CA2151770A1

CA2151770A1 - Preparation of polymers based on 1-vinylimidazoles

Info

Publication number: CA2151770A1
Application number: CA 2151770
Authority: CA
Inventors: Christian Schade; Jurgen Detering
Original assignee: Individual
Current assignee: BASF SE
Priority date: 1994-06-17
Filing date: 1995-06-14
Publication date: 1995-12-18
Also published as: JPH0820616A; EP0687694A2; DE4421178A1; EP0687694A3

Abstract

Polymers based on vinylimidazoles are prepared by free-radical precipitation polymerization in an organic solvent or solvent mixture which contains no aromatic groups and, apart from oxygen, no heteroatom.

Description

BASF Aktiengesellschaft 940188 O.Z. OOSO/44957 The preparation of polymers based on 1-vinylimidazoles The present invention relates to a novel process for preparing 5 polymers ~ased on l-vinylimidazole by precipitation polymeriza-tion in the presence of compounds which form free radicals.

1-Vinylimidazoles are normally polymerized in aqueous or ethan-olic solution. To prepare higher molecular weight or crosslinked lO polymers or special copolymers it is frequently more favorable to use the precipitation polymerization method.

EP-A 162 388 discloses the preparation of 1-vinylimidazole copolymers by precipitation polymerization in benzene.

Furthermore, A. Chapiro et al., Eur. Polym. J., 24 (1988), 1019 describe the precipitation polymerization of 1-vinylimidazole in benzene, toluene or tetrachloromethane. The preparation of copolymers of 1-vinylimidazole and 4-aminostyrene by precipita-20 tion polymerization in benzene is described by R.F.C. Bay et al.,Polymer, 32 (1991), 2456.

The polyvinylimidazoles prepared in tetrachloromethane have, how-ever, only low molecular weights, while the polymers obtained in 25 benzene or toluene result as crosslinked gels which are difficult to work up.

An additional disadvantage of this known process is that the solvents used are toxicologically very objectionable.
It is an object of the present invention to find a process which allows the use of toxicologically less objectionable reaction media.

35 We have found that this object is achieved by a process (a)-10-100% by weight of a compound of the general formula I

IRl H2C=CH-N ~ N
,~

BASF AXtiengesellschaft 940188 O.Z. 0050/44957 ~ -- 21~1770 where Rl, R2 and R3 are identical or different and each is hydrogen, Cl-Cl8-alkyl or phenyl, (b) 0-90% by weight of another monoethylenically unsaturated monomer capable of free-radical copolymerization, and (c) 0-20% by weight of a monomer which contains at least two non-conjugated ethylenic double bonds, 10 in the presence of compounds which form free radicals, wherein the polymerization is carried out in an organic solvent or solvent mixture which contains no aromatic groups and, apart from oxygen, no heteroatom and in which the resulting polymer is of low solubility or insoluble.
Suitable monomers (a) are vinylimidazoles of the formula I

Rl 20 H2C=C~-N ~ N
,1=1~

25 where Rl, R2 and R3 are identical or different and are each hydro-gen, Cl-Cl8-alkyl or phenyl, for example 1-vinylimidazole, 2-meth-yl-1-vinylimidazole, 2-ethyl-1-vinylimidazole, 2-propyl-1-vinyl-imidazole, 2-butyl-1-vinylimidazole, 2,4-dimethyl-1-vinylimid-azole, 2,5-dimethyl-1-vinylimidazole, 2-ethyl-4-methyl-1-vinyl-30 imidazole, 2-ethyl-5-methyl-1-vinylimidazole, 2,4,5-trimethyl-l-vinylimidazole, 4,5-diethyl-2-methyl-1-vinylimidazole, 4-methyl-1-vinylimidazole, 4-ethyl-1-vinylimidazole, 4,5-dime-thyl-l-vinylimidazole, 5-methyl-1-vinylimidazole, 2,4,5-tri-ethyl-l-vinylimidazole, 2-phenyl-1-vinylimidazole, 2-undecyl-1-35 vinylimidazole or 2-stearyl-1-vinylimidazole. It is also possible to use mixtures of said monomers in any desired ratios. Monomers of group ~a) which are preferably used are l-vinylimidazole, 2-methyl-1-vinylimidazole, 4(5)-methyl-1-vinylimidazole, 2-ethyl-1-vinylimidazole and 2-ethyl-4(5)-methyl-1-vinylimida-40 zole. 1-Vinylimidazole and 2-methyl-1-vinylimidazole are very particularly preferred. The monomers are used in amounts of 10-100% by weight, preferably 25-100% by weight.

