Patent Application
20080287684
The present invention describes a process for preparing ionic liquids (I) by reacting ionic liquids (II) whose anion is a halide with an acid (III), with the resulting hydrogen halide being scavenged by means of an amine and the resulting ammonium halide being able to be separated off.
Ionic liquids are becoming increasing important as solvents, e.g. for carrying out chemical reactions. For example, P. Wasserscheidt, in Chemie in unserer Zeit 37, 52 (2003), gives an overview of the use of ionic liquids in multiphase catalysis. However, other applications have also been proposed, e.g. their use in extraction or separation processes, as heat transfer media, etc.
In all these applications, the purity of the ionic liquids used is important. For example, impurities can have an adverse effect on the course of chemical reactions. Thus, P. Tyson et al. (Electrochemical Society Proceedings, Vol. 99-41, 161) have referred to problems when chloride-comprising ionic liquids are used in liquid-phase hydrogenation and in the Suzuki coupling. The preparation of ionic liquids therefore has to provide ionic liquids having a high purity.
Ionic liquids are frequently prepared by quaternization of the corresponding nitrogen or phosphorus compounds, generally using alkyl halides as alkylating reagents. The ionic liquids obtained in this way can then themselves be used as solvents, etc. However, they also serve as starting material for the preparation of ionic liquids whose anion is not a halide by replacing the anion in a metathesis reaction. However, this frequently suffers from the problem that the resulting ionic liquid still comprises traces of halide which can lead to the above-described problems when the liquid is used as solvent, etc. Otherwise, the removal of the traces of halide is technically complicated, thus incurring high operating costs and/or capital costs and thus having a highly adverse effect on the economics of the process. An example which may be mentioned is the stripping of ionic liquids comprising HCl, since stripping times of sometimes several days have to be reckoned with here.
It is therefore an object of the present invention to provide an industrially useable process for preparing ionic liquids, in particular ionic liquids having a reduced halide content.
It has been found that ionic liquids of the formula (I)
[A]+n[Y]n− (I)
where
[A]+ is a quaternary nitrogen heterocycle cation, oxonium cation, sulfonium cation or phosphonium cation;
n is 1, 2, 3 or 4; and
[Y]n− is an anion selected from among
[A]+[X]− (II)
where
[A]+ is as defined above; and
[X]− is fluoride, chloride, bromide or iodide;
with an acid of the formula III
H+n[Y]n− (III)
where n and [Y]n− are as defined above;
with the resulting acid of the formula IV
H+[X]− (IV)
where [X]− is as defined above; being scavenged by means of an amine of the formula V
NR1R1R3 (V)
where
[HNR1R2R3]+[X]− (VI)
where the radicals X, R1, R2 and R3 are as defined above;
being separated off.
The reaction of the ionic liquid of the formula II with the acid of the formula III is usually carried out a temperature of from −50° C. to 150° C., particularly preferably at from −20 to 120° C., in particular from 0 to 100° C., more preferably from 20 to 60° C.
In general, the reaction takes place under atmospheric pressure.
The ionic liquid of the formula II and the acid of the formula III are usually used in the stoichiometric ratio. In some cases, it can also be advantageous to use one or other components in excess.
In general, the amine of the formula V is used in the stoichiometric ratio or in excess relative to the acid of the formula II. In one embodiment, the amine is used in the stoichiometric ratio. In a further embodiment, the amine of the formula V is used in excess, preferably in the range from 1.5 to 2.5 times, in particular from 1.8 to 2.2 times, the stoichiometric ratio. In a further embodiment in which the amine is continuously regenerated, it is also possible to use the amine in a substoichiometric amount, based on a snapshot.
In some cases, it can be advantageous to carry out the process of the invention in bulk.
It is also possible to work in the presence of a solvent. Possible solvents are those in which the ammonium halide of the formula VI dissolves and the ionic liquid of the formula I does not dissolve. Solvents suitable for this purpose are, for example, aromatic hydrocarbons such as benzene, toluene, o-xylene, m-xylene or p-xylene, chlorinated aromatic hydrocarbons such as chlorobenzene or cyclic hydrocarbons such as cyclohexane.
