BACKGROUND

[0001] This application relates to fuel additives for a gasoline, a gasoline comprising the additives, and methods of making the gasoline.

[0002] Commercial gasoline, which is fuel for internal combustion engines, is a refined petroleum product that is typically a mixture of hydrocarbons (base gasoline), additives, and blending agents. Additives and blending agents are added to the base gasoline to enhance the performance and the stability of gasoline, for example octane boosters.

[0003] When used in high compression internal combustion engines, gasoline has the tendency to "knock." Knocking occurs when combustion of the air/fuel mixture in the cylinder does not start off correctly in response to ignition because one or more pockets of air/fuel mixture pre-ignite outside the envelope of the normal combustion front. Anti-knocking agents, also known as octane boosters, reduce the engine knocking phenomenon, and increase the octane rating of the gasoline. Prior octane boosters such as tetraethyl lead and

methylcyclopentadienyl manganese tricarbonyl (MMT) have been or are being phased out for environmental, health, or other reasons.

[0004] Preferred compounds in present use for formulating octane boosters include C ₄ oxygenate compounds such as methyl ie/ -butyl ether (MTBE), ethyl ie/ -butyl ether (ETBE), and ft-butanol and its isomers. However, the production and storage of the large quantities of these materials at oil refineries can be costly. In addition, limitations on the use of high concentrations of additives by regulatory mandate increase the difficulty and expense of refining operations that produce high-octane fuels. There is a need for a fuel additive or fuel that has an octane rating that is comparable to gasoline and that has increased combustion efficiency.

[0005] In view of the foregoing, there remains a need to provide cost-effective octane- enhancing compositions, and gasoline compositions including the octane-enhancing

compositions.

BRIEF DESCRIPTION

[0006] An unleaded gasoline composition comprises 55 to 98 volume percent of an unleaded gasoline; and 2 to 30 volume percent of a distillate oil fraction comprising, a paraffin, an olefin, a naphthene, and an aromatic at an initial boiling point cut of 180 °C, wherein the unleaded gasoline and the distillate oil fraction are selected to provide the unleaded gasoline composition with a Research Octane Number (RON) of 91 to 101, determined in accordance with ASTM D2699; and a Motor Octane Number (MON) of 81.4 to 90, determined in accordance with ASTM D2700.

[0007] The above described and other features are exemplified by the following figures, detailed description, examples, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following figures are exemplary embodiments, which are non-limiting.

[0009] FIG. 1 is a bar chart showing RON and MON for a base gasoline and gasoline blends of the base gasoline with 10 volume percent (vol. %) oil fraction 1, 2, 3, or 4,

respectively.

[0010] FIG. 2 is a graph showing distillation profiles, determined in accordance with ASTM D86, of a base gasoline, three gasoline blends, and an ASTM D86 distillation standard.

[0011] FIG.3 is a bar chart showing RON for a base gasoline and gasoline blends of the base gasoline with 10 or 20 vol. % oil fraction 1, 2, 3, or 4, respectively.

[0012] FIG.4 is a bar chart showing Reid vapor pressure (Rvp) for a base gasoline and gasoline blends of the base gasoline with 10 or 20 vol. % oil fraction 1, 2, 3, or 4, respectively.

DETAILED DESCRIPTION

[0013] Disclosed herein are octane-boosting fuel additives comprising specific distillate oil fractions, unleaded gasoline compositions including the octane-boosting fuel additives, and methods of making the unleaded gasoline compositions. The distillate oil fractions can be obtained from steam cracking and other petrochemical production processes. Addition of one of the distillate oil fractions to an unleaded gasoline results in a gasoline composition having higher Research Octane Number (RON) and the Motor Octane Number (MON) values compared to the RON and MON values of the unleaded gasoline without the distillate oil fraction, providing better combustion and improved performance in internal combustion engines, particularly for the automotive market. Additionally, the gasoline composition is characterized by a lower Reid vapor pressure (Rvp) than the unleaded gasoline without the distillate oil fraction.

