EP2473574A2

EP2473574A2 - Ionic liquids having higher viscosity

Info

Publication number: EP2473574A2
Application number: EP10747462A
Authority: EP
Inventors: Klemens Massonne; Aurelie Alemany; Dirk Gerhard
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2009-09-03
Filing date: 2010-08-31
Publication date: 2012-07-11
Also published as: US20120157360A1; WO2011026822A3; WO2011026822A2

Abstract

Disclosed is a method for adjusting the viscosity of a salt having a melting point below 100°C at a normal pressure (called an ionic liquid), characterized in that a compound containing at least 0.1 mol of functional groups per 100 grams of compound is added to the ionic liquid, said functional groups being selected from among acid groups, acid amide groups, amino groups, ammonium groups, and hydroxyl groups.

Description

Ionic liquids with improved viscosity Description

The present invention relates to a method for adjusting the viscosity of a salt having a melting point of less than 100 ° C at atmospheric pressure (abbreviated to ionic liquid), which is characterized in that a compound is added to the ionic liquid, which has a content of at least 0.1 Mol functional groups / 100g compound and the functional groups are selected from

Acid groups or their salts, acid amide, amino, ammonium and hydroxyl groups.

Ionic liquids are of great interest for a wide variety of technical applications. In addition to applications as a solvent or electrolyte are applications as a lubricant, hydraulic fluid or operating fluid, as a heat carrier, for heat transfer or as a sealing or Absperrflüssigkeit into consideration.

The use of ionic liquids as absorbents in heat pumps, i. as operating fluid, z. B. from WO 2005/1 13702 known.

Uses of ionic liquids as a hydraulic fluid, lubricant, operating fluid, stop-off or sealing fluid are e.g. also listed in WO 2006/087333. In all these uses, suitable ionic liquids must meet a variety of required properties. An essential feature in all these applications is the viscosity. Often many, but not all, of the required properties are met by a selected ionic liquid. The remaining, unfulfilled properties must, if possible, be adjusted accordingly.

Thus, e.g. for an intended use, the viscosity of the otherwise suitable ionic liquid may not be high enough.

Often, it is also undesirable if the viscosity of a selected ionic liquid has too high a temperature dependence in the temperature range of the particular application.

There are therefore desired ways to adjust the viscosity of any ionic liquid in a simple manner, in particular to increase the viscosity and / or to reduce their temperature dependence. Accordingly, the method defined above was found. Also found were compositions containing ionic liquids and defined additives as well as uses of these compositions.

To the ionic liquid

The subject of the process according to the invention is the adjustment of the viscosity of an ionic liquid by adding a compound.

The ionic liquid is a salt with a melting point of less than 100 ° C at 1 bar.

Preferably, the ionic liquid has a melting point less than 70 ° C and more preferably less than 30 ° C. In a particularly preferred embodiment, the ionic liquid is liquid under normal conditions (1 bar, 21 ° C).

The ionic liquid is a salt and therefore consists of at least one cation and at least one anion.

Preferred ionic liquids contain at least one organic compound as cation, very particularly preferably they contain only organic compounds as cations. Suitable organic cations are, in particular, organic compounds containing heteroatoms, such as nitrogen, sulfur, oxygen or phosphorus, particular preference being given to organic compounds having a cationic group selected from an ammonium group, an oxonium group, a sulfonium group or a phosphonium group.

In a particular embodiment, the ionic liquids are ammonium cation salts, which includes non-aromatic compounds having a localized positive charge on the nitrogen atom, e.g. Compounds with vierbindigem nitrogen (quaternary ammonium compounds) or compounds with three nitrogen, wherein a bond is a double bond, or aromatic compounds with delocalized positive charge and at least one, preferably one or two nitrogen atoms in the ring system are understood.

Particularly preferred organic cations are quaternary ammonium cations having preferably three or four aliphatic substituents, particularly preferably C 1 - to C 12 -alkyl groups, on the nitrogen atom. Organic cations which contain a heterocyclic ring system having one or two nitrogen atoms as part of the ring system are also particularly preferred. Suitable compounds are monocyclic, bicyclic, aromatic or non-aromatic ring systems. Examples include bicyclic systems, as described in WO 2008/043837. The bicyclic systems of WO 2008/043837 are diazabicyclo derivatives, preferably of a 7- and a 6-ring, which contain an amidinium group; in particular the 1,8-diazabicyclo- (5.4.0) undec-7-enium cation may be mentioned. Very particularly preferred organic cations comprise a five- or six-membered heterocyclic ring system having one or two nitrogen atoms as part of the ring system.

Suitable cations are e.g. Pyridinium cations, pyridazinium cations, pyrimidinium cations, pyrazinium cations, imidazolium cations, pyrazolium cations

Cations, pyrazolinium cations, imidazolinium cations, thiazolium cations, triazolium cations, pyrrolidinium cations and imidazolidinium cations. These cations are e.g. in WO 2005/1 13702. Insofar as it is necessary for a positive charge on the nitrogen atom or in the aromatic ring system, the nitrogen atoms are each represented by an organic group with generally not more than 20 C atoms.