The amine of the formula V is usually selected so that both it and the ammonium halide of the formula VI formed does not dissolve or dissolves only to a slight extent in the ionic liquid of the formula I. The solubility of the amine of the formula V or of the ammonium halide of the formula VI in the ionic liquid of the formula I is in each case preferably less than 10%, particularly preferably less than 5%, in particular less than 2% (expressed as molar ratio of amine or ammonium halide to the ionic liquid). This applies particularly when no solvent is employed.
In a further embodiment which applies particularly to the case where the reaction is carried out in the presence of a solvent, the amine of the formula V is selected so that both it and the ammonium halide of the formula VI formed are more readily soluble in the solvent used than in the ionic liquid of the formula I.
The separation of the reaction products of the formulae I and VI is carried out by liquid-liquid phase separation.
The preparation of the ionic liquid of the formula I can be carried out batchwise, continuously or by a semibatch process. The removal of the ammonium halide of the formula VI formed is adapted accordingly.
The liquid-liquid phase separation is carried out, for example, by means of techniques as are described in Ullmann's Encyclopedia of Industrial Chemistry, sixth edition, 2000 electronic release, chapter “Liquid-Liquid Extraction”, particularly in subchapter 4 “Phase-Separation Equipment”; preferably by means of decantation, phase separators, centrifugation or mixer-settler apparatuses, particularly preferably by means of phase separators.
Furthermore, it may be advantageous to recover the original amine of the formula V from the ammonium halide of the formula VI formed and, if desired, use it again in the process of the invention for preparing the ionic liquids of the formula I.
The recovery of the amines of the formula V can, for example, be effected by treating the ammonium halide of the formula VI with a strong base, e.g. NaOH, KOH, Ca(OH)2, milk of lime, Na2CO3, NaHCO3, K2CO3 or KHCO3, if appropriate in a solvent such as water, methanol, ethanol, n-propanol or isopropanol, n-butanol, n-pentanol or butanol or pentanol isomer mixtures or acetone.
In a preferred embodiment of the invention, the strong base is used in a very concentrated solution, particularly preferably an aqueous solution, for example a solution having a concentration of at least 5% by weight, preferably at least 10% by weight and particularly preferably at least 15% by weight.
The amount of base is usually selected so as to correspond to the stoichiometry. In some cases, it can be advantageous to use a substoichiometric amount or an excess. An equimolar amount is generally employed.
If the preparation of the ionic liquid of the formula I has been carried out in the absence of a solvent, the amine of the formula V can, if it forms a separate phase, be separated off or can otherwise be removed from the mixture by distillation. If necessary, the amine of the formula V can be separated off by extraction with an extractant. Possible extractants are customary solvents such as aliphatic ethers, e.g. diethyl ether or methyl tert-butyl ether, cyclic ethers such as tetrahydrofuran, 1,3-dioxane or 1,4-dioxane, hydrocarbons such as pentane, hexane, cyclopentane or cyclohexane, aromatic hydrocarbons such as benzene, toluene, o-xylene, m-xylene or p-xylene, chlorinated hydrocarbons such as methylene chloride, chloroform or 1,2-dichloroethane or chlorinated aromatic hydrocarbons such as chlorobenzene.
If necessary, the amine of the formula V can be purified further, e.g. by distillation, before reuse.
If a solvent is used in the preparation of the ionic liquid of the formula I, the amine of the formula V can be recovered by treating the solution of the ammonium halide of the formula VI with the abovementioned bases and extracting the liberated amine of the formula V with the appropriate solvent in a manner known to those skilled in the art and isolating the amine of the formula V by customary methods, e.g. distillation.
Purification can be effected by, for example, single or multiple washing, drying, filtration, stripping, distillation and/or rectification.
Drying can be carried out, for example, by removal of any water present by means of distillation or azeotropic distillation with benzene, toluene, xylene, butanol or cyclohexane.
A filtration can be useful, for example, to remove precipitated solids or to eliminate discoloration which may have occurred, for example by filtration through activated carbon, aluminum oxide, Celite or silica gel.
A distillation, for example to separate off any solvent comprised, can preferably be carried out by means of a falling film or thin film evaporator, if appropriate under reduced pressure, with a column being able to be superposed to improve the separation.
Correspondingly, the solvent used can if necessary be purified and, if desired, be reused.
