alkyl group, a C _1-14 alkyl group, a Ci-io alkyl group, a Ci-6 alkyl group or a Ci-4 alkyl group. Examples of a Ci-io alkyl group are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl or decyl. Examples of Ci-6 alkyl groups are methyl, ethyl, propyl, butyl, pentyl or hexyl. Examples of Ci-4 alkyl groups are methyl, ethyl, i-propyl, n-propyl, t-butyl, s-butyl or n-butyl. If the term "alkyl" is used without a prefix specifying the number of carbons anywhere herein, it has from 1 to 6 carbons (and this also applies to any other organic group referred to herein).

The term "cycloalkyl", as used herein, refers to a saturated or partially unsaturated cyclic hydrocarbon radical. A cycloalkyl group may be a C3-10 cycloalkyl group, a C _3-8 cycloalkyl group or a C3-6 cycloalkyl group. Examples of a C _3-8 cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexenyl, cyclohex-l,3-dienyl, cycloheptyl and cyclooctyl. Examples of a C _{3 -} 6 cycloalkyl group include cyclopropyl, cyclobutyl,

cyclopentyl, and cyclohexyl. The term "alkenyl", as used herein, refers to a linear or branched chain hydrocarbon radical comprising one or more double bonds. An alkenyl group may be a C _2- i ₈ alkenyl group, a C _2- 14 alkenyl group, a C _2- io alkenyl group, a C _2- 6 alkenyl group or a C _2- 4 alkenyl group.

Examples of a C _2- io alkenyl group are ethenyl (vinyl), propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl or decenyl. Examples of C _2- 6 alkenyl groups are ethenyl, propenyl, butenyl, pentenyl or hexenyl. Examples of C _2- 4 alkenyl groups are ethenyl, i- propenyl, n-propenyl, s-butenyl or n-butenyl. Alkenyl groups typically comprise one or two double bonds.

The term "alkynyl", as used herein, refers to a linear or branched chain hydrocarbon radical comprising one or more triple bonds. An alkynyl group may be a C2-18 alkynyl group, a C _2-14 alkynyl group, a C2-10 alkynyl group, a C2-6 alkynyl group or a C2-4 alkynyl group. Examples of a C2-10 alkynyl group are ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl or decynyl. Examples of Ci-6 alkynyl groups are ethynyl, propynyl, butynyl, pentynyl or hexynyl. Alkynyl groups typically comprise one or two triple bonds.

The term "aryl", as used herein, refers to a monocyclic, bicyclic or polycyclic aromatic ring which contains from 6 to 14 carbon atoms, typically from 6 to 10 carbon atoms, in the ring portion. Examples include phenyl, naphthyl, indenyl and indanyl groups. The term "aryl group", as used herein, includes heteroaryl groups. The term "heteroaryl", as used herein, refers to monocyclic or bicyclic heteroaromatic rings which typically contains from six to ten atoms in the ring portion including one or more heteroatoms. A heteroaryl group is generally a 5- or 6-membered ring, containing at least one heteroatom selected from O, S, N, P, Se and Si. It may contain, for example, one, two or three heteroatoms. Examples of heteroaryl groups include pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, furanyl, thienyl, pyrazolidinyl, pyrrolyl, oxazolyl, oxadiazolyl, isoxazolyl, thiadiazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, quinolyl and isoquinolyl. The terms "alkylene", "cycloalkylene", "alkenylene", "alkynylene", and "arylene", as used herein, refer to bivalent groups obtained by removing a hydrogen atom from an alkyl, cycloalkyl, alkenyl, alkynyl, or aryl group, respectively. An alkylene group may be a C1-18 alkylene group, a Ci-14 alkylene group, a Ci-10 alkylene group, a Ci-6 alkylene group or a C1-4 alkylene group. Examples of Ci-6 alkylene groups are methylene, ethylene, propylene, butylene, pentylene and hexylene. A cycloalkylene group may be a C3-10 cycloalkylene group, a C3-8 cycloalkylene group or a C3-6 cycloalkylene group. Examples of C3-6 cycloalkylene groups include cyclopentylene and cyclohexylene. An alkenylene group may be a C2-18 alkenylene group, a C _2-14 alkenylene group, a C2-10 alkenylene group, a C2-6 alkenylene group or a C2-4 alkenylene group. Examples of a C2-4 alkenylene group include ethenylene (vinylene), propenylene and butenylene. An alkynylene group may be a C2-18 alkynylene group, a C _2-14 alkynylene group, a C2-10 alkynylene group, a C2-6 alkynylene group or a C2-4 alkynylene group. Examples of a C2-4 alkynylene group include ethynylene and propynylene. Examples of arylene groups include phenylene and a diradical derived from thiophene. For alkylene, cycloalkylene, alkenylene, alkynylene, and arylene, these groups may be bonded to other groups at any two positions on the group. Thus, propylene includes - CH2CH2CH2- and -CH2CH(CH3)-, and phenylene includes ortho-, meta- and para- phenylene.

The term "substituted", as used herein in the context of substituted organic compounds, refers to an organic compound which bears one or more substituents selected from Ci-10 alkyl, aryl (as defined herein), cyano, amino, nitro, Ci-10 alkylamino, di(Ci-io)alkylamino, arylamino, diarylamino, aryl(Ci-io)alkylamino, amido, acylamido, hydroxy, oxo, halo, carboxy, ester, acyl, acyloxy, Ci-10 alkoxy, aryloxy, halo(Ci-io)alkyl, sulfonic acid, thiol, Ci-10 alkylthio, arylthio, sulfonyl, phosphoric acid, phosphate ester, phosphonic acid and phosphonate ester. Typically, the one or more substituents are selected from cyano, amino, nitro, amido, acylamido, hydroxy, oxo, halo, carboxy, ester, acyl, acyloxy, sulfonic acid, thiol, sulfonyl, phosphoric acid, phosphate ester, phosphonic acid and phosphonate ester When a compound is substituted, it may bear 1, 2 or 3 substituents. For instance, a substituted compound may have 1 or 2 substitutents.

Process

The invention provides a process for producing gasoline having a reduced alkene content and a reduced organosulfur content,

which process comprises contacting gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound, with an extraction solvent suitable for extracting alkenes and organosulfur compounds, which extraction solvent comprises a polar organic solvent,

and thereby forming

i) a first phase comprising said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound, and

ii) a second phase comprising gasoline having a reduced alkene content and a reduced organosulfur content compared to said gasoline obtainable by a fluid catalytic cracking process. The gasoline obtainable by a fluid catalytic cracking (FCC) process (also referred to as "FCC gasoline") may be contacted with the extraction solvent by any method. Typically, the FCC gasoline and the extraction solvent are contacted by mixing. Thus, the process may comprise mixing gasoline obtainable by a fluid catalytic cracking process with an extraction solvent. For instance, the FCC gasoline and the extraction solvent may be added to a vessel, reactor or mixer and the two components may be mixed. Mixing may comprise agitation of the two components by a mixing means. For instance, the two components may be mixed together by stirring or by shaking.

It is preferable that the FCC gasoline and extraction solvent are mixed to an extent to allow effective extraction of alkene compounds and organosulfur compounds from the FCC gasoline. Typically, contacting gasoline obtainable by an FCC process with the extraction solvent will comprise mixing the two components to an extent that a large interface (with a high surface area) is formed between the two components, allowing extraction of alkene compounds and organosulfur compounds by the extraction solvent. A large interface occurs when the surface area of the interface between the mixed components is 3 or more times greater that the surface area of the interface between the contacted, but unmixed, components. Typically, contacting the gasoline obtainable by an FCC process with the extraction solvent comprises mixing the gasoline and the extraction solvent to form an emulsion, and allowing the emulsion to separate, thereby forming said first and second phases. Any emulsion formed may be an extraction solvent-in-gasoline emulsion or a gasoline-in-extraction solvent emulsion. Typically any emulsion formed will separate due to gravity. The contacting of the two components may occur more than once. For instance after contacting the gasoline and the extraction solvent for the first time, the resulting two phases may be contacted again by mixing. The steps of contacting and formation of two phases may be continuous. Thus, the two components may pass through a mixing means before entering a separating chamber in which the first and second phases are formed. The contacting of the two components may be performed using a propeller, an agitation means, a Scheibel ^® column, a KARR ^® column or a centrifugal extractor.

The first phase and the second phase may be formed in the same container, or may be formed in separate containers. Typically, the first and second phase will form in the same container. The first or second phase may then be recovered. Generally, the first phase and the second phase are immiscible under the conditions of the extraction process. One of the first phase and the second phase will have a density greater than the other phase. The phase with the greater density will form the lower of the two phases. If the extraction solvent is of a greater density than gasoline, the first phase will form the lower phase. If the gasoline if of a greater density than the extraction solvent, the second phase will for the lower phase. Often, the extraction solvent will have a greater density that gasoline. Thus, the first phase may be a lower phase and the second phase may be an upper phase. The first phase is generally a liquid phase. The second phase is generally a liquid phase.

The first phase comprises said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound. The first phase may be homogenous. Typically, the at least one extracted alkene and the at least one organosulfur compound are dissolved in the extraction solvent. The first phase may comprise additional components such as other extracted compounds from the gasoline. Other extracted compounds may include one or more alkanes and one or more aromatic hydrocarbons. The first phase may comprise greater than 60 wt% of the extraction solvent, the at least one extracted alkene and the at least one extracted organosulfur compound, wherein the percentage by weight is relative to the total weight of the first phase. The first phase may comprise greater than 70 wt% of the extraction solvent, the at least one extracted alkene and the at least one extracted organosulfur compound. The first phase may comprise greater than 80 wt% of the extraction solvent, the at least one extracted alkene and the at least one extracted organosulfur compound. The first phase may comprise greater than 90 wt% of the extraction solvent, the at least one extracted alkene and the at least one extracted organosulfur compound. The first phase may consist essentially of the extraction solvent, the at least one extracted alkene and the at least one extracted organosulfur compound.

The first phase may be as described herein for the composition according to the invention or process for producing one or more further compounds according to the invention.

The second phase comprises gasoline having a reduced alkene content and a reduced organosulfur content compared to said (untreated) gasoline obtainable by a fluid catalytic cracking process. The second phase may comprise additional components such as the extraction solvent. Typically, the second phase comprises less than 10 wt% of the extraction solvent, wherein the weight percentage is relative to the total weight of the second phase. The second phase may comprise less than 5 wt% of the extraction solvent. The second phase may comprise less than 2 wt% of the extraction solvent. The second phase may comprise less than 1 wt% of the extraction solvent. The second phase may consist essentially of gasoline having a reduced alkene content and a reduced organosulfur content compared to said gasoline obtainable by a fluid catalytic cracking process.

The process often further comprises recovering said gasoline having a reduced alkene content and a reduced organosulfur content. The gasoline having a reduced alkene content and a reduced organosulfur content may be recovered by any means, and is typically recovered by a physical process. Said recovering typically comprises physically isolating the, or at least some of the, second phase. Thus, said recovering typically comprises separating at least some of the second phase from the first phase. As the two phases may already be separate in the same container due to their immiscibility, though, said recovering may simply comprise directing at least part of the second phase from a container comprising the first phase and the second phase. Said recovering may for instance comprise removing at least part of the second phase from a container comprising the first phase and the second phase. The gasoline may alternatively be recovered by removing the first phase to leave the second phase.

The process often further comprises recovering at least some of the first phase. Said at least some of the first phase typically comprises said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound. Like the second phase, the first phase may also be recovered by any means, and is typically recovered by a physical process. The recovering typically comprises physically isolating the, or at least some of the, first phase. Thus, said recovering typically comprises separating at least some of the first phase from the second phase. However, as the two phases may already be separate in the same container due to their immiscibility, said recovering may comprise directing at least part of the first phase from a container comprising the first phase and the second phase. Said recovering may comprise removing at least part of the first phase from a container comprising the first phase and the second phase. The at least part of the first phase may alternatively be recovered by removing the second phase to leave the first phase.

Often, the gasoline having a reduced alkene content and a reduced organosulfur content comprises:

a total weight percentage of alkene compounds which is less than or equal to 90% of the total weight percentage of alkene compounds in the gasoline obtainable by a fluid catalytic cracking process; and a total weight percentage of organosulfur compounds which is less than or equal to 50% of the total weight percentage of organosulfur compounds in the gasoline obtainable by a fluid catalytic cracking process.

The gasoline having a reduced alkene content and a reduced organosulfur content may comprise a total weight percentage of alkene compounds which is less than or equal to 80% of the total weight percentage of alkene compounds in the (untreated) gasoline obtainable by a fluid catalytic cracking process. The gasoline having a reduced alkene content and a reduced organosulfur content may comprise a total weight percentage of alkene compounds which is less than or equal to 70% of the total weight percentage of alkene compounds in the gasoline obtainable by a fluid catalytic cracking process. The gasoline having a reduced alkene content and a reduced organosulfur content may comprise a total weight percentage of alkene compounds which is less than or equal to 60% of the total weight percentage of alkene compounds in the gasoline obtainable by a fluid catalytic cracking process. The gasoline having a reduced alkene content and a reduced organosulfur content may comprise a total weight percentage of alkene compounds which is less than or equal to 50%, or less than or equal to 40% of the total weight percentage of alkene compounds in the gasoline obtainable by a fluid catalytic cracking process.

The gasoline having a reduced alkene content and a reduced organosulfur content may comprises a total weight percentage of organosulfur compounds which is less than or equal to 40% of the total weight percentage of organosulfur compounds in the (untreated) gasoline obtainable by a fluid catalytic cracking process. The gasoline having a reduced alkene content and a reduced organosulfur content may comprises a total weight percentage of organosulfur compounds which is less than or equal to 30% of the total weight percentage of organosulfur compounds in the gasoline obtainable by a fluid catalytic cracking process. The gasoline having a reduced alkene content and a reduced organosulfur content may comprises a total weight percentage of organosulfur compounds which is less than or equal to 20% of the total weight percentage of organosulfur compounds in the gasoline obtainable by a fluid catalytic cracking process. The gasoline having a reduced alkene content and a reduced organosulfur content may comprises a total weight percentage of organosulfur compounds which is less than or equal to 5% of the total weight percentage of organosulfur compounds in the gasoline obtainable by a fluid catalytic cracking process. The reduction of the amount of alkene compounds and the reduction of the amount of organosulfur compounds may be any of the values listed above. Thus the amount of alkene compounds may be less than or equal to 70% of that in the untreated FCC gasoline, and the amount of organosulfur compounds may be less than or equal to 20% of that in the untreated FCC gasoline.

