PROCESS FOR THE PRODUCTION OF A HYDROCARBON

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application takes priority from US provisional application Serial No. 60/987,461 , filed November 13, 2007 and US provisional application Serial No. 61/040,385, filed March 28, 2008, the disclosure of both applications is hereby incorporated by reference to the extent not inconsistent with the disclosure herein.

STATEMENT ON FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not applicable.

BACKGROUND OF THE INVENTION

[0003] This invention relates to a process for preparing hydrocarbons and in particular to a process for alkane homologation from methanol and/or dimethyl ether.

[0004] Hydrocarbons may be produced by homologation of methanol and/or dimethyl ether. For example, US4059626 describes a process for the production of triptane (2,2,3- trimethylbutane) comprising contacting methanol, dimethyl ether or mixtures thereof with zinc bromide. US4059627 describes a process for the production of triptane from methanol, dimethyl ether or mixtures thereof using zinc iodide. WO02070440 relates to a continuous or semi-continuous process for the production of triptane and/or thptene from methanol and/or dimethyl ether in which co-produced water is removed from the reactor as the reaction proceeds. WO05023733 relates to a process for the production of branched chain hydrocarbons which comprises reacting methanol and/or dimethyl ether with a catalyst comprising indium halide. WO06023516 relates to a process for the production of branched chain hydrocarbons which comprises reacting methanol and/or dimethyl ether with a catalyst comprising a metal halide selected from rhodium halide, iridium halide and combinations thereof.

[0005] Pearson in J. C. S. Chem Comm. 1974 p397 relates to conversion of methanol or trimethyl phosphate to hydrocarbons by heating in phosphorus pentoxide or polyphosphoric acid.

[0006] Kaeding et al in J Catal. 61 , 155-164 (1980) relates to conversion of methanol to water and hydrocarbons over ZSM-5 zeolite modified with phosphorus compounds. US3972832 relates to phosphorus containing zeolites.

[0007] Adamantane was reported to increase hydride transfer rates and reduce cracking in alkane isomehzation reactions using sulfated zirconia Pt/ZrO2-SO4 catalysts. (Iglesia "Isomerization of alkanes of sulfated zirconia: Promotion by Pt and by Adamantyl Hydride Transfer Species," J. Catalysis, 144, 238-253 (1993); Soled "Modification of isomerization activity and selectivity over sulfated zirconia catalysts" Studies in Surface Science and Catalysis, Acid-Base Catalysis II, Proceedings of the International Symposium on Acid-Base Catalysis II, Sapporo, December 2-4, 1993, pages 531 -536). Adamantane was reported to catalyze hydride transfer in isomerization of alkanes in strong acids (Kramer "Catalysis of hydride transfer in strong acids," Tetrahedron, 42(4) 1071 -1077 (1986); Re.33,080; US 3839490; US3803263; US4162233).

[0008] There remains a need for an alternative and/or improved process for production of hydrocarbons from methanol and/or dimethyl ether.

SUMMARY OF THE INVENTION

[0009] According to the present invention there is provided a process for the production of a hydrocarbon which process comprises contacting, in a reactor, a reactive alkane; a methylating agent; an optional diamondoid modifier and an activating catalyst, thereby generating a hydrocarbon product having a greater number of carbon atoms than the reactive alkane. Generating a "heavier" product from a "lighter" reactant is important for many processes. The reactive alkane can be generated by a reactive alkane precursor that generates the reactive alkane by, for example, a pyrolysis reaction, a cracking reaction, an isomerization reaction, or a combination thereof. In one embodiment, the reactive alkane can have from four to twenty carbon atoms. In one embodiment, there are from four to fifteen carbons in the reactive alkane. In one embodiment, there are from four to six carbon atoms in the reactive alkane. In one embodiment, there are from 4 to 10 carbons in the reactive alkane. In one embodiment, the reactive alkane contains a tertiary carbon.

In one embodiment, the reactive alkane is generated from a reactive alkane precursor. In one embodiment the reactive alkane precursor has from 4 to 10 carbons. In one embodiment, the reactive alkane precursor has at least one tertiary carbon and from 8 to 20 total carbon atoms.

[0010] In one embodiment, the reactive alkane is non-cyclic. In one embodiment, the reactive alkane contains a tertiary carbon and is non-cyclic. In one embodiment, the homologation reaction is carried out in more than one step, for example, a reactive alkane or reactive alkane precursor, optional diamondoid modifier and activating catalyst can be pre-reacted for a period of time, then a methylating agent can be added.

[0011 ] Suitable conditions for the process of the present invention are described for example in International Publication Nos. WO02070440, WO05023733 and WO06023516 the contents of which are incorporated by reference. The present methods provide both continuous and semi-continuous processes for the production of hydrocarbons. In some embodiments, for example, the process of the present invention is carried out at a temperature greater than 100 degrees Celsius. Preferably for some applications, the process of the present invention is carried out at a temperature selected over the range of 100 degrees Celsius to 450 degrees Celsius, and more preferably for some applications at a temperature selected over the range of 150 degrees Celsius to 350 degrees Celsius. For some applications when InI ₃ is used as an activating catalyst, the process of the present invention is carried out at a temperature selected over the range of 150 to 250 degrees Celsius. For some applications when InI ₃ is used as an activating catalyst, the process of the present invention is carried out at a temperature selected over the range of 160 to 220 degrees Celsius. For some applications when InI ₃ is used as an activating catalyst, the process of the present invention is carried out at a temperature selected over the range of 170 to 210 degrees Celsius. For some applications when a zinc halide is used as an activating catalyst, the process of the present invention is carried out at a temperature selected above 200 degrees Celsius. For some applications when a zinc halide is used as an activating catalyst, the process of the present invention is carried out at a temperature selected above 220 degrees

Celsius. It is understood that the temperature ranges exemplified are not intended to limit the useful temperature range.

[0012] Activating catalysts useful in the present methods include indium halide or a mixture of indium halide and other metal halides such as zinc halide, rhodium halide and iridium halide. Other activating catalysts useful in the present methods include zinc halide or a mixture of zinc halide and other metal halides such as indium halide, rhodium halide and iridium halide. Other activating catalysts useful in the present methods include catalysts that can activate the alkane and cause methylation. In one embodiment, Lewis acids or Brønsted acids may be used as activating catalysts, alone or in combination with other activating catalysts, such as those catalysts described herein and known to the art. There may be one or more catalysts used in the present methods. As will be understood by those having skill in the art, the catalyst compounds useful in the present invention may be present in a solvated or dissolved form comprising one or more cations and ions, such as metal cations and halogen anions, may be present in the form of a metal salt, or may be present in both a solvated or dissolved form and in the form of a metal salt. Metal halide catalysts used herein may be completely dissolved or may be provided in solid and dissolved states. The metal halide may be directly introduced into the reactor or may be formed in-situ by reaction of a metal source and halide source.

[0013] In one embodiment, the metal halide of the present methods is selected from the group consisting of: zinc halide, iridium halide, rhodium halide, indium halide or any combinations of these. In an embodiment of this aspect of the present invention, the metal halide catalyst of the present methods is selected from the group consisting of: ZnI ₂ , ZnBr ₂ , ZnCI ₂ , InI ₃ , InBr ₃ , InCI ₃ , RhI ₃ , RhBr ₃ , RhCI ₃ , IrI ₃ , IrBr ₃ , IrCI ₃ or any combinations of these.

[0014] In some embodiments, selection of the composition of the metal halide provides a means of selectively adjusting the branching and product distribution(s) of the hydrocarbons generated using the present methods.

[0015] The catalyst comprising metal halide, may be maintained in an active form and in an effective concentration in the reactor by recycling to the reactor, halide

compounds, such as for example hydrogen iodide and/or methyl iodide from downstream product recovery stage(s), such as described in WO02070440.

[0016] In addition to reactive alkane or reactive alkane precursor, optional diamondoid modifier, activating catalyst and methylating agent, there may also be introduced to the reactor additional feedstock components. Suitable additional feedstock components include hydrocarbons, halogenated hydrocarbons and oxygenated hydrocarbons, especially olefins, dienes, alcohols and ethers. The additional feedstock components may be straight chain, branched chain or cyclic compounds (including heterocyclic compounds and aromatic compounds). In general, any additional feedstock component in the reactor may be incorporated in the products of the reaction. The methods of the present invention may further include the step of providing one or more additional feedstock components to the reactor.

