WO2006084880A1

WO2006084880A1 - Method for producing oligomerised polyisocyanates and their use

Info

Publication number: WO2006084880A1
Application number: PCT/EP2006/050811
Authority: WO
Inventors: Eva Wagner; Bernd Bruchmann; Matthias Maase; Alfred Oftring; Joachim JÄHME
Original assignee: Basf Aktiengesellschaft
Priority date: 2005-02-11
Filing date: 2006-02-09
Publication date: 2006-08-17
Also published as: DE102005006550A1

Abstract

The invention relates to a method for producing polyisocyanates by the partial oligomerisation of diisocyanates in the presence of at least one oligomerisation catalyst from the group of ionic liquids and to the use of the polyisocyanates as polyisocyanate components in polyurethane paints.

Description

METHOD FOR THE PRODUCTION OF OLIGOMERIZED POLYISOCYANATES

AND YOUR

USE

description

The present invention relates to a novel process for the preparation of polyisocyanates by a partial oligomerization of diisocyanates in the presence of at least one oligomerization catalyst from the group of ionic liquids and the use of the polyisocyanates thus obtainable as a polyisocyanate component in polyurethane paints.

Methods for the partial or complete trimerization of organic polyisocyanates for the preparation of polyisocyanates containing biuret, allophanate or isocyanurate groups or polyurethanes having cellular or compact isocyanurate groups are known and are described in numerous literature publications.

The use of 2-hydroxyalkylammonium cations with a counterion as catalysts in the preparation of polyisocyanates is widespread and already known, for example from US 4,801,663, DE-OS 29 16 201 (= US 4,454,317), US 3,862,150, DE-OS 26 31,733 or EP 17 998.

A disadvantage of the known 2-hydroxyalkylammonium catalysts is that they are solids which, as such, are difficult to meter.

Such 2-hydroxyalkylammonium catalysts are partly commercially available, but mostly only as a solution in alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, etc. However, alcohols react with isocyanates and thus cause by-products.

JP-A 2002 097244 describes a process in which the isocyanurate formation is carried out with a known catalyst having a 2-hydroxyalkylammonium structure, in the presence of ascorbic acid as co-catalyst. Ascorbic acid is thus added as a further component, but does not represent the anion of the catalyst.

US 5905151 and US 5955609 describe lithium salicylate as a catalyst for isocyanurate formation.

A disadvantage of this catalyst lithium salicylate is that it is a hard-to-meterable solid and in addition is not readily thermally deactivatable.

WO 03/093246 describes ionic liquids which can also be used as catalysts in the oligomerization of isocyanates, which consist of a five-membered nitrogen heteroaromatic and one with 4 hydrocarbon radicals substituted ammonium or phosphonium cation, wherein the hydrocarbon radicals contain up to 3 heteroatoms and may optionally be halogen-substituted.

WO 02/092656 describes a process for the oligomerization of isocyanates with the aid of ionic liquids whose anions have 1, 2, 3 and / or 1, 2, 4

Have triazolate structure. Cations may be alkali or alkaline earth metals or ammonium or phosphonium ions substituted with 4 hydrocarbon radicals.

WO 02/092657 describes a process for the oligomerization of isocyanates with the aid of ionic liquids whose anions have a 1,2,3- and / or 1,2,4-

Have triazolate structure. Cations may be alkali or alkaline earth metals or ammonium or phosphonium ions containing hydrogen, saturated or unsaturated aliphatic or cycloaliphatic, optionally substituted aromatic or araliphatic radicals having up to 24 carbon atoms and optionally up to 3 heteroatoms and may optionally be substituted by halogen atoms or hydroxy groups , are substituted.

Such cations have the disadvantage that they are not thermally deactivatable and thus a reaction can only be stopped via catalyst poisons.

The object of the present invention was to provide further catalysts for the production of polyisocyanates by a very simple process in very good quality, which should be highly reactive, easy to dose and thermally deactivatable.

This object has been achieved by a process for the preparation of polyisocyanates containing isocyanurate, biuret and / or allophanate groups by at least partial oligomerization of diisocyanates, in which the reaction is carried out in the presence of at least one oligomerization catalyst, which is an ionic liquid the structure

and a melting point of not more than 100 ^° C

These,

wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ^{7 may} each independently be the same or different and represent a straight-chain or branched C ₁ - to C ₂ o-alkyl group, an optionally substituted C ₅ - to C ^ -cycloalkyl group, an optionally substituted C ₇ - to do-aralkyl group, or an optionally substituted C ₆ -C ₁₂ - aryl group or two or more of the radicals R ¹ to R ³ together are a 4-, 5- or 6 - form a membered alkylene chain or together with a nitrogen atom form a 5- or 6-membered ring which may contain an additional nitrogen or oxygen as a bridging member or together form a multi-membered, preferably six-membered multi-ring system, preferably Zweiringsystem, the one or more additional Nitrogen atoms, oxygen atoms or nitrogen and oxygen atoms may contain as bridge members and

R ⁴ , R ⁵ , R ⁶ and R ^{7 may} additionally be hydrogen.

Ionic liquids in the context of this document are those which compounds which consist of at least one cation and at least one anion and at normal pressure have a melting point of not more than 100 ⁰ C, preferably not more than 90 ° C, particularly preferably not more as 80 ⁰ C, most preferably of not more than 70 ⁰ C, in particular not more than 60 ⁰ C and especially not more than 50 ⁰ C.

In a preferred embodiment, it may be useful that the ionic FIüs- fluids are liquid under the reaction conditions, but upon cooling to lower temperatures, for example at least 10 ⁰ C below the reaction temperature, preferably 20 ⁰ C, particularly preferably 25 and very particularly preferably at least 30 ⁰ C below the reaction temperature, solid, so that the compounds by a separation of solids, for example, a filtration or sedimentation, can be separated off.

In a particularly preferred embodiment, the ionic liquids are liquid under the conditions of the reaction and remain so even in the reaction mixture up to a temperature of room temperature, preferably up to 20 ⁰ C, more preferably up to 15 ⁰ C and most preferably up to 15 ° C.

In the above radicals mean

a straight-chain or branched C ₁ - to C ₂ o-alkyl group, for example methyl, ethyl, propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2 Ethylhexyl, 2,4,4-trimethylpentyl, decyl, 1, 1-dimethylpropyl, 1, 1-dimethylbutyl or 1, 1, 3, 3-tetramethylbutyl, an optionally substituted C ₅ - to Ci ₂ cycloalkyl group, cyclopentyl, cyclohexyl xyl, cyclooctyl, cyclododecyl, methylcyclopentyl, dimethylcyclopentyl, Methylcyclohe- xyl, dimethylcyclohexyl, diethylcyclohexyl, butylcyclohexyl, methoxycyclohexyl, di- methoxycyclohexyl, Diethoxycyclohexyl, Butylthiocyclohexyl, chlorocyclohexyl, dichloro- cyclohexyl, dichlorocyclopentyl and a saturated or unsaturated bicyclic system such as norbornyl or norbornenyl,

an optionally substituted C ₇ to C ₁₀ aralkyl group, for example, benzyl, 1-phenylethyl, 2-phenylethyl, α, α-dimethylbenzyl, benzhydryl, p-tolylmethyl, 1- (p-butylphenyl) ethyl, o, m or p-chlorobenzyl, 2,4-dichlorobenzyl, o-, m- or p-methoxybenzyl or o-, m- or p-ethoxybenzyl,

an optionally substituted C ₆ -C ₂ aryl group for example phenyl, 2-, 3- or 4-methylphenyl, α-naphthyl or ß-naphthyl, furyl, thiophenyl, pyrryl, pyridyl, indolyl, benzoxazolyl, benzimidazolyl, benzthiazolyl, dimethylpyridyl, methylquinolyl , Dimethylpyrryl, methoxyfuryl, dimethoxypyridyl, difluoropyridyl, methylthiophenyl, isopropylthiophenyl, tert-butylthiophenyl, pyridazinyl, pyrimidinyl, pyrazinyl, imidazolyl or pyrazolyl.

Examples of R ¹ to R ³ are each independently of one another methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, phenyl, α- or β-naphthyl, benzyl, cyclopentyl or cyclohexyl.

If two or more of the radicals R ¹ to R ^{3 form} at least one ring, these may be, for example, 1,4-butylene, 1,5-pentylene, 3-oxa-1, 5-pentylene, 3-aza-1, 5-pentylene or 3-methyl-3-aza-1, 5-pentylene.

Preferred for the radicals R ¹ to R ³ are independently methyl, ethyl, Propyt, isopropyl, n-butyl, tert-butyl, phenyl and benzyl, particularly preferably methyl, ethyl, n-butyl, phenyl and benzyl, especially preferred are methyl, ethyl and n-butyl and especially methyl.

Examples of R ⁴ , R ⁵ , R ⁶ and R ⁷ are independently hydrogen, methyl, ethyl, n-propyl, n-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, phenyl , α- or ß-naphthyl, benzyl, cyclopentyl or cyclohexyl. Preference is given to hydrogen, methyl and phenyl, more preferably at least one of the radicals R ⁴ and R ^{5 is} hydrogen and very particularly preferably both radicals R ⁴ and R ^{5 are} hydrogen.

Preferred radicals R ⁶ and R ⁷ are hydrogen, methyl and phenyl, more preferably at least one of R ⁶ and R ^{7 is} hydrogen or methyl and most preferably both R ⁶ and R ^{7 are} hydrogen. Ammonium ions containing ring systems are, for example, methylated, ethylated or benzylated piperazines, piperidines, pyrrolidine, morpholines, quinuclidines (1-azabicyclo [2.2.2] octane) or triethylenediamines.