For instance, if the (untreated) gasoline obtainable by a fluid catalytic cracking process comprises 49 wt% of alkenes (i.e. has an alkene content of 49%) and the gasoline having a reduced alkene content and a reduced organosulfur content comprises 37 wt% of alkenes (i.e. has an alkene content of 37 wt%), then the gasoline having a reduced alkene content and a reduced organosulfur content comprises a total weight percentage of alkene compounds which is 75.5%) (37 wt%/49 wt%>) of the total weight percentage of alkene compounds in the (untreated) gasoline obtainable by a fluid catalytic cracking process. The percentage by weight of alkene compounds and organosulfur compounds may be measured by readily available methods such gas chromatography-mass spectrsocopy (GCMS). The process of the invention may be performed at low temperatures and often does not require distillation steps, which may be associated with additional energy usage and expense. Thus, in some embodiments, the process of the invention does not further comprise a distillation step. The process may for instance not comprise a step of heating the first phase or the second phase to a temperature of greater than or equal to 150°C or greater than or equal to 100°C.

Extraction solvent/solvent system

The extraction solvent (which may be a solvent system comprising two or more solvents) is suitable for extracting alkenes and organosulfur compounds, which extraction solvent comprises a polar organic solvent. A solvent which is suitable for extracting alkenes and organosulfur compounds is a solvent which selectively extracts alkenes and organosulfur compounds. The extraction solvent typically does not extract a large proportion of alkanes and cycloalkanes present in the FCC gasoline. The extraction solvent may be a solvent in which alkenes and organosulfur compounds are more soluble than in gasoline. The extraction solvent comprises a polar organic solvent, and polar organic solvents may interact with sulfur atoms in organosulfur compounds and alkene groups in alkenes. The extraction solvent may comprise any polar organic solvent. Thus the extraction solvent may comprise a compound selected from an alcohol, an aldehyde, a ketone, an ether, a carboxylic acid, an ester, a carbonate, an acid anhydride, an amide, an amine, a heterocyclic compound, an imine, an imide, a nitrile, a nitro compound, a sulfoxide, and a haloalkane, wherein the compound is a liquid under the conditions of the extraction. The extraction solvent preferably comprises a compound selected from an alcohol, a ketone, an ether, an ester, an amine, a heterocyclic compound, a nitrile, a sulfoxide and a haloalkane. Often, the extraction solvent comprises a compound selected from an alcohol, a ketone, an ether, an ester, and a nitrile. The extraction solvent may comprise two or more polar organic solvents. The extraction solvent may consist essentially of one or more polar organic solvents. The extraction may consist essentially of a single polar organic solvent. However, the extraction solvent may also be a binary solvent or a multinary solvent as discussed below.

The alcohol which the extraction solvent may comprise may be any Ci-io alcohol, preferably a Ci-4 alcohol. An alcohol may have the structure alkyl-OH, HO-alkylene-OH, alkenyl-OH, OH-alkenylene-OH, cycloalkyl-OH, or OH-cycloalkylene-OH. The alcohol may be an alcohol of formula ROH or HOR'OH, wherein R is a group selected from unsubstituted or substituted Ci-io alkyl, unsubstituted or substituted C3-10 alkenyl, unsubstituted or substituted C3-10 alkynyl, unsubstituted or substituted C4-10 cycloalkyl, and unsubstituted or substituted C ₆ -io aryl, and R' is a group selected from unsubstituted or substituted C2-10 alkylene, unsubstituted or substituted C2-10 alkenylene, unsubstituted or substitutued C2-10 alkynylene, unsubstituted or substituted C5-10 cycloalkylene, and unsubstituted or substituted C ₆ -io arylene. Typically, R and R' are unsubstituted.

Examples of alcohols which the extraction solvent may comprise include: monohydric alcohols such as methanol, ethanol, propanol, isopropanol (propan-2-ol), butanol (butan-1- ol), secbutanol (butan-2-ol), isobutanol (2-methylpropan-l-ol), tertbutanol (2-methylpropan- 2-ol), cyclopentanol, pentanol, cyclohexanol, hexanol, heptanol and octanol; and polyhydric alcohols such as ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1, 3 -diol, propane-l,2,3-triol (glycerol), isopropanediol, butanediol, isobutanediol, tertbutanediol, butanetriol, pentanediol, methylbutanediol, hexanediol, hexanetriol. For compounds wherein the positions of hydroxy groups are not specified, alcohols having each of the positions are covered. Thus, butanediol includes butane- 1,2-diol, butane- 1,3 -diol, butane- 1,4-diol and butane-2,3-diol. Ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1, 3 -diol, isopropanediol, and butanediol are examples of dihydric alcohols. In particular, the alcohol which the extraction solvent comprises may be selected from methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, ethylene glycol, propylene glycol, and propane-l,3-diol. For instance, the extraction solvent may comprise a polar organic solvent selected from methanol, ethanol, propanol, isopropanol, ethylene glycol and propylene glycol.

The aldehyde which the extraction solvent may comprise may be any Ci-io aldehyde, preferably a C3-6 aldehyde. An aldehyde typically has the structure alkyl-CHO. Examples of aldehydes which the extraction solvent may comprise include methanal (formaldehyde), ethanal (acetaldehyde), propanal, butanal, pentanal and hexanal.

The ketone which the extraction solvent may comprise may be any C3-10 ketone. A ketone typically has the structure alkyl-C(0)-alkyl, cycloalkyl-C(0)-alkyl, or aryl-C(0)-alkyl. The ketone may be linear, branched, or cyclic. Examples of ketones which the extraction solvent may comprise include propanone (acetone), butanone, pentan-2-one, pentan-3-one, ethyl isopropyl ketone, hexan-2-one, and hexan-3-one.

The ether which the extraction solvent may comprise may be any C2-10 ether, i.e. an ether containing from 2 to 10 carbon atoms. An ether typically has the structure alkyl-O-alkyl or that of an alicyclic ether. The ether may be linear, branched or cyclic. Examples of ethers which the extraction solvent may comprise include diethyl ether, ethyl isopropyl ether, dipropyl ether, diisopropyl ether and tetrahydrofuran.

The carboxylic acid which the extraction solvent may comprise may be any Ci _-8 carboxylic acid. A carboxylic acid typically has the structure alkyl-COOH. The carboxylic acid may be linear, branched or cyclic. Examples of carboxylic acids which the extraction solvent may comprise include methanoic acid (formic acid), ethanoic acid (acetic acid), propanoic acid, butanoic acid and pentanoic acid.

The ester which the extraction solvent may comprise may be any C2-10 ester. For instance, the ester may be a C1-5 alkyl C1-5 carboxylate. An ester typically has the structure alkyl- COO-alkyl, . Examples of the ester which the extraction solvent may comprise include methyl formate, ethyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, tertbutyl acetate, pentyl acetate, methyl propanoate, ethyl propanoate, propyl propanoate, and ethyl isopropanoate. The carbonate which the extraction solvent may comprise may be any C3-10 carbonate. A carbonate typically has the structure alkyl-OC(0)0-alkyl. Examples of the carbonate that the extraction solvent may comprise include dimethylcarbonate, ethylmethylcarbonate and diethyl carbonate. The carbonate may be propylene carbonate or trimethylene carbonate. The acid anhydride which the extraction solvent may comprise may be any C4-8 acid anhydride. An example of the acid anhydride which the extraction solvent may comprise is acetic anhydride.

The amide which the extraction solvent may comprise may be any C2-10 amide. An amide typically has the structure alkyl-CO H ₂ , alkyl-CONH(alkyl) or alkyl-CON(alkyl) ₂ .

Examples of the amide which the extraction solvent may comprise include formamide, N- methyl formamide, dimethyl formamide, dimethyl acetamide, N-vinylacetamide, pyrrolidone, N-methyl pyrrolidone, and N-vinyl pyrrolidone.

The amine which the extraction solvent may comprise may be any C2-15 amine. An amine typically has the structure R H ₂ , R ₂ H, R3N, and H ₂ RTS[H ₂ where R may be selected from C ₂ -io alkyl, C _2- io alkenyl, C _2-12 alkynyl, C ₆ -io aryl, and C ₆ -i ₂ arylalkyl, and R' may be selected from C _2- io alkylene, C _2- io alkenylene, C _2- io alkynylene, C5-10 cycloalkylene, and C ₆ -io arylene. The amine may be a primary, secondary or tertiary amine. The amine may comprise one or more, or two or more amine groups. The amine may be selected from mono-C _2- i5- alkylamines, di-Ci-7- alkylamines and tri-Ci-5-alkylamines. The amine may be a C _2- io- alkylenediamine. Examples of the amine which the extraction may comprise include ethylamine, triethylamine, tripropylamine, tributylamine, ethylenediamine,

propylenediamine, diethylenetriamine, morpholine, piperidine, and quinoline.

The heterocyclic compound which the extraction solvent may comprise may be any C3-10 heterocyclic compound. The heterocyclic compound may be any compound having from 3 to 10 carbon atoms and comprising a ring, which ring comprises a heteroatom selected from N, P, O and S. The extraction solvent may comprise a heterocyclic compound selected from furan, tetrahydrofuran, thiophene, pyrrole, pyrroline, pyrrolidine, dioxolane, oxazole, thiazole, imidazole, imidazoline, imidazolidine, pyrazole, pyrazoline, pyrazolidine, izoxazole, isothiazole, oxadiazole, pyran, pyridine, piperidine, pyridazine, and piperazine. For instance, the extraction solvent may comprise pyridine, furan or tetrahydrofuran. The imine which the extraction solvent may comprise may be a C4-10 imine. The imide which the extraction solvent may comprise may be a C4-10 imide.

The nitrile which the extraction solvent may comprise may be a C2-10 nitrile. For instance, the extraction solvent may comprise acetonitrile or propionitrile. The nitro compound which the extraction solvent may comprise may be a Ci-10 nitro compound. For instance, the extraction solvent may comprise nitromethane, nitroethane, nitropropane or nitrobenzene.

The sulfoxide compound which the extraction solvent may comprise may be a C2-10 sulfoxide compound. For instance, the extraction solvent may comprise dimethylsulfoxide (DMSO). The extraction solvent may comprise diethylsulfoxide or methylethylsulfoxide.

The haloalkane which the extraction solvent may comprise may be any Ci-10 haloalkane. For instance, the extraction solvent may comprise dichloromethane (DCM), trichloromethane, tetrachloromethane or dichloroethane.

Any of the solvent compounds listed above (an alcohol, an aldehyde, a ketone, an ether, a carboxylic acid, an ester, a carbonate, an acid anhydride, an amide, an amine, a heterocyclic compound, an imine, an imide, a nitrile, a nitro compound, a sulfoxide, or a haloalkane) may be substituted or unsubstituted. Typically, the solvent compounds are unsubstituted.

Thus, the extraction solvent may comprise a compound selected from methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, ethylene glycol, propylene glycol, propane- 1,3 -diol, propanone (acetone), butanone, pentan-2-one, pentan-3-one, diethyl ether, ethyl isopropyl ether, dipropyl ether, diisopropyl ether, tetrahydrofuran, ethanoic acid (acetic acid), propanoic acid, ethyl acetate, vinyl acetate, dimethylcarbonate, pyrrolidone, N-methyl pyrrolidone, N-vinyl pyrrolidone, ethylamine, triethylamine, tripropylamine, tributylamine, ethylenediamine, propylenediamine, diethylenetriamine, morpholine, piperidine, quinoline, pyridine, furan, tetrahydrofuran, acetonitrile, propionitrile, nitromethane, nitroethane, nitropropane, nitrobenzene, dimethylsulfoxide (DMSO), dichloromethane (DCM), trichloromethane, tetrachloromethane and dichloroethane. For instance, the extraction solvent may comprise a compound selected from methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, propane- 1,3 -diol, propanone (acetone), diethyl ether, ethyl isopropyl ether, dipropyl ether, diisopropyl ether, tetrahydrofuran, ethanoic acid (acetic acid), pyrrolidone, ethylenediamine, propylenediamine, diethylenetriamine, pyridine, furan, tetrahydrofuran, acetonitrile, dimethylsulfoxide (DMSO), and dichloromethane (DCM).

Preferably, the extraction solvent comprises a compound selected from methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, propane- 1, 3 -diol, ethylenediamine, propylenediamine, and diethylenetriamine. More preferably, the extraction solvent comprises a compound selected from methanol, ethanol, propanol, isopropanol, ethylene glycol, and propylene glycol. The extraction solvent may comprise one or more compounds selected from methanol, ethanol, propanol, isopropanol, ethylene glycol, and propylene glycol.

In one embodiment, the extraction solvent comprises a polar protic organic solvent. Thus, the extraction solvent often comprises a compound selected from an alcohol, a carboxylic acid, a primary amine and a secondary amine, wherein the compound is a liquid under the conditions of the extraction. The extraction solvent may therefore comprise a compound selected from methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, tertbutanol, cyclopentanol, pentanol, cyclohexanol, hexanol, heptanol, octanol, ethane- 1,2- diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1,3 -diol, propane-1,2,3- triol (glycerol), isopropanediol, butanediol, isobutanediol, tertbutanediol, butanetriol, pentanediol, methylbutanediol, hexanediol, hexanetriol, methanoic acid (formic acid), ethanoic acid (acetic acid), propanoic acid, butanoic acid, pentanoic acid, ethylamine, ethylenediamine, propylenediamine, diethylenetriamine, morpholine, and piperidine. Preferably, the extraction solvent comprises an alcohol. The extraction solvent may comprise any Ci-io alcohol, for instance a Ci-4 alcohol. An alcohol may comprise one or more -OH groups. The alcohol may be a primary or a secondary alcohol, preferably a primary alcohol. The extraction solvent may comprise an alcohol selected from methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, tertbutanol, cyclopentanol, pentanol, cyclohexanol, hexanol, heptanol, octanol, ethane- 1 ,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1,3 -diol, propane- 1, 2,3 -triol (glycerol), isopropanediol, butanediol, isobutanediol, tertbutanediol, butanetriol, pentanediol, methylbutanediol, hexanediol, hexanetriol. As described above, where the position of a hydroxy group is not explicitly stated, alcohols having that hydroxy group in each possible position is covered. For instance, octanol includes octan-l-ol, octan-2-ol, octan-3-ol and octan-4-ol. Preferably the extraction solvent comprises a C1-4 alcohol. For instance, the extraction solvent may comprise methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, tertbutanol, ethylene glycol, propylene glycol (propane- 1,2-diol), propane-1,3- diol, glycerol (propane-l,2,3-triol), butane- 1,2-diol, butane- 1, 3 -diol, butane- 1,4-diol, butane- 2,3-diol, butane-l,2,3-triol, and butane- 1,2,4-triol. All possible stereoisomers of any solvent molecule described herein are also included. The extraction solvent may comprise one or more alcohols in an amount of greater than of equal to 40 wt%. Often, the extraction solvent comprises one or more alcohols in an amount of greater than or equal to 80 wt%.

