EP2229365A1 - Method for improving the hydrolysis stability of ionic liquids - Google Patents

Abstract

The present invention relates to a method for improving the hydrolysis stability of ionic liquids (IL), wherein at least one tertiary amine or a quaternary ammonia compound, which is different from the ionic liquid (IL), is added to an ionic liquid (IL).

Description

 Process for improving the hydrolytic stability of ionic liquids

description

The present invention relates to a process for improving the stability to hydrolysis of ionic liquids (IL), in which at least one tertiary amine or a quaternary ammonium compound other than the ionic liquid (IL) is added to an ionic liquid (IL).

Ionic liquids are characterized by a number of interesting properties. They are thermally stable, non-flammable, have a very low, barely measurable vapor pressure, are mostly environmentally friendly, have a large liquid range and very good dissolving properties for numerous substances. In addition, due to their purely ionic structure, ionic liquids also have interesting electrochemical properties, such as electrical conductivity, which is often accompanied by high electrochemical stability. By varying the side chains of the cation and by selecting suitable anions, for example, the solubility in water or organic solvents or the melting point can be determined largely freely.

The molecular diversity of ionic liquids allows their use in a variety of technical applications. Examples include the extraction (eg extraction and purification of technical gases, isolation and purification of hydrocarbons in petrochemistry and in organic synthesis or the removal of toxic substances from waste water), sorption, drying, purification and storage of Gases (eg in sorption air conditioners), use as a solvent (eg for organic synthesis), immobilization of catalysts, use as a lubricant, hydraulic fluid or antistatic additive, use as an electrolyte (eg. in galvanic coatings, in fuel cells, capacitors, sensor and battery technology, metal finishing, photovoltaics or in electrochromic components), use as an electroelastic material (eg in actuators), use for heat transfer or for heat storage (eg thermal fluids or PCM media) or use as a special analytical agent (eg matrix materials, solvents for Karl Fischer titration or media for protein crystallization or electrophoresis).

Because of the need to tailor the properties of the ionic liquids to the particular uses, anions are also frequently used in the ionic liquids subject to hydrolysis under storage and / or use conditions. This hydrolysis can already to a small extent substantially influence the chemical and physical properties of the ionic liquids. An example of this is the change in the melting point of the ionic Liquid or the formation of corrosive hydrolysis products called. An exchange of (partially) hydrolyzed ionic liquids is therefore often mandatory.

WO 03022812 describes ionic liquids which have as anion a compound of the formula [R-SO ₄ ] in which R is a linear or branched, saturated or unsaturated, aliphatic or alicyclic, functionalized or unsubstituted alkyl radical having 3 to 36 carbon atoms These anions are stable to hydrolysis in neutral aqueous solution, in contrast to methyl or ethyl sulfate anions, but the ionic liquids containing these anions are only accessible at great expense.

It is therefore an object of the present invention to provide a process whereby the hydrolysis of customary hydrolyzable anions of ionic liquids is markedly slowed down or prevented. In this way, longer lifetimes of ionic liquids and / or, if the products of the hydrolysis of the anion have increased corrosivity, a reduction in the damaging effect on chemical compounds, chemical reactions and devices which are brought into contact with the ionic liquids, be effected. Furthermore, if possible, the ionic liquids used should be thermally disposable, biodegradable and accessible with little effort without the formation of problematic combustion gases.

Surprisingly, it has now been found that even the addition of small amounts of a tertiary amine and / or a quaternary ammonium compound other than the ionic liquid leads to a marked reduction in the decomposition of the anion of the ionic liquid, especially of sulfate anions, by hydrolysis.

The present invention therefore provides a process for improving the hydrolytic stability of an ionic liquid (IL), in which at least one tertiary amine and / or a quaternary ammonium compound other than the ionic liquid (IL) are added to the ionic liquid (IL).

In the context of the present application, ionic liquids refer to organic salts which are already liquid at temperatures below 180 ^° C. Preferably, the ionic liquids have a melting point of less than 180 ⁰ C. Further preferably, the melting point in a range of -50 ⁰ C to 150 ⁰ C, more preferably in the range of -20 ⁰ C to 120 ⁰ C and most preferably below 100 ⁰ C.

Ionic liquids already in liquid state at room temperature are described, for example, by KN Marsh et al., Fluid Phase Equilibria 219 (2004), 93-98 and JG Huddieston et al., Green Chemistry 2001, 3, 156-164.

Cations and anions are present in the ionic liquid. In this case, within the ionic liquid from the cation, a proton or an alkyl radical can be transferred to the anion, resulting in two neutral molecules. In the ionic liquid used according to the invention, therefore, there can be an equilibrium of anions, cations and neutral molecules formed therefrom.

In the context of the present invention, the term "alkyl" includes straight-chain or branched alkyl. It is preferably straight-chain or branched C 1 -C 30 -alkyl, in particular C 1 -C -alkyl, and very particularly preferably C 1 -C 12 -alkyl. Examples of alkyl groups are in particular methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, 1-methyl-butyl, tert-pentyl, neopentyl, n-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, n-heptyl, n-octyl, 1-methylheptyl, 2-ethylhexyl, 2,4,4-trimethyl-pentyl, 1,1,3,3-tetramethylbutyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl and n-eicosyl.

The term alkyl also encompasses alkyl radicals whose carbon chain is replaced by one or more nonadjacent heteroatoms or heteroatom-containing groups which are preferably selected from -O-, -S-, -NR ^E -, -PR ^E -, -SiR ^E R ^EE and / or -SO ₂ - may be interrupted. R ^E is preferably H, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl. R ^EE is preferably H, alkyl, cycloalkyl, heterocycloalkyl or aryl.

Examples of alkyl radicals whose carbon chains may be interrupted by one or two nonadjacent heteroatoms -O- are the following:

Methoxymethyl, diethoxymethyl, 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, diethoxyethyl, 2-butoxyethyl, 2-octyloxyethyl, 2-methoxypropyl, 3-methoxypropyl, 3-ethoxypropyl, 3-propoxypropyl, 2-isopropoxyethyl, 2-butoxypropyl, 3-butoxypropyl, 4-methoxybutyl, 4-ethoxybutyl, 4-propoxybutyl, 6-methoxyhexyl, 3,6-dioxa-heptyl (5-methoxy-3-oxa-pentyl), 3,6-dioxa-octyl (7-methoxy 4-oxa-heptyl), 4,8-dioxa-nonyl (7-methoxy-4-oxa-heptyl), 3,7-dioxa-octyl, 3,7-dioxa-nonyl, 4,7-dioxa-octyl , 4,7-dioxanonyl, 2- and 4-butoxybutyl, 4,8-dioxadecyl, 9-ethoxy-5-oxa-nonyl.

Examples of alkyl radicals whose carbon chains may be interrupted by three or more than three nonadjacent heteroatoms -O- are also oligo- and poly- oxyalkylenes, ie compounds having repeating units, which are preferably selected from (CH ₂ CH ₂ O) Xi, (CH (CH ₃ ) CH ₂ O) _X 2 and ((CH ₂ ) ₄ O) χ3, where x1, x2 and x3 independently represent an integer from 0 to 100, preferably from 0 to 80, with the proviso that the sum of x1, x2 and x3 is at least 3. Preferably, x1, x2 and x3 independently of one another represent an integer from 3 to 100, preferably from 3 to 80. The sum of x1, x2 and x3 preferably stands for an integer from 3 to 300, in particular 3 to 100. In polyoxyalkylenes, which have two or three different repeating units, the order is arbitrary, ie they may be random, alternating or block repeating units. Examples are 3,6,9-trioxadecyl,

3,6,9-trioxaundecyl, 3,6,9-trioxadodecyl, 4,8,12-trioxatridecyl (1-methoxy-4,8-dioxa-undecyl), 4,8,12-trioxatetradecyl, 14-methoxy 5,10-dioxa-tetradecyl, 5,10,15-trioxaheptadecyl, 3,6,9,12-tetraoxatridecyl, 3,6,9,12-tetraoxatetradecyl, 4,8,12,16-tetraoxaheptadecyl (15-methoxy) 4,8,12-trioxa-pentadecyl), 4,8,12,16-tetraoxa-octadecyl and the like.

Examples of alkyl radicals whose carbon chains by one or more, for. B. 1, 2, 3, 4 or more than 4, non-adjacent heteroatoms -S- may be interrupted, are the following:

Butylthiomethyl, 2-methylthioethyl, 2-ethylthioethyl, 2-propylthioethyl, 2-butylthioethyl, 2-dodecylthioethyl, 3-methylthiopropyl, 3-ethylthiopropyl, 3-propylthiopropyl, 3-butylthiopropyl, 4-methylthiobutyl, 4-ethylthiobutyl, 4-propylthiobutyl, 3,6-dithiaheptyl, 3,6-dithia-octyl, 4,8-dithia-nonyl, 3,7-dithia-octyl, 3,7-di-thia-nonyl, 2- and 4-butylthiobutyl, 4 , 8-dithia-decyl, 3,6,9-trithia-decyl, 3,6,9-trithia-undecyl,

3,6,9-trithia-dodecyl, 3,6,9,12-tetrathia-tridecyl and 3,6,9,12-tetrathia-tetradecyl.

Examples of alkyl radicals whose carbon chains are interrupted by one or two non-adjacent heteroatom-containing groups -NR ^E - are the following:

2-monomethyl- and 2-monoethylaminoethyl, 2-dimethylaminoethyl, 3-methylaminopropyl, 2- and 3-dimethylaminopropyl, 3-monoisopropylaminopropyl, 2- and 4-monopropylaminobutyl, 2- and 4-dimethylaminobutyl, 6-methylaminohexyl, 6- Dimethylaminohexyl, 6-methyl-3,6-diazaheptyl, 3,6-dimethyl-3,6-diazaheptyl, 3,6-diazaoctyl and 3,6-dimethyl-3,6-diazaoctyl.

Examples of alkyl radicals whose carbon chains may be interrupted by three or more than three non-adjacent heteroatom-containing groups -NR ^E - are also oligo- and polyalkyleneimines. The above for the polyoxyalkylenes applies analogously to polyalkyleneimines, wherein the oxygen atom is replaced in each case by a group NR ^E , wherein R ^{a is} preferably H or CrC ₄ -AlkVl. Examples of these are 9-methyl-3,6,9-triazadecyl, 3,6,9-trimethyl-3,6,9-triazadecyl, 3,6,9-triazaundecyl, 3,6,9-trimethyl-3,6,9-triazaundecyl, 12-methyl-3,6,9,12-tetraazatridecyl, 3,6,9,12-tetramethyl-3,6,9,12-tetraazatridecyl and like.

Examples of alkyl radicals whose carbon chains by one or more, for. B. 1 or 2 non-adjacent groups -SO2- are interrupted, are 2-methylsulfonylethyl, 2-ethylsulfonylethyl, 2-propylsulfonylethyl, 2-isopropylsulfonylethyl, 2-Butylsulfonyl- ethyl, 2-methylsulfonylpropyl, 3-methylsulfonylpropyl, 2-Ethylsulfonylpropyl, 3rd Ethylsulfonylpropyl, 2-propylsulfonylpropyl, 3-propylsulfonylpropyl, 2-butylsulfonylpropyl, 3-butylsulfonylpropyl, 2-methylsulfonylbutyl, 4-methylsulfonylbutyl, 2-ethylsulfonylbutyl, 4-ethylsulfonylbutyl, 2-propylsulfonylbutyl, 4-propylsulfonylbutyl and 4-butylsulfonylbutyl ,

The term alkyl also includes substituted alkyl radicals. Substituted alkyl groups may have one or more (eg, 1, 2, 3, 4, 5 or more than 5) substituents depending on the length of the alkyl chain. These are preferably selected independently from among cycloalkyl, cycloalkyloxy, polycyclyl, polycycloxy, heterocycloalkyl, aryl, aryloxy, arylthio, hetaryl, halogen, hydroxy, SH, = O, = S, = NR ^E , COOH, carboxylate, SO ₃ H, sulfonate , NE ¹ E ² , nitro and cyano, wherein E ¹ and E ² independently of one another are H, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl. Cycloalkyl, cycloalkyloxy, polycycloalkyl, polycycloalkyloxy, heterocycloalkyl, aryl and hetaryl substituents of the alkyl groups may themselves be unsubstituted or substituted; suitable substituents are those mentioned below for these groups.

The above comments on alkyl also apply in principle to the alkyl moieties in alkoxy, alkylamino, dialkylamino, alkylthio (alkylsulfanyl), alkylsulfinyl, alkylsulfonyl, etc.