Suitable monomers (b) are further monoethylenically unsaturated 45 monomers capable of free-radical copolymerization, or mixtures thereof, for example N-vinyllactams such as N-vinylpyrrolidone and N-vinylcaprolactam, N-vinyloxazolidinone, N-vinyltriazole, BASF Aktiengesellschaft 940188 O.Z. 0050/44957 -- 21~1770 N-vinyl-N-methylacetamide, (meth)acrylic esters such as methyl, ethyl, hydroxyethyl, propyl, hydroxypropyl, butyl, ethylhexyl, decyl, lauryl, i-bornyl, cetyl, palmityl, phenoxyethyl or stearyl acrylate or the corresponding methacrylates, (meth)acrylamides 5 such as acrylamide, N-methylolacrylamide, N,N-dimethylamino-propylacrylamide, N-tert-butylacrylamide, N-tert-octylacrylamide, N-undecylacrylamide or the corresponding methacrylamides, vinyl esters with 2-30, in particular 2-14, carbon atoms in the mole-cule such as vinyl acetate, vinyl propionate, vinyl laurate, 10 vinyl neooctanoate, vinyl neononanoate, vinyl neodecanoate, sty-rene, vinyltoluene, ~-methylstyrene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid or their anhydrides, 2-acryl-amido-2-methylpropanesulfonic acid, acrylic esters having a basic 15 nitrogen atom such as diethylaminoethyl acrylate, dimethylamino-ethyl acrylate, dimethylaminopropyl acrylate or the corresponding methacrylates, 2-vinylpyridine, 4-vinylpyridine. Particularly preferred are N-vinylpyrrolidone, N-vinylcaprolactam, alkyl (meth)acrylates, vinyl acetate, styrene, acrylic acid, meth-20 acrylic acid, maleic acid and monomers which have a basic nitro-gen atom. N-Vinylpyrrolidone is very particularly preferred. The monomers are used in amounts of 0-90% by weight, preferably 0-75%
by weight.

25 Suitable monomers (c) are those compounds which are capable of free-radical copolymerization and which contain at least two non-conjugated ethylenic double bonds in the molecule. Examples of suitable monomers (c) are diacrylates or dimethacrylates or at least dihydric saturated alcohols, eg. ethylene glycol diacry-30 late, ethylene glycol dimethacrylate, 1,2-propylene glycol diacrylate, 1,2-propylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 3-methylpentanediol diacrylate and 35 3-methylpentanediol dimethacrylate. The acrylates and meth-acrylates of alcohols with more than 2 OH groups can also be used as monomers (c), eg. trimethylolpropane triacrylate or tri-methylolpropane trimethacrylate. Also suitable are diacrylates or dimethacrylates of polyethylene glycols or polypropylene glycols 40 with molecular weights of, in each case, 100-9000. Polyethylene glycols and polypropylene glycols used to prepare the diacrylates or dimethacrylates preferably have a molecular weight of, in each case, 200-2000. Apart from the homopolymers of ethylene oxide and propylene oxide it is also possible to use block copolymers of 45 ethylene oxide and propylene oxide or copolymers of ethylene oxide and propylene oxide which contain the ethylene oxide and propylene oxide units in random distribution. The oligomers of BASF Aktiengesellschaft 940188 O.Z. 0050/44957 4 21S177~
ethylene oxide and propylene oxide are also suitable for pre-paring the crosslinkers, eg. diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacry-5 late and/or tetraethylene glycol dimethacrylate. Also suitable ascrosslinkers are vinyl esters of ethylenically unsaturated C3-C6-carboxylic acids, eg. vinyl acetate, vinyl methacrylate or vinyl itaconate. Also suitable as crosslinkers are vinyl esters of saturated carboxylic acids containing at least 2 carboxyl 10 groups, and di- and polyvinyl ethers of at least dihydric alcohols, eg. divinyl adipate, butanediol divinyl ether and trimethylolpropane trivinyl ether as well as acrylamides or methacrylamides of at least difunctional saturated amines such as methylenebis(acrylamide) or ethylenebis(methacrylamide). Further 15 suitable monomers (c) are allyl esters of ethylenically unsaturated carboxylic acids, eg. allyl acrylate and allyl meth-acrylate, allyl ethers of polyhydric alcohols, eg. pentaery-thritol triallyl ether, triallylsucrose and pentaallylsucrose.
Also suitable as crosslinkers are methylenebismethacrylamide, 20 divinylethyleneurea, divinylpropyleneurea, divinylbenzene, divi-nyldioxane, tetraallylsilane, tetravinylsilane, 1,7-octadiene, diallyl phthalate, trivinylcyclohexane, 1,9-decadiene or triallyltriazinetrione. Divinylethyleneurea, allyl methacrylate and diacrylates and dimethacrylates of at least dihydric alcohols 25 are particularly preferred.

