WO2006074401A1

WO2006074401A1 - Alkylation of hydroxyarenes with olefins, alcohols and ethers in ionic liquids

Info

Publication number: WO2006074401A1
Application number: PCT/US2006/000520
Authority: WO
Inventors: Nimal Gunaratne; Tobias J. Lotz; K. R. Seddon
Original assignee: Si Group, Inc.
Priority date: 2005-01-07
Filing date: 2006-01-06
Publication date: 2006-07-13

Abstract

Hydroxyarenes are alkylated using an ionic liquid catalyst system with olefins, alcohols, or ethers as alkylating agents. The ionic liquid catalyst system comprises chloroindate (III) anions. The reactions may be conducted at moderate temperatures and pressures to yield commercially relevant alkylated hydroxyarene compounds.

Description

ALKYLATION OF HYDROXYARENES WITH OLEFINS, ALCOHOLS

AND ETHERS IN IONIC LIQUIDS

PRIORITY INFORMATION

The present application claims priority from U.S. Provisional Application Serial number 60/641,992, filed Jan.7, 2005, and U.S. Provisional Application Serial number 60/642,026, filed Jan. 7, 2005.

FIELD OF THE INVENTION

[0001] The present invention relates to the use of ionic liquids as reaction media in organic synthesis, in particular, the alkylation of hydroxy arenes.

BACKGROUND OF THE INVENTION

[0002] Alkylated phenols and their derivatives are used in the production of resins, durable surface coatings, varnishes, wire enamels, printing inks, surface active agents, antioxidants, flame retardants, UV absorbers, fungicides, insecticides, petroleum additives, non-ionic surfactants and fragrances. For example, the triphosphate derivative of 2,4-di-t-butylphenol is employed as a stabilizer for PVC, whereas its benzotriazole derivative is used as a UV absorber in polyolefins. 4-t-Butylcatechol is utilized as a polymerization inhibitor for a number of monomers. Thymol and other isopropyl phenols have been used in the production of perfumes and thymol, in particular, has been used as a precursor of 1-menthol. [0003] Solvent-free ionic liquids, i.e., salts which are molten at room temperature, were first described by Hurley, et al. (U.S. Pat. No. 2,446,331). Ionic liquid systems generated from AlCl₃ and l-ethyl-3-methylimidazolium chloride have been investigated for a long time (Wilkes et al., J. Chem. Soc. Chem. Commun. 965-967, 1992; and Wilkes et al., Inorg. Chem. 21, 1263-1264, 1982). There are, however, serious problems associated with the class of ionic liquids containing chloroaluminate (III) anions. On exposure to moisture, these ionic liquids undergo rapid hydrolysis releasing toxic gases (Fiege et al., Phenol Derivatives, in Ullmann's Encyclopedia of Industrial Chemistry, Vol. 25, 2003). Therefore, these ionic liquids introduce problems when used in organic transformation reactions. [0004] Some organic transformations, however, have been carried out successfully in l-ethyl-3-methylimidazolium and l-butyl-3-methylimidazolium chloroaluminate (III) ionic liquids. One such example is the alkylation of unactivated aromatic hydrocarbons with long chain olefins to furnish linear alkylbenzene intermediates for detergent production (Abdul-Sada et al., WO 95/21806 (U.S. Pat. No. 5,994,602), the contents of which are incorporated by reference in their entirety; Ellis et al., WO 00/41809; and Sherif et al., WO 98/03454). The products were isolated with relative ease though the system had to be protected from exposure to moisture. Scandium triflate, immobilized in noncatalytic ionic liquids has also been used as a system to alkylate benzenoid aromatic compounds with a range of olefins (DeCastro et al., J. Catal. 196, 86-94, 2000). Seddon et al. (WO 03/028883, the contents of which are incorporated by reference in their entirety) introduced chloroindate (III) anion to the ionic liquid system as the catalytic component.

[0005] Alkylation of hydroxyaryl compounds (hydroxyarenes) with alcohols has not received the same prominence as alkylation with olefins. This is despite the fact that the alkylation of phenols is atom-efficient and inherently "green" by nature due to the generation of water as the sole by-product. Alkylation with methanol is used to produce cresols and xylenols. Sharp et al. (U.S. Pat. No. 3,642,912) used titanium dioxide (TiO₂) as a catalyst for the vapor phase alkylation of phenol with either methanol or ethanol to produce mixtures of alkylated products. Extremely high temperatures, however, are used to achieve higher conversions.

[0006] Taniguchi et al. (U.S. Pat. No. 4,329,517) describe iron-based catalysts for the vapor phase ortho alkylation of phenols with methanol to produce cresols and xylenols. These catalysts contain a variety of other metals, such as gallium, as a secondary components. Yet again extreme temperatures are necessary in the reaction. Irick, Jr. et al. (U.S. Pat. No. 5,245,089) provide a process for alkylating phenols in the presence of mixed oxides of titanium and gallium. Alkyl donor compounds could be olefins, ethers or alcohols. Temperatures as high as 425⁰C have been used for phenol/methanol alkylations. Sato et al. (J. Catal. 184(1), 180 - 188, 1999) described an alkylation process of phenol with 1-propanol catalyzed by CeO2-MgO mixed oxide matrix in the gas phase. Though some ortho selectivity was detected, higher temperatures were required for better conversions. Sato et al. (J. Catal. 178(1), 264-274, 1988) also describe an ortho selective methylation process of phenol with methanol catalyzed by the same mixed oxide and carried out in the gas phase at very high temperatures (400°C to 500⁰C).

[0007] There are also reports of the use of large pore zeolites for alkylation of phenols using alcohols as alkylating agents (Zhang et al., Apps. Catal. A: Gen 207(12), 183 - 190, 2001). [0008] Therefore, there is a need for an efficient, homogeneous catalytic process for the alkylation of aryl compounds which can be conducted at low to moderate temperatures and low to moderate pressures, using ionic liquid catalytic systems.

SUMMARY OF THE INVENTION [0009] One aspect of the present invention are processes for the production of alkyl- substituted hydroxyarene compounds comprising the step of treating at least one hydroxyarene with a least one alkylating agent selected from the group consisting of an olefin, alcohol, and ether, in the presence of at least one chloroindate (III) anion containing ionic liquid.

[0010] Another aspect of the present invention are processes wherein the hydroxyarene is selected from the group consisting of phenol, cresols, xylenols, trimethylphenols and dihydroxyarenes.

[0011] Another aspect of the present invention are processes wherein the chloroindate (III) anion is selected from the group consisting of [InCl₄]^", [In₂Cl₇]^" and [In₃CIi₀]^".

[0012] Another aspect of the present invention are processes wherein the alkylating agent is an olefin. Another aspect of the present invention are processes wherein the olefin is selected from the group consisting of ethylene, propylene, isobutylene, diisobutylene, cis-2-butene, trans-2-pentene, cyclopentene, cyclohexene, 1,4-cyclohexadiene, and 2-methyl-l-heptene.