Suitable substituted alkyl radicals are the following:

Alkyl substituted by carboxy, such as. Carboxymethyl, 2-carboxyethyl,

3-carboxypropyl, 4-carboxybutyl, 5-carboxypentyl, 6-carboxyhexyl, 7-carboxyheptyl, 8-carboxyctyl, 9-carboxynonyl, 10-carboxydecyl, 12-carboxydodecyl and 14-carboxytetradecyl;

Alkyl which is substituted by SO ₃ H, such as. Sulfomethyl, 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 5-sulfopentyl, 6-sulfohexyl, 7-sulfoheptyl, 8-sulfooctyl, 9-sulfononyl, 10-sulfodecyl, 12-sulfododecyl and 14-sulfotetradecyl;

Alkyl which is substituted by carboxylate, such as. For alkoxycarbonylalkyl, e.g. Methoxycarbonylmethyl, ethoxycarbonylmethyl, n-butoxycarbonylmethyl, 2-methoxycarbonylethyl, 2-ethoxycarbonylethyl, 2-methoxycarbonylpropyl, 2-ethoxycarbonylpropyl, 2- (n-butoxycarbonyl) propyl, 2- (4-n-butoxycarbonyl) propyl, 3-methoxycarbonylpropyl, 3-ethoxycarbonylpropyl, 3- (n-butoxycarbonyl) propyl, 3- (4-n-butoxycarbonyl) propyl, aminocarbonylalkyl, e.g. Aminocarbonylmethyl, aminocarbonylethyl, aminocarbonylpropyl and the like, alkylaminocarbonylalkyl such as methylaminocarbonylmethyl, methylaminocarbonylethyl, ethylcarbonylmethyl, ethylcarbonylethyl and the like, or dialkylaminocarbonylalkyl such as dimethylaminocarbonylmethyl, dimethylaminocarbonylethyl, dimethylcarbonylpropyl, diethylaminocarbonylmethyl, diethylaminocarbonylethyl, diethylcarbonylpropyl and the like;

Alkyl substituted by hydroxy, such as. 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 3-hydroxybutyl, 4-hydroxybutyl, 2-hydroxy-2,2-dimethylethyl,

5-hydroxy-3-oxa-pentyl, 6-hydroxyhexyl, 7-hydroxy-4-oxa-heptyl, 8-hydroxy-4-oxo-octyl, 8-hydroxy-3,6-dioxo-octyl, 9-hydroxy 5-oxa-nonyl, 1 1-hydroxy-4,8-dioxa- undecyl, 11-hydroxy-3,6,9-trioxa-undecyl, 14-hydroxy-5,10-dioxa-tetradecyl,

15-hydroxy-4,8,12-trioxa-pentadecyl and the like;

Alkyl which is substituted by amino, such as. 2-aminoethyl, 2-aminopropyl,

3-aminopropyl, 4-aminobutyl, 6-aminohexyl and the like;

Alkyl which is substituted by cyano, such as. 2-cyanoethyl, 3-cyanopropyl, 3-cyanobutyl and 4-cyanobutyl;

Alkyl which is substituted by halogen, as defined below, wherein in the alkyl group, the hydrogen atoms may be partially or completely replaced by halogen atoms, such as Ci-cis-fluoroalkyl, z. Trifluoromethyl, difluoromethyl, fluoromethyl, pentafluoroethyl, heptafluoropropyl, heptafluoroisopropyl, nonafluorobutyl, nonafluoroisobutyl, undecylfluoropentyl, undecylfluoroisopentyl and the like, Ci-Cis-chloroalkyl, z. For example, chloromethyl, dichloromethyl, trichloromethyl, 2-chloroethyl, 2- and 3-chloropropyl, 2-, 3- and 4-chlorobutyl, 1, 1-dimethyl-2-chloroethyl and the like, Ci-Ci8-bromoalkyl, z. Bromoethyl, 2-bromoethyl, 2- and 3-bromopropyl and 2-, 3- and 4-bromobutyl and the like;

Alkyl which is substituted by nitro, such as. 2-nitroethyl, 2- and 3-nitropropyl and 2-, 3- and 4-nitrobutyl and the like;

Alkyl which is substituted by amino, such as. 2-aminoethyl, 2-aminopropyl, 3-aminopropyl, 4-aminobutyl, 6-aminohexyl and the like;

Alkyl substituted by cycloalkyl, such as. Cyclopentylmethyl, 2-cyclopentylethyl, 3-cyclopentylpropyl, cyclohexylmethyl, 2-cyclohexylethyl, 3-cyclohexylpropyl and the like; Alkyl which is substituted by = 0 (oxo group), such as. 2-oxopropyl, 2-oxobutyl, 3-oxobutyl, 1-methyl-2-oxopropyl, 2-oxopentyl, 3-oxopentyl, 1-methyl-2-oxobutyl, 1-methyl-3-oxobutyl, 2-oxohexyl, 3-oxohexyl, 4-oxohexyl, 2-oxoheptyl, 3-oxoheptyl, 4-oxoheptyl, 4-oxoheptyl and the like;

Alkyl which is substituted by = S (thioxo), such as. 2-thioxopropyl, 2-thioxobutyl, 3-thioxobutyl, 1-methyl-2-thioxopropyl, 2-thioxopentyl, 3-thioxopentyl, 1-methyl-2-thioxobutyl, 1-methyl-3-thioxobutyl, 2-thioxohexyl, 3-thioxohexyl, 4-thioxohexyl, 2-thioxoheptyl, 3-thioxoheptyl, 4-thioxoheptyl, 4-thioxoheptyl and the like;

Alkyl which is substituted by = NR ^E -, preferably those in which R ^{E is} H or Ci-C4-alkyl, such as. 2-iminopropyl, 2-iminopropyl, 2-iminopropyl, 2-iminopropyl, 2-iminopropyl, 2-iminobutyl, 1-methyl-2-iminobutyl, 1-methyl-3-imino-butyl, 2- isohexyl, 3-iminohexyl, 4-iminohexyl, 2-iminoheptyl, 3-iminoheptyl, 4-iminoheptyl, 4-iminoheptyl, 2-methyliminopropyl, 2-methyliminobutyl, 3-methyliminobutyl, 1-methyl-2-methyliminopropyl, 2-methyliminopentyl, 3-methylimino-pentyl, 1-methyl-2-methyliminobutyl, 1-methyl-3-methyliminobutyl, 2-methyliminohexyl, 3-methyliminohexyl, 4-methyliminohexyl, 2-methyliminoheptyl, 3-methyliminoheptyl, 4-methyliminoheptyl, 4-methyliminoheptyl, 2-ethyliminopropyl, 2-ethyliminobutyl,

3-ethyliminobutyl, 1-methyl-2-ethyliminopropyl, 2-ethyliminopentyl, 3-ethyliminopentyl, 1-methyl-2-ethyliminobutyl, 1-methyl-3-ethyliminobutyl, 2-ethyliminohexyl, 3-ethyl-iminohexyl, 4-ethyliminohexyl, 2-ethyliminoheptyl, 3-ethyliminoheptyl, 4-ethyliminoheptyl, 4-ethyliminoheptyl, 2-propyliminopropyl, 2-propyliminobutyl, 3-propyliminobutyl, 1-methyl-2-propyliminopropyl, 2-propyliminopentyl, 3-propyliminopentyl, 1-methyl 2-propyliminobutyl, 1-methyl-3-propyliminobutyl, 2-propyliminohexyl, 3-propyliminohexyl, 4-propyliminohexyl, 2-propyliminoheptyl, 3-propyliminoheptyl, 4-propyliminoheptyl, 4-propyliminoheptyl and the like.

Alkyl substituted by aryl ("arylalkyl") has at least one unsubstituted or substituted aryl group as defined below. Suitable substituents on the aryl group are the following. In this case, the alkyl group in "arylalkyl" may carry at least one further substituent as defined above and / or by one or more nonadjacent heteroatoms or heteroatom-containing groups which are selected from -O-, -S-, -NR ^E -, and / or -SO2- be interrupted. Arylalkyl is preferably phenyl-Ci-Cio-alkyl, particularly preferably phenyl-Ci-C ₄ -alkyl, z. For benzyl, 1-phenethyl, 2-phenethyl, 1-phen-prop-1-yl, 2-phenprop-1-yl, 3-phenprop-1-yl, 1-phenbut-1-yl, 2-phenbut 1-yl, 3-phenbut-1-yl, 4-phenbut-1-yl, 1-phenbut-2-yl, 2-phenbut-2-yl, 3-phenbut-2-yl, 4-phenbut-2 -yl, 1- (phen-meth) -eth-1-yl, 1- (phen-methyl) -1- (methyl) -eth-1-yl or - (phen-methyl) -1- (methyl) -prop-1-yl; preferably for benzyl and 2-phenethyl. Alkoxy is an alkyl group bonded via an oxygen atom. Examples of alkoxy are: methoxy, ethoxy, n-propoxy, 1-methylethoxy, butoxy, 1-methylpropoxy, 2-methylpropoxy, 1, 1-dimethylethoxy, n-pentoxy, 1-methylbutoxy, 2-methylbutoxy, 3-methylbutoxy, 1 , 1-Dimethylpropoxy, 1, 2-dimethylpropoxy, 2,2-dimethylpropoxy, 1-ethylpropoxy, hexoxy, 1-methylpentoxy, 2-methylpentoxy, 3-methylpentoxy, 4-methylpentoxy, 1, 1-dimethylbutoxy, 1, 2-dimethylbutoxy , 1, 3-dimethylbutoxy, 2,2-dimethylbutoxy, 2,3-dimethylbutoxy, 3,3-dimethylbutoxy, 1-ethylbutoxy, 2-ethylbutoxy, 1, 1, 2-trimethylpropoxy, 1, 2,2-trimethylpropoxy, 1 -Ethyl-1-methylpropoxy or 1-ethyl-2-methylpropoxy, hexoxy and R ^A O- (CH ₂ CH ₂ CH ₂ CH ₂ O) _n - CH ₂ CH ₂ CH ₂ CH ₂ O- with R ^A H or C 1 -C ₄ -alkyl, preferably H, methyl or ethyl and n is 0 to 10, preferably 0 to 3.

Alkylthio (alkylsulfanyl) is an alkyl group bonded via a sulfur atom. Examples of alkylthio are methylthio, ethylthio, propylthio, butylthio, pentylthio and hexylthio.

Alkylsulfinyl is an alkyl group bonded via an S (= O) group.

Alkylsulfonyl is an alkyl group bonded via an S (= O) ₂ group.

The term "alkenyl" in the context of the present invention comprises straight-chain and branched alkenyl groups which, depending on the chain length, may carry one or more double bonds (eg 1, 2, 3, 4 or more than 4). Preference is given to C ₂ -Cis, particularly preferably C ₂ -C ₂ -alkenyl groups. The term "alkenyl" also includes substituted alkenyl groups which may carry one or more (eg, 1, 2, 3, 4, 5 or more than 5) substituents. Suitable substituents are, for. B. selected under = 0, = S, = NR ^E , cycloalkyl, cycloalkyloxy, polycyclyl, polycycloxy, heterocycloalkyl, aryl, aryloxy, arylthio, hetaryl, halogen, hydroxy, SH, COOH, carboxylate, SO3H, sulfonate, alkylsulfinyl, Alkylsulfonyl, NE ³ E ⁴ , nitro and cyano, wherein E ³ and E ^{4 are} independently H, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl.

The term "alkenyl" also includes alkenyl radicals whose carbon chain may be interrupted by one or more non-adjacent heteroatoms or heteroatom-containing groups, which are preferably selected from -O-, -S-, -NR ^E - and / or -SO ₂ - ,

Alkenyl is then for example ethenyl (vinyl), 1-propenyl, 2-propenyl, 1-methylethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, penta-1,3-di-en-1-yl, hexa-1, 4-dien-1-yl, hexa-1, 4-dien-3-yl, hexa-1, 4-dien-6-yl, hexa-1, 5-dien-1-yl, hexa-1, 5-dien-3-yl, hexa-1, 5 dien-4-yl, hepta-1, 4-dien-1-yl, Hepta-1, 4-dien-3-yl, hepta-1, 4-dien-6-yl, hepta-1, 4-dien-7-yl, hepta-1, 5-dien-1-yl, hepta- 1, 5-dien-3-yl, hepta-1, 5-dien-4-yl, hepta-1, 5-dien-7-yl, hepta-1, 6-dien-1-yl, hepta-1, 6-dien-3-yl, hepta-1, 6-dien-4-yl, hepta-1, 6-dien-5-yl, hepta-1, 6-dien-2-yl, octa-1, 4 dien-1-yl, octa-1, 4-dien-2-yl, octa-1, 4-dien-3-yl, octa-1, 4-dien-6-yl, octa-1, 4-diene 7-yl, octa-1, 5-dien-1-yl, octa-1, 5-dien-3-yl, octa-1, 5-dien-4-yl, octa-1, 5-diene-7 yl, octa-1, 6-dien-1-yl, octa-1, 6-dien-3-yl, octa-1, 6-dien-4-yl, octa-1, 6-dien-5-yl, Octa-1, 6-dien-2-yl, Deca-1,4-dienyl, Deca-1, 5-dienyl, Deca-1, 6-dienyl, Deca-1, 7-dienyl, Deca-1, 8- dienyl, deca-2,5-dienyl, deca-2,6-dienyl, deca-2,7-dienyl, deca-2,8-dienyl and the like.

The term "cycloalkyl" in the context of the present invention comprises unsubstituted as well as substituted monocyclic saturated hydrocarbon groups having generally 3 to 12 carbon ring members, preferably C3-C12-cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclopentyl , Cyclodecyl, cycloundecyl or cyclododecyl, in particular C5-Ci2-cycloalkyl. Suitable substituents are as a rule selected for alkyl, the substituents mentioned above for the alkyl groups, alkoxy and also alkylthio. Substituted cycloalkyl groups may have one or more (for example 1, 2, 3, 4, 5 or more than 5) substituents, where in the case of halogen the cycloalkyl radical is partially or completely substituted by halogen.