Atoms, preferably a hydrocarbon group, in particular a C1 to C16 alkyl group, in particular a C1 to C10, particularly preferably a C1 to C4 alkyl groups substituted. The carbon atoms of the ring system can also be substituted by organic groups having generally not more than 20 C atoms, preferably a hydrocarbon group, in particular a C1 to C16 alkyl group, in particular a C1 to C10, particularly preferably a C1 to C4 alkyl groups. Particularly preferred ammonium cations are quaternary ammonium cations, imidazolium cations, pyrimidinium cations and pyrazolium cations.

Very particular preference is given to imidazolium cations. The anion may be an organic or inorganic anion.

Suitable anions are, in particular, those from the group of halides and halogen-containing compounds of the formulas:

F-, Cl-, Br, I-, BF ₄ -, PF ₆ -, AlCk, Al ₂ Cl ₇ -, A Cho ^", AlBr ₄ -, fbase, BCK, SbF ₆ -, AsF _6, -ZnCI ₃ - , SnCIs ^" , CuC ^" , CF ₃ SO ₃ -, (CF ₃ SO ₃ ) ₂ N-, CF ₃ CO ₂ -, CCI ₃ CO ₂ -, CN ^" , SCN ^" , OCN ^" , NO ^2" , NO ^{3 "} , N (CN) -; the group of sulfates, sulfites and sulfonates of the general formulas:

S0 ₄ ² -, HSO4-, SO3 ² -, HSO3-, R ^a OS0 ₃ -, R ^a S0 ₃ -; the group of phosphates of the general formulas:

PO4 ³ -, HPO4 ² -, H2PO4 -, R ^a P0 ₄ ^{2 "} , HR ^a P0 ₄ ^" , R ^a R ^b P0 ₄ -; the group of phosphonates and phosphinates of the general formula:

R ^a HP0 ₃ -, R ^a R ^b P0 ₂ -, R ^a R ^b P0 ₃ -; the group of phosphites of the general formulas:

P0 ₃ ³ -, HPO ₃ ² -, H ² PO ₃ -, R ^a P0 ₃ ^{2 "} , R ^a HP0 ₃ -, R ^a R P0 ₃ -; the group of phosphonites and phosphinites of the general formula:

R ^a R P0 ₂ ^" , R ^a HP0 ₂ -, R ^a R ^b PO ^" , R ^a HPO ^" , the group of the carboxylates of the general formulas:

R ^a COO-; the group of borates of the general formulas:

BO3 ³ , HBO3 ² , H2BO3, R ^a R B0 ₃ -, R ^a HB0 ₃ -, R ^a B0 ₃ ^{2 "} , B (OR ^a ) (OR) (OR ^c ) (OR ^d ) -, B (HSO ₄ ) -, B (R ^a S04) -; the group of boronates of the general formulas:

R ^a B0 ₂ ^{2 "} , R ^a R ^b BO-; the group of carbonates and carbonic esters of the general formulas:

the group of silicates and silicic acid esters of the general formulas:

S1O4 ⁴ -, HS1O4 ³ -, H2S1O4 ² -, H3S1O4 -, R ^a Si0 ₄ ³ -, R ^a R Si0 ₄ ² -, R ^a RR ^c Si0 ₄ -, HR ^a Si0 ₄ ² -, H ₂ R ^a Si0 ₄ -, HR ^a R Si0 ₄ -; the group of the alkyl or aryl silane salts of the general formulas:

R ^a Si0 ₃ ³ -, R ^a R Si0 ₂ ² -, R ^a RR ^c SiO ^" , R ^a RR ^c Si0 ₃ -, R ^a RR ^c Si0 ₂ -, R ^a R ^b Si0 ₃ ² -, the group of Carboxylic imides, bis (sulfonyl) imides and sulfonylimides of the general formulas: the group of methides of the general formula:

SO ₂ -R ^a

R ^{b is} -O ₂ S ^' SO ₂ -R ^c

the group of alkoxides and aryloxides of the general formulas:

R ^a O-; the group of halometalates of the general formula

[M _r Hal _t ] ^s -,

wherein M is a metal and Hal is fluorine, chlorine, bromine or iodine, r and t are integer positive numbers and indicate the stoichiometry of the complex and s is an integer positive number indicating the charge of the complex; the group of sulfides, hydrogen sulfides, polysulfides, hydrogen polysulfides and thiolates of the general formulas:

S ² -, HS-, [Sv] ² -, [HSv] ^" , [R ^a S] -,

where v is a whole positive number from 2 to 10; and the group of complex metal ions such as Fe (CN) ₆ ^{3 ",} Fe (CN) ₆ ^4" MnCv, Fe (CO) 4 ^~

In the above anions, R ^a , R ^b , R ^c and R ^d are each independently

Hydrogen;