Preferably, R ¹ , R ² and R ^{3 are the} same and at least one of R ⁴ and R ^{5 is} hydrogen and both R ⁶ and R ^{7 are} hydrogen, more preferably R ¹ , R ² and R ^{3 are the} same and both R ⁴ and R ⁴ R ^{5 is} hydrogen and both R ⁶ and R ^{7 are} hydrogen.

Examples of ammonium cations are

2-hydroxyethyltrimethylammonium, 2-hydroxypropyltrimethylammonium, 2-hydroxyethyltriethylammonium, 2-hydroxypropyltriethylammonium, 2-hydroxyethyltri-n-butylammonium, 2-hydroxypropyltri-n-butylammonium, 2-hydroxyethyltrimethylammonium n-octylammonium, 2-hydroxypropyltri-n-octylammonium, 2-hydroxyethyldimethylbenzylammonium, 2-hydroxypropyldimethylbenzylammonium, 2-hydroxyethyldiethylbenzylammonium, 2-hydroxypropyldiethylbenzylammonium, 2-hydroxyethyl-di-n-butylbenzylammonium, 2 Hydroxypropyldi-n-butylbenzylammonium, 2-hydroxyethylmethyldiethylammonium, 2-hydroxypropylmethyldiethylammonium, 2-hydroxyethylethyldimethylammonium, 2-hydroxypropylethyldimethylammonium, 2-hydroxyethyl-di-n-butylmethylammonium, 2-hydroxypropyl-di-n- butylmethylammonium, 2-hydroxyethyl-di-n-butylethylammonium, 2-hydroxypropyl-di-n-butylethylammonium, 2-hydroxyethyl-di-iso-propylethylammonium, 2-hydroxypropyl-di-iso-propylethylammonium, N- (2-hydroxyethyl) - N, N-dimethylpiperidinium, N- (2-hydroxypropyl) -N, N-dime ethylpiperidinium, N- (2-hydroxyethyl) -N, N-diethylpiperidinium, N- (2-hydroxypropyl) -N, N-diethylpiperidinium, N- (2-hydroxyethyl) -N, N-dimethylmorpholinium, N- (2-hydroxypropyl ) -N, N-dimethylmorpholinium, N- (2-hydroxyethyl) -N, N-diethylmorpholinium, N- (2-hydroxypropyl) -N, N-diethylmorpholinium, N- (2-hydroxyethyl) -N, N-dimethylpiperazinium, N- (2-hydroxypropyl) -N, N-dimethylpiperazinium, N- (2-hydroxyethyl) -N-methyl-diazabicyclo [2,2,2] octane, N- (2-hydroxypropyl) -N-methyl-diazabicyclo [ 2,2,2] octane, N- (2-hydroxyethyl) -N-ethyl-diazabicyclo [2,2,2] octane, N- (2-hydroxypropyl) -N-ethyl-diazabicyclo [2,2,2] octane, N- (2-hydroxyethyl) -N-benzyl-diazabicyclo [2,2,2] octane or N- (2-hydroxypropyl) -N-benzyl-diazabicyclo [2,2,2] octane.

Preference is given to 2-hydroxyethyltrimethylammonium, 2-hydroxypropyltrimethylammonium, 2-hydroxyethyl-t-ethylammonium, 2-hydroxypropyltethylammonium, 2-hydroxyethyltri-n-butylammonium, 2-hydroxypropyltri-n-butylammonium, 2-hydroxyethyl tri-n-octylammonium, 2-hydroxypropyl-tri-n-octylammonium, 2-hydroxyethyldimethylbenzylammonium, 2-hydroxypropyldimethylbenzylammonium, 2-hydroxyethyl-diethylbenzylammonium and 2-hydroxypropyl-diethylbenzylammonium. Particular preference is given to 2-hydroxyethyltrimethylammonium, 2-hydroxypropyltrimethylammonium, 2-hydroxyethyltriethylammonium, 2-hydroxypropyltriethylammonium, 2-hydroxyethyltri-n-butylammonium, 2-hydroxypropyltri-n-butylammonium, 2-hydroxyethyl tri-n-octylammonium and 2-hydroxypropyl-tri-n-octylammonium.

Very particular preference is given to 2-hydroxyethyltrimethylammonium, 2-hydroxypropyltrimethylammonium, 2-hydroxyethyltriethylammonium, 2-hydroxypropyltriethylammonium, 2-hydroxyethyltri-n-butylammonium and 2-hydroxypropyltri-n-butylammonium.

Especially preferred are 2-hydroxyethyltrimethylammonium and 2-hydroxypropyltrimethylammonium and especially 2-hydroxyethyltrimethylammonium.

The corresponding anions according to the invention are arbitrary, as long as they form an ionic liquid with the above melting point with the cation. They are preferably selected from the group of the carboxylates, sulfates, sulfites, sulfonates, sulfinates, phosphates, phosphonates, phosphinates and / or metal halides.

Carboxylates are those compounds which have at least one COO ^" group, sulfates those compounds which have at least one SO ₄ ^2" - or R ^a -O- (SO ₂ ) -O ^" - group, the same applies to sulfites (SO ₃ ^{2 "-} or R ^a -O- (SO) -O ^~), sulfonates (R ^a - SO _^3"), sulfinates (R ^a - (SO) -O), phosphates (PO ₄ ^{3 ",} R ^a - O-PO ₃ ^{2 "} or (R ^a -O) ₂ -PO ₂ ^" ), phosphonates (secondary phosphites, HPO ₃ ^{2 "} , R ³ PO ₃ ^2" , (R ^b -O) -R ^a PO _{2 l} ) and phosphinates (hypophosphites, H ₂ PO ₂ ^" , R ^a R ^b PO ₂ \).

In this formula, R ^a and R ^b independently of one another denote straight-chain or branched C 1 - to C ₂₀ -alkyl groups, an optionally substituted C ₅ - to C ₁₂ -cycloalkyl group, an optionally substituted C ₇ - to C ₁₀ -aralkyl group, or an optionally substituted C ₆ -C ₁₂ aryl group in the meanings as indicated above.

Metal halides are such compounds M _x Hal / ^" ,

wherein

M is a metal of the 1st to 5th main group or the 1st to 8 subgroup or a lanthanide or actinide and also phosphorus, silicon or boron

Hal is a halide or pseudohalide x and y are independently a positive integer and z is the sum of the charge of the metal and the charges of the halides. Examples of metals M are Li, Na, K, Cs, Mg, Ca, Ba, Al, Ga, Sn, Sb, Bi, Ti, Zr, V, Nb, Cr, Mo, W, Mn, Fe, Ru, Co , Rh, Ni, Pd, Pt, Cu, Ag, Zn, Hg, Ce or Sm and also P, Si and B.

Examples of Hal are F, Cl, Br, I, SCN, OCN and CN.

x can be from 1 to 5.

y is dependent on the oxidation state of the particular metal M used, and is at least 1 greater than the sum of the charges of x metals M.

Examples of carboxylates are those of the formula R ⁸ -COO ^", wherein R ⁸ is a geradket- term or branched C ₁ - to C ₂ o alkyl group, an optionally substituted C ₅ - to Ci ₂ cycloalkyl group, an optionally substituted C ₇ - to C _O aralkyl group, an optionally substituted C ₆ -C ₂ aryl group, or optionally substituted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups or by functional groups, aryl, alkyl Aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles substituted CrC ^ alkyl or C ₆ to Ci ₂ -aryl.

In addition to the meanings given above

optionally substituted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino or interrupted by functional groups, aryl, alkyl, aryloxy, alkoxy, halogen, heteroatoms and / or heterocycles substituted C _r C ₂ o-AlkyI For example, 2-carboxyethyl, 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 , 2-isopropoxyethyl, 2-

Butoxypropyl, 2-octyloxyethyl, chloromethyl, 2-chloroethyl, trichloromethyl, trifluoromethyl, 1, 1-dimethyl-2-chloroethyl, 2-methoxyisopropyl, 2-ethoxyethyl, butylthiomethyl, 2-dodecylthioethyl, 2-phenylthioethyl, 2,2, 2-trifluoroethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 6-hydroxyhexyl, 1-hydroxy-1, 1-dimethylmethyl, 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 and optionally substituted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino or interrupted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles substituted C ₆ to C ₁₂ -A17I for example, phenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-hydroxyphenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-aminophenyl, α-naphthyl or β-naphthyl, xylyl, 4-diphenylyl, chlorophenyl, Dichlorophenyl, trichlorophenyl, difluorophenyl, methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl, diethylphenyl, / so-propylphenyl, tert-butylphenyl, dodecylphenyl, 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-dimethylaminophenyl, 4- Acetylphenyl, methoxyethylphenyl, ethoxymethylphenyl, furyl, thiophenyl, pyrryl, pyridyl, indolyl, benzoxazolyl, benzimidazolyl, benzthiazolyl, dimethylpyridyl, methylquinolyl, dimethylpyrryl, methoxyfuryl, dimethoxypyridyl, difluoropyridyl, methylthiophenyl, isopropylthiophenyl, tert-butylthiophenyl, pyridazinyl , Pyrimidinyl, pyrazinyl, imidazolyl or pyrazole yl.