Examples of cycloalkyl groups are cyclopentyl, 2- and 3-methylcyclopentyl, 2- and 3-ethylcyclopentyl, chloropentyl, dichloropentyl, dimethylcyclopentyl, cyclohexyl, 2-, 3- and 4-methylcyclohexyl, 2-, 3- and 4-ethylcyclohexyl, 3 and 4-propylcyclohexyl, 3- and 4-isopropylcyclohexyl, 3- and 4-butylcyclohexyl, 3- and 4-sec-butylcyclohexyl, 3- and 4-tert-butylcyclohexyl, chlorhexyl, dimethylcyclohexyl, diethylcyclohexyl, methoxycyclohexyl, dimethoxycyclohexyl, Diethoxycyclohexyl, butoxycyclohexyl, methylthio cyclohexyl, chlorocyclohexyl, dichlorocyclohexyl, cycloheptyl, 2-, 3- and 4-methylcycloheptyl, 2-, 3- and 4-ethylcycloheptyl, 3- and 4-propylcycloheptyl, 3- and 4-isopropyl- cycloheptyl, 3- and 4-butylcycloheptyl, 3- and 4-sec-butylcycloheptyl, 3- and 4-tert-butylcycloheptyl, cyclooctyl, 2-, 3-, 4- and 5-methylcyclooctyl, 2-, 3-, 4- and 5-ethylcyclooctyl, 3-, 4- and 5-propylcyclooctyl, partially fluorinated cycloalkyl and perfluorinated cycloalkyl of the formula C _n F 2 ( _n -a) - (ib) H 2a-b with n = 5 to 12, 0 <= a <= n and b = 0 or 1.

Cycloalkyloxy is an oxygen-bonded cycloalkyl group as defined above.

The term "cycloalkenyl" includes unsubstituted and substituted, mono- or diunsaturated hydrocarbon groups having from 3 to 5, to 8, to 12, preferably 5 to 12 carbon ring members, such as cyclopent-1-en-1-yl, cyclopent-2-ene 1-yl, cyclopent-3-en-1-yl, cyclohex-1-en-1-yl, cyclohex-2-en-1-yl, cyclohex-3-en-1-yl, Cyclohexa-2,5-dien-1-yl and the like. Suitable substituents are those previously mentioned for cycloalkyl.

Cycloalkenyloxy is an oxygen-bonded cycloalkenyl group as defined above.

The term "polycyclyl" in the context of the present invention broadly includes compounds containing at least two rings, regardless of how these rings are linked. These may be carbocyclic and / or heterocyclic rings. The rings can be saturated or unsaturated. The rings can be linked via single or double bond ("polynuclear compounds"), linked by annulation ("fused ring systems") or bridged ("bridged ring systems", "cage compounds"). Preferred polycyclic compounds are bridged ring systems and fused ring systems. Condensed ring systems may be fused (fused) aromatic, hydroaromatic and cyclic compounds by annulation. Condensed ring systems consist of two, three or more than three rings. Depending on the type of linkage, a distinction is made in condensed ring systems between an ortho-annulation, d. H. Each ring has one or two atoms in common with each neighboring ring, and a peri-annulation in which one carbon atom belongs to more than two rings. Preferred among the fused ring systems are ortho-fused ring systems. Bridged ring systems in the context of the present invention include those which do not belong to the polynuclear ring systems and not to the fused ring systems and in which at least two ring atoms belong to at least two different rings. In the bridged ring systems, one distinguishes, depending on the number of ring-opening reactions that are formally required to arrive at an open-chain compound, bi, tri, tetracyclo compounds, etc., consisting of two, three, four, etc. rings. The term "bicycloalkyl" encompasses bicyclic hydrocarbon radicals having preferably 5 to 10 C atoms, such as bicyclo [2.2.1] hept-1-yl, bicyclo [2.2.1] hept-2-yl, bicyclo [2.2.1] heptane 7-yl, bicyclo [2.2.2] oct-1-yl, bicyclo [2.2.2] oct-2-yl, bicyclo [3.3.0] octyl, bicyclo [4.4.0] decyl and the like. The term "bicycloalkenyl" includes monounsaturated, bicyclic hydrocarbon radicals preferably having 5 to 10 carbon atoms, such as bicyclo [2.2.1] hept-2-en-1-yl.

The term "aryl" in the context of the present invention comprises mononuclear or polynuclear aromatic hydrocarbon radicals which may be unsubstituted or substituted. Aryl is usually for hydrocarbon radicals having 6 to 10, to 14, to 18, preferably 6 to 10 carbon ring members. Aryl is preferably unsubstituted or substituted phenyl, naphthyl, anthracenyl, phenanthrenyl, naphthacenyl, chrysenyl, pyrenyl, etc., and particularly preferably phenyl or naphthyl. Substituted aryls may vary depending on the number and size of their ring systems or more (eg, 1, 2, 3, 4, 5, or more than 5) substituents. These are preferably selected independently from among alkyl, alkoxy, cycloalkyl, cycloalkyloxy, heterocycloalkyl, aryl, aryloxy, arylthio, hetaryl, halogen, hydroxy, SH, alkylthio, alkylsulfinyl, alkylsulfonyl, COOH, carboxylate, SO ₃ H, sulfonate, NE ⁵ E ⁶ , nitro and cyano, wherein E ⁵ and E ⁶ independently of one another are H, alkyl, cycloalkyl, cycloalkyloxy, polycyclylyl, polycycloxy, heterocycloalkyl, aryl, aryloxy or hetaryl. Aryl is particularly preferably phenyl, which in the case of a substitution can generally carry 1, 2, 3, 4 or 5, preferably 1, 2 or 3, substituents.

Aryl which carries one or more radicals is, for example, 2-, 3- and

4-methylphenyl, 2,4-, 2,5-, 3,5- and 2,6-dimethylphenyl, 2,4,6-trimethylphenyl, 2-, 3- and 4-ethylphenyl, 2,4-, 2, 5-, 3,5- and 2,6-diethylphenyl, 2,4,6-triethylphenyl, 2-, 3- and 4-propylphenyl, 2,4-, 2,5-, 3,5- and 2,6 Dipropylphenyl, 2,4,6-tripropylphenyl, 2-, 3- and 4-isopropylphenyl, 2,4-, 2,5-, 3,5- and 2,6-diisopropylphenyl, 2,4,6-triisopropyl- phenyl, 2-, 3- and 4-butylphenyl, 2,4-, 2,5-, 3,5- and 2,6-dibutylphenyl, 2,4,6-tributylphenyl, 2-, 3- and 4 -lsobutylphenyl, 2,4-, 2,5-, 3,5- and 2,6-diisobutylphenyl, 2,4,6-triisobutylphenyl, 2-, 3- and 4-sec-butylphenyl, 2,4-, 2 , 5-, 3,5- and 2,6-di-sec-butylphenyl, 2,4,6-tri-sec-butylphenyl, 2-, 3- and 4-tert-butylphenyl, 2,4- , 2,5-, 3,5- and 2,6-di-tert-butylphenyl, 2,4,6-tri-tert-butylphenyl and 2-, 3-, 4-dodecylphenyl; 2-, 3- and 4-methoxyphenyl, 2,4-, 2,5-, 3,5- and 2,6-dimethoxyphenyl, 2,4,6-trimethoxyphenyl, 2-, 3- and 4-ethoxyphenyl , 2,4-, 2,5-, 3,5- and 2,6-diethoxyphenyl, 2,4,6-triethoxyphenyl, 2-, 3- and 4-propoxyphenyl, 2,4-, 2,5 -, 3,5- and 2,6-dipropoxyphenyl, 2-, 3- and 4-isopropoxyphenyl, 2,4-, 2,5-, 3,5- and 2,6-diisopropoxyphenyl, 2-, 3- and 4-butoxyphenyl, 2-, 3-, 4-hexyloxyphenyl; 2-, 3-, 4-chlorophenyl, 2,4-, 2,5-, 3,5- and 2,6-dichlorophenyl, trichlorophenyl, 2-, 3-, 4-fluorophenyl, 2,4-, 2, 5-, 3,5- and 2,6-difluorophenyl, trifluorophenyl, such as. B. 2,4,6-trifluorophenyl, tetrafluorophenyl, pentafluorophenyl, 2-, 3- and 4-cyanophenyl; 2-nitrophenyl, 4-nitrophenyl, 2,4-dinitrophenyl, 2,6-dinitrophenyl; 4-dimethylaminophenyl; 4-acetylphenyl; Methoxyethylphenyl, ethoxymethylphenyl; Methylthiophenyl, isopropylthiophenyl or tert-butylthiophenyl; methylnaphthyl; Isopropylnaphthyl or ethoxynaphthyl. Examples of substituted aryl wherein two substituents attached to adjacent carbon atoms of the aryl ring form a fused ring or fused ring system are indenyl and fluorenyl.

The term "aryloxy" in the context of the present invention stands for aryl bound via an oxygen atom.

The term "arylthio" in the context of the present invention stands for aryl bound via a sulfur atom.

The term "heterocycloalkyl" in the context of the present invention comprises non-aromatic, unsaturated or fully saturated, cycloaliphatic groups with im Generally 5 to 8 ring atoms, preferably 5 or 6 ring atoms, in which 1, 2 or 3 of the ring carbon atoms are replaced by heteroatoms selected from oxygen, nitrogen, sulfur and a group -NR ^E - and which is unsubstituted or with one or more , For example, 1, 2, 3, 4, 5 or 6, d-Cβ-alkyl groups is substituted. Examples of such heterocycloaliphatic groups are pyrrolidinyl, piperidinyl, 2,2,6,6-tetramethylpiperidinyl, imidazolidinyl, pyrazolidinyl, oxazolidinyl, morpholidinyl, thiazolidinyl, isothiazolidinyl, isoxazolidinyl, piperazinyl, tetrahydrothienyl, dihydrothienyl, tetrahydrofuranyl, dihydrofuranyl, Tetrahydropyranyl, 1, 2-oxazolin-5-yl, 1, 3-oxazolin-2-yl and dioxanyl called. Nitrogen-containing heterocycloalkyl can in principle be bound both via a carbon atom and via a nitrogen atom.

The term "heteroaryl (hetaryl)" in the context of the present invention comprises unsubstituted or substituted, heteroaromatic, mononuclear or polynuclear groups having generally 5 to 14 ring atoms, preferably 5 or 6 ring atoms, in which 1, 2 or 3 of the ring carbon atoms one, two, three or four heteroatoms selected from O, N, -NR ^E - and S are substituted, such as furyl, thienyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, benzofuranyl, benzthiazolyl, benzimidazolyl, pyridyl, quinolinyl, acridinyl, pyridazinyl , Pyrimidinyl, pyrazinyl, pyrrolyl, imidazolyl, pyrazolyl, indolyl, purinyl, indazolyl, benzotriazolyl, 1, 2,3-triazolyl, 1, 3,4-triazolyl and carbazolyl, these heterocycloaromatic groups in the case of a substitution generally 1 , 2 or 3 substituents. The substituents are as a rule selected from C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy, hydroxyl, carboxyl, halogen and cyano.

5- to 7-membered nitrogen-containing heterocycloalkyl or heteroaryl radicals which optionally contain further heteroatoms are, for example, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, pyrrolidinyl, pyrazolinyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, Piperidinyl, piperazinyl, oxazolyl, isooxazolyl, thiazolyl, isothiazolyl, indolyl, quinolinyl, isoquinolinyl or quinaldinyl, which may be unsubstituted or substituted as mentioned above.

Halogen is fluorine, chlorine, bromine or iodine.

Carboxylate and sulfonate in the context of this invention preferably represent a derivative of a carboxylic acid function or a sulfonic acid function, in particular a metal carboxylate or sulfonate, a carboxylic acid ester or sulfonic acid ester function or a carboxylic acid or sulfonic acid amide function. These include z. As the esters with Ci-C4-alkanols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol and tert-butanol.

For the purposes of the present invention, the term "acyl" denotes alkanoyl, hetaroyl or aroyl groups having generally 1 to 11, preferably 2 to 8, carbon atoms. for example, the formyl, acetyl, propanoyl, butanoyl, pentanoyl, hexanoyl, heptanoyl, 2-ethylhexanoyl, 2-propylheptanoyl, benzoyl or naphthoyl group.

The radicals E ¹ and E ² , E ³ and E ⁴ , E ⁵ and E ⁶ are independently selected from H, alkyl, cycloalkyl and aryl. The groups NE ¹ E ² , NE ³ E ⁴ and NE ⁵ E ⁶ are preferably N, N-dimethylamino, N, N-diethylamino, N, N-dipropylamino, N, N-diisopropylamino, N, N-di-n -butylamino, N, N-di-tert-butylamino, N, N-dicyclohexylamino or N, N-diphenylamino.

Suitable ionic liquids are selected in the context of the present invention from salts of the general formula (I)

[A] ⁺ (1 / n) * [Y] "- (I),

where [A] ^{+ is} a quaternary ammonium cation and (1 / n) ^* [Y] ⁿ - is an anion equivalent of an n-charged anion, where n is an integer from 1 to 3.

Suitable compounds which are suitable for forming the cation [A] ⁺ of ionic liquids are e.g. B. in DE 102 02 838 A1. These compounds preferably contain at least one nitrogen atom, particularly preferably 1 to 10 nitrogen atoms, in particular 1 to 5 nitrogen atoms, very particularly preferably 1 to 3 nitrogen atoms and especially 1 or 2 nitrogen atoms. The latter nitrogen compounds may contain further heteroatoms such as oxygen, sulfur or phosphorus atoms.

Nitrogen atoms are, for example, suitable carriers of the positive charge in the cation of the ionic liquids. In the synthesis of ionic liquids, a cation can first be generated by quaternization on the nitrogen atom of, for example, an amine or nitrogen heterocycle. The quaternization can be carried out by protonation of the nitrogen atom. Depending on the protonation reagent used, salts with different anions are obtained. In cases where it is not possible to form the desired anion already during the quaternization, this can be done in a further synthesis step. Starting from, for example, an ammonium halide, the halide can be reacted with a Lewis acid to form a complex anion from halide and Lewis acid. Alternatively, replacement of a halide ion with the desired anion is possible. This can be done by adding a metal salt to precipitate the metal halide formed, via an ion exchanger, or by displacing the halide ion with a strong acid (to release the hydrohalic acid). Suitable methods are, for example, in Angew. Chem. 2000, 1 12, pp. 3926-3945 and the literature cited therein. Preferred cations of the ionic liquids are those compounds which have a molar mass of less than 1000 g / mol, very particularly preferably less than 600 g / mol and in particular less than 400 g / mol.