[0013] Another aspect of the present invention are processes wherein the alkylating agent is an alcohol. Another aspect of the present invention are processes wherein the alcohol is selected from the group consisting of methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, t-butyl alcohol, cyclopentyl alcohol, cyclohexyl alcohol and benzyl alcohol.

[0014] Another aspect of the present invention are processes wherein said alkylating agent is an ether. Another aspect of the present invention are processes wherein the ether is selected from the group consisting of dimethyl ether, ethyl methyl ether, diethyl ether, diisopropyl ether, and methyl t-butyl ether (MTBE).

[0015] Another aspect of the present invention is a catalytic ionic liquid system comprising a cationic component and an anionic component, wherein the cationic component is selected from the group consisting of

(a) an imidazolium cation substituted with 1, 2, or 3-alkyl groups,

(b) tetraalkylphosphonium,

(c) tetraalkylammonium,

(d) dialkylpyrrolidinium, and

(e) piperidinium;

(f) trialkylsulfonium; and the anionic component is [In_nCl_3n+]]^", where n is selected from the group consisting of 1, 2, and 3, which is generated by combining InCl₃ and [R][Cl] where x is the mole fraction OfInCl₃ with respect to InCl₃ combined with [R] [Cl]₅ 0.5< x <0.8, and R is selected from either the cationic component or ammonium or phosphonium cations bearing one or more branched alkyl groups, unbranched alkyl groups, cycloalkyl groups, conjugated aryl groups, or unconjugated aryl groups.

[0016] Another aspect of the present invention are catalytic ionic liquid systems wherein the catalytic ionic liquid system is formed by the reaction of [R][Cl] and InCl₃, where [R] is the cationic component. Another aspect of the present invention are catalytic ionic liquid systems wherein the catalytic ionic liquid system is formed by the reaction of approximately n equivalents OfInCl₃ per equivalent of [R][Cl], where n is 1, 2, or 3.

[0017] Another aspect of the present invention are processes for the alkylation of hydroxyarenes comprising the step of treating at least one hydroxyarene with at least alkylating agent selected from the group consisting of an olefin, alcohol, or ether, in the presence of any of the catalytic ionic liquid systems described above.

[0018] Another aspect of the present invention are processes further comprising a separation step following the step of treating the hydroxyarene with an alkylating agent, wherein the step of treating the hydroxyarene with an alkylating agent yields a product and further wherein:

(i) the separation step uses water;

(ii) the water separates the catalytic ionic liquid system from the product such that the product can be filtered off, and;

(iii) removal of water can regenerate the catalytic ionic liquid system.

[0019] Another aspect of the present invention are processes wherein the separation step is decantation. [0020] Another aspect of the present invention are processes wherein the reaction of [R][Cl] and InCl₃ occurs prior to step of treating at least one hydroxyarene with an alkylating agent.

[0021] Another aspect of the present invention are processes wherein the hydroxyarene is selected from the group consisting of phenol, cresols, xylenols, trimethylphenols and dihydroxyarenes. [0022] Another aspect of the present invention are processes wherein the alkylating agent is an olefin selected from the group consisting of ethylene, propylene, isobutylene, diisobutylene, cis-2-butene, trans-2-m ethyl- 1-heptene, cyclohexene.

[0023] Another aspect of the present invention are processes wherein the process is carried out at a temperature less than approximately 300⁰C. Another aspect of the present invention are processes carried out at a temperature of from about 80°C to about 18O⁰C.

[0024] Another aspect of the present invention are processes conducted at approximately atmospheric pressure without the use of a high pressure reactor.

[0025] Another aspect of the present invention are processes wherein the process is carried out at a pressure of approximately 1 atmosphere.

[0026] Another aspect of the present invention are processes wherein the hydroxyarene is catechol, the alkylating agent is diisobutylene, and wherein 4-t-octylcatechol is produced. Another aspect of the present invention are processes wherein the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to catechol. Another aspect of the present invention are such processes conducted at atmospheric pressure without the use of a high- pressure reactor.

[0027] Another aspect of the present invention are processes wherein the hydroxyarene is phenol, the alkylating agent is diisobutylene, and wherein 4-t-octylphenol is produced. Another aspect of the present invention are processes wherein the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to phenol. Another aspect of the present invention are processes conducted at atmospheric pressure without the use of high- pressure reactors.

[0028] Another aspect of the present invention are processes wherein the hydroxyarene is «7-cresol, the alkylating agent is propylene, and wherein thymol is produced. Another aspect of the present invention are processes wherein the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to rø-cresol. Another aspect of the present invention are such processes conducted at atmospheric pressure without the use of a high- pressure reactor.

[0029] Another aspect of the present invention are processes wherein: (i) the hydroxyarene is catechol; (ii) the alkylating agent is t-butanol (iii) 4-t-butylcatechol is produced; and

(iv) the reaction is carried out at approximately 110°C and approximately 1 atmosphere.

Another aspect of the present invention are such processes wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

[0030] Another aspect of the present invention are processes wherein: (i) the hydroxyarene is phenol; (ii) the alkylating agent is t-butanol (iii) 4-t-butylphenol is produced; and

(iv) the reaction is carried out at approximately 100°C and approximately 1 atmosphere.

Another aspect of the present invention are such processes wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate(III).

[0031] Another aspect of the present invention are processes wherein: (i) the hydroxyarene is p-cresol; (ii) the alkylating agent is t-butanol (iii) 2-t-butyl-p-cresol is produced; and

[0032] Another aspect of the present invention are processes wherein: (i) the hydroxyarene is p-cresol; (ii) the alkylating agent is t-butanol (iii) 2, 6-di-t-butyl-p-cresol is produced; and (iv) the reaction is carried out at approximately 100°C and approximately 1 atmosphere.

[0033] Another aspect of the present invention are processes wherein: (i) the hydroxyarene is m-cresol; (ii) the alkylating agent is isopropanol (iii) thymol is produced; and

Another aspect of the present invention are such processes wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l.,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

[0034] Another aspect of the present invention are processes further comprising administering microwave energy to at least some of the reactants to affect formation of product.

[0035] Another aspect of the present invention are processes for the production of 2-t-butyl- p-cresol comprising the step of treating p-cresol with t-butanol in the presence of at least one chloroindate (III) anion containing ionic liquid, wherein said reaction is carried out at approximately 100⁰C and microwave energy is administered to at least some of the reactants to affect formation of product. Another aspect of the present invention are such processes wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

[0036] Additional aspects, features and advantages of the present invention will become apparent from the following detailed description which illustrates, by way of example, principles of this invention.