C 1 -C 30 -alkyl and their aryl, heteroaryl, cycloalkyl, halogen, hydroxy, amino, carboxy, formyl, -O-, -CO-, -CO-O- or -CO- N <substituted components 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, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, Henicosyl, docosyl, tricosyl, tetracosyl, pentacosyl, hexacosyl, heptacosyl, octacosyl, nonacosyl, triacontyl, phenylmethyl (benzyl), diphenylmethyl, triphenylmethyl, 2-phenylethyl, 3-phenylpropyl, cyclopentylmethyl, 2-cyclopentylethyl, 3-cyclopentylpropyl , cyclohexyl methyl, 2-cyclohexylethyl, 3-cyclohexylpropyl, methoxy, ethosulfate xy, formyl, acetyl or C _q F 2 _(q - _a) + (ib) H2a + b where q <30, 0 <a <b and q = 0 or 1 (for example CF3, C2F5, CH2CH2-C (q-2) F2 (q-2) + i, C6F13, CSFI _7, C10F21, C12F25);

C 3 -C 12 -cycloalkyl and their aryl, heteroaryl, cycloalkyl, halogen, hydroxy, amino, carboxy, formyl, -O-, -CO- or -CO-O-substituted components, such as cyclopentyl , 2-methyl-1-cyclopentyl, 3-methyl-1-cyclopentyl, cyclohexyl, 2-methyl-1-cyclohexyl, 3-methyl-1-cyclohexyl, 4-methyl-1-cyclohexyl or C _q F2 ( _q-a ) - (ib) H2a-b with q <30, 0 <a <q and b = 0 or 1;

C 2 -C 30 -alkenyl and their aryl-, heteroaryl-, cycloalkyl-, halogen-, hydroxy-, amino-, carboxy-, formyl-, -O-, -CO- or -CO-O-substituted components, such as, for example 2 -Propenyl, 3-butenyl, cis-2-butenyl, trans-2-butenyl or _Cq F2 ( _q -a) - (ib) H2a-b with q <30, 0 <a <q and b = 0 or 1 ;

C 3 -C 12 -cycloalkenyl and their aryl-, heteroaryl-, cycloalkyl-, halogen-, hydroxy-, amino-, carboxy-, formyl-, -O-, -CO- or -CO-O-substituted components, such as For example, 3-cyclopentenyl, 2-cyclohexenyl, 3-cyclohexenyl, 2,5-cyclohexadienyl or C _q F2 ( _q -a) -3 (ib) H2a-3b with q <30, 0 <a <q and b = 0 or 1 ;

Aryl or heteroaryl having 2 to 30 carbon atoms and their alkyl, aryl, heteroaryl, cycloalkyl, halogen, hydroxy, amino, carboxy, formyl, -O-, -CO- or -CO-O- substituted components such as phenyl, 2-methylphenyl (2-tolyl), 3-methylphenyl (3-tolyl), 4-methylphenyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethyl - phenyl, 2,3-dimethyl-phenyl, 2,4-dimethyl-phenyl, 2,5-dimethyl-phenyl, 2,6-dimethyl-phenyl, 3,4-dimethyl-phenyl, 3,5-dimethyl-phenyl , 4-phenyl-phenyl, 1-naphthyl, 2-naphthyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl or C6F ( _5-a ) Ha with 0 <a <5; or

two radicals are an unsaturated, saturated or aromatic, optionally substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and / or heterocycles and optionally substituted by one or more oxygen and / or sulfur atoms and / or one or more substituted or unsubstituted imino groups interrupted ring.

In the above anions, R ^a , R ^b , R ^c and R ^{d are} preferably each independently a hydrogen atom or a ^{C 1 to C} 12 alkyl group.

In the above anions, Ra, Rb, Rc and Rd are preferably each independently a hydrogen atom or a C1 to C12 alkyl group. As anions are mentioned z. B. chloride; Bromide; iodide; thiocyanate; Hexafluorophosphate; trifluoromethanesulfonate; methane; the carboxylates, in particular formate; Acetate; mandelate; Nitrate; Nitrite; trifluoroacetate; Sulfate; Bisulfate; Methyl sulfate; ethyl sulfate; 1-propyl sulfate; 1-butyl sulfate; 1 -hexyl sulfate; 1-octyl sulfate; Phosphate; dihydrogen phosphate; Hydrogen phosphate; C1-C4 dialkyl phosphates; propionate;

tetrachloroaluminate; AI2CI7-; chlorozincate; Chloroferrat;

imide, bis (trifluoromethylsulfonyl); Bis (pentafluoroethylsulfonyl) imide;

Bis (methylsulfonyl) imide; Bis (p-tolylsulfonyl) imide; Tris (trifluoromethylsulfonyl) methide; Bis (pentafluoroethylsulfonyl) methide; p-tolylsulfonate; tetracarbonylcobaltate; Dimethyl glycol monomethyl ether sulfate; oleate; stearate; acrylate; methacrylate; maleate; Hydro gen citrate; vinylphosphonate; Bis (pentafluoroethyl) phosphinate; Borates such as bis [salicylato (2 -)] borate, bis [oxalato (2 -)] borate, bis [1, 2-benzenediolato (2 -) - 0,0 '] borate, tetracyano- borate, tetrafluoroborate; dicyanamide; Tris (pentafluoroethyl) trifluorophosphate;

Tris (heptafluoropropyl) trifluorophosphate, cyclic aryl phosphates such as catechol phosphate (C6H402) P (0) 0 and chlorocobaltate.