Examples of carboxylates are aromatic carboxylates, ie those in which R ^{8 is} an optionally substituted C ₆ to C ₁₂ aryl, especially an aryl containing at least one oxygen or nitrogen atom and / or substituted with at least one oxygen or nitrogen-containing substituent is particularly preferably an aryl containing at least one oxygen or nitrogen atom and / or substituted with at least one hydroxyl and / or amino group, most preferably salicylic acid and nicotinic acid are preferred.

Examples of sulfates are sulfate, hydrogen sulfate, methyl sulfate and ethyl sulfate,

Examples of sulfites are sulfite, hydrogen sulfite, methyl sulfite and ethyl sulfite,

Examples of sulfonates are methanesulfonate, trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate, p-bromobenzenesulfonate, camphorsulfonate and dodecanesulfonate

Examples of sulfinates are hydroxymethanesulfinate (formaldehyde sulfoxylate)

Examples of phosphates are phosphate, hydrogen phosphate, dihydrogen phosphate, methyl phosphate, dimethyl phosphate, ethyl phosphate, diethyl phosphate, glycerophosphate, di-n-butyl phosphate, di-2-ethylhexyl phosphate, diphenyl phosphate,

Examples of phosphonates are phenylphosphonate and methylphosphonate

Examples of phosphinates are phosphinate.

Examples of metal halides are AICI ₄ ^" , FeCl ₄ ^" , AlBr ₄ ^" , ZnCl ₃ ^" , BeCl ₃ ^" , ZnBr ₃ ^" , ZnI ₃ ^" , CuCl ₃ ^" , CuCl ₂ ^" , CoCl ₃ ^" , CoI ₃ ^" , FeI ₃ ^" FeCl ₃ ^" , TiCl ₅ ^" , TiCl ₆ ² MiCl ₄ ^" , SnCl ₃ ^" , SnCl ₄ ^" , SnCl ₄ ^{2 "} , MnCl ₃ ^" , MnCl ₄ ^{2 "} , MnBr ₃ ^" , ScCl ₄ ^" , BCI ₄ ^" , BBr ₄ ^" , GaCl ₄ ^" , ReCl ₆ ^" , ZrCl ₅ ^" , NbCl ₆ ^" , VCI ₄ ^" , CrCl ₃ ^" , MoCl ₆ ^" , YCl ₄ ^" , CdCl ₃ ^" , CdBr ₃ ^" , SbCl ₄ ^" , SbCl ₆ ^" , BiCl ₄ ^" , ZrCl ₅ ^" , UCI ₅ ^" , UCI ₆ ^2" , LaCl ₄ ^" , CeCl ₄ ^" , SmCl ₄ ^" , SmI ₃ ^" , TaCI ₆ ^" , BF ₄ ^" , PCI ₄ ^" , PCI ₆ ^" or PF ₆ ^" .

Further examples of metal halides are mixtures of halides or pseudo-halides of the abovementioned cations with Lewis acids, such as AICI ₃ , FeCl ₃ , AlBr ₃ and ZnCl ₂ , BeCl ₂ , ZnBr ₂ , ZnI ₂ , ZnSO ₄ , CuCl ₂ , CuCl, Cu (O ₃ SCF ₃ ) ₂ , CoCl ₂ , CoI ₂ , FeI ₂ , FeCl ₂ , FeCl ₂ (THF) ₂ , TiCl ₄ (THF) ₂ , TiCl ₄ , TiCl ₃ , CITi (OiPr) ₃ , SnCl ₂ , SnCl ₄ , Sn (SO ₄ ), Sn (SO ₄ ) ₂ , MnCl ₂ , MnBr ₂ , ScCl ₃ , BPh ₃ , BCI ₃ , BBr ₃ , BF ₃ -OEt ₂ , BF ₃ -OMe ₂ , BF ₃ -MeOH, BF ₃ -CH ₃ COOH, BF ₃ -CH ₃ CN, B (CF ₃ COO) ₃ , B (OEt) ₃ , B (OMe) ₃ , B (OZPr) ₃ , PhB (OH) ₂ , 3 -MeO-PhB (OH) ₂ , 4-MeO-PhB (OH) ₂ , 3-F-PhB (OH) ₂ , 4-F-PhB (OH) ₂ , (C ₂ Hs) ₃ Al, (C ₂ Hs) ₂ AICI, (C ₂ H ₅ ) AICI ₂ , (C ₈ H ₁₇ ) AICI ₂ , (C ₈ H ₁₇ J ₂ AICI ₁ (iso-C ₄ Hg) ₂ AICI, Ph ₂ AICI, PhAICI ₂ , Al (acac) ₃ , Al (OZPr) ₃ , Al (OnBu) ₃ , Al (Ose / cBu) ₃ , Al (OEt) ₃ , GaCl ₃ , ReCl ₅ , ZrCl ₄ , NbCl ₅ , VCI ₃ , CrCl ₂ , MoCl ₅ , YCl ₃ , CdCl ₂ , CdBr ₂ , SbCl ₃ , SbCl ₅ , BiCl ₃ , ZrCl ₄ , UCI ₄ , LaCI ₃ , CeCl ₃ , Er (O ₃ SCF ₃ ), Yb (O ₂ CCF ₃ ) ₃ , SmCl ₃ , SmI ₂ , B (C ₆ Hg) ₃ , TaCl ₅ .

The mixtures of halides or pseudohalides of the abovementioned cations with Lewis acids in a molar ratio of 1: 0.5 to 1: 5, preferably 1: 0.75 to 1: 3, particularly preferably 1: 0.85 to 1: 2.5, most preferably in the ratio 1: 0.9 to 1: 2 and in particular 1: 1, 0 to 1: 1, 5 selected.

According to the invention, only those of the compounds mentioned are used as ionic liquids which have a melting point below the temperature defined above.

The oligomerization catalysts of the invention are generally catalytically active over a temperature range of about 30 to 100 ° C and can be thermally deactivated at temperatures above 100 ⁰ C, which can advantageously dispense with catalyst poisons.

The preferred reaction temperature is generally 10 to 150 ° C, particularly preferably 30 to 100 ⁰ C. In the case of 1, 6-hexamethylene diisocyanate, the reaction temperature very particularly preferably 80 to 90 ⁰ C and nat in the case of Isophorondiisocya- it is very particularly preferably 60 to 70 "C.

The reaction rate of the oligomerization reaction can be at least maintained or used when using the ionic liquids according to the invention in comparison to commercially available oligomerization catalysts, such as preferably N- (2-hydroxypropyl) -N, N, N-trimethylammonium 2-ethylhexanoate (DABCO TMR® from Air Products) even increased. In addition, polyisocyanates having extremely low Hazen color numbers (DIN ISO 6271), for example preferably less than 40 (in the case of HDI), or less than 200, preferably less than 100 (in the case of IPDI), are obtained. The oligomerization catalysts which can be used according to the invention can be prepared by known processes. For the preparation of ionic liquids, the corresponding tertiary amines with an alkylating agent such as alkyl halides, dialkyl carbonates or dialkyl sulfate, in the absence or presence of solvents, such as chlorobenzene, toluene or xylene, are reacted at temperatures of preferably 100 to 180 ⁰ C for reaction. Optionally, the reaction may be carried out under pressure when the amine used is gaseous under the reaction conditions.

Preferred alkylating agents are methyl chloride, ethyl chloride, methyl iodide, dimethyl carbonate, diethyl carbonate, di-n-butyl carbonate, dimethyl sulfate and diethyl sulfate, and also benzyl chloride.

Suitable tertiary amines for the alkylation include: dimethylethanolamine, di-n-butylethanolamine, dioctylethanolamine, hydroxyethylpiperidine and hydroxyethyl morpholine.

Furthermore, the ionic liquids according to the invention can be prepared by quaternization with alkylene oxides. For this purpose, the corrsponding teriary amines are reacted with substituted or unsubstituted alkylene oxides having 2 to 24 carbon atoms, in particular with alkylene oxides having halogen, hydroxy, noncyclic ether or ammonium substituents. Particular mention may be made of: aliphatic 1,2-alkylene oxides having 2 to 4 carbon atoms, for example ethylene oxide, propylene oxide, vinyl oxirane, 1,2-butylene oxide, 2,3-butylene oxide or isobutylene oxide, aliphatic 1,2-alkylene oxides with 5 to 24 carbon atoms, cycloaliphatic alkylene oxides, for example cyclopentene oxide, cyclohexene oxide or cyclododecatriene (1, 5,9) -monoxide, araliphatic alkylene oxides, for example styrene oxide.

Preferred substituted alkylene oxides are, for example, epichlorohydrin, epibromohydrin, 2,3-epoxy-1-propanol, 1-allyloxy-2,3-epoxypropane, 2,3-epoxy-phenyl ether, 2,3-epoxypropyl-isopropyl ether, 2,3 Epoxypropyl octyl ether or 2,3-epoxypropyltrimethyl ammonium chloride.

Particular preference is given to using 1,2-alkylene oxides having 2 to 4 C atoms, in particular ethylene oxide and / or propylene oxide and especially ethylene oxide.

For this purpose, the tertiary amine and the alkylene oxide are generally used in a molar ratio of 1 to 0.4 to 1 to 10. Particularly advantageous is a molar ratio of 1 to 1 to 1 to 1, 5, in particular from 1 to 1, 03 to 1 to 1.2. The reaction of the tertiary amine with the alkylene oxide can be carried out at 20 to 200 ⁰ C. A temperature range from 30 to 150 ^° C., in particular from 40 to 100 ^° C., is preferred.