[0017] Certain additional feedstock components may advantageously act as initiators for the reaction to produce branched chain hydrocarbons. In the context of the present description, the term "initiator" refers to an additive that causes a chemical reaction or series of chemical reactions to take place and/or enhances the rate of a chemical reaction or series of chemical reactions. In some embodiments, for example, an initiator causes a reaction to take place in the liquid phase that otherwise requires the presence of a solid phase or mixed phase. Suitable initiators are preferably one or more compounds having at least 2 carbon atoms selected from alcohols, ethers, olefins and dienes. Preferred initiator compounds are olefins, alcohols, alkanes, and ethers, preferably having 2 to 8 carbon atoms. Alkanes containing at least one tertiary carbon atom, (such as 2,3-dimethylbutane), may be used as initiators for the reaction. Some examples of initiator compounds are 2- methyl-2-butene, 2,4,4-thmethylpent-2-ene, ethanol, isopropanol, methyl tert-butyl ether, 2,3-dimethylbutane, hexamethylbenzene and pentamethylbenzene. The methods of the present invention may further include the step of providing one or more initiators to the reactor.

[0018] In a further preferred embodiment, there is also present in the reactor one or more initiators selected from one or more of hydrogen halides and alkyl halides of 1

to 8 carbon atoms. Methyl halides and/or hydrogen halides are generally preferred. For the production of branched chain hydrocarbons from dimethyl ether (DME), methyl halides are especially preferred initiators. Preferably, the halide of the initiator is the same element as the halide of the metal halide catalyst.

[0019] There may also be introduced into the reactor hydrocarbons which stimulate the reaction, for example methyl substituted compounds, especially methyl substituted compounds selected from the group consisting of aliphatic cyclic compounds, aliphatic heterocyclic compounds, aromatic compounds, heteroaromatic compounds and mixtures thereof. In particular, such compounds may comprise methylbenzenes such as hexamethylbenzene and/or pentamethylbenzene.

[0020] At least one reaction product of the process of the present invention is a hydrocarbon having a greater number of carbon atoms than the reactive alkane. In one embodiment, a reaction product is a hydrocarbon with seven carbon atoms, for example triptane (2,2,3-thmethylbutane) and/or or triptene (2,3,3-thmethylbut-1 -ene). In one embodiment, a reaction product is an alkane. In one embodiment, a reaction product is triptane. In one embodiment, the reaction products comprise a branched alkane or combination of branched alkanes. In one embodiment, a reaction product is a branched alkane or combination of branched alkanes. The aggregate of triptane and triptene products is referred to as triptyls. In an embodiment, the reaction products of the present methods comprise one or more C ₆ alkanes, C ₇ alkanes, and Cs alkanes. In an embodiment, a reaction product of the present methods is one or more C ₆ alkanes, C ₇ alkanes, and Cs alkanes. In an embodiment, the reaction products of the present methods comprise one or more of xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, 2,4-dimethylpentane, 2-methylhexane, 3-methylhexane, and /so-butane. In an embodiment, a reaction product of the present methods is one or more of xylene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, 2,4-dimethylpentane, 2-methylhexane, 3-methylhexane, and /so-butane. Hydrocarbon reaction products of the present methods may be present in one or more liquid and/or vapor phases. In an embodiment, the reaction products of the present methods comprise first and second liquid phases, wherein the first liquid

phase is a hydrophilic phase comprising water, methanol, dimethyl ether or any combinations of these, and wherein the second liquid phase is a hydrophobic phase comprising one or more hydrocarbons, such as, triptane and/or thptene.

[0021] Water produced in the process of the present invention is preferably removed from the reactor. An embodiment of the present invention further comprises the step of removing water from the reactor, for example by addition of a drying agent or by physical separation means.

[0022] The reaction of the present invention is usually performed at elevated pressure for example 2 to 100 barG, preferably 5 to 80 barG, more preferably at a pressure of 10 to 80 barG. In one embodiment, the reaction can be conducted under autogeneous pressure. The reaction can be carried out under air. The reaction can be carried out using one or more gases inert to the reaction. Gases inert to the reaction are known to one of ordinary skill in the art. Some examples of gases inert to the reaction include nitrogen, argon, helium and carbon dioxide. Blends of hydrogen with gases inert to the reaction may be used. A mixture of hydrogen and carbon monoxide may be used, such as described in WO02070440, the contents of which are incorporated by reference. The reaction can be carried out using mixtures of gases, including air and one or more gases inert to the reaction.

[0023] The process of the present invention may be performed as a batch or as a continuous process. When operated as a continuous process, reactants may be introduced continuously, together or separately, into the reactor and the hydrocarbon product may be continuously removed from the reactor.

[0024] In one embodiment of the process of the present invention, the reactive alkane is added to or continuously introduced in the reaction. In this embodiment, the reactive alkane is not generated solely from methanol and/or dimethyl ether condensation reactions.

[0025] The hydrocarbon product may be removed from the reactor in a batch or continuous process together with the catalyst and water, these being separated from the hydrocarbon product and other products of the reaction, if present, and recycled

to the reactor. Unreacted reactants may also be separated from the hydrocarbon product and recycled to the reactor.

[0026] As will be understood by those having skill in the art, a range of reactors may be used in the present methods. In an embodiment, for example, the process of the present invention is performed in a reactor which is suitably an adiabatic reactor or a reactor with heat-removal mechanism(s) such as cooling coils which may remove, for example, up to 20 % of the heat of reaction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 shows thptane yield as a function of mmol 2.3-dimethylbutane used.

[0028] Figure 2 shows the MS patterns for the GC fractions of 2,3-dimethylbutane using ¹³ C-labeled MeOH.

[0029] Figure 3 shows the MS patterns for the GC fractions of triptane using ^R elabeled MeOH.

[0030] Figure 4 shows triptane yield and triptane selectivity as a function of reaction time.

[0031] Figure 5 shows the combined yield of 2-methyl and 3-methylpentane as a function of time.

DETAILED DESCRIPTION OF THE INVENTION

[0032] Unless defined otherwise, all technical and scientific terms used herein have the broadest meanings as commonly understood by one of ordinary skill in the art to which this invention pertains. In addition, herein, the following definitions apply:

[0033] As used herein, "diamondoid modifier" relates to one or more hydrogen- and carbon-containing compounds having a caged framework of carbon-carbon bonds which generally resemble part of the crystal structure of diamond. Diamondoid modifiers include lower diamondoids such as adamantane, diamantane, and triamantane; and higher diamondoids such as tetramantane and other compounds with higher numbers of carbons having the diamondoid structure. Mixtures of

different diamondoid modifiers may be used. Diamondoid modifiers also include isomers of tetramantane, isomers of pentamantane and isomers of decamantane. Diamondoid modifiers used herein may be optionally substituted with various substituents known in the art such as independently one or more C1 -C6 alkyl groups, one or more amino groups, one or more alkyl groups terminated with an amino group, one or more alkyl groups terminated by a carboxylic acid group; and other suitable substituents as long as the diamondoid modifier remains functional as described herein. The amount of diamondoid modifier used may be any suitable amount as discussed herein and easily determinable by one of ordinary skill in the art. Some suitable amounts of diamondoid modifiers include between 1 -15 mol percent as compared to the amount of reactive alkane. In one embodiment, between 1 -10 mol percent of diamondoid modifier is used as compared to the amount of reactive alkane. In one embodiment, between 0.05-15 mol percent of diamondoid modifier is used as compared to the amount of reactive alkane. In one embodiment, the molar ratio of the reactive alkane to methylating agent is selected over the range of 0.1 :1 to 10:1. In one embodiment, the molar ratio of the diamondoid modifier to the reactive alkane is selected over the range of 0.001 :1 to 0.1 :1. In one embodiment, the molar ratio of the diamondoid modifier to the methylating agent is selected over the range of 0.001 :1 to 0.1 :1. In one embodiment, the diamondoid modifier to the activating catalyst is selected over the range of 0.005:1 to 0.1 :1. In one embodiment, the molar ratio of the diamondoid modifier to the total concentration of reactive alkane and methylating agent is selected over the range of 0.0005:1 to 0.05:1. In one embodiment, the molar ratio of the diamondoid modifier to the total concentration of reactive alkane, methylating agent and activating catalyst is selected over the range of 0.0001 :1 to 0.05:1. In one embodiment, the molar ratio of the total concentration of reactive alkane and methylating agent to activating catalyst is selected over the range of 0.1 :1 to 10:1. In one embodiment, the diamondoid modifier is provided at a purity equal to or greater than 95%.