[0014] An unleaded gasoline composition comprises 55 to 98 volume percent (vol. %) of an unleaded gasoline and 2 vol. % to 30 vol. %, or 5 vol. % to 20 vol. % of a distillate oil fraction disclosed herein, based on the total volume of the unleaded gasoline composition. The distillate oil fraction comprises a paraffin, an olefin, a naphthene, and an aromatic at an initial boiling point cut of 180 °C. The unleaded gasoline and the distillate oil fraction are selected to provide the unleaded gasoline composition with a RON in the range 90 to 101, and MON in the range 81.4 to 90.

[0015] The unleaded gasoline can comprise greater than 50 vol. % of hydrocarbons having a boiling point of 30 to 230°C.

[0016] RON describes knocking behavior at a low engine load and low rotational speeds and is determined according to ASTM D2699.

[0017] The unleaded gasoline composition can have a RON at least 0.5 point higher, or at least 1.0 point higher, or at least 1.5 points higher than the RON of the unleaded gasoline without the distillate oil fraction. The unleaded gasoline composition can have a RON that is 0.5 to 20, or 1 to 15, or 1.5 to 10 points higher than the RON of the unleaded gasoline without the distillate oil fraction.

[0018] MON describes knocking behavior at a high engine load and under high thermal stress and is determined according to ASTM D2700.

[0019] The unleaded gasoline composition can have a MON at least 0.4 point higher, or at least 0.6 point higher, or at least 0.8 point higher than the MON of the unleaded gasoline without the distillate oil fraction. The unleaded gasoline composition can have a MON that is 0.4 to 10, or 0.6 to 8, or 0.8 to 5 points higher than the MON of the unleaded gasoline without the distillate oil fraction.

[0020] Rvp is a measure of the volatility of gasoline. It is defined as the absolute vapor pressure exerted by a liquid (e.g., gasoline) at 100°F (37.8°C) as determined by test method ASTM D323.

[0021] The unleaded gasoline composition can have an Rvp lower than the unleaded gasoline without the distillate oil fraction. The unleaded gasoline composition can be characterized as having an Rvp of 5.8 to 8.0 pounds per square inch (psi), or 6.0 to 7.0 psi. The unleaded gasoline composition can have an Rvp at least 0.3 psi lower, at least 0.4 pound psi lower, at least 0.5 psi lower, at least 0.7 psi lower, at least 0.9 pound psi lower, or at least at least 1.0 pound psi lower than the Rvp of the unleaded gasoline without the distillate oil fraction.

[0022] The distillate oil fraction can have a RON of 112 to 117.

[0023] The composition of the distillate oil fraction can comprise 0.08 to 5 volume percent of n-paraffins; 24 to 58 volume percent of iso-paraffins; 0.3 to 12 volume percent of olefins; 2 to 20 volume percent of naphthenes; and 20 to 65 volume percent of aromatics, determined in accordance with ASTM D6730. Preferably, the composition of the distillate oil fraction comprises 0.5 to 1.5 volume percent of n-paraffins, 38 to 58 volume percent of iso- paraffins, 0.6 to 1.9 volume percent of olefins, 4 to 12 volume percent of naphthenes, and 30 to 45 volume percent of aromatics; 0.2 to 0.6 volume percent of n-paraffins, 25 to 45 volume percent of iso-paraffins, 0.8 to 2.4 volume percent of olefins, 7 to 21 volume percent of naphthenes, and 35 to 56 volume percent of aromatics; 0.2 to 0.6 volume percent of n-paraffins, 19 to 39 volume percent of iso-paraffins, 4.5 to 13.5 volume percent of olefins, 2.2 to 6.8 volume percent of naphthenes, and 42 to 62 volume percent of aromatics; or 0.15 to 0.5 volume percent of n-paraffins, 25 to 46 volume percent of iso-paraffins, 2.4 to 7.2 volume percent of olefins, 1.8 to 5.6 volume percent of naphthenes, and 41 to 61 volume percent of aromatics.