Anions are particularly preferably those from the group of alkyl sulfates

R ^a OS0 ₃ -,

wherein R ^{a is} a C 1 to C 12 alkyl group, preferably a C 1 -C 6 alkyl group, the alkyl sulfonates

R ^a S0 ₃ -;

wherein R ^{a is} a C 1 to C 12 alkyl group, preferably a C 1 -C 6 alkyl group, halides, in particular chloride and bromide and the pseudohalides, such as thiocyanate, dicyanamide, the carboxylates R ^a COO-;

wherein R ^{a is} a C 1 to C 20 alkyl group, preferably a C 1 -C 8 alkyl group, in particular acetate, the phosphates,

in particular the dialkyl phosphates of the formula R ^a R ^b P0 ₄ -, wherein R ^a and R ^b independently of one another represent a C 1 to C ₆ alkyl group; in particular, R ^a and R ^{b are} the same alkyl group, which may be mentioned dimethyl phosphate and diethyl phosphate and the phosphonates, especially the Monoalkylphosphonsäureester of the formula R ^a R ^b P03 ^" , wherein R ^a and R ^b independently of one another represent a C 1 to C 6 alkyl group.

Very particularly preferred anions are

Chloride, bromide, hydrogen sulfate, tetrachloroaluminate, thiocyanate, dicyanamide, methylsulfate, ethylsulfate, methanesulfonate, formate, acetate, dimethyl phosphate,

Diethyl phosphate, p-tolylsulfonate, tetrafluoroborate and hexafluorophosphate, methyl methylphosphonate and methylphosphonate.

Particularly preferred ionic liquids consist exclusively of an organic cation having one of the above anions.

The molar weight of the ionic liquids is preferably less than 2000 g / mol, more preferably less than 1500 g / mol, more preferably less than 1000 g / mol, and most preferably less than 750 g / mol; in a particular embodiment, the molecular weight is between 100 and 750 or between 100 and 500 g / mol.

In a particular embodiment, they are imidazolium compounds, particularly preferably imidazolium compounds of the formula

R 1 and R 3 independently of one another represent an organic radical having 1 to 20 C atoms

R 2, R 4, and R 5 independently of one another represent an H atom or an organic radical having 1 to 20 C atoms,

X is an anion and n is 1, 2 or 3. R 1 and R 3 are preferably independently an organic group containing 1 to 10 C atoms. Particularly preferred is a coal hydrogen group which has no further heteroatoms, for example a saturated or unsaturated aliphatic group, an aromatic group or a hydrocarbon group which has both aromatic and aliphatic constituents. Very particular preference is given to a C1 to C10 alkyl group, a C1 to C10 alkenyl group, for example an allyl group, a phenyl group, a benzyl group. In particular, it is a C1 to C4 alkyl group, for example a methyl group, ethyl group, propyl group, i-propyl group or n-butyl group.

R 2, R 4 and R 5 are preferably independently of one another an H atom or an organic group which contains 1 to 10 C atoms. Particularly preferably, R 2, R 4 and R 5 are an H atom or a hydrocarbon group which has no further heteroatoms, e.g. an aliphatic group, an aromatic group or a hydrocarbon group having both aromatic and aliphatic components. Very particular preference is given to an H atom or a C1 to C10 alkyl group, a phenyl group or a benzyl group. In particular, it is an H atom or a C1 to C4 alkyl group, e.g. a methyl group, ethyl group, propyl group, i-propyl group or n-butyl group. The variable n is preferably 1.

Suitable anions X and preferred anions X are those listed above.

Particular preference is given to ionic liquids which are used as cation

Methyl tri- (1-butyl) -ammonium, 2-hydroxyethylammonium, 1-methylimidazolium, 1-ethylimidazolium, 1- (1-butyl) -imidazolium, 1- (1-octyl) -imidazolium, 1- (1-dodecyl imidazolium, 1- (1-tetradecyl) imidazolium, 1- (1-hexadecyl) -imidazolium, 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1- (1-butyl) -3- methylimidazolium, 1- (1-butyl) -3-ethylimidazolium, 1- (1-hexyl) -3-methylimidazolium, 1- (1-hexyl) -3-ethylimidazolium, 1- (1-hexyl) - 3-Butylimidazolium, 1- (1-octyl) -3-methylimidazolium, 1- (1-octyl) -3-ethylimidazolium, 1- (1-octyl) -3-butylimidazolium, 1- (1-dodecyl ) -3-methylimidazolium, 1- (1-dodecyl) -3-ethylimidazolium, 1- (1-dodecyl) -3-butylimidazolium, 1- (1-dodecyl) -3-octylimidazolium, 1- (1-tetradecyl) - 3-methylimidazolium, 1- (1-tetradecyl) -3-ethylimidazolium, 1- (1-tetradecyl) -3-butylimidazolium, 1- (1-tetradecyl) -3-octylimidazolium, 1- (1-hexadecyl) - 3-methylimidazolium, 1- (1-hexadecyl) -3-ethylimidazolium, 1- (1-hexadecyl) -3-butylimida Zolium, 1 - (1-hexadecyl) -3-octylimidazolium, 1, 2-dimethylimidazolium, 1, 2,3-trimethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1- (1-butyl) -

