CN1705640A - Ionic liquids containing a sulfonate anion - Google Patents

Abstract

The present invention relates to novel ionic liquids comprising a docusate, docusate variant, or other sulfonate anion. The ionic liquids may be conveniently made via, for example, metathesis. The ionic liquids are often hydrophobic and useful in many hydrocarbon compositions, polymer compositions, and in supercritical carbon dioxide applications. The ionic liquids are capable of hindering static electricity buildup in the hydrocarbon compositions and can therefore minimize flammability and/or explosiveness.

Description

Ionic Liquids Containing Sulfonate Anions

relevant application data

This application claims priority to the following provisional applications: U.S. Provisional Application No. 60/404,178, filed August 16, 2002, and U.S. Provisional Application No. 60/404,202, filed August 16, 2002.

field of invention

The present invention relates to compositions comprising ionic liquids comprising docusate anions, docusate variant anions or other sulfonate anions, and methods for the preparation of such compositions.

Background and overview of the invention

Ionic liquids are salts that are liquid at or near ambient temperature. Ionic liquids have many uses including replacement of organic solvents in chemical processes and reactions, extraction of organic compounds from aqueous waste streams, and as electrolytes in devices such as capacitors and batteries. This is due to the fact that, unlike common organic solvents, ionic liquids are non-volatile and non-flammable. These properties are advantageous for helping to reduce evaporation losses, eliminate volatile organic volatiles, and improve safety.

Other properties of ionic liquids have also proven to be advantageous. For example, many ionic liquids have a broad temperature range over which they remain liquid, and are also stable over a broad pH range. This is beneficial for high temperature processes with high pH requirements. Furthermore, some ionic liquid systems can be used as both solvents and catalysts. For example, [bmim] _-Al2Cl7 and [ _emim ] _-Al2Cl7 can be used as solvent and _catalyst in the Friedel-Crafts reaction, where bmim is 1-butyl-3-methylimidazolium and emim is 1- Ethyl-3-methylimidazolium.

For the above reasons, there is a need to discover new ionic liquid compounds with favorable properties. There is a further need that such compounds can be prepared by simple processes with low amounts of waste materials and impurities.

Advantageously, new ionic liquid compounds have been discovered. The compound includes docusate or other sulfonate anions, and is prepared by a simple process that enables the production of ionic liquids with high purity.

Detailed description of the invention

As used herein, "ionic liquid" means a salt comprising cations and anions. A salt (or a hydrate or solvate of a salt) is a liquid (ie, melting point, or melting range, below about 100° C.) at or near ambient temperature. An ionic liquid may include two or more different salts, such as a mixture of salts including two or more different cations, anions, or both. The ionic liquids of the invention are typically hydrated or solvated. Accordingly, both hydrates and solvates are considered within the definition of "ionic liquid".

As used herein, "hydrophilic ionic liquid" means an ionic liquid that is partially or completely miscible with water.

As used herein, "hydrophobic ionic liquid" means an ionic liquid that is relatively immiscible with water, ie forms two phases under ambient conditions.

As used herein, "composition" includes a mixture of materials comprising the composition and products formed by reaction or decomposition of the materials comprising the composition.

As used herein, "derived from" means prepared or mixed from specified materials, but does not necessarily consist of a simple mixture of those materials. A substance "derived from" a specified material may be a simple mixture of starting materials, and may also include reaction products of those materials, or may even consist entirely of reaction or decomposition products of starting materials.

"Halogen" as used herein means chlorine, bromine, fluorine or iodine, and arylene means a divalent aromatic group such as phenylene, naphthylene, biphenylene, anthracenyl, phenanthrenylene, etc., and Heteroaryl means a divalent heteroaromatic group such as pyrrolene, furyl, thienyl, pyridyl, etc., and alkylene means a divalent alkane group, which can be composed of one or more A heteroatom such as nitrogen or oxygen is substituted, cycloalkylene represents a divalent cycloalkane group, and the divalent cycloalkane group can be substituted by one or more heteroatoms such as nitrogen or oxygen, and alkenylene represents a divalent alkenyl group group, the divalent alkene group may be substituted by one or more heteroatoms such as nitrogen or oxygen.

"Docusate" as used herein means the anion of bis(2-ethylhexyl) sulfosuccinate. The chemical formula of docusate (anion) is C ₂₀ H ₃₇ O ₇ S ⁻ . As used herein, "docusate variants" are intended to include compounds described by the chemical structures I and III below, and anions including bis(organic) sulfosuccinate derivatives and bis(organic) amides of sulfosuccinate ) derivative anion.

Any numerical value recited herein includes all numerical values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if a number of components or process variables such as temperature, pressure, time, etc. are stated as values such as 1-90, preferably 20-80, more preferably 30-70, then this specification is considered to explicitly list a value such as 15 -85, 22-68, 43-51, 30-32, etc. For values less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1, as appropriate. These are only specifically intended examples, and all possible combinations of numerical values between the lowest and highest values listed are considered to be expressly stated in a similar manner in this application.