In the case where copolymerization of the crosslinking monomers (c) is desired, they are used in amounts of 0.01-20% by weight, preferably 0.02-15% by weight, particularly preferably 0.1-8% by 30 weight.

The polymerization is carried out as precipitation polymerization in a solvent in which the monomers are soluble and the resulting polymers-are of low solubility or insoluble. The solvents used 35 according to the invention are organic solvents which have no aromatic groups and, apart from oxygen, contain no heteroatom.
Suitable and preferred solvents are those selected from the group consisting of saturated hydrocarbons with 5-12 carbon atoms, dialkyl ethers with 2-12 carbon atoms, the C3-Cl2-ketones and 40 C1-C22-alkyl esters of Cl-C22-carboxylic acids.

Examples of suitable hydrocarbons are pentane, cyclopentane, hex-ane, cyclohexane, methylcyclohexane, heptane, octane or iso-octane. Examples of suitable ethers are dimethyl ether, diethyl 45 ether, diamyl ether, tert-butyl methyl ether or dibutyl ether.
Suitable ketones are dialkyl ketones such as acetone, methyl ethyl ketone, diethyl ketone or methyl amyl ketone. The reaction BASF Aktiengesellschaft 940188 O.Z. 0050/44957 215i770 can also be carried out in alcohols such as n-butanol, 2-meth-yl-2-butanol, isoamyl alcohol, hexanol, cyclohexanol, octanol or decanol. Examples of suitable alkyl carboxylates are ethyl for-mate, methyl acetate, ethyl acetate, isopropyl acetate, isobutyl 5 acetate, stearyl acetate, 2-ethylhexyl 2-ethylhexanoate, methyl stearate, isopropyl myristate or isopropyl palmitate. It is also possible to use mixtures of said solvents.

Preferred solvents are pentane, hexane, heptane, cyclohexane, 10 methylcyclohexane, tert-butyl methyl ether, acetone, methyl ethyl ketone, n-butanol, methyl acetate, ethyl acetate, isopropyl ace-tate or isobutyl acetate. Heptane, cyclohexane or ethyl acetate are very particularly preferred. The amount of solvent is prefer-ably chosen so that the reaction mixture can be stirred during 15 the polymerization. The solids content of the reaction mixture is preferably in the range from 10 to 40% by weight.

It is also possible to add to the mixture small amounts of up to 10% by weight, preferably up to 4% by weight, particularly pre-20 ferably up to 2% by weight, based on the monomers used, of water,methanol, ethanol, isopropanol, protective colloids or emulsi-fiers in order to exert a beneficial influence on the morphology of the products or the viscosity of the reaction mixture. It is also possible in this way to have a beneficial influence on other 25 properties of the copolymers, eg. the residual contents of monomers or solvents during or after a workup step. Examples of suitable protective colloids are polyvinylpyrrolidones, partially hydrolyzed polyvinyl acetates, cellulose ethers or copolymers of N-vinylpyrrolidone and vinyl acetate. The amounts of water and/or 30 emulsifiers present during the precipitation polymerization, if used, are only such that the mixture of all the components still appears homogeneous before the polymerization starts.

The molecular weight of the copolymers can, if desired, be 35 reduced by adding regulators to the polymerizing mixture, for example halogen compounds such as tetrachloromethane, chloroform, bromotrichloromethane, allyl compounds such as allyl alcohol or 2,5-diphenyl-1-hexene, aldehydes, formic acid or formic esters.
Polymerization regulators which contain sulfur in bound form are 40 preferably used. Examples of compounds of this type are inorganic bisulfites, sulfites, disulfites and dithionites or organic sul-fides, disulfides, polysulfides, sulfoxides, sulfones and mer-capto compounds. Compounds which are particularly preferably used are mercapto alcohols, mercapto carboxylic acids and mercapto-45 alkanes with from two to 30 carbon atoms in the molecule, forexample 2-mercaptoethanol, 3-mercaptopropanol, 3-mercapto-1,2-propanediol, 4-mercaptobutanol, cysteine, mercaptoacetic acid, BASF AXtiengesellschaft 940188 O.Z. 0050/44957 . ~_ 3-mercaptopropionic acid, mercaptosuccinic acid, n-butyl mercap-tan, n-hexyl mercaptan, n-dodecyl mercaptan or tert-dodecyl mer-captan. If polymerization regulators are used they are employed in amounts of 0.1-15, preferably 0.1-5, % of the weight of the 5 monomers present in the polymerization.