[0034] In an embodiment when a zinc halide catalyst is used in the alkane homologation reaction, the zinc halide is fully dissolved in the reaction mixture. In an embodiment when a zinc halide catalyst is used in the homologation of 2,3-

dimethylbutane (DMB) with methanol in the presence of adamantane, the zinc halide is fully dissolved in the reaction mixture.

[0035] In an embodiment when a zinc halide is used in the alkane homologation reaction, the methylating agentalkane mole ratio of greater than 1 :1 is used. In an embodiment when a zinc halide is used in the alkane homologation reaction, the methylating agentalkane mole ratio of greater than 3:1 is used. In an embodiment when a zinc halide catalyst is used in the homologation of 2,3-dimethylbutane (DMB) with methanol in the presence of adamantane, a methanol:DMB mole ratio of greater than 1 :1 is used. In an embodiment when a zinc halide catalyst is used in the homologation of 2,3-dimethylbutane (DMB) with methanol in the presence of adamantane, a methanol:DMB mole ratio of 3:1 ratio is used

[0036] In an embodiment when an indium halide is used in the alkane homologation reaction, the methylating agentalkane mole ratio of greater than 1 :1 is used. In an embodiment when an indium halide is used in the alkane homologation reaction, the methylating agentalkane mole ratio of greater than 3:1 is used. In an embodiment when an indium halide catalyst is used in the homologation of 2,3-dimethylbutane (DMB) with methanol in the presence of adamantane, a methanol:DMB mole ratio of greater than 1 :1 is used. In an embodiment when an indium halide catalyst is used in the homologation of 2,3-dimethylbutane (DMB) with methanol in the presence of adamantane, a methanol:DMB mole ratio of 3:1 ratio is used

[0037] Although Applicant does not wish to be bound by theory, it is believed that a carbocation of the diamondoid modifier has higher stability than carbocations of the reactive alkane or methylated products thereof. An example is illustrated in Scheme 1 below where adamantane is the diamondoid modifier and 2,3-dimethylbutane is the reactive alkane. The diamondoid modifier may reduce the probability of unwanted by-products from side reactions by hydride ion donation.

[0038] As used herein, "activating catalyst" is a catalyst that activates a tertiary carbon to form a carbocation, and also activates the methylating agent to cause methylation of the reactive alkane. The activating catalyst can be one or more catalysts.

[0039] As used herein, a "reactive alkane" is an alkane that reacts with the methylating agent and activating catalyst to produce a product having a greater number of carbon atoms than the reactive alkane. In one embodiment, the reactive alkane contains at least one tertiary carbon atom. Reactive alkanes can be produced by reactive alkane precursors through one or more of isomehzation, pyrolysis, and cracking reactions, for example. In one embodiment, a reactive alkane precursor such as isooctane can undergo a cracking reaction to form a reactive alkane. This cracking reaction can occur in the reactor. An isomerization reaction of an alkane can also be used to form a reactive alkane. If a desired product is thptane and/or another branched hydrocarbon, then isomerization of a reactive alkane precursor is preferably performed ex situ to prevent isomerization of triptane or other branched hydrocarbon product.

[0040] As used herein, "homologation" means a reaction in which that the number of carbons in the product is greater than the number of carbons in the reactant.

[0041] As used herein, "contacting" means bringing materials in sufficient physical contact so that the desired reaction can occur.

[0042] As used herein, "methylating agent" is one or more of methanol or a methanol derivative such as dimethyl ether. A methanol derivative generally is a substance that can produce methanol or a substance that functions similarly to methanol in the reaction, for example when hydrolyzed. Examples of methanol derivatives include methyl ethers such as dimethyl ether. One or more methyl halides may also be used in the reactions described herein.

[0043] Alkyl groups include straight-chain, branched and cyclic alkyl groups. Alkyl groups include those having from 1 to 30 carbon atoms. Alkyl groups include small alkyl groups having 1 to 3 carbon atoms. Alkyl groups include medium length alkyl groups having from 4-10 carbon atoms. Alkyl groups include long alkyl groups having more than 10 carbon atoms, particularly those having 10-30 carbon atoms. Cyclic alkyl groups include those having one or more rings. Cyclic alkyl groups include those having a 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-member carbon ring and particularly those having a 3-, 4-, 5-, 6-, or 7-member ring. The carbon rings in cyclic

alkyl groups can also carry alkyl groups. Cyclic alkyl groups can include bicyclic and tricyclic alkyl groups. Alkyl groups are optionally substituted. Substituted alkyl groups include among others those which are substituted with aryl groups, which in turn can be optionally substituted. Specific alkyl groups include methyl, ethyl, n- propyl, iso-propyl, cyclopropyl, n-butyl, s-butyl, t-butyl, cyclobutyl, n-pentyl, branched-pentyl, cyclopentyl, n-hexyl, branched hexyl, and cyclohexyl groups, all of which are optionally substituted. Substituted alkyl groups include fully halogenated or semihalogenated alkyl groups, such as alkyl groups having one or more hydrogens replaced with one or more fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms. Substituted alkyl groups include fully fluohnated or semifluorinated alkyl groups, such as alkyl groups having one or more hydrogens replaced with one or more fluorine atoms. An alkoxyl group is an alkyl group linked to oxygen and can be represented by the formula R-O.

[0044] Alkenyl groups include straight-chain, branched and cyclic alkenyl groups. Alkenyl groups include those having 1 , 2 or more double bonds and those in which two or more of the double bonds are conjugated double bonds. Alkenyl groups include those having from 2 to 20 carbon atoms. Alkenyl groups include small alkenyl groups having 2 to 3 carbon atoms. Alkenyl groups include medium length alkenyl groups having from 4-10 carbon atoms. Alkenyl groups include long alkenyl groups having more than 10 carbon atoms, particularly those having 10-20 carbon atoms. Cyclic alkenyl groups include those having one or more rings. Cyclic alkenyl groups include those in which a double bond is in the ring or in an alkenyl group attached to a ring. Cyclic alkenyl groups include those having a 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-member carbon ring and particularly those having a 3-, 4-, 5-, 6- or 7- member ring. The carbon rings in cyclic alkenyl groups can also carry alkyl groups. Cyclic alkenyl groups can include bicyclic and tricyclic alkyl groups. Alkenyl groups are optionally substituted. Substituted alkenyl groups include among others those which are substituted with alkyl or aryl groups, which groups in turn can be optionally substituted. Specific alkenyl groups include ethenyl, prop-1 -enyl, prop-2-enyl, cycloprop-1 -enyl, but-1-enyl, but-2-enyl, cyclobut-1 -enyl, cyclobut-2-enyl, pent-1 - enyl, pent-2-enyl, branched pentenyl, cyclopent-1 -enyl, hex-1 -enyl, branched hexenyl, cyclohexenyl, all of which are optionally substituted. Substituted alkenyl

groups include fully halogenated or semihalogenated alkenyl groups, such as alkenyl groups having one or more hydrogens replaced with one or more fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms. Substituted alkenyl groups include fully fluorinated or semifluorinated alkenyl groups, such as alkenyl groups having one or more hydrogens replaced with one or more fluorine atoms.

[0045] Aryl groups include groups having one or more 5- or 6-member aromatic or heteroaromatic rings. Aryl groups can contain one or more fused aromatic rings. Heteroaromatic rings can include one or more N, O, or S atoms in the ring. Heteroaromatic rings can include those with one, two or three N, those with one or two O, and those with one or two S, or combinations of one or two or three N, O or S. Aryl groups are optionally substituted. Substituted aryl groups include among others those which are substituted with alkyl or alkenyl groups, which groups in turn can be optionally substituted. Specific aryl groups include phenyl groups, biphenyl groups, pyridinyl groups, and naphthyl groups, all of which are optionally substituted. Substituted aryl groups include fully halogenated or semihalogenated aryl groups, such as aryl groups having one or more hydrogens replaced with one or more fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms. Substituted aryl groups include fully fluorinated or semifluorinated aryl groups, such as aryl groups having one or more hydrogens replaced with one or more fluorine atoms.