The ionic liquids of the present invention comprise one or more compounds. Thus, an ionic liquid may be a pure compound or may be a mixture of compounds. Each compound contains an anion or mixture of anions and a cation or mixture of cations as described below.

R ₁ -OC(O)-CH(SO ₃ ^- )-R ₃ -C(O)-OR ₂ ; and

I

anion

Exemplary anions of the compounds of the present invention include those having chemical formulas selected from the group consisting of R ₁ , R ₂ , R ₄ and R ₅ in formulas I and II above are independently selected from substituted or unsubstituted alkyl or alkenyl groups. The alkyl or alkenyl groups of R ₁ , R ₂ , R ₄ and R ₅ should contain a sufficient number of carbon atoms to allow the ionic liquid to have the desired properties. For example, if a hydrophobic ionic liquid is desired, the total number of carbon atoms in the ionic liquid is generally greater than if a hydrophilic ionic liquid is desired. However, if too many carbon atoms are present in the anion, the ionic liquid may be less useful as an ionic liquid due to a decrease in properties such as vapor pressure, dipole moment, polarity, etc.

For hydrophobic ionic liquids, _R1 , _R2 , _R4 and _R5 are preferably independently selected from alkyl groups containing about five or more carbon atoms, preferably about 6 to about 18 carbon atoms. A preferred group for R ₁ , R ₂ , R ₄ and R ₅ is -CH ₂ -CH(CH ₂ CH ₃ )(CH ₅ CH ₂ -CH ₃ ). This group is useful for the properties it provides to the ionic liquid and for its cost and ease of manufacture.

R ₃ in Formula I is a substituted or unsubstituted alkylene, heteroarylene, arylene or cycloalkylene. Preferably, R ₃ is substituted or unsubstituted alkylene, and even more preferably, R ₃ is —(CH ₂ ) _n —, where n is an integer from about 1 to about 10.

R ₆ , R ₇ and R ₈ are independently selected from hydrogen (H) or another substituent such as alkyl, NO ₂ , halogen, cyano, silyl and OH. Preferably, _R6 , _R7 and _R8 are H.

In some cases, two or more adjacent substituents such as R ₁ and R ₂ , R ₄ and R ₅ , R ₆ and R ₇ , and/or R ₇ and R ₈ may join together to form a ring such as 5-7 membered carbon ring. Examples of such carbocycles include cyclopentyl and cyclohexyl rings.

R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₅ , R ₇ and R ₈ may be optionally substituted with one or more substituents. The type of substituent is not particularly critical so long as the compound or mixture of compounds possesses the desired ionic liquid properties. Thus, substituents generally include typical and atypical organic substituents such as those selected from the group consisting of alkyl, _NO2 , halogen, cyano, silyl, OH and other suitable substituents. The substituents themselves can often be further branched.

Another exemplary anion that can be used in the preparation of ionic liquids is the docusate variant having the following chemical structure:

R ₁ -N(R ₂ )-C(O)-CH(SO ₃ ^- )-R ₃ -C(O)-N(R ₄ )-R ₅

III

R ₁ , R ₂ , R ₃ , R ₄ and R ₅ in the chemical structural formula III can be independently selected from hydrogen atoms (H) or carbon-containing groups, such as alkyl, alkenyl, alkynyl, aryl, benzyl , Alkyl ether, etc.

In one embodiment, the anion source is 2-ethylhexylamide sulfonate sodium salt, which can be synthesized using known techniques with the benefit of this description. For example, prepare _an anion having the above chemical structure III, wherein R _{and R} are each 2-ethylhexyl, R and _R are each a hydrogen atom, and _R is methylene. Two different ionic liquids were prepared using this anion by first isolating it as the sodium salt and then reacting it with two different cation sources. The cation in one ionic liquid is tetrabutylammonium cation. The cation in another ionic liquid is 1-methyl-3-hexylimidazolium.

In other experiments, a second anion having the above chemical structure III was prepared, wherein R and _R were each 2-ethylhexyl, _{R and R} were each ethyl, and _R was methylene. Two additional ionic liquids were prepared using this anion by first isolating it as the sodium salt and then (in a separate experiment) combining it with the same two cation sources described above, namely tetrabutylammonium cation and 1- Methyl-3-hexylimidazolium reaction.