BRIEF DESCRIPTION OF THE FIGURES [0037] Figure 1 shows the reaction of catechol with diisobutylene in the presence of the ionic liquid [bmim] [In₂Cl₇] at 100°C.

DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention relates to an ionic liquid system, which is stable to moisture and may be recovered and reused. Although alkylation of unactivated arenes with olefins has been reported to occur in chloroaluminate (III) ionic liquids, the active hydroxy-group in phenols reacts with such ionic liquids, thereby diminishing the catalytic activity. The ionic liquid system described herein is based on indium (III) chloride, InCl₃, which is catalytic but has never been used for alkylation of phenols. The present invention also describes the use of alcohols as alkylating agents for aryl compounds in chloroindate (III) anion containing ionic liquids.

[0039] The use of alcohols as alkylating agent is useful when the corresponding olefin is more expensive than its alcohol counterpart. Further, since all alcohols are either liquids or solids, it is more convenient to use an alcohol in place of a gaseous olefin (e.g., use of t-butyl alcohol instead of isobutylene to produce t-butyl phenols). Unlike chloroaluminate (III) ionic liquids, which undergo alcoholysis when exposed to alcohols, chloroindate (III) ionic liquids are devoid of this phenomenon. Additionally, chlorogallate (III) may be used in the invention.

[0040] An aspect of the present invention relates to an ionic liquid system for the alkylation of hydroxyarenes with olefins. Efficient alkylation process for alkylating phenols and catechols with olefin alkylating agents to produce predominantly p-substituted hydroybenzenes are described which produce alkyl substituted hydroxyarenes with high selectivity and energy efficiency.

[0041] Processes for the production of alkyl-substituted hydroxyarenes as described herein comprise treating alkylating agents such as olefins, alcohols or ethers with at least one hydroxyarene in the presence of at least one chloroindate (III) anion containing ionic liquid. In certain embodiments of the process of the invention, the olefin is ethylene, propylene, isobutylene, diisobutylene, cis-2-butene, trans-2-pentene, cyclopentene, cyclohexene, 1,4- cyclohexadiene, or 2-methyl-l-heptene.

[0042] In certain embodiments of the invention, the alcohol is selected from the group consisting of methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, t-butyl alcohol, cyclopentyl alcohol, cyclohexyl alcohol and benzyl alcohol. In certain embodiments of the process of the invention, the ether is selected from the group consisting of dimethyl ether, ethyl methyl ether, diethyl ether, diisopropyl ether, and methyl t-butyl ether (MTBE).

[0043] In certain embodiments of the process of the invention, the hydroxyarene is selected from the group consisting of phenol, cresols, xylenols, trimethylphenols and dihydroxyarenes.

[0044] In certain embodiments of the process of the invention, the chloroindate (III) anion of the chloroindate (III) anion containing ionic liquid is selected from the group consisting of [InCl₄]^", [In₂Cl₇]-, and [In₃Cl₁₀]^".

[0045] In other aspect of the present invention relates to a catalytic ionic liquid system comprising a cationic component and an anionic component, wherein the cationic component is selected from the group consisting of

(a) an imidazolium cation substituted with 1, 2, or 3-alkyl groups,

(b) tetraalkylphosphonium,

(c) tetraalkylammonium,

(d) dialkylpyrrolidinium, and

(e) piperidinium; and

(f) trialkylsulfonium.

[0046] In certain embodiments of the invention, the anionic component is [In_nCl_3n+!]^", where n is selected from the group consisting of 1, 2, and 3, which is generated by combining InCl₃ and [R][Cl] where x is the mole fraction OfInCl₃ with respect to InCl₃ combined with [R] [Cl], 0.5< x <0.8, and R is selected from either the cationic component or ammonium or phosphonium cations bearing one or more branched alkyl groups, unbranched alkyl groups, cycloalkyl groups, conjugated aryl groups, or unconjugated aryl groups.

[0047] In certain embodiments of the invention, the catalytic ionic liquid system is formed by the reaction of [R][Cl] and InCl₃, where [R] is the cationic component.

[0048] In certain embodiments of the invention, the catalytic ionic liquid system is formed by the reaction of approximately n equivalents OfInCl₃ per equivalent of [R][Cl], where n = 1, 2, or 3. [0049] In certain embodiments of the invention, the catalytic ionic liquid system can undergo a separation after a reaction of at least one hydroxyarene with at least one olefin in the catalytic ionic liquid system which reaction yields a product, wherein the separation uses water, the water separates the catalytic ionic liquid system from the product such that the product can be filtered off, and removal of water can regenerate the catalytic ionic liquid system.

In certain embodiments of the invention, the separation is decantation. In certain embodiments of the invention, the reaction of [R][Cl] and InCl₃ occurs prior to the reaction of at least one hydroxyarene with at least one olefin.

[0050] In certain embodiments of the invention, there is provided a process for the alkylation of hydroxyarenes comprising reacting at least one hydroxyarene with at least one olefin in the presence of any of the catalytic ionic liquid systems of the invention.

[0051] In certain embodiments of the invention, the hydroxyarene is selected from the group consisting of phenol, cresols, xylenols, trimethylphenols and dihydroxyarenes. In certain embodiments of the inventive process, the olefin is selected from the group consisting of ethylene, propylene, isobutylene, diisobutylene, cis-2-butene, trans-2-methyl-l-heptene, cyclohexene.

[0052] In certain embodiments of the invention, the process is carried out at a temperature less than approximately 300°C.

[0053] In certain embodiments of the invention, the process is conducted at approximately atmospheric pressure without the use of a high pressure reactor.

[0054] In certain embodiments of the invention, there is provided a process for the production of 4-t-octylcatechol comprising reacting catechol and diisobutylene in the presence of any of the catalytic ionic liquid systems of the invention. In certain embodiments of the inventive process, the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to catechol. In certain embodiments of the inventive process, the process is conducted at atmospheric pressure without the use of a high- pressure reactor.

[0055] In certain embodiments of the invention, there is provided a process for the production of 4-t-octylphenol comprising reacting phenol and diisobutylene in the presence of any of the catalytic ionic liquid systems of the invention. In certain embodiments of the inventive process, the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to phenol. In certain embodiments of the inventive process, the process is conducted at atmospheric pressure without the use of high- pressure reactors.

[0056] In certain embodiments of the invention, the catalytic ionic liquid system is formed by the reaction of [R][Cl] and InCl₃, where R is the cationic component.

[0057] In certain embodiments of the invention, there is provided a process for the production of thymol comprising reacting m-cresol and propylene, in the presence of any of the catalytic ionic liquid systems of the invention. In certain embodiments of the inventive process, the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to m-cresol.

[0058] In certain embodiments of the invention, In certain embodiments of the inventive process, the process is conducted at atmospheric pressure without the use of a high- pressure reactor.