[0046] The invention will now be illustrated by way of example only and with reference to the following non-limiting examples and comparative experiments.

EXAMPLE 1 :

[0047] All chemicals were purchased from Aldrich, except for indium(lll) iodide which was purchased from Alfa Aesar chemicals. InI ₃ was stored and weighed in a nitrogen filled dry box. All other chemicals were used without any treatment. It is noted that appropriate safety precautions should be taken.

[0048] To a thick-walled glass pressure tube (20 ml) was added indium(lll) iodide (InI ₃ ) (2.05 g, 4.13 mmol), 2,3-dimethylbutane (0.807 ml_, 534 mg, 6.2 mmol), and MeOH (0.5 ml, 396 mg, 12.4 mmol) in this order. The tube was then sealed using a Teflon Kontes valve. Although InI ₃ was weighed out in a dry box, all other chemicals

were added in air and the reaction was performed under an atmosphere of air. This mixture was stirred to give a colorless or light yellow solution, which contained two phases. The tube was then dipped into a preheated oil bath at 200 ⁰ C, and was heated and stirred for 2 hours, after which time it was cooled to room temperature to give two layers. The top layer is colorless and the bottom one is brown with some precipitates. This mixture was chilled in ice water and a solution of cyclohexane in chloroform was added (1 ml, 30.01 mg cyclohexane in CHCI ₃ ) and then water (1.0 ml).

[0049] The organic layer was extracted and analyzed by gas chromatography (GC) and found to contain 60 mg triptane (average of two runs) and the recovered yield of 2,3-dimethylbutane was 387 mg. This corresponds to a yield of triptane of 17% based on all converted carbon atoms.

Comparative Experiment A

[0050] With no 2,3-dimethylbutane used, and iso-propanol (50 μl, 39 mg, 0.65 mmol) added as an initiator the yield of triptane was also determined using the experimental procedure as in Example 1.

[0051] A three hour reaction gave 23 mg triptyls (average of two runs), corresponding to a triptane yield of 12% based on the total converted carbon atoms. This result is shown in Figure 1.

EXAMPLES 2, 3, 4 and 5:

[0052] Reactions were also performed using different quantities of 2,3- dimethylbutane.

[0053] Example 1 , using 6.2 mmol of 2,3-dimethylbutane, 49 mg of triptane were obtained (averages of two runs) and 387 mg of 2,3-dimethylbutane were recovered, which corresponds to a yield of 17% based on all converted carbon atoms. Example 2, using 0.76 mmol of 2,3-dimethylbutane, 32 mg of triptane were obtained (averages of two runs) and 52 mg of 2,3-dimethylbutane were recovered, which corresponds to a yield of 15% based on all converted carbon atoms. Example 3,

using 1.52 mmol of 2,3-dimethylbutane, 33 mg of triptane were obtained (averages of two runs) and 85 mg of 2,3-dimethylbutane were recovered, which corresponds to a yield of 15% based on all converted carbon atoms. Example 4, 3.04 mmol of 2,3- dimethylbutane, 40 mg of triptane were obtained (averages of two runs) and 186 mg of 2,3-dimethylbutane were recovered, which corresponds to a yield of 16% based on all converted carbon atoms. Example 5, 12.4 mmol of 2,3-dimethylbutane, 75 mg of triptane were obtained (averages of two runs) and 841 mg of 2,3-dimethylbutane were recovered, which corresponds to a yield of 18% based on all converted carbon atoms. These results are summarized graphically in Figure 1.

[0054] These experiments show the effect of the presence of 2,3-dimethylbutane in the reaction of MeOH in the presence of indium(lll) iodide catalyst to produce a hydrocarbon.

[0055] A similar experiment to Example 3 was carried out using 2,3-dimethylbutane and ¹³ C-labeled MeOH. Products were analyzed by GC/MS; Figures 2 and 3 show the MS patterns for the GC fractions of 2,3-dimethylbutane and triptane, respectively. For the former, the major set of peaks from 71 -76 m/z correspond to the (P-Me) ⁺ fragment ions. Of these, by far the largest is at 71 ( ¹² CsH ₁₁ ) and the next-largest at 72 ( ¹² C ₄ ¹³ CHn), with weaker peaks resulting from mixed isotopologs and the fully labeled isotopolog 76 ( ¹³ C ₅ H ₁₁ ). There is also a P ⁺ peak at 86 m/z for unlabeled 2,3- dimethylbutane, while the parent ions for other isotopologs are much weaker or not observed.

[0056] For triptane, the main signals again correspond to (P-Me) ⁺ ions; there is barely any detectable signal in the P ⁺ region. Table 1 shows the relative percentage of different triptane isotopologs without a single methyl group that are expected if there is complete exchange of carbon atoms in the reaction mixture and the actual values observed in the experiment. The statistical distribution was calculated assuming 59.5% of the carbon atoms are unlabelled and 40.5% are labeled. The largest signal at 91 m/z is due to fully labeled ¹³ C ₆ H ₁₃ ; the next largest, at 86 m/z, to singly labeled ¹² Cs ¹³ C ₁ H ₁₃ ; weaker peaks are observed at intermediate values.

Table 1

[0057] The data in the table shows that full scrambling of all the carbon atoms in the reaction mixture is not believed to be occurring. Instead the data suggests that a significant amount of thptane may be formed directly from the ¹³ C-labelled MeOH, which accounts for the large amount of the fully labelled isotopolog. Furthermore, a significant amount of thptane may be formed from the methylation of 2,3- dimethylbutane with ¹³ C-labelled MeOH as this would result in the formation of triptane which is labelled in a single position.

[0058] Further evidence which suggests that 2,3-dimethylbutane is being converted into triptane is the amount of aromatic products generated. When 2,3-dimethylbutane and MeOH react to form triptane, the only by-product is water. In contrast when MeOH is converted directly into triptane, one equivalent of H ₂ is required. The source of H ₂ is believed to be unsaturated species in the reaction mixture which eventually form aromatic species (which are hydrogen deficient). Thus, if some of the triptane being formed comes from the methylation of 2,3-dimethylbutane, a reduction in the amount of aromatics relative to triptane would be expected, compared with a reaction in which only MeOH is converted into triptane. The yields of triptane, pentamethylbenzene (PMB) and hexamethylbenzene (HMB) and the ratio of triptane to PMB + HMB for Examples 1 -5 and Comparative Experiment A are shown in Table 2.

Table 2

[0059] The entries in Table 2, show that the ratio of triptane to PMB + HMB is much larger in Examples 1 -5 than in comparative experiment A. This suggests that in Examples 1 -5 there is another process occurring which generates triptane but not aromatic species. This process is thought to be direct methylation of 2,3- dimethylbutane.

EXAMPLE 6: Effect of lower MeOH to InI ₃ ratio

[0060] A reaction was performed using 6.2 mmol of MeOH, 6.2 mmol of 2,3- dimethylbutane and 4.13 mmol of InI ₃ using the procedure outlined for Example 1.

[0061] The organic layer was extracted and analyzed by gas chromatography (GC) and found to contain 60 mg triptane (average of two runs) and the recovered yield of 2,3-dimethylbutane was 311 mg. This corresponds to a yield of triptane of 19% based on all converted carbon atoms. The total yield of tetramethylbenzene (TMB) was 3 mg (combined isomers), while the total yield of PMB was 1 mg. No detectable quantity of HMB was observed. The triptane to TMB + PMB + HMB ratio was 15, which suggests that most of the triptane observed is formed through the methylation of 2,3-dimethylbutane and that there is only a small amount of direct conversion of MeOH to triptane.

EXAMPLES 7, 8 and 9: Effect of Reaction Time

[0062] Reactions were also performed at different reaction times, using the amounts of reagents specified in Example 6.