[0024] The unleaded gasoline composition can further comprise 1 to 15 volume percent of an octane booster comprising a monoaromatic compound, alcohol, ester, or ether. The octane booster can comprise xylene, benzene, toluene, aniline, ethanol, methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutanol, n-butanol, sec-butyl alcohol, tert-butyl alcohol, tert-amyl alcohol, tert-pentanol, isoamyl acetate, amyl acetate, isoamyl propionate, isoamyl nonanoate, isobutyl acetate, methyl butyrate, methyl caproate, methyl caprylate, ethyl tert-butyl ether, tert- amyl methyl ether, tert-amyl ethyl ether, tert-hexyl methyl ether, diisopropyl ether, methyl tert- butyl ether, or a combination comprising at least one of the foregoing; preferably ethyl tert-butyl ether, tert-amyl methyl ether, tert-amyl ethyl ether, tert-hexyl methyl ether, diisopropyl ether, methyl tert-butyl ether or a combination comprising at least one of the foregoing. In certain embodiments, the octane booster does not contain methyl tert-butyl ether.

[0025] The unleaded gasoline composition can be prepared by combining an unleaded gasoline and a distillate oil fraction disclosed herein, and optionally an additional octane booster or other additive, either separately or in any combination.

[0026] The distillate oil fraction can be added directly to the unleaded gasoline.

However, the distillate oil fraction can be diluted with a substantially inert, normally liquid organic diluent such as mineral oil, naphtha, benzene, toluene, or xylene, to form an additive concentrate. These concentrates can comprise 0.1 to 80% by weight, or 1% to 80% by weight, or 10% to 80% by weight, of the distillate oil fraction and can contain, in addition, one or more other additives known in the art as described below. Concentrations such as 15%, 20%, 30% or 50% or higher can be used. The concentrates can be prepared by combining the desired components in any order at any temperature, for example at 23 to 70 °C.

[0027] The additive concentrate or the unleaded gasoline composition can further comprise other additives known in the art, for example an additional octane-booster as disclosed above, anti-foam agents, anti-icing agents, additional anti-knock agents, anti-oxidants, anti-wear agents, color stabilizers, corrosion inhibitors, detergents, dispersants, dyes, extreme pressure agents, lead scavengers, metal deactivators, pour point depressing agents, upper-cylinder lubricants, viscosity improvers, and the like. The amounts of such additives depend on the particular additive, and can be readily determined by one of ordinary skill in the art.

[0028] Anti-foam agents used to reduce or prevent the formation of stable foam include silicones or organic polymers. Anti-oxidants, corrosion inhibitors, and extreme pressure agents are exemplified by chlorinated aliphatic hydrocarbons, organic sulfides and polysulfides, phosphorus esters including dihydrocarbon and trihydrocarbon phosphites, molybdenum compounds, and the like. Other anti-oxidants alkylated diphenyl amines, hindered phenols, especially those having tertiary alkyl groups such as tertiary butyl groups in the position ortho to the phenolic— OH group, and the like.

[0029] Detergents and dispersants can be of the ash-producing or ashless type. The ash- producing detergents are exemplified by oil-soluble neutral and basic salts of alkali or alkaline earth metals with sulfonic acids, carboxylic acids, phenols, or organic phosphorus acids characterized by a least one direct carbon-to-phosphorus linkage. Ashless detergents and dispersants can yield a nonvolatile residue such as boric oxide or phosphorus pentoxide upon combustion, but do not ordinarily contain metal and therefore does not yield a metal-containing ash on combustion. Examples include reaction products of carboxylic acids (or derivatives thereof) containing 34 to 54 carbon atoms with nitrogen containing compounds such as amine, organic hydroxy compounds such as phenols and alcohols, and/or basic inorganic materials.