[0059] In certain embodiments of the invention, there is provided a process for the alkylation of hydroxyarenes comprising reacting at least one hydroxyarene with at least one alcohol or at least one ether in the presence of any of the catalytic ionic liquid systems of the invention.

[0060] In certain embodiments of the invention, In certain embodiments of the process of the invention, the reaction of [R][Cl] and InCB occurs prior to the reaction of the hydroxyarene with the alcohol or ether.

[0061] In certain embodiments of the invention, In certain embodiments of the process of the invention, the process is carried out at a temperature less than about 300⁰C.

[0062] In certain embodiments of the invention, In certain embodiments of the process of the invention, the process is carried out at a temperature of from about 80°C to about 180°C.

[0063] In certain embodiments of the invention, the process is carried out without the use of a high pressure reactor. In certain embodiments of the process of the invention, the process is carried out at a pressure of approximately 1 atmosphere.

[0064] In certain embodiments of the invention, there is provided a process for the production of 4-t-butyl catechol comprising reacting catechol and t-butanol in the presence of at least one chloroindate (III) anion containing ionic liquid, wherein the reaction is carried out at approximately 110⁰C and approximately 1 atmosphere. [0065] In certain embodiments of the invention, the chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylirnidazoliurn heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazoliurn heptachlorodiindate (III).

[0066] In certain embodiments of the invention, there is provided a process for the production of 4-t-butylphenol comprising reacting phenol and t-butanol in the presence of at least one indium halide, wherein the reaction is carried out at approximately 100°C and approximately 1 atmosphere.

[0067] In certain embodiments of the invention, In certain embodiments of the process of the invention, the reaction mixture comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate(III).

[0068] In certain embodiments of the invention, there is provided a process for the production of 2-t-butyl-p-cresol comprising reacting p-cresol and t-butanol, in the presence of at least one chloroindate (III) anion containing ionic liquid, wherein the reaction is carried out at approximately 100°C and at approximately 1 atmosphere. In certain embodiments of the process of the invention, the chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

[0069] In certain embodiments of the invention, there is provided a process for the production of 2,6-di-t-butyl-p-cresol comprising reacting p-cresol and t-butanol, in the presence of any of the catalytic ionic liquid systems of the invention.

[0070] In certain embodiments of the invention, there is provided a process for the production of thymol comprising reacting m-cresol and isopropyl alcohol or diisopropyl ether in the presence of l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

[0071] In certain embodiments of the invention, the process of the invention further comprises administering microwave energy to at least some of the reactants.

[0072] The synthesis of catalytic ionic liquids in accordance with the certain embodiments of the present invention is shown in Scheme 1. The catalytic ionic liquids, l-butyl-3-methylimidazolium heptachlorodiindate (III) ([bmim] [In₂Cl₇]) or l,2-dimethyl-3-butylimidazoliuni heptachlorodiindate (III) ([C₄dmim] [In₂Cl₇]) were freshly prepared each time just before the intended reaction was carried out. It is, however, within the scope of this invention that [bmim] [In₂Cl₇] and/or [C₄dmim][Iii₂Cl₇] can be prepared in situ, any time prior to use, diluted from concentrated stock solutions or used as commercially available.

[0073] In order to prepare these catalytic ionic liquids, l-butyl-3-methylirnidazolium chloride ([bmim][Cl]) or l,2-dimethyl-3-butylimidazolium chloride ([C₄dmim][Cl]) was melted with InCl₃ until it formed a smooth creamy liquid. In a preferred embodiment of the present invention, 1 equivalent of [bmim] [Cl] and/or [C₄dmim][Cl] is melted with 2 equivalents OfInCl₃. Any temperature and pressure combination suitable to combine these compounds can be used. In a preferred embodiment, the temperature required for this process ranges from approximately 80°C to approximately 100°C at approximately 1 atmospheric pressure.

(l ett) (bmim)

σ «t) (QfdnJm) n = 3 Scheme 1 : Synthesis of heptachlorodiindate (III) ionic liquids

[0074] Unlike the chloroaluminate (III) catalyst system, the chloroindate (III) ionic liquid can be extracted into water after the reaction thereof, which upon removal of water, regenerates the catalyst system. Once the reaction is complete, the chloroindate (III) anion containing ionic liquid, unlike the chloroaluminate (III) ionic liquid catalyst system, can be extracted into water, which, upon removal of water regenerates the catalyst system. Any system for the regeneration of the catalyst is within the scope of the invention. Examples include secondary purification reactions and/or steps, heating, cooling, crystallization, distillation, extractions, column chromatography, flash chromatography, HPLC, and reverse phase HPLC. [0075] Although the product formed is free of water, amounts of water that do not affect the activity of the catalyst are within the scope of the invention. Any process that dehydrates the reactants prior to the reaction, or the products after the reaction is complete, or both, is within the scope of the present invention. In a preferred embodiment, the liquid product formed is kept at about 8O⁰C under high vacuum (approximately 0.1 to approximately 1 mm Hg) for about 30 minutes to remove any traces of water, prior to conducting the respective reactions. Other methods of dehydration include heating at atmospheric pressure, application of a vacuum at room temperature, cooling to induce crystallization, drying over anhydrous salts, and addition of either chemical or physical drying agents.

[0076] This catalyst system can be used successfully to produce industrially important alkylated phenols (e.g., industrial detergents and antioxidants) by reacting appropriate phenols with the relevant olefins. The products from these reactions can be isolated by means of a simple extraction procedure. For example, some products may be isolated by a distillation under reduced pressure. The chloroindate (III) ionic liquid system can also be employed in conjunction with alcohols and ethers for alkylating hydroxyarenes at moderate temperatures.

[0077] In the examples described below, no other solvent was used, [bmim] [In₂C I₇] acts as both the solvent and the catalyst. It is within the scope of this invention to add optionally at least one solvent to the reaction mixture. Typical solvents include water, straight chain alkanes, branched alkanes, nitroalkanes, nitroarenes and haloalkanes.

[0078] Any hydroxyarene can be alkylated by the present invention. Examples include but are not limited to phenols, cresols, xylenols, trimethylphenols, dihydroxyarenes, nitrophenols and anisoles.

[0079] Similarly, it is within the scope of this invention to add optionally at least one additional catalyst to the reaction mixture. Appropriate catalysts include those that modify the reaction rate (by increasing or decreasing it), modify the product ratios, and/or modify the reactivity of the reactants.

[0080] Any substituted, unsubstituted, branched, unbranched, conjugated, unconjugated, and cyclic olefins can be used in the present invention. The olefins include alkenes, alkynes, compounds containing multiple double bonds, compounds containing multiple triple bonds, and compounds containing at least one double and at least one triple bond. Examples include ethylene, propylene, isobutylene, diisobutylene, cis-2-butene, trans-2-pentene, cyclopentene, cyclohexene, 1,4-cyclohexadiene, 2-methyl-l-heptene, cyclooctatetrene (COT), acetylene, propyne, 3-liexyne and cycloheptyne.