The present invention thus further provides a process for preparing ionic liquids of the formula I, which comprises the following steps:
reaction of an ionic liquid of the formula II with an acid of the formula III;
scavenging of the resulting acid of the formula IV by means of an amine of the formula V;
separation of the resulting ionic liquid of the formula I and the resulting ammonium halide of the formula VI by liquid/liquid phase separation;
addition of a base to the phase which comprises the ammonium halide of the formula VI formed and liberation of the amine of the formula V;
if appropriate, purification of the amine of the formula V obtained in crude form; and,
if appropriate, recirculation of the optionally purified amine to the reaction with an anionic liquid of the formula II with an acid of the formula III.
In a preferred embodiment, the ionic liquid of the formula II and the acid of the formula III are initially charged and the mixture is extracted continuously with the amine of the formula V, with the free amine being continuously regenerated from the ammonium halide which has been separated off or the ammonium halide/amine and is recirculated to the extraction process. Here, the amine can be used in a substoichiometric molar amount relative to the free acids, based on a snapshot of the extraction section. The extraction can be aided by a solvent or be carried out fully continuously, with amine phase and the phase comprising the ionic liquid being conveyed past one another continuously.
The ionic liquids of the formulae I and II and also the ammonium halide of the formula VI preferably have, independently of one another, a melting point of less than 180° C. Furthermore, the melting point is in the range from −50° C. to 150° C., preferably in the range from −20° C. to 120° C. and preferably below 100° C.
Preference is given to preparing ionic liquids of the formula I which have a molecular weight of less than 1000 g/mol, preferably less than 500 g/mol, in particular less than 250 g/mol.
Preference is given to preparing ionic liquids of the formula I in which the variables, either alone or in combination, have the following meanings:
[A]+ is a cation selected from among the compounds of the formula (Ia) to (Iv),
In the above formulae (Ia) to (Iv):
In the definitions of the radicals R and Ra to Ri, possible heteroatoms are in principle all heteroatoms which are able to formally replace a —CH2— group, a —CH═ group, a —C≡ group or a ═C═ group. If the hydrocarbon-comprising radical comprises heteroatoms, then oxygen, nitrogen, sulfur, phosphorus and silicon are preferred. Preferred groups are, in particular, —O—, —S—, —SO—, —SO2—, —NR′—, —N═, —PR′—, —PR′2 and —SiR′2—, where the radicals R′ are the remaining part of the carbon-comprising radical. In the cases in which the radicals Ra to Ri are bound to a carbon atom (and not a heteroatom) in the abovementioned formula (I), they can also be bound directly via the heteroatom.
Suitable functional groups are in principle all functional groups which can be bound to a carbon atom or a heteroatom. Suitable examples are —OH (hydroxy), ═O (in particular as carbonyl group), —NH2 (amino), ═NH (imino), —COOH (carboxy), —CONH2 (carboxamide), —SO3H (sulfo) and —CN (cyano). Functional groups and heteroatoms can also be directly adjacent, so that combinations of a plurality of adjacent atoms, for instance —O— (ether), —S-(thioether), —COO— (ester), —CONH— (secondary amide) or —CONR′— (tertiary amide), are also comprised, for example di-(C1-C4-alkyl)amino, C1-C4-alkyloxycarbonyl or C1-C4-alkyloxy.
As halogens, mention may be made of fluorine, chlorine, bromine and iodine.
The radical R is preferably
The radical R is particularly preferably unbranched and unsubstituted C1-C18-alkyl, such as methyl, ethyl, 1-propyl, 1-butyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-octyl, 1-decyl, 1-dodecyl, 1-tetradecyl, 1-hexadecyl, 1-octadecyl, in particular methyl, ethyl, 1-butyl and 1-octyl, or CH3O—(CH2CH2O)m—CH2CH2— and CH3CH2O—(CH2CH2O)m—CH2CH2— where m is 0, 1, 2 or 3.