Often, the extraction solvent comprises a monohydric alcohol. Thus, the extraction solvent may comprise a Ci-io monohydric alcohol or a Ci-4 monohydric alcohol. The extraction solvent often comprises methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, and tertbutanol.

Preferably, the extraction solvent comprises methanol or ethanol. More preferably, the extraction solvent comprises methanol. The extraction solvent may comprise methanol in an amount of greater than or equal to 50 wt%.

In some embodiments, the extraction solvent does not comprise a solvent which comprises sulfur. Thus, in some cases the extraction solvent does not comprise a sulfoxide compound, such as those listed above.

The extraction solvent may be a high boiling point solvent or a low boiling point solvent. For instance, the extraction solvent may have a boiling point of less than or equal to 100°C (e.g. a low boiling point solvent) or greater than or equal to 100°C (e.g. a high boiling point solvent). The extraction solvent may comprise one or more low boiling point solvents (e.g. with a boiling point of less than or equal to 100°C or less than or equal to 80°C) or one or more high boiling point solvents (e.g. with a boiling point of greater than or equal to 100°C or greater than or equal to 140°C).

The extraction solvent may comprise a solvent having a Hildebrand solubility parameter of from 20.0 to 35.0 MPa ^½ , for instance from 25.0 to 30.0 MPa ^½ . The extraction solvent may have a Hildebrand solubility parameter of from 20.0 to 35.0 MPa ^½ , for instance from 25.0 to 30.0 MPa ^½ . The extraction solvent may comprise a solvent having a Hansen non-polar interaction solubility parameter 5d of from 12.0 to 25.0 MPa ^½ , for instance from 16.0 to 22.0 MPa ^½ ; a Hansen polar cohesive energy solubility parameter δ _ρ of from 10.0 to 20.0 MPa ^½ , for instance from 15.0 to 19.0 MPa ^½ ; and a Hansen electron exchange parameter solubility parameter 5h of from 1.0 to 35.0 MPa ^½ , for instance from 1.0 to 10.0 MPa ^½ .

The extraction solvent may have a Hansen non-polar interaction solubility parameter 5d of from 12.0 to 25.0 MPa ^½ , for instance from 16.0 to 22.0 MPa ^½ ; a Hansen polar cohesive energy solubility parameter δ _ρ of from 10.0 to 20.0 MPa' ² , for instance from 15.0 to 19.0 MPa ^½ ; and a Hansen electron exchange parameter solubility parameter 5h of from 1.0 to 35.0 MPa ^½ , for instance from 1.0 to 10.0 MPa ^½ .

The Scatchard-Hildebrand theory has two basic underlying assumptions: (i) the forces between molecules are dispersion forces (often called van der Waals' forces); and (ii) the entropy change on forming the solution has the same value as for an ideal solution. Based on this theory Hildebrand proposed a definition for a "solubility parameter" that would provide a systemic description of the miscibility behavior of solvents. This solubility parameter is defined as the square root of the cohesive energy density, the heat of vaporization divided by the molar volume. According to Hildebrand' s solubility parameter approach two liquids are miscible if their solubility parameters δ differ by no more than about 7.0 MPa ^1/2 . Mutual miscibility decreases as the δ values of two solvents become farther apart. Higher mutual solubility will follow if the δ values of the solvents are closer.

The other solubility parameter is the Hansen solubility parameters which are proposed by Hansen. The basis of these Hansen solubility parameters is that the total energy of vaporization of a liquid consists of several individual parts. These arise from (atomic) dispersion forces, (molecular) permanent dipole-permanent dipole forces, and (molecular) hydrogen bonding (electron exchange). That means the Hildebrand solubility parameter has been divided into these three dimensions by the Hansen solubility parameters.

The three dimensions from the Hansen solubility parameters are derived from atomic force and have also been called dispersion interactions 5d in the literature. The permanent dipole- permanent dipole interactions cause a second type of cohesion energy, the polar cohesive energy δ _ρ . These are inherently molecular interactions and are found in most molecules to one extent or another. The dipole moment is primary parameter used to calculate these interactions. The third major cohesive energy source is hydrogen bonding, which can be called more generally an electron exchange parameter 5h. Hydrogen bonding is a molecular interaction and resembles the polar interactions in this respect. The basis of this type of cohesive energy is attraction among molecules because of the hydrogen bonds. The relation between the Hildebrand and Hansen solubility parameters can be described by the following equation. δ ² = (5 _d ) ² + (δ _ρ ) ² +(5 _h ) ²

Here, δ is the Hildebrand solubility parameter, 5d is the nonpolar interactions (dispersion interactions) of the Hansen solubility parameter, δ _ρ is the dipole-permanent dipole interactions (the polar cohesive energy) of the Hansen solubility parameter, 5h is the hydrogen bonding interactions (electron exchange parameter) of the Hansen solubility parameter.

A comprehensive collection of Hildebrand and Hansen solubility parameters have been given by Barton (see Barton, A. F., CRC handbook of solubility parameters and other cohesion parameters, CRC press, 1991 and Reichardt, C; Welton, T., Solvents and solvent effects in organic chemistry, John Wiley & Sons: 2011).

In some embodiments it is preferable that the extraction solvent comprises a single solvent. Thus, the extraction solvent may consist essentially of a single solvent, for instance an alcohol. In other embodiments, it is preferable that the extraction solvent comprises more than one solvent selected from those listed above. If the extraction solvent consists or consists essentially of two solvents, the extraction solvent is a binary solvent. If the extraction solvent consists or consists essentially of three or more solvents, the extraction solvent is a multinary solvent.

Often, the extraction solvent is a binary solvent. In one embodiment, the extraction solvent comprises a first solvent which is said polar organic solvent and a second solvent, which second solvent is a polar protic organic solvent. The first solvent may be any solvent listed above, for instance an alcohol, a carboxylic acid, a ketone or an amine. Typically, in this embodiment, the solvent is a binary solvent, which therefore consists of, or consists essentially of, said first and second solvents. Alternatively, in this embodiment, the extraction solvent may be a multinary solvent, comprising one or more further solvents in addition to the first and second solvents. Usually, however, it is a binary solvent.

The extraction solvent may sometimes further comprise an inorganic polar solvent, for instance water. The presence of an inorganic polar solvent (such as water) can positively influence the extraction properties of the extraction solvent. Thus, the extraction solvent may comprise an inorganic polar solvent in addition to the first solvent and, where present, the second and any further solvents. The inorganic polar solvent may be water.

The second solvent is typically selected from an alcohol, a carboxylic acid, a primary amine and a secondary amine. As with the polar organic solvent which is a first solvent, the compound is a liquid under the conditions of the extraction. The second solvent may be any polar protic organic solvent as defined above. The second solvent may be selected from methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, tertbutanol, cyclopentanol, pentanol, cyclohexanol, hexanol, heptanol, octanol, ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1, 3 -diol, propane- 1,2,3-triol

(glycerol), isopropanediol, butanediol, isobutanediol, tertbutanediol, butanetriol, pentanediol, methylbutanediol, hexanediol, hexanetriol, methanoic acid (formic acid), ethanoic acid (acetic acid), propanoic acid, butanoic acid, pentanoic acid, ethylamine, ethylenediamine, propylenediamine, diethylenetriamine, morpholine, and piperidine.

Often, the second solvent is an alcohol. The second solvent may be selected from methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, tertbutanol, cyclopentanol, pentanol, cyclohexanol, hexanol, heptanol, octanol, ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1,3 -diol, propane-l,2,3-triol (glycerol), isopropanediol, butanediol, isobutanediol, tertbutanediol, butanetriol, pentanediol, methylbutanediol, hexanediol, and hexanetriol. In some embodiments, the first and second solvents are both alcohols.

Preferably, the second solvent is a polyhydric alcohol. The second solvent may be a polyhydric alcohol comprising two, three or four hydroxy groups. For instance, the second solvent may be selected from ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1,3 -diol, propane- 1,2,3-triol (glycerol), isopropanediol, butanediol, isobutanediol, tertbutanediol, butanetriol, pentanediol, methylbutanediol, hexanediol, and hexanetriol. Often, the first solvent is a alcohol and the second solvent is a polyhydric alcohol. For instance, the first solvent may be a monohydric alcohol and the second solvent may be a polyhydric alcohol.

The second solvent is often is a dihydric alcohol. The second solvent may therefore be selected from ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1, 3 -diol, isopropanediol, butanediol, isobutanediol, tertbutanediol, pentanediol, methylbutanediol, and hexanediol. For instance, the second solvent may be selected from ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), and propane-l,3-diol. Often, the first solvent is a alcohol and the second solvent is a dihydric alcohol. For instance, the first solvent may be a monohydric alcohol and the second solvent may be a dihydric alcohol.

Preferably, the second solvent is ethylene glycol or propylene glycol. More preferably the second solvent is ethylene glycol. Thus, the first solvent is often an alcohol and the second solvent is ethylene glycol or propylene glycol.

Often, the second solvent is a carbonate solvent for instance, a C3-10 carbonate. A carbonate typically has the structure alkyl-OC(0)0-alkyl (where the two alkyl groups may be joined together to form a ring. For instance, the second solvent may be selected from

dimethylcarbonate, ethylmethylcarbonate, diethyl carbonate, propylene carbonate and trimethylene carbonate. In some preferred embodiments, the second solvent is propylene carbonate. Thus, in some embodiments, the extraction solvent may comprise a first solvent which is an alcohol (such as those listed above) and a second solvent which is a carbonate, for instance propylene carbonate.

Preferably, the first solvent is selected from methanol and ethanol. More preferably, the first solvent is selected from methanol and ethanol and the second solvent is selected from ethylene glycol and propylene glycol. The first solvent may for instance be methanol and the second solvent may for instance be ethylene glycol. The first solvent may for instance be methanol and the second solvent may for instance be glycerol. The first solvent may for instance be methanol and the second solvent may for instance be propylene carbonate. The first solvent may for instance be methanol and the second solvent may for instance be dimethylsulfoxide (DMSO). The extraction solvent may comprise greater than or equal to 80 wt% of the first and the second solvent. The extraction solvent may consist of or consist essentially of the first solvent and the second solvent, in which cases it is a binary solvent.

The first solvent and second solvent may be in any proportion. The ratio of the amounts by weight of the first solvent and the second solvent may from 10: 1 to 1 : 10. The ratio of the first solvent and the second solvent is often from 9: 1 to 1 :4. The ratio of the first solvent and the second solvent may be from 5: 1 to 1 :5. For instance, the ratio of the first and second solvent may be from 4: 1 to 1 :4. Preferably, the ratio of the first solvent and the second solvent is from 7:4 to 4:7. More preferably, the ratio of the first solvent and the second solvent may be from 2: 1 to 1 :2. For instance, the ratio of the first and the second solvents may be around 4:6 or around 6:4. Herein, the ratios of the first and second solvents are all ratios by weight. Thus, if a composition comprises 30 wt% of the first solvent, and 60 wt% of the second solvent, the ratio of the first solvent and the second solvent is 3 :6, or equivalently 1 :2. For instance, the extraction solvent may comprise a first solvent which is an alcohol and a second solvent which is a polyhydric alcohol, and the ratio of the amount by weight of the first solvent and the second solvent may be from 2: 1 to 1 :2.

When the extraction solvent is a binary or multinary solvent, the extraction solvent may comprise:

i) the first solvent in an amount of greater than or equal to 30 wt%; and ii) the second solvent in an amount of greater than or equal to 20 wt%;

wherein the percentage by weight is relative to the total weight of the extraction solvent. Thus, in this embodiment, the extraction solvent comprises at least 50 wt% of the first and second solvents. The extraction solvent may comprise the first solvent in an amount of greater than or equal to 20 wt%; and the second solvent in an amount of greater than or equal to 20 wt%; wherein the total amount of the first solvent and the second solvent is greater than or equal to 80 wt%, wherein the percentage by weight is relative to the total weight of the extraction solvent.

Often, the extraction solvent comprises:

i) the first solvent in an amount of from 30 wt% to 90 wt%; and

ϋ) the second solvent in an amount of from 10 wt% to 60 wt%; wherein the total amount of the first solvent and the second solvent is greater than or equal to 80 wt%, and wherein the percentage by weight is relative to the total weight of the extraction solvent. The extraction solvent may consist essentially of the first solvent and the second solvent. The first solvent may be any polar organic solvent described above, and the second solvent may be any polar protic organic solvent described above. For instance, the first solvent may be a monohydric alcohol, for instance a Ci-4 monohydric alcohol, and the second solvent may be a polyhydric alcohol, for instance a Ci-4 dihydric alcohol.

For instance, the extraction solvent may comprise:

i) the first solvent in an amount of from 35 wt% to 85 wt%; and

ii) the second solvent in an amount of from 15 wt% to 55 wt%;

wherein the total amount of the first solvent and the second solvent is greater than or equal to 80 wt%, or greater than or equal to 90 wt%, and wherein the percentage by weight is relative to the total weight of the extraction solvent. The extraction solvent may consist essentially of the first solvent and the second solvent. The first solvent may be any polar organic solvent described above, and the second solvent may be any polar protic organic solvent described above. For instance, the first solvent may be a monohydric alcohol, for instance a Ci-4 monohydric alcohol, and the second solvent may be a polyhydric alcohol, for instance a Ci-4 dihydric alcohol.

In one embodiment, the first solvent is methanol or ethanol and the second solvent is ethylene glycol or propylene glycol. Thus, in a preferred embodiment, the extraction solvent comprises:

i) methanol in an amount of from 50 wt% to 70 wt%;

ii) ethylene glycol in an amount of from 30 wt% to 50 wt%;

wherein the total amount of methanol and ethylene glycol is greater than or equal to 80 wt%, and wherein the percentage by weight is relative to the total weight of the extraction solvent. The extraction solvent may consist essentially of methanol and ethylene glycol.