[0030] Viscosity improvers are usually polymers, for example polyisobutenes, poly(methacrylic acid esters), hydrogenated diene polymers, polyalkyl styrenes, esterified styrene-maleic anhydride copolymers, hydrogenated alkenylarene-conjugated diene copolymers, and polyolefins.

[0031] This disclosure is further illustrated by the following examples, which are non- limiting.

EXAMPLES

[0032] The following test methods were used in the Examples.

[0033] Reid vapor pressure (Rvp) is a measure of the volatility of gasoline. It is defined as the absolute vapor pressure exerted by a liquid (e.g., gasoline) at 100°F (37.8°C) as determined by test method ASTM D323.

[0034] Research octane number (RON) describes knocking behavior at a low engine load and low rotational speeds and is determined according to ASTM D2699.

[0035] Motor octane number (MON) describes knocking behavior at a high engine load and under high thermal stress and is determined according to ASTM D2700. [0036] A base unleaded gasoline comprising a major amount of hydrocarbons boiling in the range from 30 °C to 230 °C and having the properties shown in Table 1 was used in the Examples.

[0037] Compositions of the various fractions were determined by gas chromatography followed by mass spectrometry.

Table 1. Typical Physical Properties of Base Gasoline

[0038] The composition of the distillate oil fractions used in the Examples, determined in accordance with ASTM D6730, is shown in Table 2.

Table 2. Composition (ASTM D6730) of Distillate Oil Fractions

IBP -Initial Boiling point

Examples 1-4

[0039] In Examples 1 to 4, the base gasoline was formulated with 10% by volume of oil fractions 1-4, each based on the total volume of the gasoline composition. The RON and MON of the base gasoline and Examples 1 to 4 are shown in FIG. 1. As can be seen from FIG. 1, both RON and MON are improved by the addition of oil fractions 1-4.

Examples 5-6

[0040] Oil fractions capable of boosting the octane rating of the base gasoline were selected for further study. The oil fractions are soluble in the base gasoline when blended at up to at least 20 vol. % of the blend. The distillation profiles of the base gasoline and blends of the base gasoline with 20 vol. % of oil fraction 1, 2, or 4, respectively, determined in accordance with ASTM D86, are shown graphically in FIG. 2. FIG. 2 also shows the distillation profile of an ASTM D86 distillation standard for unleaded gasoline (30-212°C). Table 3 tabulates temperature data from the distillation profiles shown in FIG. 2 for the initial boiling point (IBP), final boiling point (FBP), and at 10%, 50%, and 90% recovered.

Table 3. Distillation temperature value (D86)

IFB - Initial boiling point; FBP - Final boiling point.

[0041] As can be seen from FIG. 2, blends of the base gasoline with 20 vol. % of the oil fractions boil in the same range as the base gasoline. Addition of 20 vol. % of an oil fraction with the characteristics in Table 1 to the base gasoline does not alter the distillation temperature at 10 % or 50 % recovered dramatically from that of the base gasoline at 10 % or 50 % recovered.

[0042] In addition, the overall properties of the gasoline compositions, in particular RON and MON, show incremental improvement as the amount of the oil fraction in the blend increases from 10 to 20 vol. %. In a further advantage, the Rvp of the gasoline compositions drops. RON, measured in accordance with ASTM D2699, and Rvp, measured in accordance with ASTM D323, for the base gasoline and for gasoline blends including 10 vol. % or 20 vol. % of oil fraction 1, 2, 3, or 4 are tabulated in Table 4 below and shown graphically in FIGS. 3 (RON) and 4 (Rvp).