Based on experiments in which ionic liquids were prepared from anions of formula III, it is believed that, in the case of docusate salts and their derivatives and variants, each R group in formula III may vary in length or composition , and still produce ionic liquids when combined with suitable cations such as onium cations.

cation

The cation of the ionic liquid to be produced is not particularly critical, provided the ionic liquid has properties which render it suitable for its intended use. Typical useful cations include, for example, "onium" cations. Onium cations include cations such as substituted or unsubstituted ammonium, phosphonium and sulfonium cations. Preferred onium cations include, for example, substituted or unsubstituted N-alkyl or N-arylpyridiniums, pyridaziniums, pyrimidiniums, pyraziniums, imidazoliums, pyrazoliums, thiazoliums, oxazoliums, Azolium, imidazolinium, methylpyrrolidinium, isothiazolium, isoxazolium, oxazolium, pyrrolium and thiophenium. Substituents include one or more of the following groups: halogen, alkyl and aryl such as phenyl. In addition, two adjacent substituents can join together to form an alkylene group, thus forming a ring structure merged at N. Alkyl, phenyl and alkylene groups may be further substituted. Another particularly preferred cation is ammonium cation substituted by one or more groups such as alkyl and aryl such as phenyl. Many such cations and substituted cations are described in U.S. Patent Nos. 5,827,602 and 5,965,054, which are hereby incorporated by reference in their entirety.

Other suitable cations include BMIM, tetrabutylammonium, tributylmethylammonium, tetrabutylphosphonium, tetraethylammonium, N,N-dialkylpyrrolidinium, trimethyl 2-hydroxyethylammonium, N, N'-dialkylimidazoliums, N-alkylpyridiniums or mixtures thereof. The cation may be an onium cation and optionally contain more than 4 carbon atoms.

Process for the preparation of compounds of structural formula I-III and mixtures thereof

Ionic liquid compounds of formula I-II can be conveniently prepared by a number of different methods. One method suitable for preparing the hydrophobic or hydrophilic ionic liquids or mixtures of the present invention involves the use of displacement reactions, i.e., metathesis reactions, whereby the reaction of two or more compounds forms two or more new compounds, one of which is an ionic liquid. For example, reacting [bmim]Cl with docusate sodium will give [bmim]docusate and NaCl. The two or more compounds produced by the metathesis reaction can then be separated by any means.

The manner in which the two or more compounds are contacted to form the ionic liquid is not particularly important so long as the desired reaction occurs. In general, the compounds can be mixed in any order, can be formed in situ, or can be mixed together with a solvent such as water that is at least partially miscible and does not significantly react with any of the compounds.

Starting compounds are generally readily available and, moreover, a number of syntheses are available to those skilled in the art to prepare the desired starting compounds. Mixing conditions can vary depending on the particular compounds employed and the desired product. In most cases, it is acceptable to contact the compound and optionally a solvent such as water or dichloromethane at ambient pressure and at a temperature high enough for the reaction to occur efficiently but not so high as to decompose or boil off any starting compound. Generally, the contacting temperature may be from about 75 to about 110°C, preferably from about 85 to about 100°C. When water is used as the solvent, a temperature of from about 75 to about 110°C is sometimes preferred because this tends to disrupt the emulsion that normally forms between the ionic liquid and water. On the other hand, when the solvent is organic (such as dichloromethane), the preferred temperature is generally significantly lower, usually around room temperature such as 25°C or slightly above room temperature.

The manner in which the increased temperature is achieved and maintained is not particularly critical. When the compounds are mixed or the starting compounds can be heated separately and then mixed, generally any heating element can be used. Similarly, any vessel or reactor may be used so long as it is of appropriate size and material. It is often beneficial to employ stirring means to facilitate the reaction.

Generally, the increased temperature is maintained for at least a sufficient time until the desired reaction occurs to the desired extent. In some cases, it may be necessary to maintain the increased temperature for a longer time than is required to complete the reaction. In this way, any water or low-boiling components formed as by-products or present as solvents can be removed by boiling.

The amount of each starting compound can vary depending on the desired yield. In general, high yields are usually obtained by using approximately stoichiometric amounts of reactants, ie, about a 1:1 ratio. However, as understood by those skilled in the art, different reaction conditions can alter the ratio of reactants that yields optimal yields.

If one desires to prepare an ionic liquid mixture comprising two or more different salts, it can be done by taking a mixture of three or more different compounds such that the various salts are formed. The obtained ionic liquid salt mixture can then be used as a mixture, or if desired, the individual salts can be separated by conventional measures.

If desired, any suitable means may be used to recover the ionic liquid or ionic liquid mixture from the solvent and/or reaction mixture, where the most effective means may vary depending on the type and desired purity of the ionic liquid or mixture. Suitable recovery measures include rotary evaporation or distillation, azeotropic distillation, ion chromatography, liquid-liquid extraction, crystallization, pervaporation, desiccant and reverse osmosis.