Preference is given to the radicals Ra to Ri each being, independently of one another,
C1-C18-alkyl which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles and/or be interrupted by one or more oxygen and/or sulfur atoms and/or one or more substituted or unsubstituted imino groups;
C2-C18-alkenyl, which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles and/or be interrupted by one or more oxygen and/or; sulfur atoms and/or one or more substituted or unsubstituted imino groups;
C1-C18-alkyl which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles is preferably methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-butyl, 2-methyl-1-propyl (isobutyl), 2-methyl-2-propyl (tert-butyl), 1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2-methyl-2-butyl, 3-methyl-2-butyl, 2,2-dimethyl-1-propyl, 1-hexyl, 2-hexyl, 3-hexyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2-methyl-3-pentyl, 3-methyl-3-pentyl, 2,2-dimethyl-1-butyl, 2,3-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, 2,3-dimethyl-2-butyl, 3,3-dimethyl-2-butyl, heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethylpentyl, 1,1,3,3-tetramethylbutyl, 1-nonyl, 1-decyl, 1-undecyl, 1-dodecyl, 1-tridecyl, 1-tetradecyl, 1-pentadecyl, 1-hexadecyl, 1-heptadecyl, 1-octadecyl, cyclopentylmethyl, 2-cyclopentylethyl, 3-cyclopentylpropyl, cyclohexylmethyl, 2-cyclohexylethyl, 3-cyclohexylpropyl, benzyl (phenylmethyl), diphenylmethyl (benzhydryl), triphenylmethyl, 1-phenylethyl, 2-phenylethyl, 3-phenylpropyl, α,α-dimethylbenzyl, p-tolylmethyl, 1-(p-butylphenyl)ethyl, p-chlorobenzyl, 2,4-dichlorobenzyl, p-methoxybenzyl, m-ethoxybenzyl, 2-cyanoethyl, 2-cyanopropyl, 2-methoxycarbonylethyl, 2-ethoxycarbonylethyl, 2-butoxycarbonylpropyl, 1,2-di-(methoxycarbonyl)ethyl, methoxy, ethoxy, formyl, 1,3-dioxolan-2-yl, 1,3-dioxan-2-yl, 2-methyl-1,3-dioxolan-2-yl, 4-methyl-1,3-dioxolan-2-yl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 6-hydroxyhexyl, 2-aminoethyl, 2-aminopropyl, 3-aminopropyl, 4-aminobutyl, 6-aminohexyl, 2-methylaminoethyl, 2-methylaminopropyl, 3-methylaminopropyl, 4-methylaminobutyl, 6-methylaminohexyl, 2-dimethylaminoethyl, 2-dimethylaminopropyl, 3-dimethylaminopropyl, 4-dimethylaminobutyl, 6-dimethylaminohexyl, 2-hydroxy-2,2-dimethylethyl, 2-phenoxyethyl, 2-phenoxypropyl, 3-phenoxypropyl, 4-phenoxybutyl, 6-phenoxyhexyl, 2-methoxyethyl, 2-methoxypropyl, 3-methoxypropyl, 4-methoxybutyl, 6-methoxyhexyl, 2-ethoxyethyl, 2-ethoxypropyl, 3-ethoxypropyl, 4-ethoxybutyl, 6-ethoxyhexyl, acetyl, CmF2(m-a)+(1-b)H2a+b where m is from 1 to 30, 0≦a≦m and b=0 or 1 (for example CF3, C2F5, CH2CH2—C(m-2)F2(m-2)+1, C6F13, C8F17, C10F21, C12F25), chloromethyl, 2-chloroethyl, trichloromethyl, 1,1-dimethyl-2-chloroethyl, methoxymethyl, 2-butoxyethyl, diethoxymethyl, diethoxyethyl, 2-isopropoxyethyl, 2-butoxypropyl, 2-octyloxyethyl, 2-methoxyisopropyl, 2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl, 2-(n-butoxycarbonyl)ethyl, butylthiomethyl, 2-dodecylthioethyl, 2-phenylthioethyl, 5-hydroxy-3-oxapentyl, 8-hydroxy-3,6-dioxaoctyl, 11-hydroxy-3,6,9-trioxaundecyl, 7-hydroxy-4-oxaheptyl,11-hydroxy-4,8-dioxaundecyl, 15-hydroxy-4,8,12-trioxapentadecyl, 9-hydroxy-5-oxanonyl, 14-Hydroxy-5,10-dioxatetradecyl, 5-methoxy-3-oxapentyl, 8-methoxy-3,6-dioxaoctyl, 11-methoxy-3,6,9-trioxaundecyl, 7-methoxy-4-oxaheptyl, 11-methoxy-4,8-dioxaundecyl, 15-methoxy-4,8,12-trioxapentadecyl, 9-methoxy-5-oxanonyl, 14-methoxy-5,10-dioxatetradecyl, 5-ethoxy-3-oxapentyl, 8-ethoxy-3,6-dioxaoctyl, 11-ethoxy-3,6,9-trioxaundecyl, 7-ethoxy-4-oxaheptyl, 11-ethoxy-4,8-dioxaundecyl, 15-ethoxy-4,8,12-trioxapentadecyl, 9-ethoxy-5-oxanonyl or 14-ethoxy-5,10-oxatetradecyl.