The extraction solvent may comprise:

i) methanol in an amount of from 55 wt% to 65 wt%;

ii) ethylene glycol in an amount of from 35 wt% to 45 wt%;

wherein the total amount of methanol and ethylene glycol is greater than or equal to 80 wt%, and wherein the percentage by weight is relative to the total weight of the extraction solvent. The extraction solvent may consist essentially of methanol and ethylene glycol. The first solvent is typically suitable for extracting alkenes and organosulfur compounds; and the second solvent is typically miscible with the first solvent. The first solvent, which is a polar organic solvent, is typically suitable for extracting alkenes and organosulfur compounds because the polar groups in the first solvent can interact with alkenes and organosulfur compounds.

In order for extraction to be fully effective, there is preferably at least partial separation between the gasoline and the extraction solvent. Often, a binary solvent can be used to ensure favourable separation. The second solvent may be suitable for reducing the miscibility of the extraction solvent with the gasoline. For instance, the first solvent may be a solvent which is miscible with FCC gasoline, and the second solvent may be a solvent which is miscible with the first solvent, but the resulting extraction solvent (comprising or consisting essentially of the first and second solvents) may be immiscible with FCC gasoline. Thus, the extraction solvent may comprise "associating fluids". Associating fluids means that the first and second solvents associate and the resultant extraction solvent has reduced miscibility with FCC gasoline allowing effective phase separation.

Thus, the extraction solvent may comprise (i) a first solvent which is (partially) miscible with FCC gasoline and (ii) a second solvent which is miscible with the first solvent, wherein the extraction solvent is immiscible with FCC gasoline. The second solvent may be immiscible with FCC gasoline. The first and second solvents may be as described above. The extraction solvent may be a multinary solvent. The extraction solvent may therefore comprise a first solvent as defined above, a second solvent as defined above, and one or more further solvents, each of which further solvents may be as defined anywhere above for either the first solvent or the second solvent. The extraction solvent may comprise a first solvent, a second solvent and one further solvent. Typically, the extraction solvent is a single solvent or a binary solvent.

Process conditions

Unlike known processes for removing alkenes from gasoline obtainable by an FCC process, the process of the invention requires only mild conditions of temperature and pressure. There is no requirement for high temperatures and pressures as in catalytic processes, or high temperature gradients as in distillation methods, for instance cryogenic distillation. The process may be carried out at a temperature of less than or equal to 300°C. The process is typically carried out at a temperature of less than or equal to 200°C. Preferably, the process is carried out at a temperature of less than or equal to 150°C. For instance, the process is often carried out at a temperature of less than or equal to 100°C. The process may be carried out at an absolute pressure of less than or equal to 0.5 MPa (which is approximately 5 atmospheres). Usually, the process is carried out at an absolute pressure of less than or equal to 0.3 MPa. Preferably, the process is carried out at an absolute pressure of less than or equal to 0.2 MPa. For instance, the process may be carried out at ambient pressure (i.e. 1 atmosphere). Absolute pressure is pressure relative to the vacuum. The ratio of the amount of the gasoline obtainable by an FCC process and the amount of the extraction solvent may be varied to optimise the extraction. Many solvents are cheap and readily available in large volumes.

Typically, the ratio by weight of the gasoline obtainable by a fluid catalytic cracking process to the extraction solvent is from 5: 1 to 1 :5. Thus, 1 part extraction solvent may be used to 5 parts gasoline, or 5 parts extraction solvent may be used to 1 part gasoline. Often, the ratio by weight of the gasoline obtainable by a fluid catalytic cracking process to the extraction solvent is from 3 : 1 to 1 :3. For instance, the ratio of FCC gasoline to the extraction solvent may be from 2: 1 to 1 :2. Preferably, the ratio is from 3 :2 to 2:3. For instance, the ratio may be about 1 : 1, for instance from 1.2: 1 to 1 : 1.2. Gasoline obtainable by an FCC process

The process of the invention allows the alkene content and organosulfur content of FCC gasoline to be reduced. This produces gasoline which may comply with increasingly stringent regulations regarding alkene and organosulfur content.

As discussed above, fluid catalytic cracking can produce gasoline from heavier crude oil fractions. However, due to the cracking process, the gasoline produced has a high alkene content compared to that of gasoline obtained directly as a fraction from crude oil.

The process of the invention comprises contacting gasoline obtainable by a fluid catalytic cracking process. The gasoline may be gasoline obtained by an FCC process. The FCC process may be any FCC process. The compositions of two gasolines produced by an FCC process are shown in Tables 1 and 2 Table 1 shows the composition of Daqing FCC gasoline. Table 2 shows the composition of commercial FCC gasoline from a petroleum refinery in Hubei, China. In both instances, the amount of alkenes is greater than 40 wt%.

Composition (wt %)

Carbon number Total 3 4 5 6 7 ί I 9 10 11 12

Alkanes 31.1 0.1 0.2 3.1 1.8 6.4 7 4 4.5 1.9 4.4 1.3

Alkenes 45.2 0.1 1.1 5.7 11.8 9.4 9 7 3.5 1.7 2.2 0.0

Cycloalkanes 6.7 0.0 0.0 0.5 1.3 2.3 1 4 1.3 0.0 0.0 0.0

Aromatics 17.0 0.0 0.0 0.0 0.6 0.3 7 5 7.0 1.3 0.2 0.0

Table 1 - Group composition of Daqing FFC gasoline

Table 2 - Group composition of commercial FCC gasoline from a refinery

Therefore, the gasoline obtainable by a fluid catalytic cracking process typically comprises greater than 20 wt% of alkenes, wherein the percentage by weight is relative to the total mass of the gasoline obtainable by a fluid catalytic cracking process. In some cases, the gasoline obtainable by a fluid catalytic cracking process may comprise greater than 10 wt% of alkenes. Often, the gasoline obtainable by a fluid catalytic cracking process comprises greater than 30 wt% of alkenes, wherein the percentage by weight is relative to the total mass of the gasoline obtainable by a fluid catalytic cracking process. "Alkenes", as referred to herein, also includes cycloalkenes.

More typically, the gasoline obtainable by a fluid catalytic cracking process comprises greater than 35 wt% of alkenes, wherein the percentage by weight is relative to the total mass of the gasoline obtainable by a fluid catalytic cracking process.

Typically, the gasoline obtainable by an FCC process comprises: (i) alkanes and cycloalkanes in an amount of greater than or equal to 20 wt%; (ii) alkenes in an amount of greater than or equal to 20 wt%; and (iii) aromatic hydrocarbons in an amount of greater than or equal to 3 wt%. Typically, the gasoline obtainable by an FCC process further comprises (iv) organosulfur compounds in an amount of greater than or equal to 0.05 wt%. The total amount of components (i) to (iii), or (i) to (iv), is typically greater than or equal to 80 wt% of the gasoline obtainable by an FCC process. The gasoline obtainable by an FCC process may consist essentially of components (i) to (iii) or (i) to (iv). Often, the gasoline obtainable by an FCC process comprises:

(i) alkanes and cycloalkanes in an amount of from 20 wt% to 60 wt%;

(ϋ) alkenes in an amount of greater than or equal to 20 wt% to 60 wt%;

(iii) aromatic hydrocarbons in an amount of from 3 wt% to 20 wt%; and

(iv) organosulfur compounds in an amount of from 0.05 wt% to 2 wt%, wherein the total amount of components (i) to (iv) is greater than or equal to 80 wt%, or greater than or equal to 90 wt%.

The gasoline obtainable by an FCC process may consist essentially of:

(i) alkanes and cycloalkanes in an amount of from 20 wt% to 60 wt%;

(ii) alkenes in an amount of greater than or equal to 20 wt% to 60 wt%;

(iii) aromatic hydrocarbons in an amount of from 3 wt% to 20 wt%; and

(iv) organosulfur compounds in an amount of from 0.05 wt% to 2 wt%.

For instance, the gasoline obtainable by an FCC process may comprise:

(i) alkanes and cycloalkanes in an amount of from 20 wt% to 45 wt%;

(ii) alkenes in an amount of greater than or equal to 40 wt% to 55 wt%;

(iii) aromatic hydrocarbons in an amount of from 3 wt% to 20 wt%; and

(iv) organosulfur compounds in an amount of from 0.05 wt% to 2 wt%

wherein the total amount of components (i) to (iv) is greater than or equal to 80 wt%, or greater than or equal to 90 wt%.

The alkenes are typically one or more alkenes selected from C _4-12 alkenes and C5-8 cycloalkenes. The alkenes may be one or more compounds selected from butene, pentene, methylbutene, hexene, methylpentene, dimethylbutene, heptene, methylhexene,

dimethylpentene, octene, methylheptene, nonene, decene, undecene, dodecene and C5-8 cylcoalkenes as defined herein. For instance, the alkenes may be one or more compounds selected from pentene, methylbutene, hexene, methylpentene, dimethylbutene, ethylbutene, heptene, methylhexene, dimethylpentene, octene, methylheptene, and nonene. Typically, the alkanes and cycloalkanes present in the FCC gasoline are one or more compounds selected from C _4-12 alkanes and C5-8 cycloalkanes. For instance, the alkanes and cycloalkanes may be one or more alkanes and cycloalkanes selected from butane, isobutane, pentane, isopentane, hexane, methylpentane, dimethylbutane, heptane, methylhexane, dimethylpentane, octane, methylheptane, dimethylhexane, trimethylpentane, nonane, decane, undecane, dodecane, cyclopentane, cyclohexane, methylcyclopentane, cycloheptane, methylcyclohexane, dimethylcyclopentane and cyclooctane.

The aromatic hydrocarbons present in the FCC gasoline may be any C _6-12 aromatic hydrocarbons. For instance the aromatic hydrocarbons may be one or more compounds selected from benzene, toluene, xylene, ethylbenzene, methylethylbenzene, diethylbenzene, naphthalene, methylnaphthalene and ethylnaphthalene.

The organosulfur compounds present in the FCC gasoline may be one or more C4-10 organosulfur compounds. In particular, the gasoline may comprise one or more organosulfur compounds comprising a thiophene ring, a benzothiophene ring or a dibenzothiophene ring. For instance, the organosulfur compounds may be one or more compounds selected from substituted or unsubstituted thiophene, substituted or unsubstituted benzothiophene, and substituted or unsubstituted dibenzothiophene. Typically, if the organosulfur compound is substituted, it is substituted with one or more Ci-6 alkyl groups.

First phase recovery The process of the invention forms (i) a first phase comprising said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound, and (ii) a second phase comprising gasoline having a reduced alkene content and a reduced organosulfur content compared to said gasoline obtainable by a fluid catalytic cracking process.

Often, it is preferable to recover at least some of the first phase. The recovery of the first phase is described above.

Typically, the recovered first phase comprises greater than or equal to 2 wt% of alkene compounds, wherein the percentage by weight is relative to the total mass of the recovered extraction solvent. The recovered first phase may comprise the extraction solvent in an amount of greater than or equal to 80 wt%, and alkene compounds in an amount of greater than or equal to 2 wt%. Often, the recovered first phase comprises greater than or equal to 4 wt% of alkene compounds, wherein the percentage by weight is relative to the total mass of the recovered extraction solvent. The recovered first phase may comprise the extraction solvent in an amount of greater than or equal to 80 wt%, and alkene compounds in an amount of greater than or equal to 4 wt%.

The recovered first phase may comprise (i) the extraction solvent, (ii) one or more alkene compounds, and (iii) one or more organosulfur compounds. The recovered first phase may further comprise (iv) one or more alkane and cycloalkane compounds and/or (v) one or more aromatic hydrocarbon compounds. For instance, the recovered first phase may comprise (i) the extraction solvent in an amount of from 60 wt% to 90 wt%, (ii) one or more alkenes in an amount of from 2 wt% to 15 wt%, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The recovered first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 2 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 2 wt% to 15 wt%. The extraction solvent, the one or more alkenes, the one or more organosulfur compounds, the one or more alkanes or cycloalkane compounds and the one or more aromatic hydrocarbon compounds may be as defined anywhere herein.

The recovered first phase may have a composition as described herein for the first phase of the composition of the invention or the recovered first phase used in the process for producing one or more further organic compounds according to the invention.

Catalytic conversion of recovered extraction solvent

As discussed above, it is possible to convert small molecules such as those of the extraction solvent into useful chemical feedstock. For instance, there is interest in the catalytic conversion of methanol to olefins, aromatics and gasoline by the processes known as MTO, MTA and MTG respectively.

Thus, in one embodiment of the invention, the process further comprises performing a reaction on at least part of the recovered first phase to produce one or more further organic compounds. There may be intervening steps between the recovery of at least part of the first phase and the reaction to produce one or more further organic compounds. For instance, there may be a step of transporting the recovered first phase to another facility where the conversion reaction is carried out. Often, the reaction is a catalytic reaction. A catalytic reaction is any reaction carried out in the presence of a catalyst. The reaction is typically a heterogeneous catalytic reaction. The catalyst may be any catalyst. Often, the catalyst is a zeolite or another micro- or nano-porous catalyst. In one embodiment, said catalytic reaction comprises heating the recovered first phase in the presence of a solid acid catalyst, for example a strong acid zeolite catalyst. The zeolite catalyst may comprise any aluminosilicate zeolite. The catalyst may further comprise a metal, for instance a metal selected from any one of groups 1 to 12 of the Periodic table of the elements. Preferably, catalyst comprises one or more zeolites selected from pentasil zeolites including ZSM-5, ABC-6 zeolites including SSZ-13, faujasites including zeolite X and zeolite Y, and mordenite. Often, the catalyst may comprise one or more of ZSM-5, H-ZSM-5 and SSZ-13.

The catalytic process for producing further organic compounds will often require high temperatures and pressures. Thus, the catalytic reaction may be carried out at a temperature of greater than or equal to 200°C, or greater than or equal to 250°C. For instance, the catalytic reaction may be carried out at a temperature of greater than or equal to 300°C. The reaction may be carried out at a pressure of greater than or equal to 0.15 MPa, or greater than or equal to 0.2 MPa. For instance, the catalytic reaction may be carried out at a temperature of greater than or equal to 0.3 MPa. The one or more further organic compounds produced are typically selected from alkanes, alkenes, and aromatic hydrocarbons. Thus, the process according to the invention may further comprise performing a reaction on at least part of the recovered first phase to produce one or more alkanes. The process according to the invention may further comprise performing a reaction on at least part of the recovered first phase to produce one or more alkenes (olefins). The process according to the invention may further comprise performing a reaction on at least part of the recovered first phase to produce one or more aromatic hydrocarbons.