Although the methods described above can be used to prepare hydrophobic or hydrophilic ionic liquids, in some applications it is preferred to prepare hydrophobic ionic liquids. This is due to the fact that hydrophobic ionic liquids are generally not very soluble in water, which is commonly used as a reaction medium. Therefore, simple liquid-liquid extraction can be used to separate hydrophobic ionic liquids from soluble by-products. In contrast, hydrophilic ionic liquids are often miscible with by-products. So different separation methods such as solvent extraction can be used. For example, it may be desirable or necessary to use a hydrophobic solvent, such as an alkyl chloride such as dichloromethane, to extract the ionic liquid.

Characteristics and uses of the ionic liquid of the present invention

The purity of the ionic liquid produced by the method of the invention may generally be greater than 55%, preferably greater than 60%, more preferably greater than 70%, most preferably greater than 80%. This is often advantageous for processes requiring high purity materials such as in the electronics industry. Ionic liquids are also preferably hydrophobic and thus can be used in many processes as a replacement for organic solvents, and in mixtures containing catalysts such as _ZnCl2 , _CuCl2 , _AlCl3 , and organic catalysts.

The ionic liquids of the invention are also commonly used in mixtures containing hydrocarbons, for example alkanes such as hexane. The mixture usually has no static charge, so it is not easy to ignite or explode.

Docusate and Docusate Variants in Supercritical _CO2 Applications

Tetrabutylammonium docusate was found to be soluble in supercritical carbon dioxide ( _CO2 ). Supercritical applications using _CO2 typically operate at temperatures above 32°C and at pressures greater than about 1,070 psi. Ionic liquids based on docusate and docusate variants are believed to be useful builders, additives and detergents to be added to supercritical _CO2 for cleaning, synthesis and separation applications.

Docusate and docusate variants as antistatic agents

Ionic liquids based on docusate and docusate variants are believed to be useful antistatic additives for fuel applications and polymer applications. Ionic liquids based on docusate and docusate variants tend to be partially or completely miscible with hydrocarbons (eg alkanes such as hexane) and can be added to fuels as antistatic additives. These ionic liquids can also be added to polymers such as polyvinyl acetate as antistatic additives.

Docusate and docusate variants in ionic liquid blends

In one embodiment, two or more ionic liquids are blended together to form an improved reaction solvent. It is believed that Lewis acid ionic liquids can be advantageously blended with docusate or docusate variant based ionic liquids to form an improved reaction solvent that provides better mixing between the reactants for improved reaction kinetics study. Since docusate and docusate variant ionic liquids tend to be at least relatively miscible with hydrocarbon streams, they tend to inhibit the formation of two phases and improve mixing and contacting between reactants. Examples of Lewis acid ionic liquids believed to be useful in the preparation of blends of ionic liquids containing sulfonate anions (such as docusate and docusate variants) of the present invention are disclosed in August 2003 entitled "Lewis Acid Ionic Liquids". In the co-pending U.S. application (serial number currently unknown) filed on April 15 and invented by Roger Moulton, this document is incorporated by reference as fully set forth herein.

Exemplary Lewis acid ionic liquids for use in these blends include ionic liquids containing (i) cations selected from the group consisting of ammonium, sulfonium, and phosphonium cations and containing a total of less than 14 carbon atoms; and (ii) having Anions of the general formula Al _y R _3y+1 , wherein y is greater than 0 and R is independently selected from alkyl and halogen groups. A suitable anion for the Lewis acid ionic liquid in the blend is the aluminum chloride anion.

Suitable cations for Lewis acid ionic liquids are tetraalkylammoniums. Depending on the desired properties of the ionic liquid, it may be advantageous for one or more alkyl groups to be optionally substituted with one or more suitable substituents. Suitable substituents include, for example, halogen such as chlorine, bromine or iodine. Particularly preferred tetraalkylammonium cations include trimethylethylammonium, trimethylchloromethylammonium, trimethylbutylammonium and tributylmethylammonium.

Another suitable cation for Lewis acid ionic liquids are N-alkyl substituted saturated heterocycles such as piperidinium and morpholinium. In particular, piperidiniums substituted on the nitrogen by alkoxy or alkyl groups such as -( _CH2 ) _2OMe , butyl or propyl are of particular interest. Pyrrolidine-based cations may also be employed. The cation may include ether functionality (eg NCH ₂ CH ₂ OCH ₃ ⁺ ). The cation may include a haloalkyl group.

Exemplary Lewis acid ionic liquids for blends include those containing aluminum chloride anions and cations derived from the following ammonium salts: MeBu ₃ NCl, Me ₃ Amyl NCl, Me ₃ Butyl NCl , MeEt ₃ NCl, Me ₂ Et ₂ NCl, Cl-CH ₂ -NMe ₃ Cl, or N-methyl-N-butylpyrrolidinium Cl. Other exemplary Lewis acid ionic liquids include N-alkyl substituted piperidinium heptachlorodialuminate, trimethylchloromethylammonium heptachlorodialuminate, trimethylbutylammonium heptachlorodialuminate, and Tributylmethylammonium aluminate.