C2-C18-alkenyl which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles and/or be interrupted by one or more oxygen and/or sulfur atoms and/or one or more substituted or unsubstituted imino groups is preferably vinyl, 2-propenyl, 3-butenyl, cis-2-butenyl, trans-2-butenyl or CmF2(m-a)−(1-b)H2a−b where m≦30, 0≦a≦m and b=0 or 1.
C6-C12-aryl which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles is preferably phenyl, tolyl, xylyl, α-naphthyl, β-naphthyl, 4-diphenylyl, chlorophenyl, dichlorophenyl, trichloro-phenyl, difluorophenyl, methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl, diethylphenyl, iso-propylphenyl, tert-butylphenyl, dodecylphenyl, methoxyphenyl, dimethoxyphenyl, ethoxyphenyl, hexyloxyphenyl, methylnaphthyl, isopropylnaphthyl, chloronaphthyl, ethoxynaphthyl, 2,6-dimethylphenyl, 2,4,6-trimethylphenyl, 2,6-dimethoxyphenyl, 2,6-dichlorophenyl, 4-bromophenyl, 2-nitrophenyl, 4-nitrophenyl, 2,4-dinitrophenyl, 2,6-dinitrophenyl, 4-dimethylaminophenyl, 4-acetylphenyl, methoxyethylphenyl, ethoxymethylphenyl, methylthiophenyl, isopropylthiophenyl or tert-butylthiophenyl or C6F(5-a)Ha where 0≦a≦5.
C5-C12-cycloalkyl which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles is preferably cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, diethylcyclohexyl, butylcyclohexyl, methoxycyclohexyl, dimethoxycyclohexyl, diethoxycyclohexyl, butylthiocyclohexyl, chlorocyclohexyl, dichlorocyclohexyl, dichlorocyclopentyl, CmF2(m- a)−(1-b)H2a−b where m≦30, 0≦a≦n and b=0 or 1, or a saturated or unsaturated bicyclic system such as norbornyl or norbornenyl.
C5- to C12-cycloalkenyl which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles is preferably 3-cyclopentenyl, 2-cyclohexenyl, 3-cyclohexenyl, 2,5-cyclohexadienyl or CmF2(m-a)−3(1- b)H2a−3b where m≦30, 0≦a≦m and b=0 or 1.
A five- or six-membered, oxygen-, nitrogen- and/or sulfur-comprising heterocycle which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatom and/or heterocycles is preferably furyl, thiophenyl, pyrryl, pyridyl, indolyl, benzoxazolyl, dioxolyl, dioxyl, benzimidazolyl, benzthiazolyl, dimethylpyridyl, methylquinolyl, dimethylpyrryl, methoxyfuryl, dimethoxypyridyl or difluoropyridyl.
If two adjacent radicals together form an unsaturated, saturated or aromatic ring which may optionally be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles and may optionally be interrupted by one or more oxygen and/or sulfur atoms and/or one or more substituted or unsubstituted imino groups, they preferably form 1,3-propylene, 1,4-butylene, 1,5-pentylene, 2-oxa-1,3-propylene, 1-oxa-1,3-propylene, 2-oxa-1,3-propylene, 1-oxa-1,3-propenylene, 3-oxa-1,5-pentylene, 1-aza-1,3-propenylene, 1-C1-C4-alkyl-1-aza-1,3-propenylene, 1,4-buta-1,3-dienylene, 1-aza-1,4-buta-1,3-dienylene or 2-aza-1,4-buta-1,3-dienylene.
If the abovementioned radicals comprise oxygen and/or sulfur atoms and/or substituted or unsubstituted imino groups, the number of oxygen and/or sulfur atoms and/or imino groups is not subject to any restrictions. In general, there will be no more than 5 in the radical, preferably no more than 4 and very particularly preferably no more than 3.
If the abovementioned radicals comprise heteroatoms, there is generally at least one carbon atom, preferably at least two carbon atoms, between any two heteroatoms.