Preferred cations of the ionic liquids are furthermore those compounds which contain at least one five- to six-membered heterocycle, in particular a five-membered heterocycle, which has at least one nitrogen atom and optionally an oxygen or sulfur atom. Particular preference is given to those compounds which have at least one contain five- to six-membered heterocycle having one, two or three nitrogen atoms and a sulfur or an oxygen atom, most preferably those having two nitrogen atoms. Further preferred are aromatic heterocycles.

Accordingly, in a preferred embodiment of the process according to the invention, the hydrolysis stability of an ionic liquid (IL) which has a heterocyclic cation will be increased.

The term "heterocyclic" cation in the context of the present invention encompasses both "heteroaromatic" cations and "partially or completely saturated heterocyclic cations".

The term "heteroaromatic" cation includes cations whose structure can be derived, for example, by quaternization of a ring nitrogen atom of a "hetaryl" compound as defined above. Examples of five- or six-membered heteroaromatic cations are pyrazolium, oxazolium, isoxazolium, thiazolium, isothiazolium, imidazolium, 1, 2,4-oxadiazolium, 1, 2,4-thiadiazolium, 1, 3,4-oxadiazolium, 1, 3, 4-thiadiazolium, pyrrolium, 1, 2,3-triazolium, 1, 2,4-triazolium, pyridinium, pyridazinium, pyrimidinium, 2-pyrazinium, 1, 3,5-triazinium and 1, 2,4-triazinium.

The term "partially or fully saturated" heterocyclic cation includes cations whose structure can be deduced, for example, by quaternization of a ring nitrogen atom of a "heterocycloalkyl" compound as defined above. Examples of five- or six-membered saturated or partially unsaturated heterocyclic cations are pyrrolidinium, pyrazolidinium, oxazolidinium, isoxazolidinium,

Thiazolidinium, isothiazolidinium, imidazolidinium, 1, 2,4-oxadiazolidinium, 1, 2,4-thiazolidinium, 1, 2,4-triazolidinium, 1, 3,4-oxadiazolidinium, 1, 3,4-thiadiazolidinium, 1, 3,4-triazolidinium, 2-pyrrolinium, 3-pyrrolinium, 2-isoxazolinium, 3-isoxazolinium, 4-isoxazolinium, 2-isothiazolinium, 3-isothiazolinium, 4-isothiazolinium, 2,3-dihydropyrazolium, 3,4- Dihydropyrazolium, 4,5-dihydropyrazolium, 2,3-dihydrooxazolium,

3,4-dihydrooxazolium, piperidinium, hexahydropyridazinium, hexahydropyrimidinium, piperazinium, 1,3,5-hexahydrotriazinium or 1,2,4-hexahydrotriazinium. The ionic liquid IL used according to the invention preferably has at least one cation which is selected from the compounds of the formulas (IV.a) to (IV.v) shown below,

(IV.d) (IV.e) (IV.f)

(IV.i) (iv.j) (IVj ')

(IV.m) (IV.m ¹ ) (IV.n)

(IV.n ') (IV.o) (IV.o ¹ )

(IV.p) (IV.q) (IV.q ')

(IV.q ") (IV.r) (IV.r ')

(IV.u) (IV.v) and oligomers containing these structures, wherein R is H, alkyl, alkenyl, cycloalkyl, cycloalkenyl, polycyclyl, heterocycloalkyl, aryl or heteroaryl;

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ attached to a ring carbon independently of one another are H, a sulfo group, COOH, carboxylate, sulfonate, acyl , Alkoxycarbonyl, cyano, halogen, hydroxyl, SH, nitro, NE ¹ E ² , alkyl, alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl, alkenyl, cycloalkyl, cycloalkyloxy, cycloalkenyl, cycloalkenyloxy, polycyclyl, polycycloxy, heterocycloalkyl, aryl, aryloxy or Heteroaryl, where E ¹ and E ^2, independently of one another, are H, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,

Radicals R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ which are bonded to a ring hetero atom, for H, SO ₃ H, NE ¹ E ² , alkyl, alkoxy , Alkenyl, cycloalkyl, cycloalkenyl, polycyclyl, heterocycloalkyl, aryl or heteroaryl, where E ¹ and E ² are each independently H, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl, or

two adjacent radicals R ¹ to R ⁹ together with the ring atoms to which they are attached may stand for at least one fused, saturated, unsaturated or aromatic ring or a ring system having 1 to 30 carbon atoms, the ring or the ring system 1 to 5 non-adjacent heteroatoms or teroatomhaltige groups may have and wherein the ring or the ring system may be unsubstituted or substituted,

where two geminal radicals R ¹ to R ^{9 can} also together stand for = 0, = S or = NR ^b , where R ^{b is} H, alkyl, cycloalkyl, aryl or heteroaryl,

in the compounds of the formula (IV. u) R ¹ and R ³ or R ³ and R ^{5 may} also together be the bond moiety of a double bond between the ring atoms which carry these radicals,

B in the compounds of the formulas (IV.u) and (IV.v) together with the CN group to which it is attached form a 4- to 8-membered, saturated or unsaturated or aromatic cycle which is optionally substituted and / or may optionally have further heteroatoms or heteroatom-containing groups and / or may comprise further fused saturated, unsaturated or aromatic carbocycles or heterocycles.

With regard to the general meaning of the abovementioned radicals carboxylate, sulfonate, acyl, alkoxycarbonyl, halogen, NE ¹ E ² , alkyl, alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl, alkenyl, cycloalkyl, cycloalkyloxy, cycloalkenyl, cycloalkenyloxy, polycyclyl, polycycloxy, heterocycloalkyl , Aryl, aryloxy or heteroaryl is at the beginning made statements to the full extent. Radicals R ¹ to R ⁹ which are bonded to a carbon atom in the abovementioned formulas (IV) and have a heteroatom or a heteroatom-containing group can also be bonded to the carbon atom directly via a heteroatom.

Two adjacent radicals R ¹ to R ^9, together with the ring atoms to which they are attached, form at least one fused, saturated, unsaturated or aromatic ring or a ring system having from 1 to 30 carbon atoms, the ring or the ring system not being adjacent to 1 to 5 Heteroatoms or heteroatom-containing groups may have and wherein the ring or the ring system may be unsubstituted or substituted, these radicals may together as fused building blocks preferably 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-Ci-C4-alkyl-1 -aza-1, 3-propenylene, 1, 4-buta-1, 3-dienylene, 1-az-1, 4-buta-1, 3-dienylene or 2-aza-1,4-buta-1,3-dienylene.

The radical R in the compounds of the formulas IV.a to IV.v preferably stands for

unsubstituted C 1 -C 18 -alkyl, such as 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, 1-heptyl, 1-octyl, 1 Nonyl, 1-decyl, 1-undecyl, 1-dodecyl, 1-tetradecyl, 1-hexadecyl and 1-octadecyl;

one to several times with hydroxy, halogen, phenyl, cyano, Ci-Cβ-alkoxycarbonyl and / or SO3H substituted Ci-Cis-alkyl, especially hydroxy-Ci-Cis-alkyl, such as. 2-hydroxyethyl or 6-hydroxyhexyl; Phenyl-Ci-cis-alkyl, such as. Benzyl,

3-phenylpropyl; Cyano-Ci-Cis-alkyl, such as. For example, 2-cyanoethyl; Ci-Cβ-alkoxy-Ci-Cis-alkyl, such as. B. 2- (methoxycarbonyl) -ethyl, 2- (ethoxycarbonyl) -ethyl or 2- (n-butoxycarbonyl) -ethyl; C 1 -C 6 -fluoroalkyl, such as trifluoromethyl, difluoromethyl, fluoromethyl, pentafluoroethyl, heptafluoropropyl, heptafluoroisopropyl, nonafluorobutyl, nonafluoroisobutyl, undecylfluoropentyl, undecylfluoroisopentyl; Sulfo-Ci-Cis-alkyl, such as. For example, 3-sulfopropyl;

Hydroxyethyloxyalkyl, radicals of oligo- and polyalkylene glycols such as polyethylene glycols and polypropylene glycols and their oligomers having 2 to 100 units and an H or a d-Cs-alkyl as an end group, such as R ^A O- (CH R ^B -CH ₂ -O) n -CH R ^B -CH ₂ - with R ^A and R ^B preferably H, methyl or ethyl and n preferably 0 to 3, in particular 3-oxa-butyl, 3-oxa-pentyl, 3,6-dioxa-heptyl, 3,6-dioxa-octyl, 3,6,9-trioxa-decyl, 3,6,9-trioxa-undecyl, 3,6,9,12-tetraoxa-tridecyl and 3,6,9,12-tetraoxa tetradecyl; and

C2-C6 alkenyl, such as vinyl or propenyl.

The radical R particularly preferably stands for linear C 1 -C 6 -alkyl, such as, for example, methyl, ethyl, 1-propyl, 1-butyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-octyl, 1-decyl, 1 Dodecyl, 1-tetradecyl, 1-hexadecyl, 1-octadecyl, most preferably methyl, ethyl, 1-butyl and 1-octyl and CH ₃ O- (CH ₂ CH ₂ O) _n -CH ₂ CH ₂ - and CH ₃ CH ₂ O- (CH ₂ CH ₂ O) _m -CH ₂ CH ₂ -, wherein m is O to 3.

The radicals R ¹ to R ⁹ in the compounds of the formula IV. A to IV.v are each independently H, halogen, hydroxyl, alkoxy, alkylthio, carboxyl, -COOH, sulfonate, CN, NO ₂ , acyl, alkoxycarbonyl, NE ¹ E ² , in which E ¹ and E ^{2 have} one of the meanings given above,

C ₁ -C 6 -alkyl which is unsubstituted or substituted and / or which may be interrupted by at least one heteroatom or a heteroatom-containing group, C ₂ -C 18 -alkenyl which is unsubstituted or substituted and / or may be interrupted by at least one heteroatom , Cβ-Cio-aryl, which is unsubstituted or substituted,

_C5-Ci2 cycloalkyl which is unsubstituted or substituted,

Polycyclyl which is unsubstituted or substituted,

_C5-Ci2 cycloalkenyl, which is unsubstituted or substituted,

Heterocycloalkyl having 5 or 6 ring atoms, wherein the ring next to Kohlenstoffringglie- has 1, 2 or 3 heteroatoms or heteroatom-containing groups which are selected from oxygen, nitrogen, sulfur and NR ^E , and which is unsubstituted or substituted, or

Heteroaryl having 5 to 10 ring atoms, wherein the ring next to carbon ring members 1, 2 or 3 hetero atoms or heteroatom-containing groups which are selected from oxygen, nitrogen, sulfur and NR ^E , and which is unsubstituted or substituted.

Likewise preferred in the compounds of the formulas IV.a to IV.v are two adjacent radicals R ¹ to R ⁹ together with the ring atoms to which they are bonded, for at least one fused, saturated, unsaturated or aromatic ring or for a ring system 1 to 12 carbon atoms, wherein the ring or the ring system may have 1 to 5 non-adjacent heteroatoms or heteroatom-containing groups, which are preferably selected from oxygen, nitrogen, sulfur and NR ^E , and wherein the ring or the ring system is unsubstituted or substituted wherein the substituents are preferably independently selected from alkoxy, cycloalkyl, cycloalkoxy, polycyclyl, polycycloxy, heterocycloalkyl, aryl, aryloxy, arylthio, heteroaryl, halogen, hydroxy, SH, = 0, = S, = NR ^E , COOH, carboxylate, -SO ₃ H, sulfonate, NE ¹ E ² , nitro and cyano, wherein E ¹ and E ² independently of one another are H, alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl.

When R ¹ to R ⁹ in the compounds of the formula IV. A to IV.v are alkoxy, R ¹ to R ^{9 are} preferably methoxy or ethoxy or

R ^A O- (CH ₂ CH ₂ CH ₂ CH ₂ O) _n -CH ₂ CH ₂ CH ₂ CH ₂ O-, wherein R ^A and R ^{B are} preferably H, methyl or ethyl and n is preferably 0 to 3 ,

If R ¹ to R ⁹ in the compounds of the formula IV. A to IV.v are acyl, these are preferably selected from formyl and C 1 -C 4 -alkylcarbonyl, in particular formyl or acetyl.