The following examples are not intended to limit the invention, but are intended to illustrate only a few specific ways in which the invention may be employed.

Embodiment 1: the synthesis of tetrabutylammonium docusate

1 mole of docusate sodium (444 g) was dissolved in 2 liters of water and then 1 mole of tetrabutylammonium bromide (321 g) was added as a solid. After stirring for a few minutes, stirring was stopped and the solution separated into two layers. Collect the upper layer in a separatory funnel. It was washed twice with 1 liter of water and heated to 100° C. to facilitate phase separation. The tetrabutylammonium docusate obtained was heated to 110°C to drive off any dissolved water therein. Yield was almost quantitative (624 g, 94% yield).

Example 2-5

The ionic liquids of Examples 2-5 in Table 1 below are prepared in the same manner as in Example 1, except that about 1 mole of starting material in Table 1 replaces 1 mole of tetrabutylammonium bromide in Example 1 .

Table 1 Example starting material ionic liquid Solubility in water 2 Me(n-Bu) ₃ NBr Me(n-Bu) ₃ N docusate Hydrophobic 3 Me ₃ N(CH ₂ ) ₆ NMe ₃ Br Me ₃ N(CH ₂ ) ₆ NMe ₃ docusate Hydrophobic 4 n-Bu ₄ PBr n-Bu ₄ P docusate Hydrophobic 5 Et ₄ NBr Et ₄ N docusate Mixed

Example 6-10

The ionic liquids of Examples 6-10 in Table 2 below were prepared by dissolving docusate sodium in dichloromethane and dissolving the starting materials of Table 2 in dichloromethane in separate flasks. The two solutions were mixed and stirred for about 12 hours. The solution was then filtered to remove precipitated solid salts and evaporated to a thick slurry. The thick slurry was then extracted with ether, hexane or mixtures thereof and filtered again to remove solid salts. After rotary evaporation, the residue was redissolved in hexane/ether, and the filtration process was repeated (using progressively smaller portions of ether in the mixture) until no more solids formed. The salts obtained are then washed with water for final removal of inorganic salts, after which they are dried in vacuo.

Table 2 Example starting material ionic liquid 6 1-n-Hexyl-3-methylimidazolium bromide 1-n-Hexyl-3-methylimidazolium docusate 7 1-n-octyl-3-methylimidazolium bromide 1-n-octyl-3-methylimidazolium bromide docusate 8 1-n-Butyl-3-methylimidazolium bromide 1-n-Butyl-3-methylimidazolium docusate 9 1-Methyl-2-ethylimidazolium bromide 1-Methyl-2-ethylimidazolium docusate 10 Tetra-n-butylammonium bromide Tetra-n-butylammonium docusate

The ionic liquids of Examples 6-10 are generally hydrophobic ionic liquids. In the case of Example 6, which was 1-hexyl-3-methylimidazolium docusate, contacting it with 40 volume percent or less of water resulted in the formation of two phases, even after stirring. However, when 1-hexyl-3-methylimidazolium docusate was contacted with 50 volume percent water, agitation produced a hard, visually single-phase gel. Addition of additional water to the gel, followed by stirring, again resulted in the formation of two phases. While not wishing to be bound by any particular theory, it is believed that some ionic liquids of the present invention may hydrate or solvate when mixed with some proportion of water. This results in the formation of ionic liquids that are insoluble and form two phases when mixed with some proportions of water and a single phase at other proportions. This unique property can be very beneficial for some applications where solubility or insolubility with water is important.

Example 11

This example details the synthesis of the molten tetrabutylammonium salt of amide having formula III above. One tenth mole (50 g) of the amide-sulfonic acid sodium salt having the above chemical structure III (R ₂ and R ₄ are CH ₂ CH ₃ , R ₁ and R ₅ are each 2-ethylhexyl, and R ₃ ( _CH2 ) was dissolved in 250 mL of dichloromethane, and a tenth mole (32 g) of tetrabutylammonium bromide was added as a solid. The mixture was stirred for one day, after which time the solution was filtered first through filter paper and then through a short plug of silica gel. The eluted dichloromethane solution was washed quickly with water, dried over magnesium sulfate, and the solvent was removed in vacuo to leave the desired product in high yield (64 g, 89%). The product salt is soluble in water and also in several common organic solvents such as dichloromethane and acetone. Since the product is a viscous oil at room temperature, the melting range of the obtained salt is below about 30°C. The product salt comprises a bis(N-ethyl-N-(2-ethylhexyl)sulfosuccinic acid diamide) anion paired with a tetrabutylammonium cation.

Examples 12-19

These examples illustrate the preparation of ionic liquids from the sodium salt of sulfosuccinate, which is a docusate variant. The ester is then combined with an onium cation to prepare an onium molten salt.