2,3-dimethylimidazolium, 1- (1-hexyl) -2,3-dimethylimidazolium, 1- (1-octyl) -2,3-dimethylimidazolium, 1,4-dimethylimidazolium, 1,3,4-trimethylimidazolium,

1, 4-dimethyl-3-ethylimidazolium, 3-butylimidazolium, 1, 4-dimethyl-3-octylimidazolium, 1, 4,5-trimethylimidazolium, 1, 3,4,5-tetramethylimidazolium, 1, 4,5-trimethyl- 3-ethyl imidazolium, 1, 4,5-trimethyl-3-butylimidazolium or 1, 4,5-trimethyl-3-octylimidazolium; and as an anion, the above anions and preferred anions. Examples of ionic liquids are:

1, 3-dimethylimidazolium methylsulfate, 1, 3-dimethylimidazolium hydrogen sulfate,

1, 3-dimethylimidazolium dimethyl phosphate, 1, 3 dimethylimidazolium acetate, 1-ethyl-3-methylimidazolium methylsulfate, 1-ethyl-3-methylimidazolium-hydrogen sulfate, 1-ethyl-3-methylimidazolium thiocyanat, 1-ethyl-3-methylimidazolium acetate , 1-ethyl-3-methylimidazolium methanesulfonate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1- (1-butyl) -3-methylimidazolium methylsulfate, 1- (1-butyl) -3-methylimidazolium hydrogensulfate, 1 - ( 1-butyl) -3-methylimidazolium thiocyanate, 1- (1-butyl) -3-methylimidazolium acetate, 1- (1-butyl) -3-methylimidazolium methanesulfonate, 1- (1-dodecyl) -3-methylimidazolium methylsulfate , 1- (1-dodecyl) -3-methylimidazolium hydrogensulfate, 1- (1-tetradecyl) -3-methylimidazolium methylsulfate, 1- (1-tetradecyl) -3-methylimidazolium hydrogensulfate, 1- (1-hexadecyl) -3- methylimidazolium methylsulfate or 1- (1-hexadecyl) -3-methylimidazolium hydrogen sulfate, 2-hydroxyethylammonium formate or methyl-tributylammonium methylsulfate.

To the connection

According to the invention, the viscosity of the ionic liquid is adjusted by adding a compound.

The compound has a content of at least 0.1 mol, preferably 0.2 mol and more preferably of at least 0.5 mol of functional groups per 100 g of the compound, where the functional groups are selected from acid groups or their salts, acid amide, amino , Ammonium and hydroxyl groups.

The upper limit of the content of these functional groups, depending on the type of compound, is the theoretically maximum possible content of such functional groups; in general, the content is at most 2.5 moles, which z. B. in the diglycerol almost achieved, in particular a maximum of 2.1 mol, which z. B. can be achieved in the triglycerol and maximally 1, 4 mol, which are achieved in the polyacrylic acid. Such a high content of functional groups is generally not necessary for the advantages of the invention, very good results are achieved with a content of functional groups of 0.1 to 1.5 mol / 100 g of compound, in particular from 0.2 to 1 , 1 mol / 100g of compound, and more preferably from 0.5 to 1.1 mol / 100g of compound.

The functional groups of the compound may be exclusively acid groups or exclusively acid amide groups or exclusively amino groups or exclusively ammonium groups or exclusively hydroxy groups.

However, the compound may also contain several of the said functional groups, for. B. compounds are suitable and easy to prepare, containing both acid groups and acid amide groups. As acid groups come z. As sulfonic acid groups, phosphonic acid groups or carboxylic acid groups into consideration. The salts of these acid groups may be salts with any cations, e.g. inorganic cations, such as metal cations of the 1. or 2nd main group or the ammonium cation Nh. In particular, only a part of the acid groups may be present as a salt. For polybasic acids, i. Acids with more than one acid proton, optionally only part of the protons may be replaced by a cation.

The acid groups, preferably sulfonic acid groups and carboxylic acid groups, particularly preferably carboxylic acid groups, can easily be converted completely or partially into salt groups, eg. B. by addition of a base as a neutralizing agent, they are then present in whole or in part as a salt of the neutralizing agent. As a neutralizing agent may be mentioned by way of example NaOH.

Preference is given to sulfonic acid groups and carboxylic acid groups and, in the case of the salts, to the corresponding sulfonate groups and carboxylate groups.