When R ¹ to R ⁹ in the compounds of the formula IV. A to IV.v are Ci-Cis-alkyl, these are preferably selected from unsubstituted Ci-Cis-alkyl, such as 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-9-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-trimethyl-pentyl, 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; C 1 -C 6 -haloalkyl, especially C 1 -C 6 -fluoroalkyl, for example trifluoromethyl, difluoromethyl, fluoromethyl, pentafluoroethyl, heptafluoropropyl, heptafluoroisopropyl, nonafluorobutyl, nonofluoroisobutyl, undecylfluoropentyl, undecylisopentyl, C 6 F 13, CsFi ₇ , CioF ₂ i, C i ₂ F ₂ 5, especially Ci-Cis-chloroalkyl, such as chloromethyl, 2-chloroethyl, trichloromethyl, 1, 1-dimethyl-2-chloroethyl; Amino-Ci-Ci8-alkyl, such as 2-aminoethyl, 2-aminopropyl, 3-aminopropyl, 4-aminobutyl, 6-aminohexyl;

C 1 -C 6 -alkylamino-C 1 -C 8 -alkyl, such as 2-methylaminoethyl, 2-methylaminopropyl, 3-methylaminopropyl, 4-methylaminobutyl, 6-methylaminohexyl; Di- (C 1 -C 6 -alkyl) C 1 -C 8 -alkyl such as 2-dimethylaminoethyl, 2-dimethylaminopropyl, 3-dimethylaminopropyl, 4-dimethylaminobutyl, 6-dimethylaminohexyl; Cyano-Ci-Cis-alkyl, such as 2-cyanoethyl, 2-cyanopropyl;

C 1 -C 10 -alkoxy-C 1 -C 6 -alkyl, such as methoxymethyl, 2-methoxyethyl, 2-methoxypropyl, 3-methoxypropyl, 2-methoxyisopropyl, 4-methoxybutyl, 6-methoxyhexyl, 2-ethoxyethyl, 2-ethoxypropyl, 3-ethoxypropyl , 4-ethoxybutyl, 6-ethoxyhexyl, 2-isopropoxyethyl, 2-butoxyethyl, 2-butoxypropyl, 2-octyloxyethyl, 5-methoxy-3-oxa-pentyl, 8-methoxy-3,6-dioxo-octyl, 7-methoxy 4-oxa-heptyl, 1-methoxy-4,8-dioxa-undecyl, 9-methoxy-5-oxa-nonyl, 9-methoxy-5-oxa-nonyl, 14-methoxy-5,10-dioxa- tetradecyl, 5-ethoxy-3-oxa-pentyl, 8-ethoxy-3,6-dioxa-octyl, 7-ethoxy-4-oxa-heptyl, 1 1-Ethoxy-4,8-dioxa-undecyl, 9-ethoxy-5-oxa-nonyl or 14-ethoxy-5,10-oxa-tetradecyl, 15-methoxy-4,8,12-trioxa-pentadecyl, 1 1-methoxy-3,6,9-trioxa undecyl, 11-ethoxy-3,6,9-trioxa-undecyl, 15-ethoxy-4,8,12-trioxa-pentadecyl; Di- (C 1 -C 10 -alkoxy-C 1 -C 18 -alkyl), such as diethoxymethyl or diethoxyethyl, C 1 -C 6 -alkoxycarbonyl-C 1 -C 18 -alkyl, such as 2- (methoxycarbonyl) -ethyl, 2- (ethoxycarbonyl) -ethyl, 2- (n-butoxycarbonyl) ethyl; Di- (C 1 -C 6 alkoxycarbonyl) C 1 -C 8 -alkyl, such as 1, 2-di- (methoxycarbonyl) -ethyl; Hydroxy-C 1 -C 18 -alkyl such as 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 6-hydroxyhexyl, 2-hydroxy-2,2-dimethylethyl, 5-hydroxy-3-oxa-pentyl, 8 -Hydroxy-3,6-dioxo-octyl, 11-hydroxy-3,6,9-trioxa-undecyl, 7-hydroxy-4-oxa-heptyl, 1 1-hydroxy-4,8-dioxa-undecyl, 15- Hydroxy-4,8,12-trioxa-pentadecyl, 9-hydroxy-5-oxa-nonyl, 14-hydroxy-5,10-dioxa-tetradecyl; Ci-Ci2-alkylsulfanyl-Ci-Ci8-alkyl, such as butylthiomethyl, 2-dodecylthioethyl; C 5 -C 12 -cycloalkyl-C 1 -C 18 -alkyl, such as cyclopentylmethyl, 2-cyclopentylethyl,

3-cyclopentylpropyl, cyclohexylmethyl, 2-cyclohexylethyl, 3-cyclohexylpropyl, phenyl-Ci-Ci8-alkyl, wherein the phenyl moiety of phenyl-Ci-Ci8-alkyl is unsubstituted or mono-, di-, tri- or tetra-substituted, and the Substituents are independently selected from C 1 -C 6 -alkyl, halogen, C 1 -C 6 -alkoxy and nitro, such as benzyl (phenylmethyl), 1-phenylethyl, 2-phenylethyl, 3-phenylpropyl, p-tolylmethyl, 1- (p Butyl-phenyl) -ethyl, p-chlorobenzyl, 2,4-dichlorobenzyl, p-methoxybenzyl, m-ethoxybenzyl, phenyl-C (CH ₃ ) 2-, 2,6-dimethylphenylmethyl; Diphenyl-C 1 -C 18 -alkyl, such as diphenylmethyl (benzhydryl); Triphenyl-C 1 -C 18 -alkyl, such as triphenylmethyl; Phenoxy-C 1 -C 18 -alkyl such as 2-phenoxyethyl, 2-phenoxypropyl, 3-phenoxypropyl, 4-phenoxybutyl, 6-phenoxyhexyl; and phenylthio-Ci-Ci8-alkyl, such as 2-phenylthioethyl.

When R ¹ to R ⁹ in the compounds of the formula IV. A to IV.v are C 2 -C alkenyl, they are preferably selected from C 2 -C 6 alkenyl, such as vinyl, 2-propenyl, 3-butenyl, cis-2-butenyl, trans-2-butenyl or C2-cis-alkenyl which is partially or completely substituted by fluorine.

When R ¹ to R ⁹ in the compounds of the formula IV. A to IV.v are Cβ-Cio-aryl, R ¹ to R ^{9 are} preferably phenyl or naphthyl, where phenyl or naphthyl is unsubstituted or one or two -, tri- or tetra-substituted, where the substituents independently of one another by halogen, Ci-Cis-alkyl, Ci-Cβ-alkoxy, Ci-Ce-alkylsulfanyl, Ci-C ₆ -alkoxy-Ci-C ₆ -alkyl, Ci -C ₆ alkylcarbonyl, amino, Ci-Cβ-alkylamino, di- (Ci-C6-dialkyl) amino and nitro are selected, such as phenyl, methylphenyl (ToIyI), dimethylphenyl (XyIyI), such as. For example, 2,6-dimethylphenyl, trimethylphenyl, such. B. 2,4,6-trimethylphenyl, ethylphenyl, diethylphenyl, iso-propylphenyl, tert-butylphenyl, dodecylphenyl, chlorophenyl, dichlorophenyl, trichlorophenyl, fluorophenyl, Difluorophenyl, trifluorophenyl, tetrafluorophenyl, pentafluorophenyl, 2,6-dichlorophenyl, 4-bromophenyl, methoxyphenyl, dimethoxyphenyl, ethoxyphenyl, hexyloxyphenyl, 2,6-dimethoxyphenyl, 2-nitrophenyl, 4-nitrophenyl, 2,4-dinitrophenyl, 2,6- Dinitrophenyl, 4-dimethylaminophenyl, 4-acetylphenyl, methoxyethylphenyl, ethoxymethylphenyl, methylthiophenyl, isopropylthiophenyl, tert-butylthiophenyl, α-naphthyl, β-naphthyl, methylnaphthyl, isopropylnaphthyl, chloronaphthyl, ethoxynaphthyl, or partially fluorinated phenyl or perfluorinated phenyl ,

When R ¹ to R ⁹ in the compounds of the formula IV. A to IV.v are C 5 -C 12 -cycloalkyl, R ¹ to R ^{9 are} preferably unsubstituted. Cycloalkyl, such as cyclopentyl or cyclohexyl;

C 5 -C 12 -cycloalkyl which is monosubstituted or disubstituted, wherein the substituents are independently selected from C 1 -C 6 -alkyl, C 1 -C 6 -alkoxy, C 1 -C 6 -alkylsulfanyl or chlorine, eg. Butylcyclohexyl, methoxycyclohexyl, dimethoxycyclohexyl, diethoxycyclohexyl, butylthiocyclohexyl, chlorocyclohexyl, dichlorocyclohexyl, dichlorocyclopentyl; C5-C12-cycloalkyl which is completely or completely fluorinated.

When R ¹ to R ⁹ in the compounds of the formula IV. A to IV.v are polycyclyl, R ¹ to R ^{9 are} preferably C 5 -C 12 -cycloalkyl, such as norbornyl or C 5 -C 12 -cyclo-alkenyl, such as norbornenyl.

When R ¹ to R ⁹ in the compounds of the formula IV.a to IV.v are C 5 -C 12 -cycloalkenyl, R ¹ to R ^{9 are} preferably unsubstituted. Cycloalkenyl, such as cyclopent-2-en-1 -yl, cyclopent-3-en-i-yl, cyclohex-2-en-1-yl, cyclohex-1-en-1-yl, cyclohexa-2,5-dien-1-yl or partially or completely fluorinated cycloalkenyl.

When R ¹ to R ⁹ in the compounds of the formula IV.a to IV.v are heterocycloalkyl having 5 or 6 ring atoms, R ¹ to R ^{9 are} preferably 1,3-dioxolan-2-yl, 1, 3 Dioxan-2-yl, 2-methyl-1,3-dioxolan-2-yl, 4-methyl-1,3-dioxolan-2-yl.

When R ¹ to R ⁹ in the compounds of the formula IV.a to IV.v are heteroaryl, R ¹ to R ^{9 are} preferably furyl, thienyl, pyrryl, pyridyl, indolyl, benzoxazolyl, benzimidazolyl, benzthiazolyl. In the case of substitution, hetaryl carries 1, 2 or 3 substituents, which are selected independently of one another from C 1 -C 6 -alkyl,

C 1 -C 6 -alkoxy and halogen, for example dimethylpyridyl, methylquinolyl, dimethylpyrryl, methoxyfuryl, dimethoxypyridyl or difluoropyridyl.

Particularly preferably, the radicals R ¹ to R ⁹ in the compounds of the formula IV.a to IV.v independently of one another are hydrogen; unbranched or branched, unsubstituted or monosubstituted to poly, hydroxyl, halogen, phenyl, cyano, Ci-Cβ-alkoxycarbonyl and / or sulfo C 1 -C 18 -alkyl, such as, for example, 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, 1-heptyl, 1-octyl, 1 Nonyl, 1-decyl, 1-undecyl, 1-dodecyl, 1-tetradecyl, 1-hexadecyl, 1-octadecyl, 2-hydroxyethyl, benzyl, 3-phenyl-propyl, 2-cyanoethyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, n Butoxycarbonylmethyl, tert-butoxycarbonylmethyl,

2- (methoxycarbonyl) -ethyl, 2- (ethoxycarbonyl) -ethyl, 2- (n-butoxycarbonyl) -ethyl, trifluoromethyl, difluoromethyl, fluoromethyl, pentafluoroethyl, heptafluoropropyl, heptafluoroisopropyl, nonafluorobutyl, nonafluoroisobutyl, undecylfluoropentyl, undecylfluoroisopentyl or 6-hydroxyhexyl and 3-sulfopropyl; Hydroxyethyloxyalkyl, radicals of oligo- and polyalkylene glycols, such as polyethylene glycols and polypropylene glycols and their oligomers having 2 to 100 units and an H or a Ci-Ce-Al kyl as an end group, such as

R ^A O- (CHR ^B -CH ₂ -O) _n -CHR ^B -CH ₂ - OdOR R ^A O- (CH ₂ CH ₂ CH ₂ CH ₂ O) _n -CH ₂ CH ₂ CH ₂ CH ₂ O-, in which R ^A and R ^{B are} preferably H, methyl or ethyl and n is preferably 0 to 3, in particular 3-oxabutyl, 3-oxapentyl, 3,6-dioxaheptyl, 3,6-dioxaoctyl,

3,6,9-trioxadecyl, 3,6,9-trioxaundecyl, 3,6,9, 12-tetraoxatridecyl and 3,6,9,12-tetraoxatetradecyl;

C ₂ -C 4 alkenyl, such as vinyl and allyl; and

N, N-di-C 1 -C 6 -alkylamino, such as N, N-dimethylamino and N, N-diethylamino.

Most preferably, the radicals R ¹ to R ⁹ are each independently hydrogen; Ci-Ciβ-alkyl, such as methyl, ethyl, 1-butyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-octyl; phenyl; 2-hydroxyethyl; 2-cyanoethyl; 2- (alkoxycarbonyl) ethyl such as 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl or 2- (n-butoxycarbonyl) ethyl;

N, N- (C 1 -C 4 -dialkyl) amino, such as N, N-dimethylamino or N, N-diethylamino; Chlorine and for radicals of oligoalkylene glycol, such as CH ₃ O- (CH ₂ CH ₂ O) _n -CH ₂ CH ₂ - or CH ₃ CH ₂ O- (CH ₂ CH ₂ O) _n -CH ₂ CH ₂ -, wherein n stands for 0 to 3

Preferred pyridinium ions are compounds of the formula IV. A, in which one of the radicals R ¹ to R ^{5 is} methyl, ethyl or chlorine and the remaining radicals R ¹ to R ^{5 are} H.

Further preferred pyridinium ions are compounds of the formula IV. A, in which R ^{3 is} dimethylamino and the remaining radicals R ¹ , R ² , R ⁴ and R ^{5 are} H. Further preferred pyridinium ions are compounds of the formula IV. A, in which the radicals R ¹ to R ⁵ stand for H.

Further preferred pyridinium ions are compounds of the formula IV. A, in which R ^{2 is} carboxy or carboxamide and the remaining radicals R ¹ , R ² , R ⁴ and R ^{5 are} H.

Further preferred pyridinium ions are compounds of the formula IV.a in which R ¹ and R ² or R ² and R ³ together are 1,4-buta-1,3-dienylene and the remaining radicals R ¹ , R ² , R ⁴ and R ^{5 stands} for H.