10 grams (0.03 mol) of tetrabutylammonium bromide was dissolved in 50 mL of water, and to the stirred solution was added 12 grams (0.03 mol) of the sodium salt of di-n-hexyl sulfosuccinate as a solid. ("Di-n-hexyl sulfosuccinate" means that the sulfosuccinic acid molecule is esterified on both carbonyl groups of the sulfosuccinic acid molecule and not on the sulfo group). After stirring for several minutes, the aqueous layer was extracted with three sequential 50 mL portions of dichloromethane, which was then combined, dried over anhydrous magnesium sulfate, and evaporated to leave the desired product (13 g, 73% yield ). Since the product is a viscous oil at room temperature, the melting range of the obtained salt is below about 30°C.

The same experimental procedure was used to prepare ionic liquids of tetrabutylammonium cation and the sodium salt of the following docusate variants: (i) di-n-cyclohexyl sulfosuccinate; (ii) di-n-cyclohexyl sulfosuccinate; (iii) di-n-butyl ester of sulfosuccinic acid; (iv) diisobutyl ester of sulfosuccinic acid; (v) di-neopentyl ester of sulfosuccinic acid; (vii) di-n-heptyl ester of sulfosuccinic acid; and (vii) di-n-heptyl ester of sulfosuccinic acid. The melting range for the resulting salt is below about 80°C and typically about 40°C to 80°C. The octyl and heptyl docusate variants have lower melting ranges, as shown by the fact that they are viscous liquids at room temperature.

Representative NMR data

The structure and composition of the ionic liquids were determined by 1H-NMR spectroscopy. For all docusate salts (2-ethylhexyl sulfosuccinate diester), the spectra simply consisted of resonances from anions superimposed on those of the cations. For all docusate salts, the resonances derived from the anion were (with little variation) in the following ranges: (300Mhz, CDC13, d: 0.73-0.83 (triplet), 1.24-1.70 (overlapping multiplet), 3.05- 3-31 (composite m), 3.90-4.25 (overlap m)

Cation resonance (300MHz, CDC13, d): (1-methyl-3-hexylimidazolium): 0.79(t), 1.21-1.27(overlap m), 1.80(m), 4.03(s), 4.22(t) , 7.35(s), 7.49(s), 9.50(s).

(Tetraethylammonium): 1.32(t), 3.34(q)

(Tetrabutylammonium): 1.03(t), 1.20-1.40(overlap m), 3.23(q)

(Tetraoctylammonium): 0.86(t), 1.18-1.50(overlap m), 3.25(q)

(N-methyl-N-( _{CH2CH2OCH2CH3} )pyrrolidinium) _: 0.86(t ₎ , 1.31(m ₎ , 2.11(m), 3.0-4.2(composite overlap m)

(Trimethylhexadecylammonium): 0.87(t), 1.20-1.60(overlap m), 2.13(s), 3.15(q)

(Methyltributylammonium): 0.84(t), 1.23-1.70(overlap m), 2.20(s), 3.24(m)

(1,2-bis(tributylammonium)ethane): 0.83(t), 1.22-1.58(overlap m), 2.20(s), 3.22(m)

Ionic liquids of several docusate variants were also prepared. Like the NMR spectra of docusate derivatives, the NMR spectra of these salts consist of the spectrum of a specific anion superimposed on the spectrum of a specific cation. Below are the NMR data for the tetrabutylammonium derivatives of the three docusate variant salts. For each salt, the resonances from the cations coincided with those of the tetrabutylammonium cation of docusate, their values listed above. The following are resonances (300 MHz, CDC13, d) from the anions of these example salts:

Bis(n-hexylsulfosuccinic acid diester): 0.84 (t), 1.2-1.4 (overlap m), 1.6 (m), 3.07 (m), 4.05-4.22 (overlap m).

Bis(cyclohexyl sulfosuccinic acid diester): 1.2-1.8 (composite overlap m), 3.10 (m), 4.2-4.8 (overlap m)

Bis(neopentyl sulfosuccinate): 0.87(s), 0.90(s), 3.05-3.25(overlap m), 3.78(s), 3.80-3.93(m), 4.23-4.29(m)

Bis(N-ethyl-N-(2-ethylhexyl)sulfosuccinic acid diamide): 0.75-0.88 (triple peak), 1.21-1.78 (overlapping multiple peaks), 2.24 (m), 3.11-3-41 (composite m), 3.86-4.45 (overlap m)

Claims (59)

1. An ionic liquid composition, comprising: (a) cations containing more than 4 carbon atoms; and (b) Anions selected from the group consisting of: and I