[0063] Example 7 - under the same reaction conditions as Example 6 for a one hour reaction, 62 mg of triptane were obtained and 309 mg of 2,3-dimethylbutane were recovered, corresponding to a yield of 20% based on all converted carbon atoms. The selectivity for the conversion of 2,3-dimethylbutane to triptane was 24%. Example 8 - under the same reaction conditions as Example 6 for a thirty minute reaction, 64 mg of triptane were obtained and 354 mg of 2,3-dimethylbutane were recovered, corresponding to a yield of 24% based on all converted carbon atoms. The selectivity for the conversion of 2,3-dimethylbutane to triptane was 30%. Example 9 - under the same reaction conditions as Example 6 for a fifteen minute reaction, 65 mg of triptane were obtained and 353 mg of 2,3-dimethylbutane were recovered, corresponding to a yield of 24% based on all converted carbon atoms. The selectivity for the conversion of 2,3-dimethylbutane to triptane was 31 %. This is shown graphically in Figure 4.

[0064] The main reason that the triptane yield based on converted carbon and selectivity for the conversion of 2,3-dimethylbutane to triptane increase as time decreases is because the recovered yield of 2,3-dimethylbutane increases. The recovered yield increases because there is not as much isomehzation of 2,3- dimethylbutane into other Ce isomers at shorter reaction times. This is shown graphically in Figure 5. A similar trend is observed for the isomerization of triptane into other C7 isomers and this also plays a role in increasing the yield.

EXAMPLES 10, 11 , 12, 13, 14 and 15: Effect of Temperature on reaction

[0065] Reactions were also performed at different temperatures, using the amounts of reagents specified in Example 6. All reactions were performed for 30 minutes.

[0066] Example 10 - same reaction conditions as Example 8 with heating at 190 ⁰ C; Example 11 was heated at 180 ⁰ C; Example 12 was heated at 170 ⁰ C; Example 13 was heated at 160 ⁰ C; Example 14 was heated at 150 ⁰ C; and Example 15 was heated at 140 ⁰ C. Table 3 summarizes the triptane yield in mg, recovered yield of 2,3-dimethylbutane in mg, the triptane yield based on total converted carbon and selectivity for the formation of triptane from 2,3-dimethylbutane.

Table 3

[0067] The maximum yield of triptane was obtained at 180 ⁰ C. As the temperature is decreased from 200 ⁰ C, the extent of isomerization of 2,3-dimethylbutane and triptane decreases, which increases the yield of triptane based on total conversion. At these temperatures the rate of methylation is still relatively fast compared with isomerization. At temperatures below 180 ⁰ C, the methylation of 2,3-dimethylbutane slows down or stops altogether, and hence the yield of triptane decreases or there is no conversion.

EXAMPLE 16: Using isopentane as a feedstock

[0068] Example 16 - instead of using 2,3-dimethylbutane as the feedstock, isopentane was utilized, under similar reaction conditions to Example 1. Initially, the reaction mixture contained 4.13 mmol of InI ₃ , 4.38 mmol of isopentane and 12.4 mmol of MeOH. A yield of 35 mg for triptane was obtained and 252 mg of isopentane were recovered, corresponding to a yield of 14% based on all converted carbon atoms.

[0069] This demonstrates that alkanes other than 2,3-dimethylbutane can have a beneficial effect on the reaction and indicates that lighter alkanes can also be incorporated into triptane.

EXAMPLE 17: Incorporating ZnI ₂ into the reaction mixture

[0070] Example 17 - Instead of using only InI ₃ , a reaction was performed following the procedure outlined for Example 1 , using 2.82 mmol of InI ₃ , 0.94 mmol Of ZnI ₂ , 12.4 mmol of MeOH and 6.2 mmol of 2,3-dimethylbutane. The yield of triptane was 45 mg and 452 mg of 2,3-dimethylbutane were recovered. This corresponds to a triptane yield of 17% based on total carbon converted.

EXAMPLE 18: Using DME.

[0071] A reaction was performed using 8.42 mmol of DME, 8.42 mmol of 2,3- dimethylbutane and 4.13 mmol of InI ₃ . The reaction was heated for 2 hours at 200 degrees Celsius. The yield of triptane was 86 mg and the recovered yield of 2,3- dimethylbutane was 374 mg. This corresponds to a total converted carbon yield of 14.45%.

[0072] A comparative experiment with 8.42 mmol of DME, 4.13 mmol of InI ₃ and iso-propanol as an initiator gave a 13% yield of triptane.

EXAMPLE 19: Formation of triptane from 2.3-dimethylbutane in the presence and absence of adamantane

[0073] Table 4 compares the yield and selectivity of reactions performed in the presence and absence of adamantane. The triptane yield is based on total converted carbon, while the triptane selectivity is based on the formation of triptane from 2,3- dimethylbutane.

Table 4: Comparison of triptane yield and selectivity for homologation in the presence and absence of adamantane. ^a

Adamantane Recovered yield Triptane yield (%) ^c Triptane selectivity (mg) of 2,3- (%) ^d dimethylbutane

/o/

50 ⁶ 51 56 65 0 63 31 39 aUnless otherwise specified, reactions were performed at 180 ⁰ C for 30 minutes and used 4.13 mmol of InI ₃ , 6.2 mmol of 2,3-dimethylbutane and 6.2 mmol of MeOH. ^b Around 6 mol% of adamantane relative to 2,3-dimethylbutane. ^c Based on total converted carbon. dPercentage of converted 2,3-dimethylbutane which becomes triptane.

[0074] Table 4 shows that there is a beneficial effect in both the triptane yield and selectivity when adamantane is used in the reaction. This effect may occur because adamantane suppresses the isomehzation of both 2,3-dimethylbutane and triptane and also greatly reduces cracking side reactions which result in the formation of iso- butane and iso-pentane.

EXAMPLE 20: C6 and C7 isomehzation and cracking in the presence and absence of adamantane

[0075] Table 5 compares the extent of Ce and C ₇ isomerization and cracking in alkane homologation reactions with and without adamantane.

Table 5: Comparison of ratios of side products to starting material and triptane for homologation in the presence and absence of adamantane. ^a

Adamantane Ratio 2,3- Ratio triptane to Ratio 2,3-

(mg) dimethylbutane to other C ₇ alkanes dimethylbutane and other C ₆ alkanes triptane to iso-butane and iso-pentane

50 (49) ^b 56ϊϊ ϊ7ϊϊ 35ϊϊ

0 40^ 10j1 7j1 ^a Same reaction conditions as described in Table 1. ^b Number in parenthesis represents the amount of adamantane determined to be present at the end of the reaction by GC analysis.

[0076] Although applicant does not wish to be bound by theory, it is believed that adamantane suppresses cracking side reactions by decreasing the lifetime of the 2,3-dimethylbutyl, triptyl and other iso-heptyl carbocations in solution. This in turn decreases the rate of secondary cracking reactions. The isomerization of alkanes is presumably suppressed, relative to methylation, because adamantane rapidly traps the intermediate carbocations that are on the pathway to isomerization. Hence, after activation of 2,3-dimethylbutane to generate a carbocation (the mechanism of which is unknown) adamantane basically functions in a "repair" mechanism, capturing the isomeric carbocation before it can undergo skeletal rearrangement and returning it to the parent 2,3-dimethylbutane pool. This is shown schematically in Scheme 1. It is possible that adamantane could also transfer H ^" to the tertiary 2,3-dimethylbutyl carbocation, which at first would seem to be chain-inhibitory, but that should be reversible: the resulting adamantyl cation could take H ^" back from another molecule

of 2,3-dimethylbutane and start a new chain. The interconversion of adamantane and a tertiary 2,3-dimethylbutyl carbocation to 2,3-dimethylbutane and an adamantyl carbocation is approximately thermoneutral in the gas phase, while the reaction of adamantane with the primary 2,3-dimethylbutyl carbocation will be strongly thermodynamically favored. This supports a mechanism in which adamantane suppresses isomerization, relative to methylation.