Particularly preferred pyridinium ions are pyridinium, 2-methylpyridinium, 2-ethylpyridinium, 5-ethyl-2-methylpyridinium and 2-methyl-3-ethylpyridinium, and 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, t- (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, 9- (1-tetradecyl) -2-ethylpyridinium, 1- (1-hexadecyl) -2- ethyl pyridinium, 1, 2-dimethyl-5-ethylpyridinium, 1, 5-diethyl-2-methylpyridinium, 1- (1-butyl) -2-methyl-3-ethylpyridinium, 1- (1-hexyl ) -2-methyl-3-ethyl-pyridinium and 1- (1-octyl) -2-methyl-3-ethyl-pyridinium, 1- (1-dodecyl) -2-methyl-3-ethyl-pyridinium, 1 - (1-Tetradecyl) -2-methyl-3-ethyl-pyridinium and 1- (1-hexadecyl) -2-methyl-3-ethylpyridinium.

Preferred pyridazinium ions are compounds of the formula IV. B, in which the radicals R ¹ to R ^{4 are} H, or in which one of the radicals R ¹ to R ^{4 is} methyl or ethyl and the remaining radicals R ¹ to R ^{4 are} H.

Preferred pyrimidinium ions are compounds of the formula IV.c in which R ^{1 is} H, methyl or ethyl and R ² to R ⁴ independently of one another are H or methyl, or in which R ^{1 is} H, methyl or ethyl, R ² and R ^{4 is} methyl and R ^{3 is} H.

Preferred pyrazinium ions are compounds of the formula IV. D, in which R ^{1 is} H, methyl or ethyl and R ² to R ⁴ are each independently H or methyl, or in which R ^{1 is} H, methyl or ethyl and R ² and R ^{4 is} methyl and R ^{3 is} H or wherein R ¹ to R ^{4 are} methyl or wherein R ¹ to R ^{4 are} H. Preferred imidazolium ions are compounds of the formula IV.e, in which R ^{1 is} H, methyl, ethyl, 1-propyl, 1-butyl, 1-pentyl, 1-hexyl, 1-octyl, 2-hydroxyethyl or 2-cyanoethyl and R ² to R ^{4 are} independently H, methyl or ethyl.

Particularly preferred imidazolium ions of the formula IV.e are 1-methylimidazolium,

1-ethylimidazolium, 1- (1-propyl) -imidazolium, 1- (1-allyl) -imidazolium,

1- (1-butyl) -imidazolium, 1- (1-octyl) -imidazolium, 1- (1-dodecyl) -imidazolium,

1- (1-tetradecyl) -imidazolium, 1- (1-hexadecyl) -imidazolium, 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 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-methylimidazolium, 3-ethylimidazolium, 3-n-propylimidazolium, 3-n-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, 1, 4,5-trimethyl-3-octylimidazolium, 1-prop-1 -en-3-yl-3-methylimidazolium, and 1-prop-1 -en-3-yl-3-butyne limidazolium.

Preferred pyrazolium ions are compounds of the formulas IV.f, IV. G or IV. G ', wherein R ^{1 is} H, methyl or ethyl and R ² to R ⁴ independently of one another are H or methyl.

Further preferred pyrazolium ions are compounds of the formula IV.h in which R ¹ to R ⁴ independently of one another are H or methyl.

Particularly preferred pyrazolium ions are 1,4-dimethylpyrazolium and 1,2,4-trimethylpyrazolium.

Preferred 1-pyrazolinium ions are compounds of the formula IV. I, in which R ¹ to R ⁶ independently of one another are H or methyl. Preferred 2-pyrazolinium ions are compounds of the formula IV.j or IV.j ", in which R ^{1 is} H, methyl, ethyl or phenyl and R ² to R ⁶ are each independently H or methyl.

Preferred 3-pyrazolinium ions are compounds of the formula IV. K. or .IV.k ', wherein R ¹ and R ^{2 are} independently H, methyl, ethyl or phenyl and R ³ to R ^{6 are} independently H or methyl.

Preferred imidazolinium ions are compounds of the formula (IV.1) in which R ¹ and R ² independently of one another are H, methyl, ethyl, 1-butyl or phenyl, R ³ and R ⁴ independently of one another are H, methyl or ethyl, and R ⁵ and R ^{6 are} independently H or methyl.

Further preferred imidazolinium ions are compounds of the formula IV.m or

IV. Nϊ, wherein R ¹ and R ^{2 are} independently H, methyl or ethyl and R ³ to R ^{6 are} independently H or methyl.

Further preferred imidazolinium ions are compounds of the formula IV.n or IV. N ', where R ¹ to R ³ independently of one another are H, methyl or ethyl and R ⁴ to R ⁶ independently of one another are H or methyl.

Preferred thiazolium ions are compounds of formula IV. O or IV. O ', wherein R ^{1 is} H, methyl, ethyl or phenyl and R ² and R ^{3 are} independently H or methyl.

Preferred oxazolium ions are compounds of formula IV. P, wherein R ^{1 is} H, methyl, ethyl or phenyl and R ² and R ^{3 are} independently H or methyl.

Preferred 1,2,4-triazolium ions are compounds of the formulas IV. Q, IV. Q 'or IV. Q ", in which R ¹ and R ^2, independently of one another, are H, methyl, ethyl or phenyl and R ^{3 is} H, Methyl or phenyl.

Preferred 1,2,3-triazolium ions are compounds of the formulas IV. R, IV. R 'or IV.r ", in which R ^{1 is} H, methyl or ethyl, R ² and R ^3, independently of one another, are H or methyl or R ² and R ³ together represent 1,4-buta-1,3-dienylene.

Preferred pyrrolidinium ions are compounds of the formula IV. S, in which R ^{1 is} H, methyl, ethyl or phenyl and R ² to R ⁹ independently of one another are H or methyl. Preferred Imidazolidiniumionen are compounds of formula IV. T, wherein R ¹ and R ^{4 are} independently H, methyl, ethyl or phenyl and R ² , R ³ and R ⁵ to R ^{8 are} independently H or methyl.

Preferred diazabicycloalkenium ions of the formulas IV.u and IV.v are selected from cationic derivatives of 1, 5-diazabicyclo [4.3.0] non-5-ene (DBN) and 1,8-diazabicyclo [5.4.0] undec-7 -en (DBU).

In a particularly preferred embodiment of the process according to the invention, the hydrolysis stability of an ionic liquid IL which has at least one cation selected from the aforementioned imidazolium ions and the abovementioned pyrazolium ions is improved. Most preferably, the cation of the ionic liquid is selected from the aforementioned imidazolium ions. With regard to preferred imidazolium ions and pyrazolium ions, reference is made in full to the statements made above.

In the process according to the invention, the anion [Y] ⁿ - of the ionic liquids IL is preferably selected from compounds of the formulas (R ^a O) SO 3 ^" , (R ^a ) SO 3 ^" , (R ³ O) SO ₂ -, (R ³ O ) PO ₃ ^{2 "} , (R ^a O) (R ^b O) PO ₂ -, (R ^a O) (R ^b ) PO ₂ -, (R ³ O) PO ₂ ^2" , (R ^a O) (R ^b O) PO ^" ,

(R ^a O) (R ^b ) PO-, (R ³ O) BO ₂ ^{2 "} , (R ^a O) (R ^b O) BO-, (R ^a O) (R ^b ) BO ^" , (R ^a O) (R ^b O) (R ^c O) (R ^d O) B-, (R ^a O) CO ₂ - (R ^a O) SIOS ³ - (R ^a O) (R ^b O) SiO ₂ ² -, (R ^a O) (R ^b ) SiO ₂ ² -, (R ^a 0) (R ^b 0) (R ^d 0) Si0-, (R ^a 0) (R ^b 0) (R ^c ) Si0 - and (R ^a 0) (R ^b ) (R ^c ) Si0-, in which the radicals R ^a , R ^b , R ^c and R ^d independently of one another are H, alkyl, preferably C 1 -C 30 -alkyl, particularly preferably Cis-alkyl which is unsubstituted or substituted and / or which may be interrupted by at least one heteroatom or heteroatom-containing group,

Aryl, preferably C6-Ci4-aryl, particularly preferably Cβ-Cio-aryl which is unsubstituted or substituted, cycloalkyl, preferably C5-Ci ₂ cycloalkyl, unsubstituted or substituted heterocycloalkyl, preferably heterocycloalkyl having 5 or 6 ring atoms which, wherein the ring in addition to carbon ring atoms 1, 2 or 3 heteroatoms or heteroatom-containing groups which is unsubstituted or substituted, heteroaryl, preferably heteroaryl having 5 to 10 ring atoms, wherein the ring in addition to carbon ring atoms 1, 2 or 3 heteroatom or heteroatom-containing groups which are selected under oxygen, nitrogen, sulfur and NR ^E , which is unsubstituted or substituted, wherein in anions having a plurality of radicals R ^a to R ^d , also each two of these radicals together with the part of the anion to which they are attached, for at least a saturated, unsaturated or aromatic ring or a ring system having 1 to 12 carbon atoms, wherein the ring or the ring system may have from 1 to 5 non-adjacent heteroatoms or heteroatom-containing groups which are preferably selected from oxygen, nitrogen, sulfur and NR ^E , and wherein the ring or the ring system is unsubstituted or may be substituted.

With regard to suitable and preferred C 1 -C 30 -alkyls, in particular C 1 -C 6 -alkyls, C 6 -C 14 -aryls, in particular C 6 -C 10 -aryls, C 1 -C 12 -cycloalkyls, heterocycloalkyls having 5 or 6 ring atoms and heteroaryls having 5 or 6 Ring atoms is referred to the statements made at the outset. Regarding suitable and preferred substituents at d-Cso-alkyl, especially Ci-C ₈ alkyl, C ₆ -C ₂ aryl, C ₅ -C ₂ cycloalkyl, heterocycloalkyl with 5 or 6 ring atoms and heteroaryl with 5 or 6 ring atoms also referred to the statements made at the outset to substituents.

If at least one of the radicals R ^a to R ^{d is} optionally substituted C 1 -C 18 -alkyl, then it is preferably methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, Heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethylpentyl, decyl, dodecyl, tetradecyl, heptadecyl, octadecyl, 1,1-dimethylpropyl, 1,1-dimethylbutyl, 1,1,3,3-tetramethylbutyl, Benzyl, 1-phenylethyl, α, α-dimethylbenzyl, benzhydryl, 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, 2-methoxyethyl, 2-ethoxyethyl, 2-butoxyethyl, diethoxymethyl, Diethoxyethyl, 1,3-dioxolan-2-yl, 1,3-dioxan-2-yl, 2-methyl-1,3-dioxolan-2-yl, 4-methyl-1,3-dioxolan-2-yl yl, 2-isopropoxyethyl, 2-butoxypropyl, 2-octyloxyethyl, chloromethyl, trichloromethyl, trifluoromethyl, 1, 1-dimethyl-2-chloroethyl, 2-methoxy sopropyl, 2-ethoxyethyl, butylthiomethyl, 2-dodecylthioethyl, 2-phenylthioethyl, 2,2,2-trifluoroethyl,

2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 6-hydroxyhexyl, 2-aminoethyl, 2-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 or 6-ethoxyhexyl.

If at least one of the radicals R ^a to R ^{d is} interrupted by one or more non-adjacent heteroatoms or heteroatom-containing Ci-Ci8-alkyl, it is preferably 5-hydroxy-3-oxapentyl, 8-hydroxy-3,6-dioxa octyl, 11-hydroxy-3,6,9-trioxa-undecyl, 7-hydroxy-4-oxa-heptyl, 1-hydroxy-4,8-dioxa-undecyl, 15-hydroxy-4,8,12- trioxa-pentadecyl, 9-hydroxy-5-oxa-nonyl, 14-hydroxy-5,10-oxa-tetradecyl, 5-methoxy-3-oxa-pentyl,

8-methoxy-3,6-dioxa-octyl, 1-methoxy-3,6,9-trioxa-undecyl, 7-methoxy-4-oxa-heptyl, 1-methoxy-4,8-dioxa-undecyl, 15-methoxy-4,8,12-trioxa-pentadecyl, 9-methoxy-5-oxa-nonyl, 14-methoxy-5,10-oxa-tetradecyl, 5-ethoxy-3-oxa-pentyl, 8-ethoxy-3,6-dioxa-octyl, 1-ethoxy-3 , 6,9-trioxa-undecyl, 7-ethoxy-4-oxa-heptyl, 1-ethoxy-4,8-dioxa-undecyl, 15-ethoxy-4,8,12-trioxa-pentadecyl, 9-ethoxy 5-oxa-nonyl or 14-ethoxy-5,10-oxa-tetradecyl.

If two radicals R ^a to R ^{d form} a ring, these radicals can be taken together, for example, as fused building block 1, 3-propylene, 1, 4-butylene, 2-oxa-1,3-propylene, 1-oxa-1, 3 propylene, 2-oxa-1, 3-propenylene, 1-aza-1, 3-propenylene, 1-C 1 -C 4 -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 mean.

The number of non-adjacent heteroatoms or heteroatom-containing groups of the radicals R ^a to R ^d is basically not critical and is usually limited only by the size of the respective residue or ring building block. As a rule, it is not more than 5 in the respective radical, preferably not more than 4 or very particularly preferably not more than 3. Furthermore, at least one, preferably at least two, carbon atoms are generally present between two heteroatoms.

Substituted and unsubstituted imino groups may be, for example, imino, methylimino, iso-propylimino, n-butylimino or tert-butylimino.