Particular preference is given to the radicals Ra to Ri each being, independently of one another,
Very particular preference is given to the radicals Ra to Ri each being, independently of one another, hydrogen or C1-C18-alkyl such as methyl, ethyl, 1-butyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-octyl, phenyl, 2-hydroxyethyl, 2-cyanoethyl, 2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl, 2-(n-butoxycarbonyl)ethyl, N,N-dimethylamino, N,N-diethylamino, chlorine or CH3O—(CH2CH2O)m—CH2CH2— and CH3CH2O—(CH2CH2O)m—CH2CH2— where m is 0, 1, 2 or 3.
Very particularly preferred pyridinium ions (Ia) are those in which
As very particularly preferred pyridinium ions (IVa), mention may be made of 1-methylpyridinium, 1-ethylpyridinium, 1-(1-butyl)pyridinium, 1-(1-hexyl)pyridinium, 1-(1-octyl)pyridinium, 1-(1-hexyl)pyridinium, 1-(1-octyl)pyridinium, 1-(1-dodecyl)pyridinium, 1-(1-tetradecyl)pyridinium, 1-(1-hexadecyl)pyridinium, 1,2-dimethylpyridinium, 1-ethyl-2-methylpyridinium, 1-(1-butyl)-2-methylpyridinium, 1-(1-hexyl)-2-methylpyridinium, 1-(1-octyl)-2-methylpyridinium, 1-(1-dodecyl)-2-methylpyridinium, 1-(1-tetradecyl)-2-methylpyridinium, 1-(1-hexadecyl)-2-methylpyridinium, 1-methyl-2-ethylpyridinium, 1,2-diethylpyridinium, 1-(1-butyl)-2-ethylpyridinium, 1-(1-hexyl)-2-ethylpyridinium, 1-(1-octyl)-2-ethylpyridinium, 1-(1-dodecyl)-2-ethylpyridinium, 1-(1-tetradecyl)-2-ethylpyridinium, 1-(1-hexadecyl)-2-ethylpyridinium, 1,2-dimethyl-5-ethylpyridinium, 1,5-diethyl-2-methylpyridinium, 1-(1-butyl)-2-methyl-3-ethylpyridinium, 1-(1-hexyl)-2-methyl-3-ethylpyridinium and 1-(1-octyl)-2-methyl-3-ethyl-pyridinium, 1-(1-dodecyl)-2-methyl-3-ethylpyridinium, 1-(1-tetradecyl)-2-methyl-3-ethylpyridinium and 1-(1-hexadecyl)-2-methyl-3-ethylpyridinium.
Very particularly preferred pyridazinium ions (Ib) are those in which
Very particularly preferred pyrimidinium ions (Ic) are those in which
Very particularly preferred pyrazinium ions (Id) are those in which
Very particularly preferred imidazolium ions (Ie) are those in which
As very particularly preferred imidazolium ions (IVe), mention may be made of 1-methylimidazolium, 1-ethylimidazolium, 1-(1-butyl)imidazolium, 1-(1-octyl)imidazolium, 1-(1-dodecyl)imidazolium, 1-(1-tetradecyl)imidazolium, 1-(1-hexadecyl)imidazolium, 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1-(1-butyl)-3-methylimidazolium, 1-(1-butyl)-3-ethylimidazolium, 1-(1-hexyl)-3-methylimidazolium, 1-(1-hexyl)-3-ethylimidazolium, 1-(1-hexyl)-3-butylimidazolium, 1-(1-octyl)-3-methylimidazolium, 1-(1-octyl)-3-ethylimidazolium, 1-(1-octyl)-3-butylimidazolium, 1-(1-dodecyl)-3-methylimidazolium, 1-(1-dodecyl)-3-ethylimidazolium, 1-(1-dodecyl)-3-butylimidazolium, 1-(1-dodecyl)-3-octylimidazolium, 1-(1-tetradecyl)-3-methylimidazolium, 1-(1-tetradecyl)-3-ethylimidazolium, 1-(1-tetradecyl)-3-butylimidazolium, 1-(1-tetradecyl)-3-octylimidazolium, 1-(1-hexadecyl)-3-methylimidazolium, 1-(1-hexadecyl)-3-ethylimidazolium, 1-(1-hexadecyl)-3-butylimidazolium, 1-(1-hexadecyl)-3-octylimidazolium, 1,2-dimethylimidazolium, 1,2,3-trimethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1-(1-butyl)-2,3-dimethylimidazolium, 1-(1-hexyl)-2,3-dimethylimidazolium, 1-(1-octyl)-2,3-dimethylimidazolium, 1,4-dimethylimidazolium, 1,3,4-trimethylimidazolium, 1,4-dimethyl-3-ethylimidazolium, 3-butylimidazolium, 1,4-dimethyl-3-octylimidazolium, 1,4,5-trimethylimidazolium, 1,3,4,5-tetramethylimidazolium, 1,4,5-trimethyl-3-ethylimidazolium, 1,4,5-trimethyl-3-butylimidazolium and 1,4,5-trimethyl-3-octylimidazolium.