As acid amide groups come z. As the amides of the above acid groups into consideration, preferably the sulfonic acid amides and carboxylic acid amides. The carboxylic acid amides may be cyclic or non-cyclic amides. The cyclic amides are referred to as lactams.

Amino groups may be primary, secondary or tertiary amino groups. Amino groups may also be part of heterocyclic ring systems, such as. In imidazole.

By ammonium groups are meant groups having at least one nitrogen atom and one positive charge. It may be

to form quaternary ammonium groups, i. Groups with four substituents and a localized positive charge on the nitrogen atom,

- groups with two singly bound substituents, a substituent bound by double bond and a localized positive charge on the nitrogen atom or

- aromatic, heterocyclic ring systems having at least one, in particular one or two nitrogen atoms in the ring system and a delocalized positive charge.

The hydroxyl groups may be bonded to aromatic or aliphatic groups of molecules, preferred are hydroxyl groups which are bonded to an aliphatic carbon atom. Any compounds satisfying the above conditions are contemplated.

The compound may be solid or liquid at room temperature (21 ° C). Preferred compounds are homogeneously miscible with water at 21 ° C. (1 bar) or have a solubility of at least 20 g, preferably at least 30 g of compound in 100 g of water at 21 ° C. (1 bar) in water.

The compound preferably contains a total of at least 4, more preferably at least 5, functional groups per molecule, which may be a single or combinations of said functional groups; for oligomeric or polymeric compounds this is an average.

In a preferred embodiment, the compound contains only one kind of said functional groups, e.g. B. only amino groups, only carboxylic acid groups or wholly or partially their salts (carboxylate groups) or only Sulfonsäuregrup- pen or wholly or partially their salts (sulfonate) or only Hydroxylgrupppen. It is therefore preferably an oligomeric or polymeric compound, e.g. is obtainable by (poly) condensation, (poly) adduct formation or free-radical polymerization from starting compounds.

The compound can therefore have a molecular weight of z. B. 100g / mol to 250,000 g / mol. Preferred compounds have a molecular weight of 200 to 100,000 g / mol, particularly preferred compounds have a molecular weight of 300 to 50,000 g / mol. In the above molecular weight is defined compounds to the actual molecular weight Mg, in oligomeric or polymeric compounds is the number average molecular weight Mn, which can be determined by known methods, such as gel permeation chromatography or end group determination.

Hereinafter, preferred compounds are mentioned.

Compounds with carboxylic acid groups or carboxylate groups are, for. Example, poly (meth) acrylic acid or (meth) acrylic acid copolymers which at least 30 wt.%, In particular at least 50 wt.% Of acrylic acid or methacrylic acid (short (meth) acrylic acid) exist.

Polystyrenesulfonic acid, or polystyrenesulfonates, or polymers containing styrenesulfonic acid or styrenesulfonates may be mentioned as compounds with sulfonic acid groups or sulfonate groups. Mention may also be made of copolymers which contain AMPS (Lupasol® PR-140) or its salts. AMPS is an unsaturated acid amide with a sulfonic acid or sulfonate group.

Poly (meth) acrylic acid or (meth) acrylic acid copolymers can be obtained by free-radical polymerization, in particular by solution or bulk polymerization, of acrylic acid or methacrylic acid and in the case of the copolymers of further free-radically polymerizable monomers.

Suitable (meth) acrylic acid copolymers are those with any desired comonomers, e.g. one or more comonomers selected from acrylates, vinyl esters, vinyl ethers, vinyl aromatics such as styrene, olefins such as ethylene or propylene, or vinyl halides. The comonomers may contain functional groups, e.g. As the above-mentioned as mandatory acid groups, acid amide groups or hydroxyl groups or other functional groups.

Preference is given to poly (meth) acrylic acid or (meth) acrylic acid copolymers of acrylic acid or methacrylic acid with maleic acid or maleic anhydride. Poly (meth) acrylic acid and (meth) acrylic acid copolymers are e.g. B. offered by BASF under the brand Sokalan®.

Compounds with Carbonsäureamidgruppen are z. B. (meth) acrylamide copolymers, polyvinylformamide or vinylformamide copolymers. Compounds having cyclic amide groups (lactams) are, in particular, polyvinylpyrrolidone and vinylpyrrolidone copolymers which preferably contain at least 30% by weight, in particular at least 50% by weight, of vinylpyrrolidone, for example copolymers of vinylpyrrolidone and vinylimidazole (Sokalan® HP56) The temperature dependence The viscosity of mixtures of ionic liquid with these polymers is particularly low. Such mixtures are therefore particularly suitable for the applications below, for. B. as hydraulic fluid. Compounds with amino groups are for. As polyvinylamine or vinylamine copolymers which at least 30 wt.%, In particular at least 50 wt.% Viny- consist of lamin. Vinylamine copolymers are especially those with vinylformamide. Such copolymers may, for. B. be prepared by partial hydrolysis of polyvinylformamide.