Preferred functional groups of the radicals R ^a to R ^{d are} carboxy, carboxamide, hydroxy, di (C 1 -C ₄ -alkyl) amino, C 1 -C ₄ -alkyloxycarbonyl, cyano or C 1 -C ₄ -alkoxy. Alkyl of different radicals R ^c to R ^f may also be mono- or polysubstituted by Ci-C ₄ -alkyl, preferably methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl or tert-butyl.

If at least one of the radicals R ^a to R ^{d is} optionally substituted C 6 -C 12 aryl, then it is preferably phenyl, methylphenyl (ToIyI), XyIyI, α-naphthyl, β-naphthyl, chlorophenyl, dichlorophenyl, trichlorophenyl, difluorophenyl, 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- or 4-nitrophenyl, 2,4- or 2,6-dinitrophenyl, 4-dimethylamino-phenyl, 4-acetylphenyl, methoxyethylphenyl or ethoxymethylphenyl.

If at least one of the radicals R ^a to R ^{e is} optionally substituted C 5 -C 12 -cycloalkyl, it preferably represents cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, diethylcyclohexyl, butylcyclohexyl, methoxycyclohexyl, dimethoxycyclohexyl , Diethoxycyclohexyl, butylthiocyclohexyl, chlorocyclohexyl, Dichlorcyclohexyl, dichlorocyclopentyl and a saturated or unsaturated bicyclic system such as norbornyl or norbornenyl.

If at least one of the radicals R ^a to R ^{e is} an optionally substituted five- or six-membered heterocycle, it preferably represents furyl, thienyl, pyryl, pyridyl, indolyl, benzoxazolyl, dioxolyl, dioxyl, benzimidazolyl, benzothiazolyl, Dimethylpyridyl, methylquinolyl, dimethylpyryl, methoxifuryl, dimethoxypyridyl, difluoropyridyl, methylthiophenyl, isopropylthiophenyl or tert-butylthiophenyl.

When in anions which have a plurality of radicals R ^a to R ^e , in each case two of these radicals together with the part of the anion to which they are attached represent at least one saturated, unsaturated or aromatic ring or a ring system having 1 to 12 carbon atoms where the ring or the ring system may have 1 to 5 non-adjacent heteroatoms or heteroatom-containing groups, which are preferably selected from oxygen, nitrogen, sulfur and NR ^E , the ring or the ring system is unsubstituted or carries 1, 2, 3, 4, 5 or more than 5 substituents. The substituents are preferably independently selected from alkyl, alkoxy, alkylsulfanyl, cycloalkyl, cycloalkoxy, polycyclyl, heterocycloalkyl, aryl, aryloxy, arylthio and heteroaryl.

The abovementioned anions or anion equivalents are generally at least partially subject to hydrolysis in ionic liquids.

In a particularly preferred embodiment of the process, the anion [Y] ⁿ - of the ionic liquid (IL) is selected from compounds of the formulas (R ^a O) SO ₃ ^" , (R ^a ) SO ₃ ^" , (R ³ O) PO ₃ ^{2 "} and (R ^a O) (R ^b O) PO ₂ ^" in which R ^a and R ^b independently of one another are alkyl, cycloalkyl or aryl, especially unsubstituted C ₁ -C ₄ -alkyl. Most preferably, the anion [Y] ⁿ - the ionic liquid (IL) is selected from compounds of the formula (R ^a O) SO 3 ", especially mono-C 1 -C 4 -alkyl sulfates, such as, for example, ethyl sulfate.

The anions mentioned as being particularly preferred are subject to hydrolysis in ionic liquids to a particular degree. In particular by the hydrolysis of compounds of formula (R ^a O) SO 3 ^"get sulfuric acid may have a damaging effect on chemical compounds, chemical reactions and apparatus by their corrosive properties with which an ionic liquid containing them is brought into contact.

In a first embodiment of the process according to the invention tertiary amines or mixtures of tertiary amines are used to increase the hydrolytic stability of the ionic liquid (IL). Suitable tertiary amines are compounds of the formula NR ¹ R ² R ³ , wherein R ¹ , R ² and R ^{3 have} one of the previously given for R ¹ to R ⁹ , different meanings of H.

In a specific embodiment, the tertiary amines used according to the invention are selected from compounds of the formula NR ¹ R ² R ³ , where R ¹ , R ² and R ³ independently of one another are each optionally substituted C 1 -C 30 -alkyl, C 5 -C 8 -cycloalkyl or aryl where C 1 -C 30 -alkyl can also be interrupted as defined above by one or more nonadjacent heteroatoms or heteroatom-containing groups.

Examples of suitable unsubstituted tertiary amines are triethylamine, diethyl-n-propylamine, diethylisopropylamine, diethyl-n-butylamine, diethyl-tert-butylamine, diethyl-n-pentylamine, diethylhexylamine, diethylcyclohexylamine, diethyloctylamine, diethyl (2-ethylhexyl) amine, diethyldodecylamine Tri-n-propylamine, di-n-propylethylamine, di-n-propylbutylamine, di-n-propyl-n-pentylamine, di-n-propylhexylamine,

Di-n-propylcyclohexylamine, di-n-propyloctylamine, di-n-propyl (2-ethylhexyl) amine, di-n-propyldodecylamine, triisopropylamine, diisopropylethylamine, diisopropyl-n-propylamine, diisopropylbutylamine, diisopropylpentylamine, diisopropylhexylamine, diisopropylcyclohexylamine, diisopropyloctylamine, Diisopropyl- (2-ethylhexyl) -amine, diisopropyldodecylamine, tri-n-butylamine, di-n-butylethylamine, di-n-butyl-n-propylamine, di-n-butyl-n-pentylamine, di-n-butylhexylamine, Di-n-butylcyclohexylamine, di-n-butyloctylamine, di-n-butyl (2-ethylhexyl) amine, di-n-butyldodecylamine, N-benzyl-N-ethylaniline, N-benzyl-Nn-propylaniline, N- Benzyl-N-iso-propylaniline, N-benzyl-Nn-butylaniline, N, N-dimethyl-p-toluidine, N, N-diethyl-p-toluidine, N, N-di-n-butyl-p-toluidine, Diethylbenzylamine, di-n-propylbenzylamine, di-n-butylbenzylamine, diethylphenylamine, di-n-propylphenylamine and di-n-butylphenylamine.

Examples of suitable substituted tertiary amines are tri (2-hydroxyethyl) amine, di (2-hydroxyethyl) n-propylamine, di (2-hydroxyethyl) isopropylamine, di (2-hydroxyethyl) -n-butylamine, di (2-hydroxyethyl) tert-butylamine, di (2-hydroxyethyl) -n-pentylamine,

Di (2-hydroxyethyl) hexylamine, di (2-hydroxyethyl) cyclohexylamine, di (2-hydroxyethyl) octylamine, di (2-hydroxyethyl) (2-ethylhexyl) amine, di (2-hydroxyethyl) nonylamine, di (2- hydroxyethyl) decylamine, di (2-hydroxyethyl) dodecylamine, di-n-propyl (2-hydroxyethyl) amine, diisopropyl (2-hydroxyethyl) amine, di-n-butyl (2-hydroxyethyl) amine, N-benzyl N- (2-hydroxyethyl) aniline, N, N-di (2-hydroxyethyl) -p-toluidine, di (2-hydroxyethyl) benzylamine, di (2-hydroxyethyl) phenylamine and derivatives thereof which have been prepared by alkoxylation, specifically by ethoxylation, which can be provided 2-hydroxyethyl groups. Usually, the abovementioned alkoxylated derivatives of the tertiary amines are present as mixtures and have on average 1 to 50, preferably 1 to 20 and more preferably 2 to 10 alkylene oxide units per 2-hydroxyethyl group. Preferred substituted tertiary amines are di (2-hydroxyethyl) (Ci-Ci2-alkyl) amines and Tri (2-hydroxyethyl) amine and their alkoxylated derivatives. A particularly preferred substituted tertiary amine is tri (2-hydroxyethyl) amine.

Also suitable are mixtures of tertiary amines of the formula NR ¹ R ² R ³ , in which the meanings of at least one of the radicals R ¹ , R ² or R ³ of a mixture of straight-chain and branched Ci-C3o-alkyl, especially Cs-ds Alkyl, and Ci-C3o-alkenyl, especially Cs-ds-alkenyl, as it is accessible from natural or synthetic fatty acids and fatty alcohols and from oxo alcohols derives. These include, for example, mixtures of n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, myristyl, pentadecyl, palmityl (= cetyl), heptadecyl, octadecyl, nonadecyl, arrachinyl (arachidyl) , Behenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, especially oleyl, nonadecenyl, linolyl, linolenyl or eleostearyl.

Preference is given to mixtures of tertiary amines of the formula NR ¹ R ² R ³ in which at least one of the radicals R ¹ , R ² or R ^{3 is} a mixture of straight-chain and branched C 1 -C 30 -alkyl and C 1 -C 30 -alkenyl and at least one further , especially two, of R ¹ , R ² or R ^{3 is} 2-hydroxyethyl or alkoxylated 2-hydroxyethyl.

In a further specific embodiment, the tertiary amines used according to the invention are selected from compounds of the formula NR ¹ R ² R ³ , in which R ¹ together with R ² and together with the nitrogen atom to which they are bonded represent a five- to six-membered heterocycle R ^{3 has} one of the meanings given above or may stand together with an adjacent substituent of the heterocycle for the single bond moiety of a chemical double bond.

Heterocyclic tertiary amines NR ¹ R ² R ³ are preferred in which at least one ring carbon atom adjacent to a ring nitrogen atom has a substituent other than H, in particular a C 1 -C 4 -alkyl substituent.

Examples of suitable heterocyclic tertiary amines NR ¹ R ² R ³ are pyridine compounds, pyridazine compounds, pyrimidine compounds, pyrazine compounds, imidazole compounds, pyrazole compounds, 1, 2,4-triazole compounds or 1,2,4-triazole compounds, in particular those which in adjacent position to a ring nitrogen atom have at least one substituent.

Examples of suitable pyridine compounds are 2-methylpyridine, 2-ethylpyridine, 2,3-dimethylpyridine, 2,4-dimethylpyridine, 2,5-dimethylpyridine, 2,6-dimethylpyridine, 5-ethyl-2-methylpyridine and 2-methyl-3- ethylpyridine. Suitable pyridazine compounds are, for example, 3-methylpyridazine, 3-ethylpyridazine, 3,4-dimethylpyridazine, 3,5-dimethylpyridazine, 3,6-dimethylpyridazine.

Suitable pyrimidine compounds are, for example, 2-methylpyrimidine, 4-methylpyrimidine, 2,4-dimethylpyrimidine, 2,5-dimethylpyrimidine, 4,5-dimethylpyrimidine, 4,6-dimethylpyrimidine, 2,4,5-trimethylpyrimidine, 2,4,6- Trimethylpyrimidine, 2-ethyl-pyrimidine, 2-ethyl-4-methylpyrimidine, 2-ethyl-5-methylpyrimidine, 2-ethyl-4,5-dimethylpyrimidine or 2-ethyl-4,6-dimethylpyrimidine.

Suitable pyrazine compounds are, for example, 2-methylpyrazine,

2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, 2,3,5-trimethylpyrazine, 2,3,6-trimethylpyrazine, 2,3,5,6-tetramethylpyrazine, 2-ethylpyrazine, 2- Ethyl 3-methylpyrazine, 2-ethyl-5-methylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-3,5-dimethylpyrazine, 2-ethyl-3,6-dimethylpyrazine or 2,3,5, 6-tetramethylpyrazine.

Examples of suitable imidazole compounds are 1, 2-dimethylimidazole, 1-ethyl-2-methylimidazole, 1-n-propyl-2-methylimidazole, 1-isopropyl-2-methylimidazole, 1-n-butyl-2-methylimidazole, 1-sec. Butyl 2-methylimidazole, 1-tert-butyl-2-methylimidazole, 1- (2-hydroxyethyl) -2-methylimidazole, 1, 4-dimethylimidazole, 1-ethyl-4-methylimidazole, 1- n -propyl-4-methylimidazole, 1-isopropyl-4-methylimidazole, 1-n-butyl-4-methylimidazole, 1-sec-butyl-4-methylimidazole, 1-tert-butyl-4-methylimidazole, 1 - (2-hydroxyethyl) -4-methylimidazole, 1, 2,4-trimethylimidazole, 1, 2,5-trimethylimidazole, 1, 4,5-trimethylimidazole or 1, 2,4,5-tetramethylimidazole.

Examples of suitable pyrazole compounds are 1, 3-dimethylpyrazole, 1-ethyl-3-methylpyrazole, 1-n-propyl-3-methylpyrazole, 1-isopropyl-3-methylpyrazole, 1-n-butyl-3-methylpyrazole, 1-sec. Butyl 3-methylpyrazole, 1-tert-butyl-3-methylpyrazole, 1- (2-hydroxyethyl) -3-methylpyrazole, 1, 5-dimethylpyrazole, 1-ethyl-5-methylpyrazole, 1-n-propyl 5-methylpyrazole, 1-isopropyl-5-methylpyrazole, 1-n-butyl-5-methylpyrazole, 1-sec-butyl-5-methylpyrazole, 1-tert-butyl-5-methylpyrazole, 1- (2-hydroxyethyl ) -5-methylpyrazole, 1, 3,4-trimethylpyrazole, 1, 3,5-trimethylpyrazole, 1, 4,5-trimethylpyrazole or 1, 3,4,5-tetramethylpyrazole.