[0081] In one embodiment of the present invention, the reactions are run at an arene:olefin initial mole ratio of approximately 1:1. In another embodiment of the present invention, the olefin was added to the reaction vessel containing the catalytic ionic liquid and the hydroxyarene, in a stepwise manner resulting in an final hydroxyarene:olefϊn mole ratio of approximately 1 :1. The initial and/or final mole ratios can range from approximately 1 :100 to approximately 100:1, preferably approximately 1 :50 to approximately 50:1, more preferably approximately 1:10 to 10:1.

[0082] In another embodiment of the present invention, the reactions are run at an arene:alcohol initial mole ratio of approximately 1 :1. In another embodiment of the present invention, the alcohol is added stepwise to reach the final mole ratio of approximately 1:1. The initial and/or final mole ratios can range from approximately 1 : 100 to approximately 100:1, preferably approximately 1:50 to approximately 50:1, more preferably approximately l:10 to 10:1.

[0083] In a preferred embodiment of the present invention, the reaction vessel is flushed with nitrogen gas to prevent possible oxidation of the hydroxybenzenes (especially when using catechol). When catechol is used as the substrate, it is desirable to keep the entire reaction vessel at the appropriate temperature in order to minimize catechol deposits on the top of the reaction vessel due to sublimation. Reactions with catechol are preferably conducted at a temperature above its melting point (104⁰C) in order to maintain a liquid phase.

[0084] All examples show excellent para selectivity, giving rise to high yields of para- substituted products. A typical product profile (such as that of Example 17) is shown in Figure 1. An advantage of the present invention is that the heptachlorodiindate (III) catalyst system essentially suppresses di-and tri-alkylation of the hydroxyarene substrates.

[0085] AU the examples involving olefins shown herein use gaseous olefins. Nonetheless, it is within the scope of the present invention that solid, liquid or gaseous olefins can be used. If used in gaseous form, the olefin may be bubbled into the reaction mixture as quickly as it reacts.

[0086] Any substituted, unsubstituted, branched alkyl, unbranched alkyl, cycloalkyl, conjugated aryl, or unconjugated aryl alcohols can be used as an alkylating agent in the present invention. Examples include, but are not limited to methyl alcohol, ethyl alcohol, n- propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, t-butyl alcohol, n-pentyl alcohol, sec-pentyl alcohol, isopentyl alcohol, neo-pentyl alcohol, chloromethyl alcohol, β-bromoethyl alcohol, γ-iodooctyl alcohol, cyclopentyl alcohol, and benzyl alcohol.

[0087] When t-butyl alcohol was used as the alkylating agent, good para selectivity was observed for the cases studied for this patent. With isopropyl alcohol, however, mixtures of alkylated phenols were obtained with moderate selectivity. In light of the commercial importance of thymol (3-methyl-6-isopropylphenol), it is useful that m-cresol can be combined with isopropyl alcohol to introduce the isopropyl group and form thymol (see, Example 6).

[0088] Ethers can also be used as alkylating agents according to the invention. Example 14 shows an example of the use of dialkyl ethers as alkylating agents with the same catalyst system. Any substituted, unsubstituted, branched alkyl, unbranched alkyl, cycloalkyl, conjugated aryl, or unconjugated aryl ethers can be used in the present invention. The substituents attached to the ether oxygen atom can be the same or different (i.e., mixed ethers). The alkylating agents can contain several ether oxygens. Examples of ethers that can be used in accordance with the present invention include dimethyl ether, ethyl methyl ether, diethyl ether, diisopropyl ether, methyl t-butyl ether (MTBE), glyme, diglyme, cyclic ethers such as tetrahydrofuran and tetrahydropyran.

[0089] Any hydroxyarene can be alkylated by the present invention. Examples include, but are not limited to, phenol, cresols, xylenols, catechol, m-nitrophenol, and p-methyl anisole. Non-limiting examples of illustrative reactions are shown below:

EXAMPLE l:

[0090] l-Butyl-3-methylimidazolium chloride (0.17 g, 1.0 mmol) and indium (III) chloride (98%, 0.44 g, 2.0 mmol; Aldrich) were melted together to generate [C₄mim] [In₂Cl₇] as described previously. Phenol (99% crystalline colorless solid, 9.4 g, 100 mmol; Aldrich) was added to the ionic liquid and heated at 80°C in a container sealed with a rubber septum. Diisobutylene (97%, 16 ml, 100 mmol; Aldrich) was added to this reaction mixture in a stepwise manner over 2 hours. To the warm reaction mixture water (4 ml) was added, stirred for 15 minutes, cooled, and filtered to remove the water-containing catalyst. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product indicated that the major product was 4-t-octylphenol, as shown by the following product distribution:

4-t-Octylphenol 83% 2-t-Octylphenol 0.5% 2, 4-Di-t-octylphenol 7.7% 2-M3utyl-4-/-octylphenol 3.2% EXAMPLE 2:

[0091] l-Butyl-3-methylimidazolium chloride (0.22 g, 1.25 mmol) and InCl₃ (98%, 0.55 g, 2.5 mmol; Aldrich) were melted together to generate [bmim] [In₂Cl₇]. Phenol (99% colorless solid, 0.94 g, 10 mmol; Aldrich) was added to the ionic liquid and heated at approximately 90⁰C-IOO⁰C), in a sealed reactor, to form a homogeneous liquid. To this liquid, t-butyl alcohol (98%, 0.95 ml, 10 mmol; Lancaster) was added in a stepwise manner over 2 hours. Once the addition of t-butanol was completed, the sealed reactor was further heated for 2 hours to allow the process to complete. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product indicated that the major product was 4-t-butylphenol, as shown by the following product distribution:

4-t-Butylphenol 71%

4-t-Butylphenol 71% 2-t-Butylphenol 1.6%

2,4-Di-t-butylphenol 12.5%

4-Octylphenol 5.9%

EXAMPLE 3:

[0092] l-Butyl-3-methylimidazolium chloride (0.17 g, 1.0 mmol) and indium (III) chloride (98%, 0.44 g, 2 mmol; Aldrich) were melted together to generate [C₄mim] [In₂Cl₇] as described previously. Phenol (99% crystalline colorless solid, 9.4 g, 100 mmol; Aldrich) was added to the ionic liquid and heated at 8O⁰C in a container sealed with a rubber septum. 2- Methyl-1-heptene (97%, 16 ml, 100 mmol, Aldrich) was added to this reaction mixture in a stepwise manner over 2 hours. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H- NMR analysis of the crude product indicated it is predominantly ¥-(2-methyl-l-heptyl) phenol.