The reaction can be carried out both at atmospheric pressure or at reduced pressure, as well as at elevated pressure, for example at a pressure of 0.8 to 50 bar, in particular at a pressure of 1 to 10 bar.

Examples of suitable tertiary amines for the alkoxylation are: trimethylamine, triethylamine, Th-n-butylamine, ethyldiisopropylamine, N, N'-dimethylpiperazine, N-methoxyphenylpiperazine, N-methylpiperidine, N-ethyl piperidine, quinuclidine and trialkylamines, such as Trimethyl-, triethyl- and tripropylamine and preferably 1, 4-dimethyl-piperazine, N, N-dimethylbenzylamine and triethylenediamine.

When an amine reacts with an unsymmetrically substituted epoxide, the amine usually reacts with the least substituted carbon atom. Depending on the steric demand of the amine, mixtures of the two possible regioisomers can form.

The tetrasubstituted ammonium ions obtainable after quaternization with the alkylating agent as counterion, such as chloride, iodide, methyl carbonate or methyl sulfate, if they are not already the ionic liquids according to the invention are then converted in a preferred embodiment by treatment with an anion exchanger, in the tetrasubstituted ammonium hydroxide , which can then be subsequently reacted with the corrosive acid of the desired counterion. The resulting equivalent amounts of water can either be left in the catalyst or can preferably be removed or depleted by treatment with a desiccant such as molecular sieve or zeolite, or azeotropic distillation with an entraining agent such as cyclohexane, benzene or toluene , As a rule, a water content in the catalyst below 0.5% by weight is sufficient for use in the reaction according to the invention and is desired.

The presence of water in the reaction usually results in hydrolysis of the isocyanates and decarboxylation of the resulting carbamic acids to amines, which in turn react with isocyanates to poorly soluble, undesirable ureas.

One can also perform a direct exchange on an ion exchange column. For this purpose, a basic ion exchange resin (eg Amberlyst®, Dowex® or Sephadex® type) is activated with potassium hydroxide solution or sodium hydroxide solution and loaded with the corrosive acid of the desired counterion. Thereafter, the chromatography column with the quart. Ammonium salt is charged and eluted. The Eluate contains the desired quart. Ammonium salt. The solvent can be removed by applying a vacuum.

In the case of the quart. Ammonium halides, the catalysts can also be obtained by cation exchange in solution in a very pure form, when used as reactants, the anions underlying silver salts.

The preparation of the catalysts according to the invention can be carried out, for example, analogously to the working instructions, as described in US Pat. No. 5,691,440, Sp. 11, Z. 24 - Sp. 12, Z. 41.

The alkylation of tertiary amines can be carried out, for example, as follows: the tertiary amine is optionally in a suitable solvent, for example a C ₁ -C ₄ -AlkOhOl, preferably methanol or ethanol, with the alkylating agent in over or under stoichiometric or preferably equimolar Amounts, for example 0.75-1.25 mol / mol, preferably 0.9-1.1 mol / mol, based on the tertiary amine, if appropriate at elevated pressure for 30 minutes to 24 hours at a temperature between room temperature and 120 ° C, optionally reacted with increasing temperature in the course of the reaction. After completion of the reaction, the volatiles are separated by distillation and optionally washed or recrystallized.

The tetrasubstituted ammonium ion thus obtained with the counterion of the alkylating agent can then be exchanged, for example, with an anion exchanger charged with hydroxide ions for a hydroxide genion, as described, for example, in DE-OS 25 27 242, page 6, bottom or ebda, in US Pat Production Examples 1 and 2 are described on pages 13 and 14.

The tetrasubstituted ammonium hydroxide thus obtained or a commercially available one can then be reacted with the desired corresponding counterion to the catalyst of the present invention. For this purpose, for example, the tetra-substituted ammonium hydroxide is initially charged, for example in a solvent, preferably a solvent which forms an azeotrope with water, for example a C ₁ -C ₄ -AlkOhOl, preferably methanol or ethanol, and to the desired corresponding counterion, optionally also in the same or a different solvent, added slowly. The addition may be from 0 to 100 ^° C., preferably from 0 to 80, particularly preferably from 0 to 60, very particularly preferably from 10 to 40 ^° C., and in particular at room temperature. After removal of the optionally present solvent with water of reaction formed, for example by distillation, if appropriate under reduced pressure, the catalyst according to the invention can be used and optionally can be taken up in a solvent. Such a solvent may also contain isocyanate-reactive groups. The catalyst of the invention can be used in bulk or as a solution, preferably in bulk as a melt.

It may be useful to use the catalyst in solution, although it is already liquid as an ionic liquid, for example, to be able to better dose a more dilute solution.

If the catalyst is used as a solution, depending on the solubility in the solvent used, a 10 to 80%, preferably 10 to 50, particularly preferably 15 to 45, and very particularly preferably 30 to 40% strength by weight solution is generally employed ,

As oligomerization catalysts it is also possible to use mixtures with other known oligomerization catalysts, these being used in wide proportions, e.g. in proportions of 90:10 to 10:90, preferably 80:20 to 20:80 and particularly preferably 60:40 to 40:60 can be mixed.

For the preparation of polyisocyanates, the oligomerization catalysts according to the invention, depending on their catalytic activity, are expediently used in the smallest possible effective amounts which can be determined experimentally in a simple manner.

In general, in the process according to the invention, the ionic liquids are used in an amount of from 0.002 to 0.05% by weight, preferably from 0.005 to 0.02% by weight, based on the weight of the diisocyanates.

The process according to the invention can be used to prepare biuret, allophanate and / or isocyanurate-containing polyisocyanates via ionic liquids. For this, of course, in the preparation of allophanate groups at least one hydrox groups-containing compound or in the production of biuret at least one biuretizing agent, such as amine, water or dehydrating compounds, such as tert-butanol, and / or a urea present be.

The process according to the invention is expediently carried out at a temperature in the range from 10 to 100 ° C. and reaction times of 10 minutes to 6 hours, preferably from 20 minutes to 3 hours, particularly preferably from 20 minutes to 2 hours.

When using the ionic liquids of the invention are preferably reaction temperatures above 50 ⁰ C, particularly preferably from 60 to 120 ⁰ C Wandt reasonable and receive substantially colorless oligomerization. The oligomerization can be carried out continuously, semicontinuously or discontinuously, preferably batchwise.

In general, it is of minor importance which components are submitted or added. In most cases, the isocyanate to be oligomerized is initially charged, preferably completely, and the at least one catalyst is added slowly and / or in portions, then brought to the desired reaction temperature and the remainder of the catalyst, if appropriate in portions, is added.

An alternative production variant proceeds as follows: In the batch process, work is carried out in a stirred reactor. The mixture of diisocyanate and catalyst is usually initially charged at not more than 40 ⁰ C, since at this temperature usually no reaction takes place. Subsequently, the temperature of the reaction mixture to initiate the oligomerization to 50 to 120 ⁰ C, preferably increased to 55 to 90 ⁰ C. Alternatively, the catalyst can also be metered in after the diisocyanate has reached the temperature necessary for the reaction. The oligomerization is usually exothermic, the catalyst can preferably be used in pure form. It is also possible to dissolve the catalyst in a suitable solvent and to use it in this form.

A continuous oligomerization is conveniently carried out in a reaction coil with continuous, simultaneous addition of diisocyanate and the catalyst at 50 to 140 ⁰ C and within 30 seconds to 4 hours. A reaction coil with a small diameter leads to the achievement of high flow velocities and consequently good mixing. Furthermore, it is advantageous to heat the diisocyanate / catalyst mixture before entry into the reaction coil to about 50 to 6O ⁰ C. For more accurate metering and optimal mixing of the catalyst, it is also advantageous to dissolve the catalyst in a suitable solvent. Suitable in principle are those solvents in which the catalyst has good solubility. The continuous oligomerization can also be carried out in a kettle cascade. Also conceivable is a combination of boiler cascade and tubular reactor.

The reaction is usually carried out in a gas or gas mixture which is inert under the reaction conditions, for example those having an oxygen content of less than 2, preferably less than 1, particularly preferably less than 0.5,% by volume, nitrogen, argon, helium, nitrogen-noble gas mixtures are preferred. particularly preferred is nitrogen. In addition or alone, carbon dioxide (CO ₂ ) can also be used as the gas. This is preferred, for example, when 1,6-hexamethylene diisocyanate is used, but less preferably when isophorone diisocyanate is used.

After reaching the desired degree of oligomerization or NCO content or degree of conversion (based on the NCO content before the reaction) of the oligomer / Diisocyanate reaction mixture and what usually reaction times of 0.05 to 4 hours, preferably from 10 minutes to 3 hours, are required, the oligomerization reaction can be terminated, for example, thermally or by deactivating the oligomerization catalyst.

In general, a conversion of 10 to 60% (based on the NCO content before the reaction) is desired. In the case of 1,6-hexamethylene diisocyanate, the conversion is preferably controlled to 20 to 50%, with isophorone diisocyanate preferably to 10 to 40%.

The product may contain, in addition to monomeric isocyanate, further compounds which have one or more oligomer structures, for example isocyanurate, uretdione, biuret, urethane, oxadiazinetrione, iminooxadiazinetrione, urea, amide and / or allophanate groups , Compounds of this type are described in the literature.