Suitable 1,2,4-triazole compounds are, for example, 1,3-dimethyl-1, 2,4-triazole, 1-ethyl-3-methyl-1, 2,4-triazole, 1 -n-propyl-3-methyl- 1, 2,4-triazole, 1-isopropyl-3-methyl-1, 2,4-triazole, 1-n-butyl-3-methyl-1, 2,4-triazole, 1-sec-butyl-3 -methyl-1, 2,4-triazole, 1-tert-butyl-3-methyl-1, 2,4-triazole, 1- (2-hydroxyethyl) -3-methyl-1,2,4-triazole, 1 , 5-Dimethyl-1, 2,4-triazole, 1-ethyl-5-methyl-1, 2,4-triazole, 1-n-propyl-5-methyl-1, 2,4-triazole, 1-iso propyl-5-methyl-1, 2,4-triazole, 1-n-butyl-5-methyl-1, 2,4-triazole, 1-sec-butyl-5-methyl-1, 2,4- triazole, 1-tert-butyl-5-methyl-1, 2,4-triazole, 1- (2-hydroxyethyl) -5-methyl-1, 2,4-triazole or 1, 3,5-trimethyl-1 , 2,4-triazole. Suitable 1,2,3-triazole compounds are, for example, 1,4-dimethyl-1,3,3-triazole, 1-ethyl-4-methyl-1,3,3-triazole, 1-n-propyl-4-methyl- 1, 2,3-triazole, 1-isopropyl-4-methyl-1,2,3-triazole, 1-n-butyl-4-methyl-1,2,3-triazole, 1-sec-butyl-4 -methyl-1,2,3-triazole, 1-tert-butyl-4-methyl-1,2,3-triazole, 1- (2-hydroxyethyl) -4-methyl-1,2,3-triazole, 1 , 5-Dimethyl-1, 2,3-triazole, 1-ethyl-5-methyl-1,2,3-triazole, 1-n-propyl-5-methyl-1,2,3-triazole, 1-isopropyl 5-methyl-1,2,3-triazole, 1-n-butyl-5-methyl-1,2,3-triazole, 1-sec-butyl-5-methyl-1,2,3-triazole, 1 tert-butyl-5-methyl-1,2,3-triazole, 1- (2-hydroxyethyl) -5-methyl-1,2,3-triazole or 1, 4,5-trimethyl-1,2, 3-triazole.

Also suitable are 1, 5-diazabicyclo [4.3.0] non-5-ene (DBN) and 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU).

The heterocyclic tertiary amines of the formula NR ¹ R ² R ^{3 used} according to the invention are preferably selected from the abovementioned imidazole and pyrazole compounds. Particularly preferably, the heterocyclic tertiary amine is 1, 2-dimethylimidazole.

In another embodiment, various quaternary ammonium compounds or mixtures of quaternary ammonium compounds are used to increase the hydrolytic stability of the ionic liquid (IL) from the ionic liquid (IL).

Suitable quaternary ammonium compounds for example, by quaternization tion of the aforementioned tertiary amines NR ¹ R ² R ³ be provided, wherein compounds of the formula [NR ¹ R ² R ³ R] ⁺ (1 / n) ^* [Y '] ^{n ~} Get in which R has one of the meanings given with respect to the ionic liquids and (1 / n) ^* [Y '] ^{n - represents} an anion equivalent. Preferably R in the quaternary ammonium compounds of the formula [NR ¹ R ² R ³ R] ⁺ (1 / n) ^* [Y '] ^{n ~ is} C 1 -C ₄ -alkyl, particularly preferably methyl. The meaning of the anion equivalent (1 / n) ^* [Y '] ⁿ ' is usually given by the quaternization method used, but may be varied by anion exchange, in one particular embodiment [Y '] ⁿ - one of the Y] ⁿ - given meanings.

Suitable methods for quaternization of tertiary amines are known to the person skilled in the art. Suitable methods include, in particular, the reaction of tertiary amines of the formula NR ¹ R ² R ³ with C ¹ -C ⁴ -alkyl halides, such as methyl iodide, or with di-C ¹ -C ⁴ -alkyl sulfates, such as dimethyl sulfate or diethyl sulfate.

Preferred quaternary ammonium compounds are (C 1 -C 4 -alkyl) (C 1 -C 8 -alkyl) -di (2-hydroxyethyl) ammonium compounds and (C 1 -C 4 -alkyl) tri (2-hydroxyethyl) ammonium compounds and their alkoxylated derivatives, in particular those which have as counterion a Ci-C4 Alkylsulfatanion. Particularly preferred quaternary Ammonium compounds are methyltri (2-hydroxyethyl) ammonium compounds, in particular their methyl or ethyl sulfates, and also the alkoxylated derivatives of methyltri (2-hydroxyethyl) ammonium compounds.

Furthermore, mixtures are preferred quaternary ammonium compounds in which the meanings of at least one of the radicals R ^1, R ² or R ³ of a mixture of overall radkettigem and branched Ci-C3o-alkyl, especially Cs-ds-alkyl, and Ci-C3o- Alkenyl, especially Cs-C-is-alkenyl, as it is accessible from natural or synthetic fatty acids and fatty alcohols and from oxo alcohols derives. These include, for example, mixtures of n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, myristyl, pentadecyl, palmityl (= cetyl), heptadecyl, octadecyl, nonadecyl, arrachinyl ( Arachidyl), behenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, especially oleyl, nonadecenyl, linolyl, linolenyl or eleostearyl.

Particular preference is given to those mixtures of quaternary ammonium compounds in which at least one of the radicals R ¹ , R ² or R ^{3 is} a mixture of straight-chain and branched C 1 -C 30 -alkyl and C 1 -C 30 -alkenyl and at least one further, especially two, of the radicals R ¹ , R ² or R ^{3 is} 2-hydroxyethyl or alkoxylated 2-hydroxyethyl. Such mixtures are commercially available, for example, under the trade name Ammoeng ™ 100 (Solvent Solution).

The tertiary amines and / or quaternary ammonium compounds used according to the invention are preferably used in an amount of from 0.01 to 50% by weight, preferably in an application rate of from 0.05 to 30% by weight and more preferably 0.1 to

20 wt .-%, each based on the total weight of the ionic liquid IL added.

The ionic liquids IL used according to the invention and the tertiary amines and / or quaternary ammonium compounds used according to the invention are advantageously completely miscible with one another, ie. H. Addition of the tertiary amine and / or the quaternary ammonium compound to an ionic liquid IL produces a homogeneous liquid composition.

The present invention is explained in more detail below by way of non-limiting examples.

Examples

1. Hydrolysis of ionic liquids as a function of the additive A mixture of 1-ethyl-3-methylimidazolium ethylsulfate (EMIM-EtSO ₄ ), 2 wt% water and 0.1 to 16 wt% of an additive (each based on the weight of EMIM-EtSO ₄ ) stirred at 150 ⁰ C for one hour. Subsequently, a sample was taken and examined by ¹ H-NMR spectroscopy. Based on this spectrum, the molar ratio of ethanol (hydrolysis product) to EMIM-EtSO _{4 was} determined by integration. From this ratio, the percentage hydrolysis of the ionic liquid (IL) used was determined. The experiment was repeated three times for each additive. Table 1 shows the average results of this experiment.

Table 1

^* : Reference measurement for examples 1.2 to 1.4

^** : Comparative Examples (not according to the invention)

^*** : reference measurement to example 1.8

[1]: Siligen APE <™ ⁾ = tri (2-hydroxyethyl) methylammonium methylsulfate

[2]: Golpanol ^"™) = 2-Butin-1, 4-diol

2. Stabilization of ionic liquids

A mixture of 1-ethyl-3-methylimidazolium ethylsulfate (EMIM-EtSO ₄ ), 10% by weight of water and 16% by weight of an additive (each based on the weight of EMIM-EtSO ₄ ) was 90 minutes for one hour ⁰ C stirred. At the times indicated in Table 2, samples were taken and the acid number and pH (after addition of 10% water to the sample taken) were determined. The results are summarized in Table 2. By adding the quaternary ammonium compounds of the invention, the ionic liquid is stabilized at an approximately neutral pH.

^* : Reference measurement for examples 2.1 to 2.9

[1]: Siligen APE <™ ⁾ = tri (2-hydroxyethyl) methylammonium methylsulfate

[3]: Ammoeng 100 <™> = mixture of compounds of the following formula

CH _Q

N 0 (EO) -H

(Cocoyl)

0- (EO) _n -H where EO is ethyleneoxy and the sum of m and n is in the range of 4 to 14.

Claims

claims

A process for improving the hydrolytic stability of an ionic liquid (IL), comprising adding to the ionic liquid (IL) at least one tertiary amine and / or a quaternary ammonium compound other than the ionic liquid (IL).

2. The method according to claim 1, wherein the ionic liquid (IL) is selected from salts of the general formula (I)

[A] ⁺ (1 / n) * [Y] "- (I),

where [A] ^{+ is} a quaternary ammonium cation and (1 / n) ^* [Y] ⁿ - is an anion equivalent of an n-fold anion.

3. The method according to claim 2, wherein the cation [A] ^{+ of} the ionic liquids (IL) is selected from compounds having a molar mass of less than 1000 g / mol.

4. The method according to any one of claims 2 or 3, wherein the cation [A] ^{+ is} selected from compounds having a heterocyclic cation.

5. The process according to any of claims 2 to 4, wherein the cation [A] ^{+ is} selected from pyridinium ions, pyridazinium ions, pyrimidinium ions, pyrazinium ions, imidazolium ions, pyrazolium ions, thiazolium ions, oxazolium ions,

1, 2,4-Triazoliumionen, 1, 2,3-Triazoliumionen, Pyrrolidiniumionen, Imidazolidiniu- ions and Diazabicycloalkeniumionen.

6. A process according to claim 5, wherein the cation [A] ^{+ is} selected from imidazolium ions and pyrazolium ions.

A process according to claim 6, wherein the cation [A] ^{+ is} an imidazolium ion.

8. The method according to any one of the preceding claims, wherein the anion [Y] ⁿ - the ionic liquids (IL) is selected from compounds of the formulas

(R ³ O) SO ₃ -, (R ^a ) SO ₃ -, (R ³ O) SO ₂ -, (R ³ O) PO ₃ ^{2 "} , (R ³ O) (R ¹ O) PO ₂ -, (R ³ O) (R ^b) PO ₂ -, (R ³ O) ₂ PO ^{2 "(R 3} 0) (R ^b 0) P0, (R ³ 0) (R ^b) P0, (R ³ O) BO ₂ ^{2 "(R 3} 0) (R ^b 0) ^B0" (R ³ 0) (R ^b) B0, (R ³ 0) (R 0 ^b) (R ^c 0) (R ^d 0) B-, (R ³ O) CO ₂ -, (R ³ O) SiO ₃ ^{3 "} , (R ³ O) (R ¹ O) SiO ₂ ² -, (R ³ O) (R ^b ) SiO ₂ ² -, (R ³ 0) (R ^b 0) (R ^d 0) Si0-, (R ³ 0) (R ^b 0) (R ^c ) Si0- and (R ³ O) (R ^b ) (R ^c ) SiO-,

wherein R ^a , R ^b , R ^c and R ^d are each independently H, alkyl, aryl, cycloalkyl, heterocycloalkyl or heteroaryl, or

in each case two of the radicals R ^a to R ^d together with the part of the anion to which they are attached represent at least one saturated, unsaturated or aromatic ring or a ring system having 1 to 12 carbon atoms, the ring or the ring system being 1 to 5 may have non-adjacent heteroatoms or heteroatom-containing groups.

9. The method according to claim 8, wherein the anion [Y] ⁿ "is selected from compounds of the formulas (R ³ O) SO ₃ -, (R ^a ) SO ₃ -, (R ³ O) PO ₃ ^2" and (R ^a O) (R ^b O) PO ₂ -, in which R ^a and R ^b independently of one another are alkyl, cycloalkyl or aryl.

A process according to claim 9 wherein the anion [Y] ⁿ "is a compound of formula (R ³ O) SO ₃ -.

1 1. The method according to any one of the preceding claims, wherein the ionic liquid (IL) is added to increase the stability to hydrolysis, a tertiary amine or a mixture of tertiary amines.

12. The method according to claim 1 1, wherein the tertiary amine is selected from di (2-hydroxyethyl) (Ci-Ci6-alkyl) amines, tri (2-hydroxyethyl) amine, the alkoxylated th derivatives of these compounds and mixtures thereof.

13. The process according to claim 11, wherein the tertiary amine is selected from heterocyclic tertiary amines.

14. The process according to claim 13, wherein at least one ring carbon atom of the heterocyclic tertiary amine adjacent to a ring nitrogen atom has a substituent other than H.

15. The method according to any one of claims 13 or 14, wherein the heterocyclic tertiary amine is selected from imidazole compounds, pyrazole compounds and mixtures thereof.

16. The method according to any one of the preceding claims, wherein the ionic liquid (IL) is added to increase the stability to hydrolysis of the ionic liquid (IL) different quaternary ammonium compounds or a mixture of quaternary ammonium compounds.

17. The method according to claim 16, wherein the cation of the quaternary ammonium compounds is selected from (Ci-C4-alkyl) (Ci-Ci6-alkyl) di (2-hydroxyethyl) - ammonium ions and (Ci-C4-alkyl) tri (2- hydroxyethyl) ammonium ions and among the alkoxylated derivatives of these compounds.

18. The method according to any one of claims 16 or 17, wherein the anion of the quaternary ammonium compounds is selected from Ci-C4-Alkylsulfatanionen.

19. The method according to any one of the preceding claims, wherein the tertiary amines and / or quaternary ammonium compounds in an amount of 0.01 to

50% by weight, based on the total weight of the ionic liquid (IL).

20. The method according to any one of the preceding claims, wherein the ionic liquids (IL) and the tertiary amines and / or quaternary ammonium compounds used according to the invention are completely miscible with each other.