4-(2-Methyl-l-heptyl)phenol 81 % (estimated by ^] H-NMR)

2-(2-Methyl-l-heptyl)phenol 5%

2, 4-(Di-2-Methyl-l-heptyl)phenol 2% EXAMPLE 4:

[0093] l-Butyl-3-methylimidazolium chloride (0.22 g, 1.25 mmol) and InCl₃ (98%, 0.55 g, 2.5 mmol; Aldrich) were melted together to generate [bmim] [In₂Cl₇] as described previously. Phenol (99% colorless solid, 0.94 g, 10 mmol; Aldrich) was added to the ionic liquid and heated at 120°C in a sealed reactor, to form a homogeneous liquid. To this liquid, cyclohexanol (98%, 0.95 ml, 10 mmol; Lancaster) was added in a stepwise manner over 2 hours. After the addition of cyclohexanol was completed, the sealed reactor was further heated for 2 hours to allow the reaction to complete. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product showed the following product distribution:

2-Cyclohexylphenol 21%

4-Cyclohexylphenol 12.8%

2,4-Dicyclohexylphenol 23.6%

2,6-Dicyclohexylphenol 9.4% EXAMPLE 5:

+ alter (KoAicte

[0094] l-Butyl-3-methylimidazolium chloride (0.17 g, 1.0 mmol) and indium (III) chloride (98%, 0.44 g, 2 mmol; Aldrich) were melted together to generate [C₄mim] [In₂Cl₇] as described previously. Phenol (99% crystalline colorless solid, 9.4 g, 100 mmol; Aldrich) was added to the ionic liquid and heated at 100°C in a glass vessel that was connected to a bubbler. Isobutylene gas (97%; Aldrich) was bubbled through this reaction mixture while maintaining an approximate flow rate of 20 ml/min. Analysis of the reaction mixture indicated that after approximately 180 minutes, essentially all the starting material was consumed. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product indicated it is predominantly 2,4-di-t-butylphenol.

4-M3utylphenol 1.5 % 2-t-Butylphenol 0.05 %

2, ¥-Di-t-butylphenol 78 %

2, 4, d-tri-t-butylphenol 13 %

EXAMPLE 6:

+ other products

[0095] l-Butyl-3-methylimidazolium chloride (0.22 g, 1.25 mmol) and InCl₃ (98%, 0.55 g, 2.5 mmol; Aldrich) were melted together to generate [bmim] [In₂Cl₇] as described previously. m-Cresol (99% colorless solid, 1.08 g, 10 mmol; Aldrich) was added to the ionic liquid and heated at 120°C in a sealed reactor, to form a homogeneous liquid. To this liquid, isopropyl alcohol (98%, 0.95 ml, 10 mmol; Lancaster) was added in a stepwise manner over 2 hours. After the addition of isopropyl alcohol was completed, the sealed reactor was further heated for 2 hours to allow the reaction to complete. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude showed the following product distribution:

Thymol 30%

5-Isopropyl-m-cresol 6%

4-Isopropyl-m-cresol 16%

4,6-Diisopropyl-m-cresol 9.4%

EXAMPLE 7:

+ other products [0096] l-Butyl-3-methylimidazolium chloride (0.17 g, 1.0 mmol) and indium (III) chloride (98%, 0.44 g, 2 mmol; Aldrich) were melted together to generate [C₄IrUm][In₂Cl₇] as described previously. rø-Cresol (10.5 g, 100 mmol; Aldrich) was added to the ionic liquid and heated at 100°C in a glass vessel that was connected to a bubbler. Propylene gas (97%; Aldrich) was bubbled through this reaction mixture maintaining an approximate flow rate of 20 ml/min. Analysis of the reaction mixture indicated that after approximately 90 minutes essentially all the starting material was consumed. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product indicated the following product distribution:

Thymol 12 %

2, 6-Diisopropyl-3-methylphenol 6 %

4, 6-Diisopropyl-3-methylphenol 15 %

Diisopropyl-3-methylphenol isomer 23 % EXAMPLE 8:

+ minor pπxkitis

[0097] l-Butyl-3-methylimidazolium chloride (0.35 g, 2 mmol) and InCl₃ (98%, 0.885 g, 4 mmol; Aldrich) were melted together to generate [bmim] [In₂Cl₇] as described previously. p-Cresol (99% colorless solid, 6.6 g, 60 mmol; Aldrich) was added to the ionic liquid and heated at 110°C in a sealed reactor, to form a homogeneous liquid. To this liquid, t-butanol (98%, 5.66 ml, 60 mmol; Lancaster) was added in a stepwise manner over 2 hours. After the addition of t-butanol was completed, the sealed reactor was further heated for 2 hours to allow the reaction to complete. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H- NMR analysis of the crude indicated that the major product was 2-t-butyl-4-methylphenol, as shown in the following product distribution:

2-t-Butyl-4-methyl phenol 75% 2,6-Di-t-butyl-4-methyl phenol 9.9% Unknown t-butylated product 1.0%

EXAMPLE 9:

+ πάnαrprodkicis

[0098] Reaction 5 was carried out by removing water under reduced pressure from the reaction 4 to reactivate the catalyst system. Another equivalent of t-butanol was added to the same reaction mixture and heated for further 4 hours.

EXAMPLE 10:

+ minor prockuls

[0099] Phenol (0.94 g, 10 mmol) and absolute ethanol (0.3 ml, 5.2 mmol) were allowed to react at 180°C in sealed reactor in presence of JbHiIm][In₂Cl₇] (1.2 mmol). After 12 hours, the reaction mixture was subjected to usual work-up and the following product distribution was seen:

2-Ethylphenol 17%

4-Ethylphenol 17%

3-Ethylphenol 4%

Phenyl ethyl ether 5%

EXAMPLE I l :

minor products

[0100] Phenol (0.94 g, 10 mmol) and dry methanol (0.3 ml, 5.2 mmol) were allowed to react at 18O⁰C in sealed reactor in presence of [bmim] [In₂Cl₇] (1.25 mmol). After 12 hours, the reaction mixture was subjected to the usual work-up and the following product distribution was seen:

Anisole 19% o-Cresol 10% m, p-Cresol 4% EXAMPLE 12:

+ other products

[0101] l-Butyl-3-methylimidazolium chloride (0.22 g, 1.25 mmol) and InCl₃ (98%, 0.56 g, 2.5 mmol; Aldrich) were melted together to generate [bmim] [In₂Cl₇] as described previously. Catechol (98% colorless solid, 1.1 g, 10 mmol; Aldrich) was added to the ionic liquid and heated at 100°C in a sealed reactor, to form a homogeneous liquid. To this liquid, isopropyl alcohol (98%, 0.76 ml, 10 mmol; Lancaster) was added in a stepwise manner over 1 hour. After the addition of isopropyl alcohol was completed, the sealed reactor was further heated for 2 hours to allow the reaction to complete. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC analysis indicated the presence of the following product distribution.