Wherein R ₁ , R ₂ , R ₄ and R ₅ are independently selected from substituted or unsubstituted alkyl or alkenyl; Wherein _R is substituted or unsubstituted alkylene, heteroarylene, arylene or cycloalkylene; wherein R ₆ , R ₇ and R ₈ are independently selected from H, alkyl, NO ₂ , halogen, cyano, silyl and OH; Or _R1 and _R2 can join together to form a ring: Or _R4 and _R5 can join together to form a ring: Or R ₆ and R ₇ or R ₇ and R ₈ can be combined to form a ring. 2. The composition of claim 1, wherein the anion is of formula I. 3. The composition of claim 2, wherein _R1 and _R2 are independently selected from alkyl groups containing about five or more carbon atoms. 4. The composition of claim 2, wherein _R1 and _R2 are independently selected from alkyl groups containing about 6 to about 18 carbon atoms. 5. The composition of claim 2, wherein _R3 is -( _CH2 ) _n- , wherein n is an integer from about 1 to about 10. 6. The composition of claim 5, wherein _R1 and _R2 are independently selected from alkyl groups containing from about 6 to about 18 carbon atoms. 7. The composition _of claim 6, wherein n is 1 and _R1 and _R2 are _-CH2 -CH( _CH2CH3 )( _CH5 - _CH2 - _CH3 ). 8. The composition of claim 1, wherein the anion has the chemical structure II. 9. The composition of claim 8, wherein _R6 , _R7 and _R8 are H. 10. The composition of claim 8, wherein _R4 and _R5 are independently selected from alkyl groups containing about five or more carbon atoms. 11. The composition of claim 8, wherein _R4 and _R5 are independently selected from alkyl groups containing from about 6 to about 18 carbon atoms. 12. The composition of claim 9, wherein _R4 and _R5 are independently selected from alkyl groups containing about five or more carbon atoms. 13. The composition of claim 9, wherein _R4 and _R5 are _-CH2 -CH( _CH2CH3 )( _{CH2 - CH2} - _CH3 ). 14. The composition of claim 2, further comprising a catalyst. 15. The composition of claim 7, further comprising a catalyst. 16. The composition of claim 2, further comprising a hydrocarbon. 17. The composition of claim 7, further comprising a hydrocarbon. 18. The composition of claim 8, further comprising a catalyst. 19. The composition of claim 9, further comprising a catalyst. 20. The composition of claim 8, further comprising a hydrocarbon. 21. The composition of claim 9, further comprising a hydrocarbon. 22. The composition of claim 1, wherein the cation is a quaternary ammonium or phosphonium. 23. The composition of claim 22, wherein the quaternary ammonium cation is independently selected from substituted or unsubstituted pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, Triazolium, imidazolinium, methylpyrrolidinium, isothiazolium, isoxazolium, oxazolium, pyrrolium and thiophenium. 24. The composition of claim 1, wherein the cation is an ammonium cation substituted with one or more groups selected from the group consisting of alkyl and aryl. 25. The composition of claim 22, wherein the quaternary ammonium cation is BMIM. 26. The composition of claim 1, wherein the cation is tetrabutylammonium, tributylmethylammonium, tetrabutylphosphonium, tetraethylammonium, N,N-dialkylpyrrolidinium, trimethyl 2-hydroxyethyl alkylammonium, N,N'-dialkylimidazolium, N-alkylpyridinium or mixtures thereof. 27. An ionic liquid composition comprising at least about 55 wt% ionic liquid, the ionic liquid comprising: (a) Cation: and (b) Anions selected from the group consisting of:

and I

Wherein R ₁ , R ₂ , R ₄ and R ₅ are independently selected from substituted or unsubstituted alkyl or alkenyl; Wherein _R is substituted or unsubstituted alkylene, heteroarylene, arylene or cycloalkylene; Wherein R ₆ , R ₇ and R ₈ are independently selected from H, alkyl, alkoxy, alkylthio, SO ₃ H, NO ₂ , halogen, cyano, silyl and OH; or _R and _R can be joined together to form a ring; Or _R4 and _R5 can be joined together to form a ring; Or R ₆ and R ₇ or R ₇ and R ₈ can be combined to form a ring. 28. The composition of claim 27, wherein the ionic liquid is hydrophobic. 29. The composition of claim 28, wherein the cation is a quaternary ammonium or phosphonium. 30. The composition of claim 29, wherein the quaternary ammonium cation is independently selected from substituted or unsubstituted pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, Triazolium, imidazolinium, methylpyrrolidinium, isothiazolium, isoxazolium, oxazolium, pyrrolium and thiophenium. 31. The composition of claim 30, wherein the cation is an ammonium cation substituted with one or more groups selected from alkyl and aryl. 32. The composition of claim 30, wherein the quaternary ammonium cation is BMIM. 33. The composition of claim, wherein the cation is tetrabutylammonium, tributylmethylammonium, tetrabutylphosphonium, tetraethylammonium, N,N-dialkylpyrrolidinium, trimethyl 2-hydroxyethyl Ammonium, N,N'-dialkylimidazoliums, N-alkylpyridiniums or mixtures thereof. 34. The composition of claim 27, wherein the anion is docusate. 35. The composition of claim 27, wherein the anion has formula I and is hydrophobic. 36. The composition of claim 27, wherein the anion has Formula II and is hydrophobic. 37. The composition of claim 27, wherein the anion has formula I and is hydrophilic. 38. The composition of claim 27, wherein the anion has formula II and is hydrophilic. 39. The composition of claim 1, wherein the ionic liquid is hydrophobic. 40. The composition of claim 1, wherein the ionic liquid is hydrophilic. 41. The composition of claim 1, wherein the anion is an anion selected from the group consisting of: (i) di-n-cyclohexyl ester of sulfosuccinic acid; (ii) di-n-octyl ester of sulfosuccinic acid; (iii) sulfosuccinic acid Di-n-butyl ester of sulfosuccinic acid; (iv) diisobutyl ester of sulfosuccinic acid; (v) di-neopentyl ester of sulfosuccinic acid; (vi) di-n-heptyl ester of sulfosuccinic acid ester; and (vii) di-n-heptyl ester of sulfosuccinic acid. 42. The composition of claim 41, wherein the cation is tetrabutylammonium. 43. An ionic liquid composition comprising: (a) onium cations; and (b) Anions having the structure: R ₁ -N(R ₂ )-C(O)-CH(SO ₃ ^- )-R ₃ -C(O)-N(R ₄ )-R ₅ III Wherein R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are independently selected from hydrogen atoms and carbon-containing groups; and wherein the melting point of the ionic liquid is less than about 100°C. 44. The composition of claim 43, wherein R ₁ is 2-ethylhexyl, R ₂ is ethyl, R ₃ is methylene, R ₄ is ethyl, and R ₅ is 2-ethylhexyl. 45. The composition of claim 44, wherein the cation is tetrabutylammonium. 46. The composition of claim 44, wherein the cation is 1-methyl-3-hexylimidazolium. 47. The composition of claim 43, wherein R ₁ is 2-ethylhexyl, R ₂ is a hydrogen atom, R ₃ is methylene, R ₄ is a hydrogen atom, and R ₅ is 2-ethylhexyl. 48. The composition of claim 47, wherein the cation is tetrabutylammonium. 49. The composition of claim 47, wherein the cation is 1-methyl-3-hexylimidazolium. 50. The composition of claim 43, further comprising a hydrocarbon. 51. The composition of claim 1, wherein the cation and the anion form a molten salt having a melting point below about 100° C., the molten salt being selected from the group consisting of tetrabutylammonium docusate, MeBu ₃ N docusate, Me ₃ N(CH ₂ ) ₆ NMe ₃ docusate, Bu ₄ P docusate, Et ₄ N docusate, 1-hexyl-3-methylimidazolium docusate, 1-octyl-3-methylimidazolium bromide docusate ester, 1-butyl-3-methylimidazolium docusate, and 1-methyl-2-ethylimidazolium docusate. 52. A composition comprising: (a) an ionic liquid comprising an anion selected from the group consisting of (i) docusate, (ii) anions of bis(organic) sulfosuccinate derivatives and (iii) bis(organic amide) sulfosuccinate derivatives Anions of substances; and (b) _CO2 in the supercritical state; Wherein the ionic liquid is dissolved in CO ₂ . 53. A composition comprising: (a) hydrocarbon fuels; and (b) an ionic liquid comprising an anion selected from the group consisting of (i) docusate, (ii) anions of bis(organic) sulfosuccinate derivatives and (iii) bis(organic amide) sulfosuccinate derivatives anion of the substance. 54. A composition comprising: (a) polymers; and (b) an antistatic additive comprising an ionic liquid comprising an anion selected from the group consisting of (i) docusate, (ii) anions of bis(organic) sulfosuccinate derivatives and (iii) sulfo Anion of a bis(organoamide) derivative of succinic acid. 55. The composition of claim 54, wherein the polymer is polyvinyl acetate. 56. An ionic liquid composition comprising: (a) onium cations containing more than 4 carbon atoms; and (b) Anions selected from docusate and docusate variants. 57. The ionic liquid composition of claim 56, wherein the ionic liquid melts in a temperature range above about 40°C but below about 80°C. 58. A composition comprising: the first ionic liquid combined with the second ionic liquid, (a) the first ionic liquid comprises: (i) a cation selected from ammonium, sulfonium and phosphonium cations, which cation is non-tetrahedrally symmetrical; (ii) an anion having the general formula Al _y R _3y+1 , wherein y is greater than 0 and R is independently selected from alkyl and halo groups; (b) a second ionic liquid comprising an anion selected from the group consisting of (i) docusate, (ii) anions of bis(organic) sulfosuccinate derivatives and (iii) bis(organic) amide sulfosuccinate ) derivative anion. 59. The composition of claim 58, further comprising a reactant, the first and second ionic liquids being effective reaction solvents for the reactant.