Table 4. RON & Rvp data for gasoline blends

Composition RON Rvp

20% Oil fraction-2 + 80% Base gasoline 93 5.95

10% Oil fraction-3 + 90% Base gasoline 91.8 6.34

20% Oil fraction-3 + 80% Base gasoline 93 6.1

10% Oil fraction-4 + 90% Base gasoline 91.3 6.45

20% Oil fraction-4 + 80% Base gasoline 91.8 6.25

[0043] Accordingly, use of the distillate oil fractions as described herein can provide unleaded gasoline compositions having octane numbers and other properties similar to gasoline blended with MTBE, but with a lower Rvp. The unleaded gasoline compositions comprising a distillate oil fraction disclosed herein have the advantage of increased RON and MON, for improved combustion and performance, while having lower Rvp which has the advantage of reducing evaporative emissions from gasoline that contribute to ground-level ozone, thereby diminishing the effects of ozone-related health problems.

[0044] This disclosure further encompasses the following aspects.

[0045] Aspect 1. An unleaded gasoline composition comprises 55 to 98 volume percent of an unleaded gasoline; and 2 to 30 volume percent of a distillate oil fraction comprising, a paraffin, an olefin, a naphthene, and an aromatic at an initial boiling point cut of 180 °C, wherein the unleaded gasoline and the distillate oil fraction are selected to provide the unleaded gasoline composition with a Research Octane Number of 90 to 101, determined in accordance with ASTM D2699; and a Motor Octane Number of 81.4 to 90, determined in accordance with ASTM D2700.

[0046] Aspect 2. The unleaded gasoline composition of aspect 1, wherein the Research Octane Number of the unleaded gasoline composition is at least 0.8 point higher, or at least 1.0 point higher, or at least 1.5 points higher than the Research Octane Number of the unleaded gasoline without the distillate oil fraction; or the Motor Octane Number of the unleaded gasoline composition is at least 0.4 point higher, or at least 0.5 point higher, or at least 0.8 point higher than the Motor Octane Number of the unleaded gasoline without the distillate oil fraction.

[0047] Aspect 3. The unleaded gasoline composition of aspect 1 or 2, having a Reid Vapor Pressure, determined in accordance with ASTM D323, lower than the unleaded gasoline without the distillate oil fraction.

[0048] Aspect 4. The unleaded gasoline composition of aspect 3, having a Reid Vapor Pressure at least 0.3 pound per square inch lower, at least 0.4 pound per square inch lower, at least 0.5 pound per square inch lower, at least 0.7 pound per square inch lower, at least 0.9 pound per square inch lower, or at least at least 1.0 pound per square inch lower than the Reid Vapor Pressure of the unleaded gasoline without the distillate oil fraction.

[0049] Aspect 5. The unleaded gasoline composition of any one or more of aspects 1 to 4, wherein the unleaded gasoline comprises greater than 50 volume percent of hydrocarbons having a boiling point of 30 to 230°C.

[0050] Aspect 6. The unleaded gasoline composition of any one or more of aspects 1 to

5 wherein the distillate oil fraction has a Research Octane Number of 112 to 117.

[0051] Aspect 7. The unleaded gasoline composition of any one or more of aspects 1 to

6 wherein the composition of the distillate oil fraction, determined in accordance with ASTM D6730, comprises 0.08 to 5 volume percent of n-paraffins; 24 to 58 volume percent of iso- paraffins; 0.3 to 12 volume percent of olefins; 2 to 20 volume percent of naphthenes; and 20 to 65 volume percent of aromatics.

[0052] Aspect 8. The unleaded gasoline composition of any one or more of aspects 1 to

7 wherein the compositions of the distillate oil fraction, determined in accordance with ASTM D6730, comprises 0.5 to 1.5 volume percent of n-paraffins; 38 to 58 volume percent of iso- paraffins; 0.6 to 1.9 volume percent of olefins; 4 to 12 volume percent of naphthenes; and 30 to 45 volume percent of aromatics

[0053] Aspect 9. The unleaded gasoline composition of any one or more of aspects 1 to 7 wherein the composition of the distillate oil fraction, determined in accordance with ASTM D6730, comprises 0.2 to 0.6 volume percent of n-paraffins; 25 to 45 volume percent of iso- paraffins; 0.8 to 2.4 volume percent of olefins; 7 to 21 volume percent of naphthenes; and 35 to 56 volume percent of aromatics.