3-Isopropylcatechol 17.4%

4-Isopropylcatechol 27.4%

Diisopropylcatechol 1 12%

Diisopropylcatechol 2 19.3%

EXAMPLE 13:

N ΓWΪ other products

[0102] l-Butyl-3-methylimidazolium chloride (0.22 g, 1.25 mmol) and InCl₃ (98%, 0.55 g, 2.5 mmol; Aldrich) were melted together to generate [bmim] [In₂Cl₇] as described previously. Catechol (98% colorless solid, 1.1 g, 10 mmol; Aldrich) was added to the ionic liquid and heated at 90°C, in a sealed reactor, to form a homogeneous liquid. To this liquid, t-butanol (98%, 0.95 ml, 10 mmol; Lancaster) was added to this reaction mixture in a stepwise manner over 1 hour. After the addition of t-butanol was completed, the sealed reactor was further heated for 2 hours to allow the reaction to complete. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product indicated that it is essentially 4-t-butylcatechol.

Product distribution at 9O⁰C Product distribution at 110°C

4-t-Butylcatechol 83.8% 4-t-Butylcatechol 88%

4-t-Butylcatechol ether 9.6% 4-t-Butylcatechol ether 6%

4-Octylcatechol 3.2% 4-Octylcatechol 1.1%

EXAMPLE 14:

other products

[0103] l-Butyl-3-methylimidazolium chloride (0.22 g, 1.25 mmol) and InCl₃ (98%, 0.55 g, 2.5 mmol; Aldrich) were melted together to generate [bmim] [In₂Cl₇] as described previously. m-Cresol (99% colorless solid, 1.08 g, 10 mmol; Aldrich) was added to the ionic liquid and heated at 120°C in a sealed reactor, to form a homogeneous liquid. To this liquid, diisopropyl ether (98%, 0.95 ml, 10 mmol, Lancaster) was added, sealed, and heated to 100°C to 120°C in a microwave reactor for 6 hours. The reaction mixture was poured into water (5 ml). After the usual work up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product showed the following product distribution:

Thymol 35%

5-Isopropyl-m-cresol 13%

4-Isopropyl-m-cresol 10% 4,6-Diisopropyl-m-cresol 15% EXAMPLE 15:

major prodαct minor protkic±

[0104] l-Butyl-3-niethylimidazolium chloride (0.17 g, 1.0 mmol) and indium (III) chloride (098%, 44 g, 2 mmol; Aldrich) were melted together to generate [C₄mim] [In₂Cl₇] as described previously. p-Cresol (10.5 g, 100 mmol; Aldrich) was added to the ionic liquid and heated at 100°C in a glass vessel that is connected to a bubbler. Isobutylene gas (97%; Aldrich) was bubbled through this reaction mixture at an approximate flow rate of 20 ml/min. Analysis of the reaction mixture indicated that after approximately 90 min essentially all the starting material was consumed. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product indicated it to be essentially 2-t- butyl-4-methylphenol .

2-t-Butyl-4-methylphenol 71 %

2,<5-Di-/-butyl-4-methylphenol 6 %

2-/-Octyl-4-methylphenol 4 %

[0105] It is possible to promote the production of 2,6-di-t-butyl-4-methylphenol (BHT) by bubbling a second equivalent of isobutylene into the reaction mixture, thereby indicating the controllability of this reaction.

EXAMPLE 16:

[0106] l-Butyl-3-methylimidazolium chloride (0.17 g, 1.0 mmol) and indium (III) chloride (98%, 0.44g, 2 mmol; Aldrich) were melted together to generate [C₄mim] [In₂Cl₇] as described previously. Catechol (99% colorless flakes, 11.0 g, 100 mmol; Aldrich,) was added to the ionic liquid and heated at 110°C in a glass vessel connected to a bubbler. Isobutylene gas (97%; Aldrich) was bubbled through this reaction mixture maintaining an approximate flow rate of 20 ml/min. Analysis of the reaction mixture indicated that after approximately 90 minutes essentially all the catechol was consumed. The reaction mixture was poured into water (5 ml) and extracted with ether. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product indicated it to be predominantly 4-t-butylcatechol.

4-M3utylcatechol 85%

3, 5-Di-t-butylcatechol 7%

4-t-Octylcatechol 2%

EXAMPLE 17:

[0107] l-Butyl-3-methylimidazolium chloride (0.17 g, 1.0 mmol) and indium (III) chloride (98%, 0.44 g, 2 mmol; Aldrich) were melted together to generate [C₄mim] [In₂Cl₇] as described previously. Catechol (99% colorless flakes, 11 g, 100 mmol; Aldrich) was added to the ionic liquid and in a reaction vessel connected to a condenser. After flushing the system with nitrogen, the reaction mixture was heated at 110°C in order to homogenize the catechol in the ionic liquid. A portion of diisobutylene (97%, 10 mmol; Aldrich) was added to the reaction vessel. After the addition of this portion of diisobutylene, the reaction vessel was cooled to approximately 90°C to 100°C. The remaining diisobutylene (90 mmol) was added to this reaction mixture in a stepwise manner over 2 hours. Water (5 ml) was added to the warm reaction mixture, stirred for 15 minutes, and filtered to remove the catalyst and water. After the usual work-up, the crude product was isolated. GC and ¹H-NMR analysis of the crude product indicated it to be predominantly 4-t-Octylcatechol.

4-t-Octylcatechol 85%

4-t-Butyl-catechol 3.2%

3,5-Di-t-Octylcatechol 2.4% [0108] Non-limiting examples of catalytic ionic liquids that are within the scope of the present invention are shown below:

X = OorS

[A] = [In_nY_3n+I] , where:

Y is a halogen, preferably Cl; n is 1 < n < 3; and

R¹ to R⁶ are independently selected from substituted alkyl groups, unsubstituted alkyl groups, branched alkyl groups, unbranched alkyl groups, cycloalkyl groups, conjugated aryl groups, or unconjugated aryl groups.

[0109] Although the present invention has been described in terms of preferred and alternate embodiments, it is intended that the present invention encompass all modifications and variations that occur to those skilled in the art, upon consideration of the disclosure herein, those embodiments that are within the broadest proper interpretation of the claims and their requirements.

Claims

We claim :

1. A process for the production of alkyl-substituted hydroxyarene compounds comprising the step of treating at least one hydroxyarene with a least one alkylating agent selected from the group consisting of an olefin, alcohol, and ether, in the presence of at least one chloroindate (III) anion containing ionic liquid.

2. The process of claim 1, wherein the hydroxyarene is selected from the group consisting of phenol, cresols, xylenols, trimethylphenols and dihydroxyarenes.

3. The process of claims 1-2 wherein the chloroindate (III) anion is selected from the group consisting of [InCl₄]^", [In₂Cl₇]^' and [In₃Cl₁₀]^".