If the process comprises producing one or more alkene compounds, the catalyst typically comprises SSZ-13. If the process comprises producing one or more alkane compounds, the catalyst typically comprises ZSM-5 or H-ZSM-5. In particular, the process may further comprise performing a reaction on at least part of the recovered first phase, which recovered first phase comprises an alcohol, for instance methanol, to produce one or more further organic compounds. Thus, the process may further comprise performing a methanol to gasoline (MTG) reaction, a methanol to olefins (MTO), or a methanol to aromatic hydrocarbons (MTA) reaction.

Process for producing one or more organic compounds

The invention also provides a process for producing one or more further organic compounds, which process comprises:

a) providing a recovered first phase, which recovered first phase is obtainable by: contacting gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound, with an extraction solvent suitable for extracting alkenes and organosulfur compounds, which extraction solvent comprises a polar organic solvent,

and thereby forming

i) a first phase comprising said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound, and

ii) a second phase comprising gasoline having a reduced alkene content and a reduced organosulfur content compared to said gasoline obtainable by a fluid catalytic cracking process,

and recovering at least part of the first phase; and

b) performing a reaction on at least part of the recovered first phase to produce one or more further organic compounds.

Part (b) of the process may be as defined hereinbefore. Thus, said reaction is typically a catalytic reaction. Said catalytic reaction often comprises heating the recovered first phase in the presence of a zeolite catalyst.

The one or more further organic compounds produced are typically selected from alkanes, alkenes, and aromatic hydrocarbons.

Contacting gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound, with an extraction solvent suitable for extracting alkenes and organosulfur compounds, which extraction solvent comprises a polar organic solvent is as defined in any one of claims may be as defined anywhere hereinbefore.

In particular, the extraction solvent may comprise a polar protic organic solvent such as those defined hereinbefore. For instance, the extraction solvent may comprise an alcohol. The extraction solvent (an thus the recovered first phase) preferably comprises a monohydric alcohol. The recovered first phase often comprises an extraction solvent which comprises methanol.

The recovered first phase may comprise (i) the extraction solvent, (ii) one or more alkene compounds, and (iii) one or more organosulfur compounds. The recovered first phase may further comprise (iv) one or more alkane and cycloalkane compounds and/or (v) one or more aromatic hydrocarbon compounds.

The recovered first phase typically comprises (i) the extraction solvent in an amount of greater than or equal to 60 wt%, (ii) one or more alkenes in an amount of greater than or equal to 2 wt%, and (iii) one or more organosulfur compounds in an amount of greater than or equal to 0.01 wt %. The recovered first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of greater than or equal to 0.5 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of greater than or equal to 0.5 wt%.

The recovered first phase may comprise (i) the extraction solvent in an amount of greater than or equal to 70 wt%, (ii) one or more alkenes in an amount of greater than or equal to 4 wt%, and (iii) one or more organosulfur compounds in an amount of greater than or equal to 0.01 wt %. The recovered first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of greater than or equal to 0.5 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of greater than or equal to 0.5 wt%. The recovered first phase may comprise (ii) one or more alkenes in an amount of greater than or equal to 6 wt%, or (ii) one or more alkenes in an amount of greater than or equal to 8 wt%.

For instance, the recovered first phase may comprise (i) the extraction solvent in an amount of from 60 wt% to 90 wt%, (ii) one or more alkenes in an amount of from 2 wt% to 15 wt%, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The recovered first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 0.5 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 0.5 wt% to 15 wt%.

The recovered first phase may comprise (i) the extraction solvent in an amount of from 70 wt% to 95 wt%, (ii) one or more alkenes in an amount of from 4 wt% to 15 wt%, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The recovered first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 0.5 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 0.5 wt% to 15 wt%.

The extraction solvent, the one or more alkenes, the one or more organosulfur compounds, the one or more alkanes or cycloalkane compounds and the one or more aromatic

hydrocarbon compounds may be as defined anywhere hereinbefore.

The recovered first phase may comprise (i) an alcohol, for instance a monohydric alcohol such as methanol, in an amount of from 60 wt% to 90 wt%, (ii) one or more alkenes in an amount of from 2 wt% to 15 wt%, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The recovered first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 0.5 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 0.5 wt% to 15 wt%.

The alkenes are typically one or more alkenes selected from C _4-12 alkenes (including cycloalkenes). Often, the alkenes are selected from C4-9 alkenes. The alkenes may be one or more compounds selected from butene, pentene, methylbutene, hexene, methylpentene, dimethylbutene, heptene, methylhexene, dimethylpentene, octene, methylheptene, nonene, decene, undecene, dodecene, cyclopentene, cyclohexene, methylcyclohexene, cycloheptene, methylcyclohexene, dimethylcyclopentene and ethylcyclopentene. For instance, the alkenes may be one or more compounds selected from pentene, methylbutene, hexene,

methylpentene, dimethylbutene, ethylbutene, heptene, methylhexene, dimethylpentene, ethylpentene, octene, methylheptene, dimethylhexene, ethylhexene, trimethylpentene, ethyldimethylpentene, nonene, cyclopentene, cyclohexene, methylcyclohexene,

cycloheptene, methylcyclohexene, dimethylcyclopentene and ethylcyclopentene. As discussed above, each alkene includes all structural and geometric isomers of the alkene with that name. For instance, methylpentene includes 2-methylpentene and 3 -methylpentene; and 2-methylpentene includes 2-methylpent-l-ene, 2-methylpent-2-ene, 2-methylpent-3-ene, and 2-methylpent-4-ene.

Thus, the recovered first phase may comprise (ii) one or more alkenes in an amount of greater than or equal to 2 wt%, wherein the one or more alkenes are selected from C4-9 alkenes and C5-7 cycloalkenes. The recovered first phase may comprise (ii) one or more alkenes in an amount of greater than or equal to 2 wt%, or greater than or equal to 4 wt%, wherein the one or more alkenes are selected from pentene, methylbutene, hexene, methylpentene, dimethylbutene, ethylbutene, heptene, methylhexene, dimethylpentene, ethylpentene, octene, methylheptene, dimethylhexene, ethylhexene, trimethylpentene, ethyldimethylpentene, nonene, cyclopentene, cyclohexene, methylcyclohexene, cycloheptene, methylcyclohexene, dimethylcyclopentene and ethylcyclopentene.

The recovered first phase may comprise (i) an alcohol, for instance a monohydric alcohol such as methanol, in an amount of from 60 wt% to 90 wt%, (ii) one or more alkenes in an amount of from 2 wt% to 15 wt%, wherein the one or more alkenes are selected from C4-9 alkenes and C5-7 cycloalkenes, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The recovered first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 0.5 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 0.5 wt% to 15 wt%.

Typically, the alkanes and cycloalkanes present in the recovered first phase are one or more compounds selected from C4-12 alkanes and C5-8 cycloalkanes. For instance, the alkanes and cycloalkanes may be one or more alkanes and cycloalkanes selected from butane, isobutane, pentane, isopentane, hexane, methylpentane, dimethylbutane, heptane, methylhexane, dimethylpentane, octane, methylheptane, dimethylhexane, trimethylpentane, nonane, decane, undecane, dodecane, cyclopentane, cyclohexane, methylcyclopentane, cycloheptane, methylcyclohexane, dimethylcyclopentane and cyclooctane.

The aromatic hydrocarbons present in the recovered first phase may be any C _6-12 aromatic hydrocarbons. For instance the aromatic hydrocarbons may be one or more compounds selected from benzene, toluene, xylene, ethylbenzene, methylethylbenzene, diethylbenzene, naphthalene, methylnaphthalene and ethylnaphthalene. The organosulfur compounds present in the FCC gasoline may be one or more C4-10 organosulfur compounds. In particular, the gasoline may comprise one or more organosulfur compounds comprising a thiophene ring, a benzothiophene ring or a dibenzothiophene ring. For instance, the organosulfur compounds may be one or more compounds selected from substituted or unsubstituted thiophene, substituted or unsubstituted benzothiophene, and substituted or unsubstituted dibenzothiophene. Typically, if the organosulfur compound is substituted, it is substituted with one or more Ci-6 alkyl groups.

The process for producing one or more further organic compounds may comprise:

a) providing a recovered first phase, which recovered first phase comprises (i) an alcohol, for instance a monohydric alcohol such as methanol, in an amount of from 60 wt% to 90 wt%, (ii) one or more alkenes in an amount of from 2 wt% to 15 wt%, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%.; and

b) performing a reaction on at least part of the recovered first phase to produce one or more further organic compounds.

The reaction is typically a catalytic reaction. The catalyst used in the catalytic reaction is often a zeolite catalyst. The zeolite catalyst may comprise any aluminosilicate zeolite. The catalyst may further comprise a metal, for instance a metal selected from any one of groups 1 to 12 of the Periodic table of the elements. Preferably, the catalyst comprises one or more zeolites selected from pentasil zeolites including ZSM-5, ABC-6 zeolites including SSZ-13, faujasites including zeolite X and zeolite Y, and mordenite. Often, the catalyst may comprise one or more of ZSM-5, H-ZSM-5 and SSZ-13.

Composition

The invention also provides a composition comprising:

a) a first phase which comprises an extraction solvent suitable for extracting alkenes and organosulfur compounds (which extraction solvent comprises a polar organic solvent), at least one extracted alkene, and at least one extracted organosulfur compound; and b) a second phase, which second phase comprises gasoline having a reduced alkene content and a reduced organosulfur content compared to gasoline obtainable by a fluid catalytic cracking process.

For instance, the composition may comprise:

a) a first phase which comprises an extraction solvent suitable for extracting alkenes and organosulfur compounds (which extraction solvent comprises a polar organic solvent), at least one extracted alkene, at least one extracted organosulfur compound, at least one extracted alkane or cycloalkane compound, and at least one extracted aromatic hydrocarbon compound; and

b) a second phase, which second phase comprises gasoline having a reduced alkene content and a reduced organosulfur content compared to gasoline obtainable by a fluid catalytic cracking process.

The first phase may consist essentially of the given components. The second phase may consist essentially of the given components.

The composition typically comprises two distinct phases, as described above for the process of the invention. Thus, the composition may comprise a denser first or second phase which has settled below a less dense second or first phase. The first phase and the second phase may alternatively be mixed as an emulsion.

In particular, the extraction solvent may comprise a polar protic organic solvent such as those defined hereinbefore. For instance, the extraction solvent may comprise an alcohol. The extraction solvent (an thus the first phase) preferably comprises a monohydric alcohol. The first phase often comprises an extraction solvent which comprises methanol.

The first phase may comprise (i) the extraction solvent, (ii) one or more alkene compounds, and (iii) one or more organosulfur compounds. The first phase may further comprise (iv) one or more alkane and cycloalkane compounds and/or (v) one or more aromatic hydrocarbon compounds. The first phase typically comprises (i) the extraction solvent in an amount of greater than or equal to 60 wt%, (ii) one or more alkenes in an amount of greater than or equal to 2 wt%, and (iii) one or more organosulfur compounds in an amount of greater than or equal to 0.01 wt %. The first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of greater than or equal to 0.5 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of greater than or equal to 0.5 wt%.

The first phase may comprise (i) the extraction solvent in an amount of greater than or equal to 70 wt%, (ii) one or more alkenes in an amount of greater than or equal to 4 wt%, and (iii) one or more organosulfur compounds in an amount of greater than or equal to 0.01 wt %. The first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of greater than or equal to 0.5 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of greater than or equal to 0.5 wt%.

The first phase may comprise (ii) one or more alkenes in an amount of greater than or equal to 6 wt%, or (ii) one or more alkenes in an amount of greater than or equal to 8 wt%. For instance, the first phase may comprise (i) the extraction solvent in an amount of from 60 wt% to 90 wt%, (ii) one or more alkenes in an amount of from 2 wt% to 15 wt%, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 0.5 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 0.5 wt% to 15 wt%.

The first phase may comprise (i) the extraction solvent in an amount of from 70 wt% to 95 wt%, (ii) one or more alkenes in an amount of from 4 wt% to 15 wt%, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 0.5 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 0.5 wt% to 15 wt%.

The extraction solvent, the one or more alkenes, the one or more organosulfur compounds, the one or more alkanes or cycloalkane compounds and the one or more aromatic

hydrocarbon compounds may be as defined anywhere hereinbefore. The first phase may comprise (i) an alcohol, for instance a monohydric alcohol such as methanol, in an amount of from 60 wt% to 90 wt%, (ii) one or more alkenes in an amount of from 2 wt% to 15 wt%, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 0.5 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 0.5 wt% to 15 wt%.

The alkenes are typically one or more alkenes selected from C _4-12 alkenes (including cycloalkenes). Often, the alkenes are selected from C4-9 alkenes. The alkenes may be one or more compounds selected from butene, pentene, methylbutene, hexene, methylpentene, dimethylbutene, heptene, methylhexene, dimethylpentene, octene, methylheptene, nonene, decene, undecene, dodecene, cyclopentene, cyclohexene, methylcyclohexene, cycloheptene, methylcyclohexene, dimethylcyclopentene and ethylcyclopentene. For instance, the alkenes may be one or more compounds selected from pentene, methylbutene, hexene,

methylpentene, dimethylbutene, ethylbutene, heptene, methylhexene, dimethylpentene, ethylpentene, octene, methylheptene, dimethylhexene, ethylhexene, trimethylpentene, ethyldimethylpentene, nonene, cyclopentene, cyclohexene, methylcyclohexene,

cycloheptene, methylcyclohexene, dimethylcyclopentene and ethylcyclopentene. As discussed above, each alkene includes all structural and geometric isomers of the alkene with that name. For instance, methylpentene includes 2-methylpentene and 3 -methylpentene; and 2-methylpentene includes 2-methylpent-l-ene, 2-methylpent-2-ene, 2-methylpent-3-ene, and 2-methylpent-4-ene.

Thus, the first solvent may comprise (ii) one or more alkenes in an amount of greater than or equal to 2 wt%, wherein the one or more alkenes are selected from C4-9 alkenes and C5-7 cycloalkenes. The first solvent may comprise (ii) one or more alkenes in an amount of greater than or equal to 2 wt%, or greater than or equal to 4 wt%, wherein the one or more alkenes are selected from pentene, methylbutene, hexene, methylpentene, dimethylbutene, ethylbutene, heptene, methylhexene, dimethylpentene, ethylpentene, octene, methylheptene, dimethylhexene, ethylhexene, trimethylpentene, ethyldimethylpentene, nonene, cyclopentene, cyclohexene, methylcyclohexene, cycloheptene, methylcyclohexene, dimethylcyclopentene and ethylcyclopentene. The first phase may comprise (i) an alcohol, for instance a monohydric alcohol such as methanol, in an amount of from 60 wt% to 90 wt%, (ii) one or more alkenes in an amount of from 2 wt% to 15 wt%, wherein the one or more alkenes are selected from C4-9 alkenes and C5-7 cycloalkenes, and (iii) one or more organosulfur compounds in an amount of from 0.01 wt % to 1 wt%. The first phase may further comprise (iv) one or more alkane or cycloalkane compounds in an amount of from 0.5 wt% to 15 wt% and/or (v) one or more aromatic hydrocarbon compounds in an amount of from 0.5 wt% to 15 wt%.