Scheme 1 [0077] It appears that adding adamantane increases the conversion of 2,3- dimethylbutane, but this does not mean that adamantane increases the rate of the homologation process. In fact, it is believed that adamantane does not accelerate the homologation process in any way; rather it suppresses side reactions that use up the methylating agent. For example, several experiments were performed with adamantane using either a 1 :1 or 1 :2 ratio of 2,3-dimethylbutane to MeOH. The synthesis of triptane requires only one equivalent of MeOH and 2,3-dimethylbutane; yet it was observed that MeOH (in most cases) is completely consumed, while only a fraction of the 2,3-dimethylbutane has been converted. This suggests that a significant quantity of MeOH is 'wasted' by side reactions, and once there is no more

MeOH present, homologation can not occur. Thus, if side reactions (such as the homologation of alkanes which are not on the pathway to triptane) are suppressed, the MeOH is utilized more efficiently for homologating 2,3-dimethylbutane. This results in a higher conversion of 2,3-dimethylbutane, and is not related to the rate of alkane homologation.

[0078] The hypothesis of MeOH 'waste' causing a decrease in the conversion of 2,3-dimethylbutane was tested by stopping reactions after very short times, so that the reactions were analyzed before all the MeOH was consumed. These reactions showed that the rate of MeOH consumption is slowed when adamantane is present. This observation is consistent with more efficient use of MeOH when adamantane is present. In calculating methanol consumption, the presence of any methanol derivatives that may form in-situ during the reaction, for example dimethyl ether and methyl iodide, are taken into account.

[0079] GC indicates that the reaction is catalytic in adamantane (the yield of adamantane by GC is 90-100%). One reason for this is that the adamantyl carbocation is unlikely to undergo side reactions because isomehzation or cracking reactions require the formation of less stable secondary cations or stehcally hindered alkenes. Therefore, the adamantyl carbocation is likely to abstract H ^" from another alkane, to regenerate adamantane and another reactive carbocation. The loading of adamantane was varied between 1 -11 mol% (relative to 2,3-dimethylbutane) and this had almost no effect on the triptane yield or selectivity.

[0080] Adamantane can be used in other homologation reactions, as shown below.

EXAMPLE 21 : Homologation of iso-pentane with MeOH

[0081] Given the large quantities of iso-pentane produced as a by product in oil refineries, any conversion of iso-pentane into more valuable products is significant. A series of experiments were performed, which demonstrate that InI ₃ and adamantane can be used to homologate iso-pentane with MeOH, to generate 2,3-dimethylbutane and triptane, predominantly. The results of these experiments are summarized in Table 6.

Table 6: Summary of homologation reactions between MeOH and iso-pentane catalyzed by InI ₃ . ³

InI ₃ MeOH iso- Time Temperature Triptane Triptane Triptane + 2,3- (mmol) (mmol) pentane (min) ( ⁰ C) yield selectivity dimethylbutane (mmol) (%) ^b (%) ^c selectivity (%) ^d

4.13 6.2 6.2 60 180 22 23 41 4.13 12.4 6.2 300 200 19 26 45 4.13 18.6 6.2 750 200 10 25 40 ^a AII reactions contained 0.367 mmol of adamantane. Based on total converted carbon. Percentage of converted iso-pentane which becomes triptane. ^d Percentage of converts iso-pentane which becomes either 2,3-dimethylbutane or triptane.

[0082] The data in Table 6 indicates that at a variety of different ratios of MeOH:iso- pentane, it is possible to homologate iso-pentane. As the amount of MeOH present increases, the rate of reaction decreases significantly and higher temperatures and longer reaction times are required. This is consistent with previous results for alkane isomehzation catalyzed by InI ₃ , which suggest that as the amount of MeOH present is increased, the activation of alkanes becomes slower. Furthermore, MeOH appears to be converted to other products without effecting iso-pentane, as the triptane yield decreases when the amount of MeOH is increased but the triptane selectivity (a measure of selectivity of the conversion of iso-pentane to triptane) remains almost constant.

[0083] Along with triptane, significant quantities of 2,3-dimethylbutane were also generated from the homologation of iso-pentane with MeOH, which is consistent with the proposed pathway for triptane formation from iso-pentane as illustrated in Scheme 2. It is postulated that iso-pentane is activated by InI ₃ , to form a tertiary carbocation, which can lose a proton to form 2-methyl-2-pentene. Methylation of 2- methyl-2-pentene to give the most substituted carbocation, results in the formation of the tertiary 2,3-dimethylbutyl carbocation, which can either pick up a hydride to form 2,3-dimethylbutane or lose a proton to form 2,3-dimethyl-2-butene. The methylation of 2,3-dimethy-2-butene to form triptane can then occur, as described above. 2,3- dimethylbutane can be further methylated to produce triptane in good yields (as shown above), so it is not a waste product.

Scheme 2

[0084] In an analogous fashion to the homologation of 2,3-dimethylbutane, products resulting from isomerization and cracking are observed in the homologation of iso- pentane. The ratio of 2,3-dimethylbutane to other Ce alkanes is around 2.5:1 (depending on the exact reaction conditions), while the ratio of triptane to C ₇ alkanes is around 5:1. The ratio of 2,3-dimethylbutane and triptane to isobutane (the only observed product of cracking) is approximately 5.5:1. If adamantane is not present, more isomerization and cracking occurs. Furthermore, there is some consumption of adamantane in the reactions and GC indicates that only 50% of the starting adamantane is present at the end of the reaction. At this stage the fate of the consumed adamantane is unclear. Volatility of iso-pentane may affect mass balance.

EXAMPLE 22: Homologation of iso-butane with MeOH

[0085] Iso-butane is also produced as a volatile and unreactive waste product in oil refineries and thus the homologation of iso-butane with MeOH was also investigated. A series of reactions using a number of different ratios of MeOH to isobutane were performed. The results of these reactions are summarized in Table 7.

Table 7: Summary of homologation reactions between MeOH and iso-butane catalyzed by InI ₃ . ³

InI ₃ MeOH iso- Time Triptane Triptane Triptane + Triptane + (mmol) (mmol) butane (min) yield selectivity 2,3-DMB 2,3-DM B + (mmol) (%) ^b (%) ^c selectivity iso-

(%) ^d pentane selectivity (%) ^e

3.49 5.2 5.2 60 4 4 5 22

3.49 10.5 5.2 300 5 6 8 36

3.49 15.8 5.2 720 5 ^f 7 10 42 ^a AII reactions were performed at 200 ⁰ C and contained 0.367 mmol of adamantane. biased on total converted carbon. Percentage of converted iso-butane which becomes triptane. ^d Percentage of converted iso-butane which becomes either 2,3-dimethylbutane or triptane. ^e Percentage of converted iso-butane which becomes either iso-pentane, 2,3-dimethylbutane or triptane. ^f This reaction also produced 10 mg of pentamethylbenzene (PMB) and 7 mg of hexamethylbenzene (HMB), indicating that some direct conversion of MeOH to triptane was occurring.

[0086] Table 7 shows that some triptane and 2,3-dimethylbutane are formed from the homologation of isobutane with MeOH. However, the major product of homologation is iso-pentane, which is presumably formed from the methylation of isobutylene, which is formed by deprotonation of the tertiary iso-butyl carbocation. The formation of triptane and 2,3-dimethylbutane from iso-pentane probably follows the path described earlier. In a similar fashion to reactions with iso-pentane, longer reaction times are required when the MeOH to iso-butane ratio is increased and the best selectivity for the conversion of iso-butane into branched products is obtained when a 2:1 ratio is used. It should be noted that although the selectivity appears to increase when a 3:1 ratio of MeOH to iso-butane was used, significant quantities of aromatics were produced in these reactions, indicating that there was some direct conversion of MeOH to triptane. The triptane selectivity calculation assumes there is no direct conversion of MeOH to triptane. Overall, these results clearly show that it is possible to both convert iso-butane into triptane or into a fuel mixture which is less volatile and has a higher octane number. Volatility of the isobutane may affect mass balance.

EXAMPLE 23: Homologation of 2-methylpentane with MeOH

[0087] In order to demonstrate that InI ₃ catalyzed alkane homologation can be used to homologate C ₆ alkanes other than 2,3-dimethylbutane, a reaction was performed using 2-methylpentane as the starting alkane. The reaction was performed using 6.2 mmol of MeOH, 6.2 mmol of 2-methylpentane, 4.13 mmol of InI ₃ and 0.367 mmol of adamantane. A similar procedure to that described above for 2,3-dimethylbutane was used and the reaction was heated at 180 ⁰ C for 30 minutes. GC analysis indicated that at the end of the reaction 27.4 mg of 2,3-dimethylpentane was formed and 267 mg of 2-methylpentane were recovered. A breakdown of the product distribution is shown in Table 8.