4. The process of claims 1-3 wherein the alkylating agent is an olefin.

5. The process of claims 1-3 wherein the alkylating agent is an alcohol.

6. The process of claims 1-3 wherein the alkylating agent is an ether.

7. The process of claim 4, wherein the olefin is selected from the group consisting of ethylene, propylene, isobutylene, diisobutylene, cis-2-butene, trans-2-pentene, cyclopentene, cyclohexene, 1,4-cyclohexadiene, and 2-methyl-l-heptene.

8. The process of claim 5, wherein the alcohol is selected from the group consisting of methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, t-butyl alcohol, cyclopentyl alcohol, cyclohexyl alcohol and benzyl alcohol.

9. The process of claim 6, wherein the ether is selected from the group consisting of dimethyl ether, ethyl methyl ether, diethyl ether, diisopropyl ether, and methyl t-butyl ether (MTBE).

10. A catalytic ionic liquid system comprising a cationic component and an anionic component, wherein the cationic component is selected from the group consisting of

(a) an imidazolium cation substituted with 1, 2, or 3-alkyl groups,

(b) tetraalkylphosphonium,

(c) tetraalkylammonium,

(d) dialkylpyrrolidinium, and (e) piperidinium;

(f) trialkylsulfonium; and the anionic component is [In_nCl_3n+]]^", where n is selected from the group consisting of 1, 2, and 3, which is generated by combining InCl₃ and [R][Cl] where x is the mole fraction OfInCl₃ with respect to InCl₃ combined with [R] [Cl], 0.5< x <0.8, and R is selected from either the cationic component or ammonium or phosphonium cations bearing one or more branched alkyl groups, unbranched alkyl groups, cycloalkyl groups, conjugated aryl groups, or unconjugated aryl groups.

11. The catalytic ionic liquid system of claim 10, wherein the catalytic ionic liquid system is formed by the reaction of [R][Cl] and InCl₃, where [R] is the cationic component.

12. The catalytic ionic liquid system of claim 11 wherein the catalytic ionic liquid system is formed by the reaction of approximately n equivalents OfInCl₃ per equivalent of [R][Cl], where n is 1, 2, or 3.

13. A process for the alkylation of hydroxyarenes comprising a step of treating at least one hydroxyarene with at least one alkylating agent selected from the group consisting of an olefin, alcohol, or ether, in the presence of the catalytic ionic liquid system of claims 10-12.

14. The process of claim 13 comprising a separation step following the step of treating the hydroxyarene with the alkylating agent, wherein the step of treating the hydroxyarene with the alkylating agent yields a product and further wherein:

(i) the separation step uses water;

(iii) removal of water can regenerate the catalytic ionic liquid system.

15. The process of claim 14, wherein the separation step is decantation.

16. The process of claims 13-15, wherein the reaction of [R][Cl] and InCl₃ occurs prior to step of treating at least one hydroxyarene with the alkylating agent.

17. The process of claims 13-16 wherein the hydroxyarene is selected from the group consisting of phenol, cresols, xylenols, trimethylphenols and dihydroxyarenes.

30

4003Q1660v2

18. The process of claims 13-17 wherein the alkylating agent is an olefin selected from the group consisting of ethylene, propylene, isobutylene, diisobutylene, cis-2-butene, trans-2- methyl-1-heptene, cyclohexene.

19. The process of claim 19, wherein the process is carried out at a temperature less than approximately 300°C.

20. The process of claims 13-18, wherein the process is carried out at a temperature of from about 8O⁰C to about 180°C.

21. The process of claims 13-20, wherein the process is conducted at approximately atmospheric pressure without the use of a high pressure reactor.

22. The process of claims 13-21, wherein the process is carried out at a pressure of approximately 1 atmosphere.

23. The process of claim 13 wherein the hydroxyarene is catechol, the alkylating agent is diisobutylene, and wherein 4-t-octylcatechol is produced.

24. The process of claim 23, wherein the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to catechol.

25. The process of claims 23-24 conducted at atmospheric pressure without the use of a high- pressure reactor.

26. The process of claim 13 wherein the hydroxyarene is phenol, the alkylating agent is diisobutylene, and wherein 4-t-octylphenol is produced.

27. The process of claim 26, wherein the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to phenol.

28. The process of claim 26-27 conducted at atmospheric pressure without the use of high- pressure reactors.

29. The process of claim 13 wherein the hydroxyarene is m-cresol, the alkylating agent is propylene, and wherein thymol is produced.

30. The process of claim 29, wherein the concentration of the catalytic ionic liquid system is from approximately 0.1 mole % to approximately 1 mole % with respect to rø-cresol.

31. The process of claims 29-30 conducted at atmospheric pressure without the use of a high- pressure reactor.

32. The process of claim 1 wherein:

31 zmmni ήήfiv? (i) the hydroxyarene is catechol; (ii) the alkylating agent is t-butanol (iii) 4-t-butylcatechol is produced; and

(iv) the reaction is earned out at approximately 110°C and at approximately 1 atmosphere.

33. The process of claim 32, wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

34. The process of claim 1 wherein:

(i) the hydroxyarene is phenol; (ii) the alkylating agent is t-butanol (iii) 4-t-butylphenol is produced; and

(iv) the reaction is carried out at approximately 100°C and at approximately 1 atmosphere.

35. The process of claim 34, wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or

1 ,2-dimethyl-3-butylimidazolium heptachlorodiindate(III).

36. The process of claim 1 wherein:

(i) the hydroxyarene is p-cresol; (ii) the alkylating agent is t-butanol (iii) 2-t-butyl-p-cresol is produced; and

37. The process of claim 36, wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

38. The process of claim 1 wherein:

(i) the hydroxyarene is p-cresol; (ii) the alkylating agent is t-butanol

(iii) 2, 6-di-t-butyl-p-cresol is produced; and

(iv) the reaction is carried out at approximately 100⁰C and at approximately 1 atmosphere.

39. The process of claim 38, wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

40. The process of claim 1 wherein:

(i) the hydroxyarene is m-cresol;

(ii) the alkylating agent is isopropanol

(iii) thymol is produced; and

41. The process of claim 40, wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).

42. The process of claims 1-9, 13-41, further comprising administering microwave energy to at least some of the reactants to affect formation of product.

43. A process for the production of 2-t-butyl-p-cresol comprising the step of treating p-cresol with t-butanol in the presence of at least one chloroindate (III) anion containing ionic liquid, wherein said reaction is carried out at approximately 100°C and microwave energy is administered to at least some of the reactants to affect formation of product.

44. The process of claim 43, wherein the at least one chloroindate (III) anion containing ionic liquid comprises l-butyl-3-methylimidazolium heptachlorodiindate (III) or l,2-dimethyl-3-butylimidazolium heptachlorodiindate (III).