Suitable deactivating agents are, for example, inorganic acids, e.g. Hydrogen chloride, phosphorous acid or phosphoric acid, carboxylic acid halides, e.g. Acetyl chloride or benzoyl chloride, sulfonic acids or esters, e.g. Methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid methyl or ethyl ester, m-chloroperbenzoic acid and preferably dialkyl phosphates such as e.g. Di-2-ethylhexyl phosphate and especially dibutyl phosphate.

The deactivating agents may be used in equivalent or excess amounts relative to the oligomerization catalysts, with the smallest effective amount which can be determined experimentally being preferred for economic reasons. For example, the deactivating agent in relation to the oligomerization catalyst of 1 - 2.5: 1 mol / mol, preferably 1 - 2: 1, more preferably 1-1, 5: 1 and most preferably 1-1, 2: 1 mol / mol used.

The addition depends on the type of deactivating agent. Thus, hydrogen chloride is preferably passed through gaseous or preferably through the reaction mixture, liquid deactivating agents are usually added in bulk or as a solution in a solvent inert under the reaction conditions and solid deactivating agent in bulk or as a solution or suspension in a solvent inert under the conditions of reaction ,

The addition of the deactivating agent is usually carried out at the reaction temperature, but can also be carried out at a lower temperature.

However, preferred is the thermal deactivation of the catalyst, which is particularly preferably connected to the separation of excess monomer (see below). It may also be by brief heating of the reaction mixture in the reactor or in a downstream tubular reactor to temperatures above 130 ⁰ C, for example 140-180 ⁰ C with a few seconds residence time.

The process according to the invention is preferably carried out solvent-free. However, when the diisocyanates are partially oligomerized in the presence of solvents or diluents, both inert nonpolar and inert polar solvents or diluents, e.g. Toluene, xylene, cyclic ethers, carboxylic acid esters and ketones or their mixtures.

The biuret, allophanate and / or isocyanurate groups prepared by the novel polyisocyanates can in known manner, for example by thin film distillation at a temperature of 100 to 180 ° C, optionally in vacuo, optionally additionally with passing inert stripping gas, or Extraction of any existing solvent or diluent and / or preferably be liberated from excess, unreacted diisocyanates, so that the polyisocyanates with a content of monomeric diisocyanates of eg below 1, 0 wt .-%, preferably below 0.5 wt .-%, more preferably below 0.3, most preferably below 0.2 and in particular not more than 0.1 wt% are available.

Without separation of the excess monomeric diisocyanates, the polyisocyanates containing biuret, allophanate and / or isocyanurate groups are suitable, for example, for the production of PU foams, cellular or compact elastomers, potting compounds and adhesives. The monomer-free and monomer-containing biuret, allophanate and / or isocyanurate groups containing polyisocyanates can also be prepared in a conventional manner by introduction of e.g. Urethane, allophanate, urea, biuret and / or carbodiimide groups are modified and / or the isocyanate groups with suitable blocking agents, such. ε-caprolactam, dimethyl malonate, acetoacetic ester or aromatic hydroxyl groups are blocked.

Any organic diisocyanates containing aromatic, araliphatic, aliphatic and / or cycloaliphatic bound isocyanate groups or their mixtures can be oligomerized by the process according to the invention.

Aromatic isocyanates are those containing at least one aromatic ring system.

Cycloaliphatic isocyanates are those which contain at least one cycloaliphatic ring system.

Aliphatic isocyanates are those which contain exclusively straight or branched chains, ie acyclic compounds. Suitable (cyclo) aliphatic diisocyanates advantageously have 3 to 16 C atoms, preferably 4 to 12 C atoms in the linear or branched alkylene radical and suitable cycloaliphatic diisocyanates advantageously 4 to 18 C atoms, preferably 6 to 15 C atoms in the cycloalkylene radical. Examples include: 1, 4-diisocyanato-butane, 2-ethyl-1, 4-diisocyanato-butane, 1, 5-diisocyanato-pentane, 2-methyl-1, 5-diisocyanato-pentane, 2,2-dimethyl 1, 5-diisocyanato-pentane, 2-propyl-2-ethyl-1, 5-diisocyanato-pentane, 2-butyl-2-ethyl-1, 5-diisocyanato-pentane, 2-alkoxymethylene-1,5-diisocyanato pentane, 3-methyl, 3-ethyl-1,5-diisocyanato-pentane, 1,6-hexamethylene diisocyanate, 2,4,4- and / or 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 1, 7-diisocyanatoheptane, 1, 8-diisocyanato-octane, 1, 10-diisocyanato-decane, 1, 12-diisocyanato-dodecane, 4,4'-diisocyanato-dicyclohexylmethane, 2,4'-diisocyanato dicyclohexylmethane and mixtures of diisocyanatodicyclohexylmethane isomers, 1, 3-diisocyanato-cyclohexane and isomer mixtures of diisocyanato-cyclohexanes and 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane. As (cyclo) aliphatic diisocyanates are preferably used 1, 6-hexamethylene diisocyanate, isomeric aliphatic diisocyanates having 6 carbon atoms in the alkylene radical and mixtures thereof, 2-butyl-2-ethyl-1, 5-diisocyanato-pentane and 1-isocyanato-3 -isocyanatomethyl-3,5,5-trimethylcyclohexane, more preferably 1, 6-hexamethylene diisocyanate and 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane and mixtures thereof, for example in the ratio 10:90 - 90: 10, preferably 20:80 - 80:20 and more preferably 33:67 - 67:33.

Suitable aromatic and araliphatic diisocyanates are 2,4- or 2,6-tolylene diisocyanate and their isomer mixtures, o-, m- or p-xylylene diisocyanate, tetramethyl-m-xylylene diisocyanate (m-TMXDI), 2,4'- or 4,4 '- Diisocyanatodiphenylmethane and their isomer mixtures, 1, 3 or 1, 4-phenylene diisocyanate, 1-chloro-2,4-phenylene diisocyanate, 1, 5-naphthylene diisocyanate, diphenyl-4,4'-diisocyanate, 4,4'-diisocyanato 3,3'-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate, tetramethylxylylene diisocyanate, 1,4-diisocyanatobenzene or diphenyl ether-4,4'-diisocyanate.

The catalysts according to the invention are preferred for the oligomerization (cyclo) of aliphatic isocyanates, more preferably for the oligomerization of hexamethylene diisocyanate (1,6-diisocyanatohexane) or 1-isocyanato-3,3,5-trimethyl-5- (isocyanatomethyl) cyclohexane (isophorone diisocyanate)

The novel oligomerization catalysts according to the invention can be used for the oligomerization of diisocyanates prepared by any desired method, for example according to a phosgene-free or phosgene process route. The diisocyanates which can be used according to the invention can be prepared by any desired process, for example by phosgenation of the corresponding diamines and thermal cleavage of the intermediately formed dicarbamic acid chlorides. Diisocyanates prepared by phosgene-free processes contain no chlorine compounds as by-products and therefore have a fundamentally different by-product spectrum due to their production.

Of course, it is also possible to use mixtures of isocyanates prepared by the phosgene process and by phosgene-free processes.

It was found that the oligomerization catalysts which can be used according to the invention have good catalytic activity in the oligomerization of diisocyanates prepared by the phosgene process and give polyisocyanates with a low color number.

The diisocyanates which can be used in the process according to the invention and which are obtainable by a phosgene-free process and in particular by thermal cleavage of dicarbamic esters are not restricted, diisocyanates obtainable by thermal cleavage of dicarbamic acid esters from group 1, hexamethylenediisocyanate, 2-butyl-2-ethyl- pentamethylene diisocyanate-1, 5 and 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane are particularly preferably used.

In a preferred embodiment of the invention, isocyanates are used which have a total chlorine content of 100 ppm by weight or less, preferably 80 ppm by weight or less, whereas isocyanates derived from a phosgenation process often have a total chlorine content of 100-400 mg / kg exhibit.

Polyisocyanates containing biuret, allophanate and / or isocyanurate groups prepared by these process variants are particularly suitable for the preparation of polyurethane coatings, e.g. of textile and leather coatings, dispersions and adhesives and are used in particular as polyisocyanate component in one and two-component polyurethane systems for high-quality and weather-resistant polyurethane coatings.

In the following, another embodiment of the present invention will be described:

In addition to the above-mentioned ionic liquids used as a catalyst for the oligomerization reaction, at least one other ionic liquid other than the ionic liquid used as the catalyst may be used in the process. These are also compounds which consist of at least one cation and at least one anion and which have the abovementioned melting points. However, in contrast to the above-mentioned catalysts, these ionic liquids are generally not thermally deactivatable.

Preferred as a cation are ammonium or phosphonium ions, or such cations containing at least one 5- to 6-membered heterocycle having at least one phosphorus or nitrogen atom and optionally an oxygen or sulfur atom, more preferably those compounds having at least one five- to containing six-membered heterocycle having one, two or three nitrogen atoms and a sulfur or an oxygen atom, most preferably those having one or two nitrogen atoms.

Particularly preferred ionic liquids are those which have a molecular weight of less than 1000 g / mol, very particularly preferably less than 350 g / mol.

Furthermore, preference is given to those cations which are selected from the compounds of the formulas (Ia) to (Iw)

(F)

(g) (h) (i)

(J) (k) (I)

(O)

(m)

(P) (q) (r)

(S) (t) (U)

(V) (W)

and oligo- or polymers containing these structures,

wherein

R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently hydrogen, C ₁ - C ₁₈ -AlkVl, optionally by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups are interrupted C ₂ -C ₁₈ -alkyl, C ₆ -C ₁₂ -aryl, C ₅ -C ₁₂ -cycloalkyl or a five- to six-membered, oxygen-, nitrogen- and / or sulfur-containing heterocycle or two of them together form an unsaturated, saturated or aromatic ring optionally interrupted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups, said radicals being in each case denoted by functional groups, aryl, alkyl, aryloxy , Alkyloxy, halogen, heteroatoms and / or heterocycles.