Table 8: Products from the homologation of 2-methylpentane with MeOH.

Product Yield (mg)

Iso-butane 23.5

Iso-pentane 10.7

2,3-dimethylbutane 1.76

2-methylpentane 267

3-methylpentane 73.0

2,4-dimethypentane 12.1

Triptane 5.03

2-methylhexane 5.25

2,3-dimethylpentane 27.4

3-methylhexane 8.48

Cs alkanes 17.3

[0088] The reaction is presumed to initially result in the methylation of 2- methylpentane to 2,3-dimethylpentane. The mechanism is proposed to be analogous to that described above for 2,3-dimethylbutane; initial abstraction of a hydride from 2- methylpentane to form the tertiary 2-methylpentyl carbocation, deprotonation to give 2-methyl-2-pentene, methylation to give the most substituted carbocation, in this case the tertiary 2, 3-dimethylpentyl carbocation, which subsequently picks up a hydride to form 2,3-dimethylpentane. Under the reaction conditions, 2,3- dimethylpentane is unstable and undergoes both isomerization and cracking reactions to form some of the other products observed. Isomerization of 2,3-

dimethylpentane results in other C ₇ alkanes, while products such as iso-butane and iso-pentane form from cracking (these cracking products are also probably formed from the C ₆ and C ₈ alkanes present). The reaction is not as selective as the methylation of 2,3-dimethylbutane to triptane because both 2-methylpentane and 2,3-dimethylpentane are more likely to undergo isomehzation reactions than 2,3- dimethylbutane or triptane. This is because 2-methylpentane and 2,3- dimethylpentane can undergo isomerization without a change in the length of main carbon backbone. Despite these isomerization side reactions, 2,3-dimethylpentane comprises approximately 50% of the C ₇ fraction and highly branched C ₇ alkanes (2,3- dimethylpentane, 2,4-dimethylpentane and triptane) comprise approximately 75% of the C ₇ fraction. Furthermore, the presence of C ₈ alkanes (determined using mass spectrometry) indicates that further methylation of C ₇ species has occurred. Given the mechanism of methylation, it is believed that these species are also highly branched and will be more significantly more branched than 2-methylpentane. Thus, overall this is a process which increases the branching (often correlated with increased octane number) of the alkanes present. Attempts to homologate hexane with MeOH resulted in only small quantities of C ₇ products and extremely long reaction times were required.

EXAMPLE 24: Effect of adamantane on alkane isomerization

[0089] Given the effect of adamantane on homologation reactions of alkanes with MeOH, the effect of adamantane on alkane isomerization reactions (in the absence of MeOH) was studied. A small amount of adamantane was added to a reaction mixture containing 2,3-dimethylbutane and InI ₃ . The mixture was heated for 30 minutes at 200 ⁰ C and the product distribution analyzed by GC. Table 9 compares the product distribution from the isomerization of 2,3-dimethylbutane in the presence and absence of adamantane.

Table 9: Summary of product distribution from isomerization of 2,3-dimethylbutane in the presence and absence of adamantane. ^a Unless otherwise stated all quantities are in milligrams.

Adamantane Time iso- iso- 2,3- 2,2- 2- 3- Hexane (mmol) (min) butane pentane DMB ^b DMB ^b MP ^C MP ^C

0.367 30 3.5 4.0 310 33.2 56.2 37.6 6.8 0 30 0.83 0.58 453 0 trace trace trace 0 150 35.8 nr ^d 63.8 0 141 83.8 5.35 ^a AII reactions were heated at 200 ⁰ C and contained 4.13 mmol of lnl ₃ and 6.2 mmol of 2,3- dimethylbutane. ^b DMB = dimethylbutane. ^C MP = methylpentane. ^d nr = Not recorded.

[0090] Table 9 clearly shows that adamantane increases the rate of isomerization of 2,3-dimethylbutane. After 30 minutes a significant amount of isomerization had occurred in the presence of adamantane, while almost no isomerization had occurred in the absence of adamantane. It is postulated that adamantane increases the rate because hydride transfer is the rate limiting step and adamantane is a better hydride transfer agent than other alkanes present in solution. Interestingly, there is also a difference in the product distribution between reactions with and without adamantane. The decrease in the extent of cracking when adamantane is present is expected (the shorter lifetime of Ce carbocations should decrease rate of secondary reactions such as cracking), however, the observation of 2,2-dimethylbutane as a product is surprising. The formation of 2,2-dimethylbutane requires the rate limiting conversion of a tertiary carbocation to a secondary carbocation, which is proposed to require extended lifetimes for carbocations. The presence of adamantane should shorten the lifetime of carbocations and thus it is unclear why 2,2-dimethylbutane is only formed in reactions with adamantane. At this stage it appears that adamantane is an additive required in sub-stoichiometric amounts, rather than a catalyst, as GC indicates that only 50% of the starting adamantane is present at the end of the reaction.

[0091] The isomerization of hexane is a more challenging problem than the isomerization of 2,3-dimethylbutane because the linear alkane does not contain a relatively weak hydrogen atom bonded to a tertiary carbon atom. Nevertheless, when adamantane is used as an additive, it is possible to isomehze hexane, which is essentially unreactive without adamantane, as shown in Table 10. If the products of

the isomerization of hexane are then methylated with MeOH, using the process described above, highly branched products can be generated from a linear alkane using InI ₃ as a catalyst.

Table 10: Summary of product distribution from isomerization of hexane in the presence and absence of adamantane. ^a Unless otherwise stated all quantities are in milligrams.

Adamantane Time iso- iso- hexane 2,3- 2,2- 2- 3- (mmol) (min) butane pentane DMB ^b DMB ^b MP ^C MP ^C

0.367 120 3.5 4.0 206 19.3 18.1 123 72.3 0 150 trace trace 520 trace 0 trace trace

³ AIl reactions were heated at 200 ⁰ C and contained 4.13 mmol of lnl ₃ and 6.2 mmol of 2,3- dimethylbutane. ^b DMB = dimethylbutane. ^C MP = methylpentane.

EXAMPLE 25: Zinc catalyzed reactions

[0092] Homologation of alkanes can also be catalyzed with Zn halides, such as ZnI ₂ .

[0093] Table 11 shows results for several ZnI ₂ catalyzed methanol conversion carried out at 230 ⁰ C. Most notably, in contrast to the behavior at 200 ⁰ C, DMB initiates reaction, resulting in approximately the same triptane yield as a reaction initiated with ¹ PrOH (although this reaction was allowed to react longer, the results are comparable, because in each case MeOH/DME has been completely consumed, and we have shown that alkanes do not significantly react further); and essentially no olefins are detected. The average triptane yield, 45 mg, is lower than the triptyls yield obtained for an otherwise similar reaction at 200 ⁰ C (60 mg). The yield of aromatics appears to drop significantly, but that is probably due to the longer reaction time, leading to formation of heavier compounds not observable in the GC analysis employed. Adamantane (AdH) also initiates reaction at 230 ⁰ C, and its presence significantly improves the triptane yield. Previous studies on InI ₃ catalyzed alkane homologation showed that AdH decreases the rate of the reaction but increases the selectivity by inhibiting side reactions that waste methanol; slowing reaction should be much less of a problem at the higher temperatures of these studies.

Table 11 : Yields of selected products from ZnI ₂ catalyzed reactions at 230 °C ^a . Unless otherwise stated all quantities are in milligrams.

Time Added Added Added Recovered Recovered Iso- Iso- Triptane ⁰ PMB

(h) ¹ PrOH DMB AdH DMB AdH butane pentane +

HMB

3 39 0 0 8.1 - 29.0 20.3 42.2 41.6

6 39 0 49.9 8.1 26.0 38.4 23.4 61.5 39.0

6 0 0 49.9 7.6 31.6 28.8 19.4 54.6 47.3

16 0 32.9 0 31.7 - 41.5 25.3 45.3 16.6

16 0 32.9 0 28.8 - 30.7 23.4 48.2 11.1

16 0 32.9 0 31.6 - 32.9 24.5 43.7 15.6

³ AII reactions contained 7.52 mmol of ZnI ₂ and 24.7 mmol of methanol. No triptene was detected.