Furthermore, compounds are mentioned in which the amino group is part of a ring system, such as. In imidazole. A suitable such compound is in particular polyvinylimidazole or a vinylimidazole copolymer which consists of more than 30% by weight, in particular at least 50% by weight, of vinylimidazole.

Compounds with ammonium groups can be obtained in a simple manner by protonation of compounds containing amino groups, preferably the compounds provided. The protonation can be done by adjusting the necessary pH. Compounds with hydroxyl groups are for. Example, polyvinyl alcohol or vinyl alcohol copolymers, which are preferably at least 30 wt.%, In particular at least 50 wt.% Of vinyl alcohol, and polyglycerols.

Particularly preferred are polyglycerols.

Polyglycerols (English polyglycerol) are condensation products of glycerol.

Diglycerol is the condensation product (with dehydration) of two glycerol units and accordingly contains an ether group and 4 hydroxyl groups.

Similarly, triglycerin, tetraglycerol, pentaglycerol, etc. are the condensation products of a corresponding number of glycerol units. Since the condensation proceeds with the participation of different hydroxyl groups, a uniform degree of condensation is generally also isomeric mixtures.

In the context of the present invention, polyglycerols (English polyglycerol) having a number average molecular weight of 250 to 1000 g / mol are particularly preferred. To the procedure

The term "ionic liquid" shall in the following also be understood to mean a mixture of ionic liquids, and the term "compound" shall in the following also mean a mixture of compounds.

The compound is preferably added to the ionic liquid in an amount of 0.1 to 30 parts by weight per 100 parts by weight, more preferably in amounts of 1 to 20 parts by weight, and most preferably in amounts of 2 to 15 parts by weight 100 wt. Part added to ionic liquid.

The addition increases the viscosity of the ionic liquid. The compound can be added to the pure ionic liquid, but it can also be added to mixtures which contain other substances in addition to the ionic liquid; it may be e.g. to act substances such as solvents or substances dissolved in the ionic liquid. Such mixtures may, for. B. arise during use of ionic liquids. It is therefore also an advantage of the process according to the invention that the viscosity can be increased or adjusted during the use of the ionic liquid (see below) by adding the compound.

In a particularly preferred embodiment, it is additionally possible to add to the ionic liquid another nonionic solvent. It is preferably a solvent which is homogeneously miscible with the ionic liquid at 21 ° C (1 bar) and at 21 ° C, 1 bar has a dielectric constant greater than 7.5.

Preferred solvents are polar aliphatic solvents having hydroxyl groups or ether groups.

Particularly preferred are water and methanol or mixtures thereof. The amount of nonionic solvent, in particular water or methanol, is preferably at least 1 part by weight, in particular at least 5 parts by weight, more preferably at least 10 parts by weight and most preferably at least 20 parts by weight per 100 parts by weight ionic Liquid.

The non-ionic solvent may preferably divide the ionic liquid in amounts of from 1 to 150 parts by weight, more preferably from 5 to 100% by weight, and very preferably especially preferably from 10 to 80 parts by weight, in particular from 20 to 60 parts by weight, per 100 parts by weight of ionic liquid are added.

About the type and time of addition here apply the above comments on the addition of the compound.

The addition of the nonionic solvent reduces the temperature dependence of the viscosity, which is important for many applications with a broad temperature range.

By adding the compound to the ionic liquid according to the present invention, there are available compositions containing an ionic liquid and the above compound. Also obtainable are compositions containing an ionic liquid, the above compound and the above solvent.

The compositions may contain more than 70% by weight, in particular more than 90% by weight and more preferably more than 95% by weight, more than 98% by weight or exclusively (100% by weight) of the ionic Liquid, the compound and ggb. The solvent exist. This is especially the case before their use; During use, other substances may be included in the composition due to the nature of the use.

The viscosity of the composition, when it is more than 90% by weight of the ionic liquid, the compound and the solvent, is preferably 10 mPa ^* s to 2,500 mPa ^* s at 20 ° C. The viscosity stated is the dynamic viscosity.

The composition of the invention is suitable for a variety of uses. Called z. B. uses as a lubricant, hydraulic fluid, operating fluid in devices, eg. B. as an absorbent in thermodynamic cycle processes, which are based on absorption and desorption, as heat transfer, for heat transfer or as a sealing or Absperrflüssigkeit.

Examples

Used ionic liquids

The following salts of 1-ethyl-3-methyl-imidazolium (EMIM) were used: EMIM-methylsulfonate (EMIM-MeSOs)

EMIM ethylsulfate (EMIM-EtS0 ₄ )

EMIM acetate (EMIM OAc) EMIM thiocyanate (EMIM SCN)

Tris-2 (hydroxyethyl) -methylammonium-methylsulfate (FS01) As polymeric compounds were used:

Sokalan® PA 80 S, an acrylic acid-maleic acid copolymer from BASF

Sokalan® PA 1 10 S, an acrylic acid-maleic acid copolymer from BASF Sokalan® HP56K from BASF, a copolymer of vinylpyrrolidone and vinylimidazole

Polystyrenesulfonic acid (weight average molecular weight Mw = 75,000)

Polyvinylpyrrolidone K 60 (K 60 is the Fikentscher K value, which is a measure of the molecular weight).