R ¹⁷ can moreover be C ₁ -C ₁₈ -alkyloxy (alkylcarbonyl), C ₁ -C ₁₈ -alkyloxycarbonyl, C ₅ -C ₁₂ -cycloalkylcarbonyl or C ₆ -C ₁₂ -aryloyl (arylcarbonyl), where the radicals mentioned are in each case represented by functional groups Groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles may be substituted.

In the radicals R to R mean

optionally C ₁ -C ₁₈ -alkyl substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles, for example methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, Pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethylpentyl, decyl, dodecyl, tetradecyl, hetadecyl, octadecyl, 1,1-dimethylpropyl, 1,1-dimethylbutyl, 1,1,3,3-tetramethylbutyl, benzyl, 1-phenylethyl, 2-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-methoxycarbonethyl, 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, 2-isopropoxyethyl, 2-butoxypropyl, 2-octyloxyethyl, chloromethyl, 2-chloroethyl, trichloromethyl, trifluoromethyl, 1, 1-dimethyl-2- chloroethyl, 2-methoxyisopropyl, 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, 3-aminopropyl, 4-aminobutyl, 6-aminohexyl, 2-methylaminoethyl, 2-methylaminopropyl 1, 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 and,

optionally interrupted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino C ₂ - C ₁₈ -alkyl, for example, 5-hydroxy-3-oxa-pentyl, 8-hydroxy-3,6-dioxa- octyl, 11-hydroxy-3,6,9-trioxa undecyl, 7-hydroxy-4-oxa-heptyl, 11-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, 11-methoxy-4,8-dioxa-undecyl, 15-methoxy-4,8,12-trioxa-pentadecyl, 9-methoxy 5-oxa-nonyl, 14-methoxy-5,10-octadecyl, 5-ethoxy-3-oxa-pentyl, 8-ethoxy-3,6-dioxa-octyl, 1-ethoxy-3,6, 9-trioxa undecyl, 7-ethoxy-4-oxa-heptyl, 11-ethoxy-4,8-dioxa-undecyl, 15-ethoxy-4,8,12-trioxapentadecyl, 9-ethoxy-5-oxa nonyl or 14-ethoxy-5,10-oxa-tetradecyl.

If two radicals form a ring, these radicals may together be 1, 3-propylene, 1, 4-butylene, 2-oxa-1, 3-propylene, 1-oxa-1, 3-propylene, 2-oxa 1, 3-propylene, 1-oxa-1, 3-propenylene, 1-aza-1, 3-propenylene, 1-CrC 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.

The number of oxygen and / or sulfur atoms and / or imino groups is not limited. As a rule, it is not more than 5 in the radical, preferably not more than 4, and very particularly preferably not more than 3.

Furthermore, at least one carbon atom, preferably at least two, is usually present between two heteroatoms. Substituted and unsubstituted imino groups may be, for example, imino, methylimino, iso-propylimino, n-butylimino or tert-butylimino.

Furthermore mean

functional groups carboxy, carboxamide, hydroxy, di ^ CrC ^ alky ^ amino, C ₁ -C ₄ - alkyloxycarbonyl, cyano or -C ₄ alkyloxy,

optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen,

C ₆ -C ₁₂ -aryl substituted heteroatoms and / or heterocycles, for example phenyl, ToIyI, XyIyI, α-naphthyl, β-naphthyl, 4-diphenylyl, chlorophenyl, dichlorophenyl, trichlorophenyl, difluorophenyl, methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl, Diethylphenyl, isopropylphenyl, tert-butylphenyl, dodecylphenyl, methoxyphenyl, dimethoxyphenyl, ethoxyphenyl, hexyloxyphenyl, methylnaphthyl, isopropylnaphthyl, chloronaphthyl, ethoxynaphthyl, 2,6-dimethylphenyl, 2,4,6-trimethylphenyl, 2,6-di methoxyphenyl, 2,6-dichlorophenyl, 4-bromophenyl, 2- or 4-nitrophenyl, 2,4- or 2,6-dinitrophenyl, 4-dimethylaminophenyl, 4-acetylphenyl, methoxyethylphenyl or ethoxymethylphenyl,

optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles C ₅ - Ci ₂ cycloalkyl, for example cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, methylcyclopentyl, dimethylcyclohexylamine pentyl, methylcyclohexyl, dimethylcyclohexyl, diethylcyclohexyl, butylcyclohexyl , Methoxycyclohexyl, dimethoxycyclohexyl, diethoxycyclohexyl, butylthiocyclohexyl, chlorocyclohexyl, dichlorocyclohexyl, dichlorocyclopentyl and a saturated or unsaturated bicyclic system such as norbornyl or norbornenyl,

a five- to six-membered heterocycle having oxygen, nitrogen and / or sulfur atoms, for example furyl, thiophenyl, pyrryl, pyridyl, indolyl, benzoxazolyl, dioxolyl, dioxyl, benzimidazolyl, benzthiazolyl, dimethylpyridyl, methylquinolyl, dimethylpyrryl, methoxyfuryl, Dimethoxypyridyl, difluoropyridyl, methylthiophenyl, isopropylthiophenyl or tert-butylthiophenyl and

C ₁ to C ₄ alkyl, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl or tert-butyl.

C ₁ -C ₁₈ -alkyloxy (alkylcarbonyl) may be, for example, acetyl, propionyl, n-butyloyl, sec-butyloyl, tert-butyloyl, 2-ethylhexylcarbonyl, decanoyl, dodecanoyl, chloroacetyl, trichloroacetyl or trifluoroacetyl. C ₁ -C ₁₈ -alkyloxycarbonyl can be, for example, methyloxycarbonyl, ethyloxycarbonyl, propyloxycarbonyl, isopropyloxycarbonyl, n-butyloxycarbonyl, sec-butyl oxycarbonyl, tert-butyloxycarbonyl, hexyloxycarbonyl, 2-ethylhexyloxycarbonyl or benzyloxycarbonyl.

C ₅ - C ₂ cycloalkylcarbonyl may be cyclopentylcarbonyl, cyclohexyl carbonyl or Cyclododecylcarbonyl example.

C ₆ -C ₁₂ -aryloyl (arylcarbonyl) may be, for example, benzoyl, toluyl, xyloyl, α-naphthoyl, β-naphthoyl, chlorobenzoyl, dichlorobenzoyl, trichlorobenzoyl or trimethylbenzoyl.

Preferably R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ^{16 are} independently hydrogen, methyl, ethyl, n-butyl, 2-hydroxyethyl, 2-cyanoethyl, 2- (methoxycarbonyl) -ethyl, 2- ( Ethoxycarbonyl) -ethyl, 2- (n-butoxycarbonyl) -ethyl, dimethylamino, diethylamino and chloro.

R ¹⁷ is preferably hydrogen, methyl, ethyl, n-butyl, 2-hydroxyethyl, 2-cyanoethyl, 2- (methoxycarbonyl) -ethyl, 2- (ethoxycarbonyl) -ethyl, 2- (n-butoxycarbonyl) -ethyl, acetyl, Propionyl, t-butyryl, methoxycarbonyl, ethoxycarbonyl or n-butoxycarbonyl.

Particularly preferred pyridinium ions (Ia) are those in which one of the radicals R ¹¹ to R ^{15 is} methyl, ethyl or chlorine, R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and all others are hydrogen, or R ^{13 is} dimethylamino, R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and all others are hydrogen or R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and all others are hydrogen or R ^{12 is} carboxy or carboxamide, R ^{17 is} hydrogen, acetyl, Methyl, ethyl or n-butyl and all others are hydrogen or R ¹¹ and R ¹² or R ¹² and R ^{13 is} 1, 4-buta-1, 3-dienylene, R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and all other hydrogen are.

Particularly preferred pyridazinium ions (Ib) are those in which one of the radicals R ¹¹ to R ^{14 is} methyl or ethyl, R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and all other hydrogen or R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl, and all others are hydrogen.

Particularly preferred pyrimidinium ions (Ic) are those in which R ¹² to R ^{14 is} hydrogen or methyl, R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and R ^{11 is} hydrogen, methyl or ethyl, or R ¹² and R ^{14 is} methyl , R ^{13 is} hydrogen and R ^{11 is} hydrogen, methyl or ethyl and R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl.

Particularly preferred pyrazinium ions (Id) are those in which R ¹¹ to R ^{14 are} all methyl and R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl or R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and all others are hydrogen.

Particularly preferred imidazolium ions (Ie) are those in which independently of one another

R ^{11 is} selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-octyl, n-decyl, n-dodecyl, 2-hydroxyethyl or 2-cyanoethyl,

R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and

R ¹² to R ¹⁴ independently of one another denote hydrogen, methyl or ethyl.

Particularly preferred 1 H-pyrazolium ions (If) are those in which independently of one another

R ¹¹ is hydrogen, methyl or ethyl,

R ¹² , R ¹³ and R ^{14 are selected} from hydrogen or methyl and R ^{17 is selected} from hydrogen, acetyl, methyl, ethyl or n-butyl.