Typically, the alkanes and cycloalkanes present in the first phase are one or more compounds selected from C4-12 alkanes and C5-8 cycloalkanes. For instance, the alkanes and cycloalkanes may be one or more alkanes and cycloalkanes selected from butane, isobutane, pentane, isopentane, hexane, methylpentane, dimethylbutane, heptane, methylhexane,

dimethylpentane, octane, methylheptane, dimethylhexane, trimethylpentane, nonane, decane, undecane, dodecane, cyclopentane, cyclohexane, methylcyclopentane, cycloheptane, methylcyclohexane, dimethylcyclopentane and cyclooctane.

The aromatic hydrocarbons present in the first phase may be any C5-12 aromatic

hydrocarbons. For instance the aromatic hydrocarbons may be one or more compounds selected from benzene, toluene, xylene, ethylbenzene, methyl ethy lb enzene, diethylbenzene, naphthalene, methylnaphthalene and ethylnaphthalene.

The organosulfur compounds present in the FCC gasoline may be one or more C _4-10 organosulfur compound. In particular, the gasoline may comprise one or more organosulfur compounds comprising a thiophene ring, a benzothiophene ring or a dibenzothiophene ring. For instance, the organosulfur compounds may be one or more compounds selected from substituted or unsubstituted thiophene, substituted or unsubstituted benzothiophene, and substituted or unsubstituted dibenzothiophene. Typically, if the organosulfur compound is substituted, it is substituted with one or more Ci-6 alkyl groups.

The second phase comprises gasoline having a reduced alkene content and a reduced organosulfur content compared to gasoline obtainable by a fluid catalytic cracking process. Thus, the second phase may comprise gasoline having the composition of gasoline obtainable by an FCC process as described above, wherein the amount of alkene compounds is reduced by 10 %, or is reduced by 15 %.

For instance, the second phase may comprise (i) one or more alkanes and cycloalkanes in an amount of greater than or equal to 40 wt%, (ii) one or more alkenes and cycloalkenes in an amount of less than or equal to 45 wt%, and (iii) one or more aromatic hydrocarbon compounds in an amount of greater than or equal to 8 wt%. Each of these components may be as described anywhere herein. For instance, as described for the alkenes, cycloalkenes, alkanes, cycloalkanes and aromatic hydrocarbon compounds present in the first phase. The second phase may consist essentially of components (i) to (iii). Some of the extraction solvent may be present in the second phase, although this is preferably in an amount of less than or equal to 3 wt%. Typically, the second phase comprises less than or equal to 1 wt% of the extraction solvent.

Often, the second phase comprises (i) one or more alkanes and cycloalkanes in an amount of greater than or equal to 45 wt%, (ii) one or more alkenes and cycloalkenes in an amount of less than or equal to 40 wt%, and (iii) one or more aromatic hydrocarbon compounds in an amount of greater than or equal to 10 wt%.

Typically, the second phase will have a low organosulfur content. Preferably, the organosulfur content of the second phase is less than or equal to 0.1 wt% (relative to the total weight of the second phase).

Apparatus

The invention also provides an apparatus for producing gasoline having a reduced alkene content and a reduced organosulfur content, wherein the apparatus comprises:

a) a first reservoir comprising gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound;

b) a second reservoir comprising an extraction solvent, which extraction solvent is suitable for extracting alkenes and organosulfur compounds, and which extraction solvent comprises a polar organic solvent; and

c) a reactor which is connected in fluid communication with the first and second reservoirs.

The gasoline obtainable by an FCC process may be as described anywhere hereinbefore. The extraction solvent may be as described anywhere hereinbefore. For instance, the extraction solvent may comprise methanol or ethanol as a first solvent and ethylene glycol or propylene glycol as a second solvent. Each of the other components may be as described anywhere hereinbefore.

The first and second reservoirs may be any reservoirs suitable for holding a liquid composition. Thus, the reservoir may be a tank or container. The reactor may be connected in fluid communication with the first and second reservoirs by any means. Typically, they are connected by one or more supply lines or pipes.

Typically, the reactor contains at least some of the gasoline obtainable by a fluid catalytic cracking process and at least some of the extraction solvent. The ratio of the FCC gasoline and the extraction solvent may be as described for a process according to the invention. For instance, the ratio of FCC gasoline to extraction solvent may be from 3 : 1 to 1 :3. The reactor may be any reactor suitable for mixing the contents of the first and second reservoirs. The term "reactor" does not require that any chemical reaction occurs within the reactor. The reactor allows the contents of the two reservoirs to contact in order to allow the extraction of one or more alkene compounds and one or more organosulfur compounds.

The reactor generally comprises a mixing means. This may be a propeller or an agitation means. The reactor may be a vessel which can be agitated or shaken in order to mix the contents of the two reservoirs. For instance, the reactor may be selected from a Scheibel ^® column, a KARR ^® column or a centrifugal extractor.

The gasoline obtainable by a fluid catalytic cracking process may be as defined hereinbefore, and/or the extraction solvent may be as defined hereinbefore.

Typically, the reactor comprises

i) a first phase comprising said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound, and

ii) a second phase comprising gasoline having a reduced alkene content and a reduced organosulfur content compared to said gasoline obtainable by a fluid catalytic cracking process. The first phase and the second phase may be as described anywhere hereinbefore.

The apparatus typically further comprises one or more of

d) a first supply line for recovering at least part of the first phase, and

e) a second supply line for recovering at least part of the second phase.

The first or second supply line may be any suitable supply line, for instance a pipe. One phase will typically have a greater density than another phase, and thus one supply line will be attached to the reactor at a higher point than the other supply line is attached to the reactor. Thus, one of the first and second supply lines is typically placed above the other supply line for recovering the second or first phase. The first phase often has a higher density that the second phase. The first supply line may be connected to the reactor at a point lower than the point at which the second supply line is connected to the reactor. The first supply line may be connected to a point in the top 40% of the exterior reactor surface, and the second supply line may be connected to a point in the bottom 40% of the exterior reactor surface. Use

The invention also provides the use of an extraction solvent for extracting at least one alkene and at least one organosulfur compound from gasoline obtainable by a fluid catalytic cracking process, which extraction solvent comprises a polar organic solvent. The extraction solvent may be as defined anywhere herein. For instance, the extraction solvent may comprise a compound selected from an alcohol, a ketone, an ether, an ester, and a nitrile. The extraction solvent may comprise a compound selected from monohydric alcohols such as methanol, ethanol, propanol, isopropanol (propan-2-ol), butanol (butan-1- ol), secbutanol (butan-2-ol), isobutanol (2-methylpropan-l-ol), tertbutanol (2-methylpropan- 2-ol), cyclopentanol, pentanol, cyclohexanol, hexanol, heptanol and octanol; and polyhydric alcohols such as ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane- 1, 3 -diol, propane-l,2,3-triol (glycerol), isopropanediol, butanediol, isobutanediol, tertbutanediol, butanetriol, pentanediol, methylbutanediol, hexanediol, hexanetriol. The extraction solvent may comprise an alcohol selected from methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, ethylene glycol, propylene glycol, and propane- 1,3-diol.

In one embodiment, the extraction solvent is a binary solvent, which binary solvent comprises a first solvent which is said polar organic solvent and a second solvent, which second solvent is a polar protic organic solvent. The first solvent may be any solvent listed above, for instance an alcohol, a carboxylic acid, a ketone or an amine. If the solvent is a binary solvent, the second solvent is a polar protic organic solvent. Preferably, the second solvent is an alcohol.

The extraction solvent may sometimes further comprise an inorganic polar solvent, for instance water. The presence of an inorganic polar solvent (such as water) can positively influence the extraction properties of the extraction solvent. Thus, the extraction solvent may comprise an inorganic polar solvent in addition to the first solvent and, where present, the second and any further solvents. The inorganic polar solvent may be water.

The second solvent may be selected from methanol, ethanol, propanol, isopropanol, butanol, secbutanol, isobutanol, tertbutanol, cyclopentanol, pentanol, cyclohexanol, hexanol, heptanol, octanol, ethane- 1,2-diol (ethylene glycol), propane- 1,2-diol (propylene glycol), propane-1,3- diol, propane-l,2,3-triol (glycerol), isopropanediol, butanediol, isobutanediol, tertbutanediol, butanetriol, pentanediol, methylbutanediol, hexanediol, and hexanetriol. In some

embodiments, the first and second solvents are both alcohols.

The ratio of the first solvent and the second solvent may be from 7:4 to 4:7. Preferably, the ratio of the first solvent and the second solvent may be from 2: 1 to 1 :2. For instance, the ratio of the first and the second solvents may be around 4:6 or around 6:4. Herein, the ratios of the first and second solvents are all ratios by weight. Thus, if a composition comprises 30 wt% of the first solvent, and 60 wt% of the second solvent, the ratio of the first solvent and the second solvent is 3 :6, or equivalently 1 :2. When the extraction solvent is a binary or multinary solvent, the extraction solvent may comprise:

i) the first solvent in an amount of greater than or equal to 30 wt%; and ii) the second solvent in an amount of greater than or equal to 20 wt%;

wherein the percentage by weight is relative to the total weight of the extraction solvent.

Often, the extraction solvent comprises:

i) the first solvent in an amount of from 30 wt% to 90 wt%; and

ii) the second solvent in an amount of from 10 wt% to 60 wt%;

wherein the total amount of the first solvent and the second solvent is greater than or equal to 80 wt%, and wherein the percentage by weight is relative to the total weight of the extraction solvent. The extraction solvent may consist essentially of the first solvent and the second solvent. The first solvent may be any polar organic solvent described above, and the second solvent may be any polar protic organic solvent described above. For instance, the first solvent may be a monohydric alcohol, for instance a Ci-4 monohydric alcohol, and the second solvent may be a polyhydric alcohol, for instance a Ci-4 dihydric alcohol.

In the use according to the invention, extracting at least one alkene and at least one organosulfur compound from gasoline obtainable by a fluid catalytic cracking process typically comprises: contacting gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound, with an extraction solvent suitable for extracting alkenes and organosulfur compounds, which extraction solvent comprises a polar organic solvent,

and thereby forming i) a first phase comprising said extraction solvent, at least one extracted alkene, and at least one extracted organosulfur compound, and

ii) a second phase comprising gasoline having a reduced alkene content and a reduced organosulfur content compared to said gasoline obtainable by a fluid catalytic cracking process.

Contacting gasoline obtainable by a fluid catalytic cracking process, which gasoline comprises at least one alkene and at least one organosulfur compound, with an extraction solvent suitable for extracting alkenes and organosulfur compounds which comprises a polar organic solvent may be as defined anywhere above for a process according to the invention. The invention will be further described in the Examples which follow.

EXAMPLES

Example 1 - Reduction of alkene and organosulfur content of model FCC gasoline mixture. Model FCC gasoline mixture (MFGM)

1-pentene and 1-hexene were purchased from Acros Organics Company with purity of 97% (impurities including i- and n-pentane, i- and n-hexane, 2-pentene, and 2-hexene). N-octane with purity of 99.0%>, methanol with purity of 99.9%, ethylene glycol with purity of 99.0%>, thiophene with purity of 99.9%, ethylbenzene with purity of 99.9% and dimethyl carbonate (DMC) with purity of 99.9% were purchased from Sigma Aldrich Company. These agents were used without further purification. Because 1-pentene is a volatile substance with a low boiling point of 303 K, the liquid components of solutions were measured by weight rather than volume. All the experiments were carried out at 298 K and 101 kPa.

Preparation of the model FCC gasoline mixture (MFGM) was referred to the existing literature, which illustrated the required composition of FCC gasoline. In FCC gasoline, the major part of the olefin fraction comprises C5-8 olefins, while C5 and C ₆ olefins contribute most to the olefin fraction. Therefore, the C5 olefin 1-pentene and C ₆ olefin 1-hexene were chosen as the model, target olefins used in this work. Moreover, due to the fact that C ₈ aromatics typically contribute the largest mass fraction among all the aromatics in FCC gasoline, ethylbenzene was chosen as the model aromatic. The abundance of each compound in the MFGM was based on a commercial FCC gasoline, Daqing FCC gasoline (the composition of which is shown in Table 1 above). From the table, the mass fraction of C ₅ and C ₆ olefins and C ₈ aromatics are 5.65%, 1 1.83%> and 7.51%, respectively.

Furthermore, based on the literature survey, it has been found that the most important class of sulfur compounds present in FCC gasoline is thiophene and its light alkyl derivatives, in addition to benzothiophene. Thus, thiophene was chosen as the target sulfur-compound of this study, which has the greatest contribution to FCC gasoline' s organosulfur content. The general mass fraction of OSCs in FCC gasoline is approximately 1000 ppm (0.1%>). Thus, to replace all the other OSCs in FCC gasoline, the mass fraction of thiophene in the MFGM was set at 0.1%.

For the purpose of optimizing the experimental procedure, the mass fraction of the C ₅ olefin, the C ₆ olefin, the C ₈ aromatic hydrocarbon and the OSC have been set as 6.0%>, 12.0%, 8.0%> and 0.1%), respectively. All other gasoline components have been balanced with n-octane, the mass fraction of which is 73.9%. The composition of the MFGM used in this Example is set out below in Table 3.

Table 3 - Composition of MFGM for Example 1

Experimental method for MFGM extraction

The extraction experiment adopted mixing and separating methods. Methanol was used as the extraction solvent. A specific quantity of MFGM and methanol were premixed to produce different extracted ratio solutions. Five 10 g MFGM samples were prepared, and different quantities of methanol were added into these samples. The weight ratios of extractant methanol to MFGM in each sample were (i) 3 : 1, (ii) 2: 1, (iii) 1 : 1, (iv) 1 :2 and (v) 1 :3.