EXAMPLE 26: ¹³ C labeled MeOH

[0094] The use Of ZnI ₂ in alkane homologation with methanol was studied. In one embodiment, useful conditions for InI ₃ catalyzed homologation involve a 1 :1 Methanol:DMB ratio, but ZnI ₂ is considerably less soluble in that composition; most remains undissolved, and the product distribution of such a reaction (Table 12, Entry 1 ) resembles that expected for direct conversion of methanol with no participation of DMB. However, at a ratio of approximately 3:1 Methanol:DMB, the ZnI ₂ catalyst can be completely dissolved, and (in the presence of AdH, which as noted above substantially improves yield and selectivity in the Inl ₃ -system) gives triptane yields much higher than can be accounted for by the methanol alone: the average yield (Entries 2-4 of Table 12) is about 68 mg, vs. 54 mg obtained for a comparable reaction using twice as much methanol, with AdH but without DMB (data not shown). The following labelling study was performed to demonstrate the incorporation of DMB into triptane: ZnI ₂ (4.13 mmol) was predissolved in labelled methanol (12.4 mmol). Unlabelled DMB (3.84 mmol) and adamantane (0.367 mmol) were added and the reaction heated to 230 ⁰ C for 6 hours. The largest triptane signal in the GC/MS spectrum appears at 86 m/z, corresponding to (P-Me) ⁺ for singly labelled triptane (there is also a strong signal at 91 m/z corresponding to fully-labelled triptane resulting from direct methanol conversion). This finding is identical to that obtained for the analogous reaction over InI ₃ at 200 ⁰ C, and confirms that DMB is homologated to triptane here as well.

Table 12: ZnI ₂ catalyzed homologation of DMB at 230 °C. ^a Unless otherwise stated all quantities are in milligrams.

Time Added Added Recovered Recovered Iso- Iso- Triptyls PMB

(h) MeOH DMB DMB AdH butane pentane +

HMB

3 199 (6.2) ^D 533 (6.2) ^D 404.5 38.9 7.8 3.4 15.6 4.2

6 398 (12.4) ^b 330 (3.8) ^b 198.4 40.9 28.1 17.4 66.3 22.5

6 398 (12.4) ^b 330 (3.8) ^b 182.9 38.8 26.8 15.6 68.6 23.5

6 398 (12.4) ^b 330 (3.8) ^b 203.6 37.2 28.1 15.5 68.1 25.0 ^a AII reactions contained 4.13 mmol Of ZnI ₂ and 0.367 mmol (49.9 mg) of AdH and were heated at 230 ⁰ C for 3 hours. ^b Number in parenthesis is the quantity in mmol.

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

[0095] All references throughout this application, for example patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).

[0096] When a group of substituents is disclosed herein, it is understood that all individual members of those groups and all subgroups, including any isomers and enantiomers of the group members, and classes of compounds that can be formed using the substituents are disclosed separately. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included in the disclosure. When a compound is described herein such that a particular isomer or enantiomer of the compound is not specified, for example, in a formula or in a chemical name, that description is intended to include each isomer and enantiomer of the compound described individually or in any combination. When an atom is described herein, including in a composition, any isotope of such atom is intended to be included. Specific names of compounds are intended to be exemplary, as it is known that one of ordinary skill in the art can name the same compounds differently.

Every formulation or combination of components described or exemplified herein can be used to practice the invention, unless otherwise stated. Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure.

[0097] All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art, in some cases as of their filing date, and it is intended that this information can be employed herein, if needed, to exclude (for example, to disclaim) specific embodiments that are in the prior art. For example, when a compound is claimed, it should be understood that compounds known in the prior art, including certain compounds disclosed in the references disclosed herein (particularly in referenced patent documents), are not intended to be included in the claim.

[0098] The invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention. It will be apparent to one of ordinary skill in the art that methods, devices, device elements, materials, procedures and techniques other than those specifically described herein can be applied to the practice of the invention as broadly disclosed herein without resort to undue experimentation. All art-known functional equivalents of methods, devices, device elements, materials, procedures and techniques described herein are intended to be encompassed by this invention. Whenever a range is disclosed, all subranges and individual values are intended to be encompassed. This invention is not to be limited by the embodiments disclosed, including any shown in the drawings or exemplified in the specification, which are given by way of example or illustration and not of limitation.

[0099] The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and

described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments, exemplary embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. All claims included in any multiple-dependent claim are intended to be included in the specification and claims to the same extent as if they were written as separate claims. The specific embodiments provided herein are examples of useful embodiments of the present invention and it will be apparent to one skilled in the art that the present invention may be carried out using a large number of variations of the devices, device components, methods steps set forth in the present description. As will be obvious to one of skill in the art, methods and devices useful for the present methods can include a large number of optional composition and processing elements and steps.

[00100] Many of the molecules disclosed herein contain one or more ionizable groups [groups from which a proton can be removed (e.g., -COOH) or added (e.g., amines) or which can be quaternized (e.g., amines)]. All possible ionic forms of such molecules and salts thereof are intended to be included individually in the disclosure herein. With regard to salts of the compounds herein, one of ordinary skill in the art can select from among a wide variety of available countehons those that are appropriate for preparation of salts of this invention for a given application. In specific applications, the selection of a given anion or cation for preparation of a salt may result in increased or decreased solubility of that salt.

[00101 ] Every formulation or combination of components described or exemplified herein can be used to practice the invention, unless otherwise stated.

[00102] Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that

any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.

[00103] All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art. For example, when composition of matter are claimed, it should be understood that compounds known and available in the art prior to Applicant's invention, including compounds for which an enabling disclosure is provided in the references cited herein, are not intended to be included in the composition of matter claims herein.

[00104] As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of" excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms "comprising", "consisting essentially of and "consisting of may be replaced with either of the other terms. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

[00105] One of ordinary skill in the art will appreciate that starting materials, biological materials, reagents, synthetic methods, purification methods, analytical methods, assay methods, and biological methods other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding

any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

References

[I] M. S. Dresselhaus, I. L. Thomas, Nature 414 (2001 ) 332. [2] G. A. Olah, Angew. Chem., Int. Ed. Engl. 44 (2005) 2636.

[3] G. A. Olah, A. Molnar. Hydrocarbon Chemistry, 2nd ed.; John Wiley & Sons:

Hoboken, NJ, 2003.

[4] C. D. Chang, Catal. Today 13 (1992) 103.

[5] J. F. Haw, W. Song, D. M. Marcus, J. B. Nicholas, Ace. Chem. Res. 36 (2003) 317.

[6] U. Olsbye, M. Bjørgen, S. Svelle, K.-P. Lillerud, S. Kolboe, Catal. Today 106

(2005) 108.

[7] L. Kim, M. M. WaId, S. G. Brandenburger, J. Org. Chem. 43 (1978) 3432. [8] Chang, Clarence D. The methanol-to-hydrocarbons reaction: a mechanistic perspective. ACS Symposium Series (2000), 738 (Shape-Selective

Catalysis), 96-114. . [9] D. M. McCann, D. Lesthaeghe, P. W. Kletnieks, D. R. Guenther, M. J.

Hayman, V. Van Speybroeck, M. Waroquier, J. F. Haw, Angew. Chem., Int.

Ed. Engl. 47 (2008) 5179. [10] J. E. Bercaw, P. L. Diaconescu, R. H. Grubbs, R. D. Kay, S. Kitching, J. A.

Labinger, X. Li, P. Mehrkhodavandi, G. E. Morris, G. J. Sunley, P. Vagner, J.

Org. Chem. 71 (2006) 8907.

[I I] J. E. Bercaw, R. H. Grubbs, N. Hazari, J. A. Labinger, X. Li, Chem. Commun. (2007) 2974.

[12] J. E. Bercaw, P. L. Diaconescu, R. H. Grubbs, N. Hazari, R. D. Kay, J. A.

Labinger, P. Mehrkhodavandi, G. E. Morris, G. J. Sunley, P. Vagner, Inorg.

Chem. 26 (2007) 11371. [13] J. E. Bercaw, N. Hazari, J. A. Labinger, V. J. Scott, G. J. Sunley, J. Am.

Chem. Soc. 130 (2008) 11988. [14] D. E. Pearson, J. Chem. Soc, Chem. Commun. (1974) 397.