Particularly preferred 3H-pyrazolium ions (Ig) are those in which independently of one another

R ¹¹ is hydrogen, methyl or ethyl, R ¹² , R ¹³ and R ¹⁴ are hydrogen or methyl and

R ^{17 are selected} from hydrogen, acetyl, methyl, ethyl or n-butyl.

Particularly preferred 4H-pyrazolium ions (Ih) are those in which independently of one another R ¹¹ to R ¹⁴ are hydrogen or methyl and

R ^{17 are selected} from hydrogen, acetyl, methyl, ethyl or n-butyl.

Particularly preferred 1-pyrazolinium ions (Ii) are those in which independently of one another R ¹¹ to R ¹⁶ are hydrogen or methyl and

R ^{17 are selected} from hydrogen, acetyl, methyl, ethyl or n-butyl.

Particularly preferred 2-pyrazolinium ions (Ij) are those in which, independently of one another, R ¹¹ is hydrogen, methyl, ethyl or phenyl,

R ^{17 is selected} from hydrogen, acetyl, methyl, ethyl or n-butyl and R ¹² to R ¹⁶ are selected from hydrogen or methyl.

Particularly preferred 3-pyrazolinium ions (Ik) are those in which independently of one another

R ¹¹ or R ¹² is hydrogen, methyl, ethyl or phenyl, R ¹⁷ is hydrogen, acetyl, methyl, ethyl or n-butyl and R ¹³ to R ¹⁶ are selected from hydrogen or methyl.

Particularly preferred imidazolinium ions (II) are those in which independently of one another R ¹¹ or R ¹² is hydrogen, methyl, ethyl, n-butyl or phenyl, R ¹⁷ is hydrogen, acetyl, methyl, ethyl or n-butyl and R ¹³ or R ^{14 are selected} from hydrogen, methyl or ethyl and R ¹⁵ or R ¹⁶ are selected from hydrogen or methyl.

Particularly preferred imidazolinium ions (Im) are those in which independently of one another

R ¹¹ or R ¹² is hydrogen, methyl or ethyl,

R ¹⁷ is hydrogen, acetyl, methyl, ethyl or n-butyl and

R ¹³ to R ¹⁶ are selected from hydrogen or methyl.

Particularly preferred imidazolinium ions (In) are those in which independently of one another

R ¹¹ , R ¹² or R ¹³ is hydrogen, methyl or ethyl,

R ^{17 is} hydrogen, acetyl, methyl, ethyl or n-butyl and R ¹⁴ to R ¹⁶ are selected from hydrogen or methyl.

Particularly preferred thiazolium ions (lo) or oxazolium ions (Ip) are those in which independently of one another R ¹¹ is hydrogen, methyl, ethyl or phenyl, R ¹⁷ is hydrogen, acetyl, methyl, ethyl or n-butyl and R ¹² or R ¹³ Hydrogen or methyl are selected.

Particularly preferred 1,2,4-triazolium ions (Iq) and (Ir) are those in which, independently of one another, R ¹¹ or R ¹² is hydrogen, methyl, ethyl or phenyl, R ¹⁷ is hydrogen, acetyl, methyl, ethyl or n- Butyl and R ^{13 are selected} from hydrogen, methyl or phenyl.

Particularly preferred 1,2,3-triazolium ions (Is) and (It) are those in which, independently of one another

R ¹¹ is hydrogen, methyl or ethyl,

R ¹⁷ is hydrogen, acetyl, methyl, ethyl or n-butyl and

R ¹² or R ¹³ are selected from hydrogen or methyl or

R ¹² and R ^{13 are} 1, 4-buta-1, 3-dienylene and all others are hydrogen.

Particularly preferred pyrrolidinium ions (Iu) are those in which independently of one another R ¹¹ and R ^{17 are selected} from hydrogen, acetyl, methyl, ethyl or n-butyl and R ¹² , R ¹³ , R ¹⁴ and R ^{15 are} hydrogen.

Particularly preferred ammonium ions (Iv) are those in which independently of one another

R ¹⁷ is hydrogen, acetyl, methyl, ethyl or n-butyl and

R ¹¹ , R ¹² , and R ^{13 are selected} from methyl, ethyl, n-butyl, 2-hydroxyethyl, benzyl or phenyl.

Particularly preferred phosphonium ions (Iw) are those in which independently of one another

R ^{17 is selected} from hydrogen, acetyl, methyl, ethyl or n-butyl; and R ¹¹ , R ¹² , and R ^{13 are selected} from phenyl, phenoxy, ethoxy and n-butoxy.

Among these, the ammonium, phosphonium, pyridinium and imidazolium ions are preferred.

Very particular preference is given as cations to 1,2-dimethylpyridinium, 1-methyl-2-ethylpyridinium, 1-methyl-2-ethyl-6-methylpyridinium, N-methylpyridinium, 1-butyl-2-methylpyridinium, 1-butyl-2- ethylpyridinium, 1-butyl-2-ethyl-6-methylpyridinium, N-butylpyridinium, 1-butyl-4-methylpyridinium, 1-methylimidazolium, 1-butylimidazolium, 1, 3-dimethylimidazolium, 1, 2,3-thymethylimidazolium, 1- n-butyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium, 1, 3,4,5-tetramethylimidazolium, 1, 3,4-trimethylimidazolium, 2,3-dimethylimidazolium, 1-butyl-2,3-dimethylimidazolium, 3,4-dimethylimidazolium, 2-ethyl-3,4-dimethylimidazolium, 3-methyl-2-ethylimidazole, 3-butyl-1-methylimidazolium, 3-ethyl-1-methylimidazolium, 3-butyl-1-ethylimidazolium, 3 Butyl-1,2-dimethylimidazolium, 1,3-di-n-butylimidazolium, 3-butyl-1, 4,5-trimethylimidazolium, 3-butyl-1,4-dimethylimidazolium, 3-butyl-2-methylimidazolium, 1, 3-dibutyl-2-methylimidazolium, 3-butyl-4-methylimidazolium, 3-butyl-2-ethyl-4-methylimidazole and 3-butyl-2-ethylimidazolium, 1-methyl-3-octylimidazolium, 1-decyl-3-methylimidazolium.

Particularly preferred are 1-methylimidazolium, 1-butylimidazolium, 1-butyl-4-methylpyridinium, 1-n-butyl-3-methylimidazolium, 1-ethyl-3-methylimidazolium and 1-n-butyl-3-ethylimidazolium.

As anions, in principle all anions are conceivable.

Preferred anions are halides, F ^" , Cl ^" , Br ^" , I ^" , acetate CH ₃ COO ^" , trifluoroacetate CF ₃ COO ^" , triflate CF ₃ SO ₃ ^" , sulfate SO ₄ ^2" , hydrogen sulfate HSO ₄ ^" , methyl sulfate CH ₃ OSO ₃ ^" , ethyl sulfate C ₂ H ₅ OSO ₃ ^' , methanesulfonate H ₃ C-SO ₃ ^" , trifluoromethanesulfonate F ₃ C-SO ₃ ^" , sulfite SO ₃ ^2" , hydrogen sulfite HSO ₃ ^" , thiocyanate SCN ^" , aluminum chlorides AICI ₄ ^" AI ₂ CI ₇ ^" , Al ₃ Cl ₁₀ ^" , aluminum tribromide AIBr ₄ ^" , nitrite NO ₂ ^" , nitrate NO ₃ ^" , copper chloride CuCl ₂ ^" , phosphate PO ₄ ^3" , hydrogen phosphate HPO ₄ ^{2 "} , dihydrogen phosphate H ₂ PO ₄ ^" , diethyl phosphate, carbonate CO ₃ ^{2 "} , bicarbonate HCO ₃ ^" .

Particularly preferred are acetates, sulfonates, tosylate P-CH ₃ C ₆ H ₄ SO ₃ ^" , sulfates, phosphates, bis (trifluoromethylsulfonyl) imide (CF ₃ SO ₂ ) ₂ N ^" .

These other ionic liquids can be used in one embodiment of the invention as a solvent for the catalyst to better distribute the catalyst in the reaction mixture. For this purpose, the catalyst is dissolved as a 10 to 90% solution, preferably 20 to 80, more preferably 30 to 70 and most preferably 40 to 60% solution in the further ionic liquid and used this solution as the catalyst solution.

In a further embodiment of the present invention, the further ionic liquid may be used to extract the catalyst or its residues or reaction by-products. For this example, the reaction mixture, optionally after thermal or chemical deactivation of the catalyst or cooling the reaction mixture to a temperature at which the reaction is no longer significant, for example, 5 to 30% by weight, preferably 10 to 25 and particularly preferably 10 bis 20% by weight of the further ionic liquid is mixed and then the phases are separated.

If the other ionic liquid is not catalytically active, it can also be used to stop the reaction by extraction of the catalyst.

Extraction may preferably be carried out if the solubility of the diisocyanate or its oligomer in the ionic liquid is less than 10% by weight, preferably less than 5, more preferably less than 3, most preferably less than 2 and especially less than 1 % By weight and, conversely, the solubility of the ionic liquid in the diisocyanate and / or its oligomer is less than 10% by weight, preferably less than 5, more preferably less than 3, most preferably less than 2 and especially less than 1% by weight.

Technically, all known extraction and washing processes and apparatuses can be used for such extraction, for example those described in Ullmann's Encyclopedia of Industrial Chemistry, 6th ed, 1999 Electronic Release, Chapter: Liquid - Liquid Extraction Apparatus. For example, these may be one-stage or multistage, preferably single-stage extractions, as well as those in cocurrent or countercurrent mode, preferably countercurrent mode. Sieve bottom or packed or packed columns, stirred tanks or mixer-settler apparatuses and columns with rotating internals are preferably used. The catalyst can be separated in such an extraction and impurities, for example, resulting from the disintegration or deactivation of the catalyst and which are partially farbzahlverschlechtemd.