After mixing and complete phase separation, these resulting mixtures were separated and analysed. Then, the upper phase and lower phase solutions were weighed and their weight was recorded. Because liquid-liquid phase separation was not observed in the 4: 1 ratio mixture (under ambient conditions, 298 K), the maximum extractant to gasoline mixing ratio was chosen as 3 : 1 in this study. Table 4 demonstrates that the extractant methanol and extracted compounds are located at the lower phase of the samples, because methanol has a higher density than octane. n-octane pent-l-ene hex-l-ene thiophene ethylbenzene methanol

Density

0.703 0.64 0.673 1.051 0.867 0.792 (g/cm ³ )

- Density of MFGM components

Following the extraction, the gas chromatography-mass spectrometry (GCMS) method was applied to quantify the content of olefins, OSCs and aromatics in the mixture at the upper phase. The upper (gasoline) phases of samples (i) to (v) were measured successively. The GCMS analyser was a SHFMADZU GCMS-QP2010 SE gas chromatography mass spectrometer. The main operating parameters of GCMS meter were: column oven

temperature 30°C/303K; injection temperature 200°C /473 K; injection mode split;

temperature rising rate from 30 to 35°C was l°C/min, and after 35°C the rate was changed to 10°C /min, until it reached 200°C. Results and discussion

The results of mass transfer analysis experiments are listed in Table 5. After the extraction, the weight of the methanol phase of samples (i) to (v) was increased by 8.15 g, 7.04 g, 3.61 g, 1.64 g and 0.67 g respectively. Each sample's MFGM phase had the equivalent amount of weight lost. This means that part of the solutes was moved from the upper MFGM phase to the lower methanol phase in samples (i) to (v), or that these solutes were extracted by methanol from the MFGM. With different ratios of extractant to MFGM, the methanol phase weight gain was different. This weight gain exhibited a positive correlation with the methanol to MFGM ratio. This is observed from Figure 1 which is based on the mass transfer results. Thus, the feasibility of the extraction process has been established through the observed mass transfer to methanol phase. Sample

number and MFGM Upper layer Methanol Lower layer extractant to weight before weight after weight before weight after gasoline ratio extraction (g) extraction(g) extraction (g) extraction(g) i, 3 to 1 10 1.85 30 38.15 ii, 2 to 1 10 2.96 20 27.04 iii, 1 to 1 10 6.39 10 13.61 iv, 1 to 2 10 8.36 5 6.64 v, 1 to 3 10 9.33 3.33 4

Table 5 - weights of the two phases of samples (i) to (v) before and after extraction

GCMS was employed to identify the amounts of the olefins and thiophene in the upper (MFGM) phase, and to analyze the efficiency of this extractive technology. The GCMS results of the methanol (lower) phase showed peaks in the chromatogram appearing at the retention time of 2.3 min, 3.1 min and 4.6 min which were calibrated by the system as 1- pentene, 1-hexene and thiophene, respectively. These peaks were present in the lower phases of all five samples in the GCMS profiles. The two olefins and thiophene were therefore confirmed to exist in the lower phase of the mixture following the extraction process.

Consequently, the feasibility of the extraction process was confirmed by these GCMS results in the aliquot which demonstrate the existence of 1-pentene, 1-hexene and thiophene.

To determine the effectiveness of this extraction procedure, the upper phase solution of each sample was measured using GCMS. The chromatograms from the GCMS results of the upper (MFGM) phases of samples (i) to (v) are shown in Figure 2. Through these chromatograms, the content of the upper phase mixture can be determined. The peaks for 1- pentene, 1-hexene and thiophene appeared at around 2.3 min, 3.1 min and 4.6 min respectively in the chromatograms. The peaks for the internal standard dimethyl carbonate (DMC), n-octane and ethylbenzene appeared around 3.6 min, 8.6 min and 10.5 min, respectively.

Sampl e composition (wt %)

Compound MFGM i (3 : 1) ii (2: 1) iii (1 : 1) iv (l :2) v (l :3)

1-pentene 6.0 0.9 1.1 1.1 1.5 4.2

1-hexene 12.0 4.0 4.9 5.1 6.0 9.3 thiophene 0.1 0.0 0.0 0.0 0.0 0.0 octane 73.9 90.5 88.8 86.7 83.7 78.3 ethylbenzene 8.0 4.6 5.2 7.1 8.7 8.3

Table 6 - composition of the upper phase of each sample after extraction After the quantitative analysis of these GCMS results, the mass fractions of 1-pentene, 1- hexene, thiophene, n-octane and ethylbenzene in the upper phase were derived. Comparing each compound's mass fraction after the extraction with its original mass fraction in the gasoline phase, the effectiveness of the extraction with different extraction solvent to gasoline proportion was obtained. These results are presented with the data in Table 6 and Figure 3.

The maximum extraction rate occurred for sample (i), wherein the extraction solvent to MFGM ratio was 3 : 1 before the extraction. The reduced mass fractions of 1-pentene, 1- hexene and thiophene were from 6.00% to 0.87%, 12.00% to 3.96% and 0.10% to 0.00%, respectively. The mass fraction of n-octane increased from 73.90% to 90.49%>. Based on the original composition (mass fraction) of each compound in the MFGM:

1) 1-Pentene mass fraction less than 6.00%>;

2) 1-Hexene mass fraction less than 12.00%>;

3) Thiophene mass fraction less than 10 ppm (0.01%>), based on the regulation; and

4) n-octane mass fraction more than 73.90%>; and from the composition results after extraction, the minimum extractant to gasoline ratio for effective extraction is demonstrated to be 1 : 1. With a 1 : 1 extractant ratio, thel-pentene fraction was reduced to 1.05%, 1-hexene fraction was reduced to 5.10%, and thiophene fraction was reduced to zero. However, the n-octane mass fraction was raised 12.76 percentages points compare with the original MFGM. Then, considering the 1-pentene, 1- hexene and thiophene mass fractions in the original MFGM, the gasoline phase olefin and thiophene (OSCs) reduction rate of sample (i) to (v) is shown in Table 7. Moreover, Tables 8 and 9 show the different technologies with various catalysts/processes and their olefin reduction or desulfurization rate after refining, respectively.

Sample i ii iii iv V

Fraction (3 : 1) (2: 1) (1 : 1) (1 :2) (1 :3)

Olefin reduction rate (%) 73.2 66.8 65.8 58.5 25.3

Thiophene (OSCs) reduction rate (%) 100 100 100 94.7 83.3

Table 7 - olefin and thiophene (OSCs) reduction rate for samples (i) to (v) Olefin

content

Original after Olefin Olefin refining reduction

Catalyst content (%) process (%) rate (%)

C0-M0/AI2O3 and -M0/AI2O3 30.3 14 53.795

HZSM-5 39.8 18.3 54.02 nanoscale HZSM-5 (20-50 nm) with Ga ₂ 0 ₃ 49.6 15.1 69.556

SAPO-11 with HZSM-5 41.7 11.1 73.381

HMOR with HZSM-5 41.7 9.8 76.499

Ηβ with HZSM-5 41.7 8.7 79.137

SAPO-11, Ηβ, HMOR with HZSM-5 41.7 6.5 84.412

SAPO-11, HMOR with HZSM-5 41.7 7.3 82.494

Mesoporous Zeolite L (M-L) 33.9 5.15 84.808

SAPO-11, Ηβ with HZSM-5 41.7 6.3 84.892

Table 8. Hydroisomerization and aromatization methods with various catalysts and their olefin reduction rate

Compared with the other catalysts in Table 8, the highest rate olefin reduction rate of 84.892% was obtained by applying a SAPO-11, Ηβ with HZSM-5 catalyst. However, this refining process not only consumes a lot of energy, but also requires severe conditions, such as high temperature, high pressure and a hydrogen reactor. By contrast, the method of the invention demonstrates a high olefin reduction rate of 73.2% and requires far more mild conditions, and the advantages of the extractive approach using an extraction solvent such as methanol are apparent.

Table 9. Different technologies with various processes and their desulfurization (OSCs reduction) rate As for the desulfurization of the MFGM, the novel extractive process of the invention is able to provide a higher organosulfur reduction rate than extractive desulfurization (EDS), prevaporation desulfurization (PV), biodesulfurization (BDS), oxidative desulfurization (ODS) and olefinic alkylation desulfurization (OATS) processes (Table 9).

Moreover, due to the simplicity of the treatment process, this novel process is expected to consume much less energy and have a lower capital or operational cost than

hydrodesulfurization (HDS), adsorptive desulfurization (ADS) and photochemical or photocatalytic desulfurization process during the practical industry application (Table 9). Thus, the inventors have demonstrated that the liquid extraction method of the invention is a highly effective and efficient process for the reduction of alkene content and the reduction of organosulfur content in FCC gasoline.

Example 2 - Reduction of alkene and organosulfur content of commercial FCC gasoline Commercial FCC gasoline

The commercial FCC gasoline was purchased from a petroleum refinery in Hubei, China, and its group composition listed in the Table 2 (also above).

Table 2 - Group composition of commercial FCC gasoline from a refinery

Experimental method for commercial FFC gasoline extraction

The extraction experiment adopted mixing and separating methods. A specific quantity of FCC gasoline and either (a) ethylene glycol or (b) an ME (methanol and ethylene glycol) mixture, were premixed to produce different extracted ratio solutions. Five 10 g commercial FCC gasoline samples were prepared, and different quantities of ethylene glycol were added into these samples. The weight ratios of extractant ethylene glycol to FCC gasoline in each sample are (vi) 3 : 1, (vii) 2: 1, (viii) 1 : 1, (ix) 1 :2 and (x) 1 :3.

Five other 10 g FCC gasoline samples (xi) - (xv) were also prepared using the ME mixture as the extraction solvent. The weight ratios of extractant ME mixture to FCC gasoline in each sample are all equal to 1 : 1. However, different mixing ratios of ethylene glycol to methanol were used for each sample. The ethylene glycol: methanol ratio for each sample was as follows: (xi) 80:20, (xii) 60:40, (xiii) 40:60, (xiv) 20:80, and (xv) 10:90.

After mixing and complete phase separation, these resulting mixtures were separated and analysed. Then, the upper phase and lower phase solutions were weighed and the weights were recorded.

Following the extraction, gas chromatography-mass spectrometry (GCMS) was applied to quantify the paraffin, olefin and aromatics content in the upper phase of each sample. The upper phases of samples (vi) to (xv) were analysed. The GCMS analyser was an AGILENT gas chromatography mass spectrometer.

Results and discussion

Methanol showed excellent olefin reduction and desulfurization performance when dealing with "Model FCC Gasoline Mixture" (MFGM). However, through an initial investigation, it was found the phase separation was not observed when methanol was used as the sole extraction solvent to deal with this specific commercial FCC gasoline.

Therefore, ethylene glycol has been added into methanol to modify its specific extraction properties with FCC gasoline. The extraction effectiveness of ethylene glycol alone with commercial FCC gasoline and the extraction effectiveness of a methanol-ethylene glycol (ME) mixture with commercial FCC gasoline have both been analysed. Through observation by eye of the mixture of extraction solvent and gasoline during the extraction, it was found that the dark content in the upper phase moved to lower phase after the extraction process. This dark content is due to the presence of OSCs. This means the extractant ethylene glycol or extractant ME mixture can extract most of the OSCs content from the FCC gasoline. This can be seen in Figure 4. Sample number Ethylene

and gasoline to FCC gasoline Upper phase glycol weight Lower phase ethylene glycol weight before weight after before weight after ratio extraction (g) extraction (g) extraction (g) extraction(g) vi, 3 to 1 10 10.29 3.33 3.04 vii, 2 to 1 10 10.27 5 4.73 viii, 1 to 1 10 10.68 10 9.32 ix, 1 to 2 10 10.4 20 19.6 x, 1 to 3 10 10.66 30 29.34

Table 10 - weight of phases of samples (vi) to (x) before and after extraction

Sample number

and ethylene FCC gasoline Upper phase ME mixture Lower phase glycol to weight before weight after weight before weight after methanol ratio extraction (g) extraction(g) extraction (g) extraction(g) xi, 80% to 20% 10 10.36 10 9.64 xii, 60% to 40% 10 10.04 10 9.96 xiii, 40% to 60% 10 9.44 10 10.56 xiv, 20% to 80% 10 7.88 10 12.12 xv, 10% to 90% 10 3.24 10 16.76

Table 11 - weight of phases of samples (xi) to (xv) before and after extraction

Moreover, the results of the mass transfer analysis are listed in the Tables 10 and 11. The results listed in the Table 10 indicate that, after extraction, a small weight change is observed for the upper and lower phases of samples (vi) and (x). However, if methanol is used in combination with ethylene glycol as the extractant, the weight change is increased. Based on the mass transfer results in the Table 11, the weight gain of the lower phase after extraction exhibited a positive correlation with the mass fraction of methanol in the extractant ME mixture (Figure 5). Thus, the feasibility of the extraction process and extractant was established through the colour change and the mass transfer of extractant phase.

After the quantitative analysis of the GCMS results, the mass fractions of each group composition in the upper phase were derived. Comparing the mass fraction of each group composition after the extraction with its original mass fraction in the FCC gasoline phase, the effectiveness of the extraction with different ethylene glycol to gasoline/ methanol to ethylene glycol proportion was obtained.

The results of applying ethylene glycol as the extractant are presented with the data in Table 12 and Figure 6. From these results, we find the total fraction of the paraffin has a positive correlation with the amount of the extractant ethylene glycol. Whereas olefin and aromatics content in the upper FCC gasoline phase show a negative correlation with the amount of the ethylene glycol. This means, with larger quantity of the extractant ethylene glycol, we can achieve higher olefin reduction rate.