Very particularly preferred pyrazolium ions (If), (Ig) and (Ig′) are those in which
Very particularly preferred pyrazolium ions (Ih) are those in which
Very particularly preferred 1-pyrazolinium ions (Ii) are those in which
Very particularly preferred 2-pyrazolinium ions (Ij) and (Ij′) are those in which
Very particularly preferred 3-pyrazolinium ions (Ik) and (Ik′) are those in which
Very particularly preferred imidazolinium ions (II) are those in which
Very particularly preferred imidazolinium ions (Im) and (Im′) are those in which
Very particularly preferred imidazolinium ions (In) and (In′) are those in which
Very particularly preferred thiazolium ions (Io) and (Io′) and oxazolium ions (Ip) are those in which
Very particularly preferred 1,2,4-triazolium ions (Iq), (Iq′) and (Iq″) are those in which
Very particularly preferred 1,2,3-triazolium ions (Ir), (Ir′) and (Ir″) are those in which
Very particularly preferred pyrrolidinium ions (Is) are those in which
Very particularly preferred imidazolidinium ions (It) are those in which
Very particularly preferred phosphonium ions (Iu) are those in which
Among the abovementioned heterocyclic cations, preference is given to the pyridinium ions, pyrazolinium ions, pyrazolium ions and the imidazolinium ions and the imidazolium ions.
Particular preference is given to 1-methylpyridinium, 1-ethylpyridinium, 1-(1-butyl)pyridinium, 1-(1-hexyl)pyridinium, 1-(1-octyl)pyridinium, 1-(1-hexyl)pyridinium, 1-(1-octyl)pyridinium, 1-(1-dodecyl)pyridinium, 1-(1-tetradecyl)pyridinium, 1-(1-hexadecyl)pyridinium, 1,2-dimethylpyridinium, 1-ethyl-2-methylpyridinium, 1-(1-butyl)-2-methylpyridinium, 1-(1-hexyl)-2-methylpyridinium, 1-(1-octyl)-2-methylpyridinium, 1-(1-dodecyl)-2-methylpyridinium, 1-(1-tetradecyl)-2-methylpyridinium, 1-(1-hexadecyl)-2-methylpyridinium, 1-methyl-2-ethylpyridinium, 1,2-diethylpyridinium, 1-(1-butyl)-2-ethylpyridinium, 1-(1-hexyl)-2-ethylpyridinium, 1-(1-octyl)-2-ethylpyridinium, 1-(1-dodecyl)-2-ethylpyridinium, 1-(1-tetradecyl)-2-ethylpyridinium, 1-(1-hexadecyl)-2-ethylpyridinium, 1,2-dimethyl-5-ethylpyridinium, 1,5-diethyl-2-methylpyridinium, 1-(1-butyl)-2-methyl-3-ethylpyridinium, 1-(1-hexyl)-2-methyl-3-ethylpyridinium, 1-(1-octyl)-2-methyl-3-ethylpyridinium, 1-(1-dodecyl)-2-methyl-3-ethylpyridinium, 1-(1-tetradecyl)-2-methyl-3-ethylpyridinium, 1-(1-hexadecyl)-2-methyl-3-ethylpyridinium, 1-methylimidazolium, 1-ethylimidazolium, 1-(1-butyl)-imidazolium, 1-(1-octyl)imidazolium, 1-(1-dodecyl)-imidazolium, 1-(1-tetradecyl)imidazolium, 1-(1-hexadecyl)imidazolium, 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1-(1-butyl)-3-methylimidazolium, 1-(1-hexyl)-3-methylimidazolium, 1-(1-octyl)-3-methylimidazolium, 1-(1-dodecyl)-3-methylimidazolium, 1-(1-tetradecyl)-3-methylimidazolium, 1-(1-hexadecyl)-3-methylimidazolium, 1,2-dimethylimidazolium, 1,2,3-trimethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1-(1-butyl)-2,3-dimethylimidazolium, 1-(1-hexyl)-2,3-dimethylimidazolium and 1-(1-octyl)-2,3-dimethylimidazolium, 1,4-dimethylimidazolium, 1,3,4-trimethylimidazolium, 1,4-dimethyl-3-ethylimidazolium, 3-butylimidazolium, 1,4-dimethyl-3-octylimidazolium, 1,4,5-trimethylimidazolium, 1,3,4,5-tetramethylimidazolium, 1,4,5-trimethyl-3-ethylimidazolium, 1,4,5-trimethyl-3-butylimidazolium and 1,4,5-trimethyl-3-octylimidazolium.