Polyglycerol-4, a polyglycerol from Solvay Chemicals, which consists predominantly of linear tetraglycerol and contains low levels of diglycerol and triglycerol. The starting materials were mixed in the amounts indicated in the table, wherein in each case 100 parts by weight of the ionic liquid, the stated parts by weight of compound were added. Optionally, this mixture was added to water. The viscosity of the mixtures was determined at different temperatures.

Table 1 shows the composition of the mixtures and the viscosities.

In addition, the viscosity index of mixtures according to DIN ISO 2909 was determined. The viscosity index is determined from viscosities at 40 ° C. and 100 ° C. according to the calculation specified in DIN ISO 2909. The higher the viscosity index, the lower the temperature dependence of the viscosity.

Table 1: Viscosities

Table 2: Viscosity index

Sok :: Sokalan PA 80 S

Table 3: EMIM methylsulfonate + Sokalan HP56K

"Blend" in the 1st column refers only to EMIM methyl sulfonate and Sokalan HP56K and indicates the weight fraction of EMIM methyl sulfonate, the difference to 100 being the weight fraction of Sokalan HP56K.

"Water content" in the 2nd column indicates the additionally contained parts by weight of water per 100 parts by weight of the mixture of the 1st column.

Claims

claims

A method for adjusting the viscosity of a salt having a melting point of less than 100 ° C at atmospheric pressure (abbreviated to ionic liquid), characterized in that the ionic liquid is added to a compound having a content of at least 0.1 mol of functional groups / 100g compound and the functional groups are selected from acid groups or their salts, acid amide, amino, ammonium and hydroxyl groups.

A method according to claim 1, characterized in that it is the ionic liquid is a salt with an organic heterocyclic cation having one or two nitrogen atoms as part of the heterocyclic ring system.

A method according to claim 1 or 2, characterized in that it is the ionic liquid is a salt with an imidazolium cation.

A method according to any one of claims 1 to 3, characterized in that the added compound contains on average at least 4 of the functional groups in the molecule.

A method according to any one of claims 1 to 4, characterized in that the content of the functional groups is at least 0.2 mol / 100g of compound.

Method according to one of claims 1 to 5, characterized in that the compound at 21 ° C (1 bar) is homogeneously miscible with water or at 21 ° C (1 bar) in water has a solubility of at least 20g compound in 100 g of water ,

A process according to any one of claims 1 to 6, characterized in that the compound is poly (meth) acrylic acid or a

(Meth) acrylic acid copolymer which is more than 30% by weight

(Meth) acrylic acid is.

8. The method according to any one of claims 1 to 6, characterized in that it is the compound is a polyglycerol (condensed glycerol).

9. The method according to any one of claims 1 to 6, characterized in that it is the compound is polyvinylimidazole or a Vinylimidazolcopoly- mer, which consists of more than 30 wt.% Of vinylimidazole is.

Process according to one of Claims 1 to 6, characterized in that the compound is polyvinylpyrrolidone or a vinylpyrrolidone copolymer which is more than 30% by weight of vinylpyrrolidone.

A process according to any one of claims 1 to 10, characterized in that the compound is added in an amount of from 0.1 to 30 parts by weight per 100 parts by weight of ionic liquid.

Method according to one of claims 1 to 1 1, characterized in that the ionic liquid is additionally added a solvent which is homogeneously miscible with the ionic liquid at 21 ° C (1 bar) and has a dielectric constant greater than 7.5.

A method according to claim 12, characterized in that it is the solvent to water, methanol or mixtures thereof.

A process according to claim 12 or 13, characterized in that the solvent is added in amounts of from 0.1 to 50 parts by weight per 100 parts by weight of ionic liquid.

A composition containing an ionic liquid and a compound which

- Has a content of at least 0.1 moles of functional groups / 100 g of compound, wherein the functional groups are selected from acid, acid amide, amino, ammonium and hydroxyl groups, and

- At 21 ° C (1 bar) is homogeneously miscible with water or at 21 ° C (1 bar) in water has a solubility of at least 20g compound in 100 g of water.

16. The composition according to claim 15, characterized in that the composition additionally contains a solvent which is homogeneously miscible with the ionic liquid at 21 ° C (1 bar) and has a dielectric constant greater than 7.5.

17. A composition according to any one of claims 15 or 16, characterized in that it consists of more than 90 wt.% Of the ionic liquid, the compound and optionally the solvent. 18. A composition according to any one of claims 15 to 17, characterized in that the viscosity of the composition is 10 mPa ^* s to 2,500 mPa ^* s at 20 ° C.

19. Use of the composition according to one of claims 15 to 18 as a lubricant, hydraulic fluid, operating fluid, as a heat transfer medium, for

Heat transport or as sealing or Absperrflüssigkeit.