FCC

Sample name gasoline vi, 3 to 1 vii, 2 to 1 viii, 1 to 1 ix, 1 to 2 x, 1 to 3

Paraffin Wl %

C4 0.76 0 0.732 0 0 0.729 C5 15.928 12.667 12.916 13.716 11.06 11.951 C6 16.6 19.952 20.699 23.553 22.997 21.433 C7 8.516 11.158 11.597 12.815 18.302 18.518 C8 3.881 2.97 4.024 5.695 6.249 7.602

Total 45.685 46.747 49.968 55.779 58.608 60.233

Olefin Wt %

C4 10.178 6.968 3.496 4.318 3.119 2.222 C5 22.19 19.893 24.303 17.584 14.18 20.95 C6 10.808 15.102 13.726 15.121 15.269 10.66 C7 4.204 4.048 2.949 3.35 7.692 4.49 C8 1.888 0 0 0 0 0.575

Total 49.268 46.011 44.474 40.373 40.26 38.897

Aromatics Wt%

C7 3.007 3.599 2.628 1.868 0.564 0.47 C8 1.034 2.95 2.34 1.63 0.568 0.4 C9 1.006 0.693 0.59 0.35 0 0

Total 5.047 7.242 5.558 3.848 1.132 0.87

Table 12 - upper phase composition of each sample after extraction by applying ethylene glycol

Sample name

and ethylene

glycol to

methanol FCC xi, 80% to xii, 60% to xiii, 40% xiv, 20% to xv, 10% to percentage gasoline 20% 40% to 60% 80% 90%

Paraffin Wt %

C4 0.76 0.663 0.951 0 0 0

C5 15.928 10.134 8.63 8.904 20.816 15.819

C6 16.6 17.108 18.553 17.851 15.409 18.144

C7 8.516 13.111 13.374 12.624 13.354 14.373

C8 3.881 4.739 4.483 4.897 1.008 6.753

Total 45.685 45.755 45.991 44.276 50.587 55.089

Olefin Wt %

C4 10.178 8.609 4.925 4.94 6.996 6.168

C5 22.19 20.244 19.86 17.535 16.972 15.388

C6 10.808 8.325 8.899 8.196 7.407 7.026

C7 4.204 4.192 4.052 4.596 4.016 3.633 C8 1.888 1.586 1.682 1.823 1.982 1.442

Total 49.268 42.956 39.418 37.09 37.373 33.657

Aromatics Wt%

C7 3.007 4.315 3.714 4.274 3.396 2.025

C8 1.034 3.619 4.039 7.951 4.55 3.041

C9 1.006 3.355 6.838 6.409 4.094 6.188

Total 5.047 11.289 14.591 18.634 12.04 11.254

Table 13 - upper phase composition of each sample after extraction by applying the ME mixture

Furthermore, the results of applying ME mixture as the extraction solvent are presented with the data in Table 13 and Fig. 7. The mixing ratio between ME mixture and FCC gasoline is fixed, and it is equal to 1 : 1. The ratio of methanol to ethylene glycol in the ME mixture varies for each sample.

Given these GCMS results, combined with the previous mass transfer analysis results with larger proportion of methanol in the extractant ME mixture, the extraction process can obtain a high olefin reduction rate. However, the weight of the FCC gasoline phase is reducing with the increasing methanol proportion in the ME mixture, and this could lead to low gasoline productivity during practical industrial production.

In addition, because aromatics have higher octane number than paraffin and olefin, larger fractions of aromatics in the gasoline represent higher quality of the gasoline. Based on this point of view, it is found that the ME mixture with 60% methanol and 40% ethylene glycol obtains the highest aromatics content (18.634%) after the extraction process. At the same time, applying the ME mixture under this methanol to ethylene glycol ratio also can obtain a relatively high olefin reduction rate and gasoline productivity than the ME mixture with other proportions.

In combining these results, it can be concluded that a high extraction performance under 1 : 1 extractant to FCC gasoline ratio is achieved by applying the ME mixture with 60% methanol and 40%) ethylene glycol.

Example 3 - Reduction of alkene and organosulfur content of commercial FCC gasoline

Commercial FCC gasoline was purchased from a SINOPEC petroleum refinery in Jingmen, Hubei, China, and its group composition listed in the Table 2. The total OSCs concentration of this FCC gasoline is 750 ppm.

- Group composition of commercial FCC gasoline from refinery

Organic solvents with various polarity, Hildebrand and Hansen solubility parameters were introduced into the extraction process and blended with methanol at different ratios. These solvents and their properties are presented in the Table 15, and the polarity of methanol was set to 1 (smallest) and the polarity of DMSO was set to 5 (largest).

Table 15 - Solvent applied in the test and their properties

Methanol, ethylene glycol and glycerol were used with 99.0% purity and were purchased from Sinopharm Chemical Reagent co., Ltd in China. Propylene carbonate and dimethyl sulfoxide were also with 99.0% purity and were purchased from Aladdin Industrial

Corporation.

Experimental methods

Mass transfer analysis

The extraction experiment adopted mixing and separating methods. A specific quantity of FCC gasoline and various solvent mixtures were premixed to produce different extracted ratio solutions. Firstly, twelve 10 g FCC gasoline samples were prepared. Then, twelve 10 g solvent mixtures which consist of methanol and other organic solvents at different mixing ratio were added into these samples. According to their constitution they have been separated into four groups. Table 16 shows all the twelve solvent mixtures and their contents. After mixing and complete phase separation, these resulting mixtures were separated and analysed. The upper (oil) phase and lower (solvent) phase solutions were weighted and recorded, respectively.

Table 16 Twelve solvent mixtures and their contents

Extraction effectiveness: Olefin and aromatics reduction analysis by GCMS

Following the extraction, the Gas Chromatography-Mass Spectrometry (GCMS) method was applied to quantify the paraffin, olefin and aromatics content in the mixture at the upper (oil) phase. Thereupon, the upper phase of (i) to (xii) samples were measured in proper order successively. The GCMS analyser was an AGILENT gas chromatography mass

spectrometer. GC system is Agilent Technologies 7890A; MS system is Agilent

Technologies 5975C inert XL MSD with triple- Axis Detector; column is Agilent + 190915- 433, HP-5MS; split ratio is 75: 1; process is 30°C hold for 2 minutes, then 2°C/min to 80°C, then 5°C/min to 260°C, then 20°C/min to 290°C, then hold 2 minutes; input is Ιμΐ per one injection.

Extraction effectiveness: Desulfurization analysis by Fluorescence OSCs Detector (FOD)

Fluorescence OSCs Detector (FOD) was introduced to quantify the OSCs content in the mixture. After extraction the upper (oil) phase of (i) to (xii) samples were measured in proper order successively. The FOD is ZDS-2000 Fluorescence OSCs Detector from Jiangyan High Tech Analysis Instalment Company. The test was undertaken at atmosphere pressure (1 atm) and room temperature (25°C).

Results and discussions

Colour and mass transfer analysis Through eye-observation of the mixture solution during the extraction, it was found the dark colour content in the upper phase moved to lower phase after the extraction process. This phenomenon occurred in every sample. The dark colour content always consisted of organosulfur compounds (OSCs). From this point of view, it can be initially confirmed that the solvent mixtures can extract OSCs content from the FCC gasoline. Table 17 - The weight of two phase mixture for (i) to (xii) samples before and after extraction

Table 17 ^' - The weight of two phase mixture for (i) to (xii) samples before and after extraction

The results of mass transfer analysis are listed in the Table 17 and shown in Figure 8. With the same constitution (group) of solvent mixture the weight gain of the lower phase after extraction exhibited a positive correlation with methanol's mixing ratio during the extraction process. That means the increasing of the methanol in the solvent mixture can lead to better mass transfer performance.

The mass transfer results indicate that the Hildebrand parameter of solvent mixture also affect the mass transfer (extraction) performance. The Hildebrand parameter of the mixture in this case presents a negative correlation with the performance. Considering the polarity of these solvent mixtures, ethylene glycol and glycerol have similar polarity, DMSO and propylene carbonate have relatively higher polarity. From the above results, after the extraction process, methanol+DMSO and methanol+propylene carbonate sample have relatively heavier lower (solvent) phase than the methanol+ethylene glycol or methanol+glycerol sample. Therefore, the polarity shows positive correlation with the mass transfer performance (negative correlation with the mass loss of the extraction process).

However, the three Hansen parameters of the mixtures do not in this case present a clear trend or relationship to the transfer (extraction) performance.

GCMS analysis Through quantitative analyze of the GCMS results, the mass fractions of each group composition in the upper (oil) phase have been derived. Comparing each the mass fraction of each group composition after the extraction with its original mass fraction in the FCC gasoline, the effectiveness of the extraction with various solvent mixtures is obtained.

Olefin reduction performance The olefin reduction performance results of applying various organic solvent with different mixing ratio as the extractant in the extraction process are presented with the data in Table 17 and Figure 9.

Table 17 - upper (oil) phase olefin mass fraction before and after the extraction From the 1 : 1 mixing ratio results, the total fraction of the olefin content at upper (oil) phase after extraction indicates a negative correlation with the Hildebrand parameter of the solvent mixture. On the contrary, with 3 : 1 mixing ratio, the upper layer olefin content of the sample indicates a positive correlation with the Hildebrand parameter of the solvent mixture. The polarity and Hansen parameters of the solvent mixture do not present a very clear relationship with the olefin content at upper (oil) phase. However, comparing the olefin reduction performance of methanol + DMSO/methanol + propylene carbonate and methanol + ethylene glycol/methanol + glycerol, the results indicate higher polarity does improve the olefin reduction performance. Here, ethylene glycol and glycerol have similar polarity, DMSO and propylene carbonate have relatively higher polarity.

Regarding the mixing ratio influence, the result shows that the extraction process can achieve better olefin reduction performance with larger mixing ratio of methanol to another solvent. However, the result of the methanol + glycerol group does not so clearly follow this relationship. This is because, apart from glycerol, all of the other solvents have smaller or very similar Hildebrand parameters compared with the major solvent methanol. Therefore, only in the methanol + glycerol case when methanol to glycerol ratio increases, the solvent mixture's overall Hildebrand parameter decreases. For the other solvent mixtures the Hildebrand parameter is increasing or balancing under this circumstance. Hence, comparde with the others, the olefin reduction performance of methanol + glycerol becomes less efficient when the methanol mixing ratio increases.

Moreover, considering the economical efficiency and sustainability of the process, the use of methanol as the main solvent is preferable. With a higher mixing ratio the process can achieve more efficient olefin reduction performance and better olefin reduction performance can be achieved when a solvent mixture with smaller Hildebrand parameter and higher mixing ratio of methanol is used.

Aromatics reduction performance

The aromatics reduction performance results of applying various organic solvent with different mixing ratio in the extraction process are presented with the data in Table 18 and Figure 10. Mixing ratio Polarity Hildebrand Hansen solubility Mixing ratio

parameter parameters

(MPa ^1/2 ) (MPa ^1/2 ) 1 to 1 2 to 1 3 to 1

5 _d δ _Ρ 5 _h Aromatics (wt%)

Original FCC 55.32 55.32 55.32 gasoline

Methanol + 3 33.8 17.4 12.1 29.3 55.61 54.47 52.65

Glycerol

Methanol + 2 29.9 17.0 1 1.0 26.0 53.62 53.03 52.47

Ethylene

glycol

Methanol + 5 24.5 18.4 16.4 10.2 49.52 49.23 48.84

DMSO

Methanol + 4 27.2 20.0 18.0 4.1 47.96 47.59 47.21

Propylene

carbonate

Table 18 - Upper (oil) phase aromatics mass fraction before and after the extraction

Similar to the olefin reduction data, compared to the lower polarity solvent mixtures methanol + ethylene glycol and methanol + glycerol, mixtures with relatively higher polarity (methanol + DMSO and methanol + propylene carbonate) achieve better aromatics reduction performance. The Hildebrand parameter does not show an obvious connection to the reduction of the aromatics content at upper (oil) phase.

Compare to these two factors, the behaviour of the Hansen parameters indicates some difference. When the solvent mixture gets larger electron exchange parameter <¾, its aromatics reduction performance becomes less efficient. The dispersion interactions parameter Sd and the polar cohesive energy parameter Sd of the Hansen parameters do not display any obvious trend with the performance.

Furthermore, in each group higher methanol mixing ratio leads better aromatics reduction performance. This phenomenon is most obvious for the methanol + glycerol group. It is because when the methanol mixing ratio increasing the methanol + glycerol group' s overall Hildebrand parameter decreases. The trend is the sharpest for this group. Lower Hildebrand parameters for the solvent mixture can cause better aromatics reduction performance and the aromatics reduction performance of the methanol+glycerol group shows the most obvious development when the methanol mixing ratio is increasing. Fluorescence OSCs Detector (FOD) analysis Desulfurization performance

As the reason of DMSO contains sulphur itself. That means it will bring sulphur to the FCC gasoline during the extraction process. Therefore, DMSO is not considered in the

desulfurization process. The desulfurization performance results of applying various organic solvent except DMSO with different mixing ratio in the extraction process are presented with the data in Table 19 and Figure 11.

Table 19 - upper (oil) phase OSCs concentration before and after the extraction

The polarity of the solvent mixture does not present a clear relationship with its

desulfurization performance. However, higher polarity solvents do have some improvements for the desulfurization performance. These can be observed when comparing the results of methanol + glycerol/methanol + ethylene glycol and methanol + propylene carbonate.

Glycerol and ethylene glycol have very similar polarity. When they are mixed with methanol they present similar desulfurization performance. Compared to glycerol and ethylene glycol, propylene carbonate has relatively higher polarity and it shows relatively better

desulfurization performance. From this point of view, it can be concluded that the polarity has a positive correlation with the desulfurization performance of the solvent mixture (extractant).

Unlike the influence of polarity, the Hildebrand parameter of the solvent mixture shows a negative correlation with the desulfurization performance. When Hildebrand parameter of the solvent mixture is lower, more OSCs can be extracted to the lower (solvent) phase by the extractant (solvent mixture). This procedure is easier for an extractant with a relatively low Hildebrand parameter compared with an extractant having a higher Hildebrand parameter.

Similar to the Hildebrand parameter, the electron exchange parameter δη of the Hansen parameters also shows a negative correlation with the desulfurization performance. On the other aspect, the results indicate higher methanol ratio in the solvent mixture leads better desulfurization performance.

Conclusion

In Example 3, the feasibility and effectiveness of applying methanol blend with various organic solvents as the extractant (solvent mixture) in the FCC gasoline extractive purification process has been investigated. The analysis data represent very positive results.

After analysis of all the results from the tests, it can be concluded that polarity shows complex relationship to the olefin, aromatics reduction and desulfurization performance. However, solvent mixtures with relatively higher polarity do improve all these performances to a greater extent than the lower polarity mixtures. The gasoline mass loss of the extraction process increases with the growing polarity/mixing ratio and decreasing Hildebrand parameter of the extractant (solvent mixture). On the other hand, at higher methanol mixing ratios, Hildebrand solubility parameter of the solvent shows negative correlation with olefin reduction and desulfurization efficiency. The aromatics reduction and desulfurization performance indicate similar negative trends with the electron exchange parameter Sh of the Hansen parameters. In addition, higher methanol mixing ratios lead to better overall purification performance.

Based on the above conclusion, it could be proposed that, while a wide range of solvents are suitable, the ideal solvent mixture (extractant) of the extraction process should has relatively high polarity, relatively low Hildebrand solubility parameter and low electron exchange parameter Sh of the Hansen parameters. Therefore, with the advantages of efficient olefin/aromatics reduction and desulfurization performance and relatively low mass loss of the FCC gasoline phase, a solvent mixture consist of about 75% methanol and about 25% ethylene glycol exhibited relatively better performance than all the other solvent mixtures in the extraction process.