In a preferred embodiment, such further ionic liquids are used to extract or dissolve the catalyst, which are formed by protonation of the corresponding bases, ie those in which R ^{17 is} hydrogen. These have the advantage that they can be purified by treatment of a base, for example sodium or potassium hydroxide solution or milk of lime and converted into the corresponding bases, can be purified, for example by distillation, and then converted back into the ionic liquids by protonation. So it is possible to regenerate spent extractant without great losses.

The regeneration can also take place, for example, by back-extraction of the ionic liquid to be regenerated with another solvent in which the catalyst is more soluble than in the ionic liquid or by precipitation or crystallization. Thus, also those ionic liquids can be regenerated, in which R ^{17 is} not hydrogen.

Ppm and percentages used in this specification, unless otherwise indicated, are by weight percent and ppm.

The following examples are intended to illustrate but not to limit the invention.

Examples

In a stirred apparatus consisting of a 250 ml four-necked flask with stirrer, internal thermometer, reflux condenser, nitrogen inlet tube and oil bath

Presented 100 g of hexamethylene diisocyanate (HDI) and heated at 80 ° C bath temperature to 75 ⁰ C internal temperature.

Then, 60 μl of a 16.7% strength solution of the catalyst 2-hydroxyethyltrimethylammonium salicylate (melting point below room temperature, 100 ppm on HDI) dissolved in 2-propanol / propylene carbonate 1: 4 were added. The internal temperature rises to about 85 ⁰ C. The heating was removed until the internal temperature had fallen back to 80 ⁰ C was. Stirring was continued at this temperature until the NCO value dropped from the original 49% to 40%.

The mixture was then cooled to room temperature with the aid of a water bath and the reaction was stopped by adding 15 μl of bis (2-ethylhexyl) phosphate (= 150 ppm to HDI).

The resulting reaction mixture had a Hazen color number of 16.

Claims

claims

A process for the preparation of isocyanurate, biuret and / or allophanate group-containing polyisocyanates by at least partial oligomerization of diisocyanates, characterized in that one carries out the reaction in the presence of at least one oligomerization catalyst, which is an ionic liquid having the structure

and a melting point of not more than 100 ° C

These,

wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ can each independently be the same or different and represent a straight-chain or branched C 1 to C ₂ o-alkyl group, an optionally substituted C ₅ - to C ₁₂ -Cycloalkylgruppe, an optionally substituted C ₇ - to Cio-aralkyl group, or an optionally substituted C ₆ -C ₂ -aryl group or two or more of the radicals R ¹ to R ³ together are each a 4-, 5- or Form 6-membered alkylene chain or together with a nitrogen atom form a 5- or 6-membered ring which may contain an additional nitrogen or oxygen as a bridging member or together form a multi-membered, preferably six-membered multi-ring system, preferably Zweiringsystem, which still one or more may contain additional nitrogen atoms, oxygen atoms or nitrogen and oxygen atoms as bridge members, and

R ⁴ , R ⁵ , R ⁶ and R ^{7 may} additionally be hydrogen.

2. The method according to claim 1, characterized in that An ^"is selected from the group of carboxylates, sulfates, sulfites, sulfonates, sulfinates, phosphates, phosphonates, phosphinates and metal halides

3. The method according to any one of the preceding claims, characterized in that R ¹ , R ² and R ^{3 are the} same and at least one of R ⁴ and R ^{5 is} hydrogen. 4. The method according to any one of the preceding claims, characterized in that the cation is selected from the group consisting of 2-hydroxyethyl trimethylammonium, 2-hydroxypropyl-trimethylammonium, 2-hydroxyethyl triethylammonium, 2-hydroxypropyl-triethylammonium, 2-hydroxyethyl tri-n-butylammonium and 2-hydroxypropyl-tri-n-butylammonium.

5. The method according to any one of claims 2 to 4, characterized in that the metal halide is a compound M _x Hal / ^" ,

wherein

Hal is a halide or pseudohalide

x and y are independently a positive integer and

z is the sum of charge of metal and charges of halides

mean

and M is selected from the group consisting of Li, Na, K, Cs, Mg, Ca, Ba, Al, Ga, Sn, Sb, Bi, Ti, Zr, V, Nb, Cr, Mo, W, Mn, Fe , Ru, Co, Rh, Ni, Pd, Pt, Cu, Ag, Zn, Hg, Ce, Sm, P, Si, and B.

Process according to one of claims 2 to 4, characterized in that the metal halide is selected from the group consisting of AICI ₄ ^" , FeCl ₄ ^" , AIBr ₄ ^" , ZnCl ₃ ^" , BeCl ₃ ^" , ZnBr ₃ ^" , ZnI ₃ ^" , CuCl ₃ ^" , CuCl ₂ ^" , CoCl ₃ ^" , CoI ₃ ^" , FeI ₃ ^" , FeCl ₃ ^" , TiCl ₅ ^" , TiCl ₆ ² JiCl ₄ ^" , SnCl ₃ ^" , SnCl ₄ ^" , SnCl ₄ ^{2 "} , MnCl ₃ ^" , MnCl ₄ ^2" , MnBr ₃ ^" , ScCl ₄ ^" , BCI ₄ ^" , BBr ₄ ^" , GaCl ₄ ^" , ReCl ₆ ^" , ZrCl ₅ ^" , NbCl ₆ ^" , VCI ₄ ^" , CrCl ₃ ^" , MoCl ₆ ^" , YCl ₄ ^" , CdCl ₃ ^" , CdBr ₃ ^" , SbCl ₄ ^" , SbCl ₆ ^" , BiCl ₄ ^" , ZrCl ₅ ^" , UCI ₅ ^" , UCI ₆ ^{2 "} , LaCl ₄ ^" , CeCl ₄ ^" , SmCl ₄ ^" , SmI ₃ ^" , TaCI ₆ ^" , BF ₄ ^" , PCI ₄ ^" , PCI ₆ ^" and PF ₆ ^" .

Process according to one of Claims 2 to 4, characterized in that the metal halide is a mixture of halides or pseudohalides of a cation according to one of Claims 1 to 4 with Lewis acids selected from the group AICI ₃ , FeCl ₃ , AIBr ₃ and ZnCl ₂ , BeCl ₂ , ZnBr ₂ , ZnI ₂ , ZnSO ₄ , CuCl ₂ , CuCl, Cu (O ₃ SCF ₃ ) ₂ , CoCl ₂ , CoI ₂ , FeI ₂ , FeCl ₂ , FeCl ₂ (THF) ₂ . TiCl ₄ (THF) ₂ , TiCl ₄ , TiCl ₃ , CITi (OiPr) ₃ , SnCl ₂ , SnCl ₄ , Sn (SO ₄ ), Sn (SO ₄ ) ₂ , MnCl ₂ , MnBr ₂ , ScCl ₃ , BPh ₃ , BCI ₃ , BBr ₃ , BF ₃ -OEt ₂ , BF ₃ -OMe ₂ , BF ₃ -MeOH, BF ₃ -CH ₃ COOH, BF ₃ -CH ₃ CN, B (CF ₃ COO) ₃ , B (OEt) ₃ , B (OMe) ₃ , B (OZPr) ₃ , PhB (OH) ₂ , 3-MeO-PhB (OH) ₂ , 4-MeO-PhB (OH) ₂ , 3-F-PhB (OH) ₂ , 4 -F-PhB (OH) ₂ , (C ₂ Hs) ₃ Al, (C ₂ Hs) ₂ AICI, (C ₂ H ₅ ) AICI ₂ , (C ₈ H ₁₇ ) AICI ₂ , (C ₈ H ₁₇ ) ₂ AICI, (iso-C ₄ H ₉ ) ₂ AICI,

Ph ₂ AICI, PhAlCl ₂ , Al (acac) ₃ , Al (OZPr) ₃ , Al (OnBu) ₃ , Al (Ose / cBu) ₃ , Al (OEt) ₃ , GaCl ₃ , ReCl ₅ , ZrCl ₄ , NbCl ₅ , VCI ₃ , CrCl ₂ , MoCl ₅ , YCl ₃ , CdCl ₂ , CdBr ₂ , SbCl ₃ , SbCl ₅ , BiCl ₃ , ZrCl ₄ , UCI ₄ , LaCl ₃ , CeCl ₃ , Er (O ₃ SCF ₃ ), Yb ( O ₂ CCF ₃ ) ₃ , SmCl ₃ , SmI ₂ , B (C ₆ Hg) ₃ and TaCl ₅ .

8. The method according to any one of claims 2 to 7, characterized in that it is the salicylate or nicotinate in the carboxylate.

9. Mixture containing

at least one diisocyanate, at least one ionic liquid as defined in any one of claims 1 to 8, optionally at least one urethane, alcohol, amine or water and optionally at least one further ionic liquid.

10. Use of ionic liquids as defined in any one of claims 1 to 8 in the preparation of polyisocyanates.

11. Use of biuret, allophanate and / or isocyanurate-containing polyisocyanates obtainable according to one of claims 1 to 8 in the preparation of polyurethane coatings, dispersions and adhesives and as a polyisocyanate component in one and two-component polyurethane systems for polyurethane coatings ,