[Y]n− is an anion selected from among
In a preferred embodiment, ionic liquids of the formula II in which the variable [A]+ is as defined under the ionic liquids of the formula I and X— is chloride or bromide, preferably chloride, are used. The preferences for [A]+ apply in an analogous way.
In a preferred embodiment, amines of the formula V in which the radicals
In a further embodiment, amines of the formula V in which
In a particular embodiment, use is made of diethylhexylamine, diethyloctylamine, diethyl(2-ethylhexyl)amine, di-n-propylbutylamine, di-n-propyl-n-pentylamine, di-n-propylhexylamine, di-n-propyloctylamine, di-n-propyl(2-ethylhexyl)amine, diisopropylbutylamine, diisopropylpentylamine, diisopropylhexylamine, diisopropyloctylamine, diisopropyl-(2-ethylhexyl)amine, di-n-butylethylamine, di-n-butyl-n-propylamine, di-n-butyl-n-pentylamine, di-n-butylhexylamine, di-n-butyloctylamine, di-n-butyl-(2-ethylhexyl)amine, dioctylamine, diethylhexylamine, dinonylamine, tripentylamine, trihexylamine, trioctylamine, trinonylamine, tridecylamine, methyldi(2-ethylhexyl)amine, ethyldi(2-ethylhexyl)amine, propyldi(2-ethylhexyl)amine, butyldi(2-ethylhexyl)amine, isopropyldi(2-ethylhexyl)amine, isobutyldi(2-ethylhexyl)amine or tris(2-ethylhexyl)amine, preferably diethylhexylamine, diethyloctylamine, diethyl(2-ethylhexyl)amine, di-n-propylbutylamine, di-n-propyl-n-pentylamine, di-n-propylhexylamine, di-n-propyloctylamine, di-n-propyl(2-ethylhexyl)amine, di-isopropylbutylamine, diisopropylpentylamine, diisopropylhexylamine, diisopropyloctylamine, diisopropyl-(2-ethylhexyl)amine, di-n-butylethylamine, di-n-butyl-n-propylamine, di-n-butyl-n-pentylamine, di-n-butylhexylamine, di-n-butyloctylamine, di-n-butyl-(2-ethylhexyl)amine, dioctylamine, diethylhexylamine, dinonylamine, tripentylamine, trihexylamine, trioctylamine, trinonylamine or tridecylamine.
The present invention is illustrated by the following examples.
13.11 g of 1-butyl-3-methylimidazolium chloride (75 mmol), 7.247 g (75 mmol) of methanesulfonic acid and 42.11 g of trihexylamine (150 mmol) in 42.11 g of toluene were heated to 40° C. After stirring for about 1 hour, the mixture was cooled to room temperature and the phases which formed were separated. The lower phase is dried at 80° C. and a pressure of 10 mbar. This gave 14.4 g of butyl-3-methylimidazolium methylsulfonate (which comprised 3.3% by weight of chloride).
8.74 g of 1-butyl-3-methylimidazolium chloride (50 mmol), 3.00 g (50 mmol) of acetic acid (99%) and 28.00 g of trihexylamine (100 mmol) in 28 g of toluene were heated to 40° C. After stirring for about 1 hour, the mixture was cooled to room temperature and the phases which formed were separated. The lower phase is dried at 80° C. and a pressure of 10 mbar. This gave 7.0 g of butyl-3-methylimidazolium acetate.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 055 815.1 | Nov 2005 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP06/68465 | 11/15/2006 | WO | 00 | 6/30/2008 |