[0054] Aspect 10. The unleaded gasoline composition of any one or more of aspects 1 to 7 wherein the composition of the distillate oil fraction, determined in accordance with ASTM D6730, comprises 0.2 to 0.6 volume percent of n-paraffins; 19 to 39 volume percent of iso- paraffins; 4.5 to 13.5 volume percent of olefins; 2.2 to 6.8 volume percent of naphthenes; and 42 to 62 volume percent of aromatics.

[0055] Aspect 11. The unleaded gasoline composition of any one or more of aspects 1 to 7 wherein the compositions of the distillate oil fraction, determined in accordance with ASTM D6730, comprises 0.15 to 0.5 volume percent of n-paraffins; 25 to 46 volume percent of iso- paraffins; 2.4 to 7.2 volume percent of olefins; 1.8 to 5.6 volume percent of naphthenes; and 41 to 61 volume percent of aromatics. [0056] Aspect 12. The unleaded gasoline composition of any one or more of aspects 1 to 11, further comprising 1 to 15 volume percent of an octane booster comprising a

monoaromatic compound, alcohol, ester, or ether.

[0057] Aspect 13. The unleaded gasoline composition of aspect 12, wherein the octane booster comprises xylene, benzene, toluene, aniline, ethanol, methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutanol, n-butanol, sec-butyl alcohol, tert-butyl alcohol, tert-amyl alcohol, tert-pentanol, isoamyl acetate, amyl acetate, isoamyl propionate, isoamyl nonanoate, isobutyl acetate, methyl butyrate, methyl caproate, methyl caprylate, ethyl tert-butyl ether, tert- amyl methyl ether, tert-amyl ethyl ether, tert-hexyl methyl ether, diisopropyl ether, methyl tert- butyl ether, or a combination comprising at least one of the foregoing.

[0058] Aspect 14. The unleaded gasoline composition of aspect 13, wherein the octane booster comprises ethyl tert-butyl ether, tert-amyl methyl ether, tert-amyl ethyl ether, tert-hexyl methyl ether, diisopropyl ether, methyl tert-butyl ether or a combination comprising at least one of the foregoing.

[0059] Aspect 15. The unleaded gasoline composition of aspect 12, wherein the octane booster does not contain methyl tert-butyl ether.

[0060] Aspect 16. The unleaded gasoline composition of any one or more of aspects 1 to 15, further comprising a dispersant, viscosity adjuster, oxidation inhibiting agent, corrosion inhibiting agent, pour point depressing agent, extreme pressure agent, anti-wear agent, color stabilizer, anti-foam agent, or a combination comprising at least one of the foregoing.

[0061] Aspect 17. A method for preparing a gasoline composition, comprising combining a base gasoline and a distillate oil fraction o to form the gasoline composition of any one or more of aspects 1 to 16.

[0062] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of, any appropriate materials, steps, or components herein disclosed. The compositions, methods, and articles can additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any materials (or species), steps, or components, that are otherwise not necessary to the achievement of the function or objectives of the compositions, methods, and articles.

[0063] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other (e.g., ranges of "up to 25 wt.%, or, more specifically, 5 wt.% to 20 wt.%", is inclusive of the endpoints and all intermediate values of the ranges of "5 wt.% to 25 wt.%," etc.). "Combinations" is inclusive of blends, mixtures, reaction products, and the like. The terms "a" and "an" and "the" do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. "Or" means "and/or" unless clearly stated otherwise. Reference throughout the specification to "some aspects", "an aspect", and so forth, means that a particular element described in connection with the aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects.

[0064] Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

[0065] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0066] While particular aspects have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.