The monomers are subjected to free-radical polymerization, ie.
compounds which form free radicals under the polymerization conditions are needed to initiate the homo- or copolymerization.
10 Initiators which form free radicals are all conventional peroxy and azo compounds, for example peroxides, hydroperoxides and per-oxy esters such as hydrogen peroxide, dibenzoyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, diacyl perox-ides such as dilauroyl peroxide, didecanoyl peroxide and diocta-lS noyl peroxide or peresters such as tert-butyl peroctanoate, tert-butyl perpivalate, tert-amyl perpivalate or tert-butyl perneode-canoate, as well as azo compounds such as 2,2'-azobis(2-amidino-propane) dihydrochloride, 2,2'-azobis[2-(2-imidazolinyl)propane]
dihydrochloride, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azo-20 bis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), dimethyl 2,2'-azobis(isobuty-rate), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis(2,4,4-trime-thylpentane) or 2-(carbamoylazo)isobutyronitrile. It is also, of 25 course, possible to use mixtures of initiators or the known redox initiators. Examples of redox initiators are combinations of at least one peroxo compound such as potassium, sodium or ammonium persulfate, sodium hypochlorite, sodium perborate, sodium percar-bonate, hydrogen peroxide, tert-butyl hydroperoxide or di-tert-30 butyl peroxide and at least one reducing agent such as ascorbicacid, lactic acid, citric acid, sodium sulfite or sodium bisul-fite, acetone sulfite, sodium dithionite, sodium N-hydroxymethyl-sulfinate or a tertiary amine such as dimethylaniline. The initi-ators are employed in conventional amounts, eg. 0.1-6% of the 35 weight of the monomers to be polymerized.

The precipitation polymerization is normally carried out under inert gas atmosphere. The polymerization can be carried out, for example, by introducing all the components present during the 40 polymerization into a polymerization vessel, starting the reac-tion and, if necessary, cooling the reaction mixture in order to control the temperature. However, it is also possible to start the polymerization with only a few or a portion of the components and to meter the remainder of the components in continuously or 45 batchwise, singly or together, over periods which may differ according to circumstances, depending on the progress of the polymerization. However, it is also possible for initially only BASF Aktiengesellschaft 940188 O.Z. 0050/44957 7 21517~0 the diluent to be present and for the monomers and the polymer-ization initiators to be introduced separately, batchwise or con-tinuously.

5 The temperature during the polymerization is generally from 40 to 160, preferably from 50 to 120 C. It can be controlled variously during the reaction by a program. The polymerization is prefer-ably carried out under atmospheric pressure but can also be car-ried out under reduced or elevated pressure. If the polymeriza-10 tion temperature is above the boiling point of the solvent, thepolymerization is carried out in pressure-tight equipment under pressures up to 8 bar.

The polymerization process is preferably controlled so that the 15 resulting copolymer is in the form of a fine-particle powder. The average particle size of the polymer powder is 0.01-500, prefer-ably 0.5-200, ~m. After the polymerization, the crosslinked copo-lymer is separated from the other components of the reaction mix-ture, for example by filtration, decantation or centrifugation.
20 The resulting powder can be subjected, if necessary, to further suitable separating, washing, drying or m; 11; ng processes.

Those polymers obtained by the process according to the invention which are soluble in water or another suitable solvent preferably 25 have K values (determined by the method of H. Fikentscher, Cellu-lose-Chemie, 13 (1932) 58-64 and 71-74 in aqueous solution at 25 C
and a polymer concentration of 1% by weight) in the range from 10 to 200.

30 After the reaction, the polymers can be converted in the same medium, or after isolation in another medium, by a suitable reagent to a quaternized form. Suitable for the quaternization are, for example, alkyl halides having 1-18 carbon atoms in the moleculej eg. methyl chloride, ethyl chloride, propyl chloride, 35 hexyl chloride, dodecyl chloride or lauryl chloride, as well as benzyl halides such as benzyl chloride. The corresponding iodine or bromine compounds are also, of course, suitable. Further suitable quaternizing agents are dialkyl sulfates, in particular dimethyl sulfate and diethyl sulfate. In some cases it is also 40 sufficient to convert the polymers into the salt form by treat-ment with an acid. The quaternization can take place completely or partially.

The polymers obtained according to the invention can be used, for 45 example, for binding bile acids in the blood to reduce the cho-lesterol level or for selective removal of heavy metal ions from solutions, and as auxiliaries in cosmetic formulations, for BASF Aktiengesellschaft 940188 O.Z. 0050/44957 _ 8 215177~
example to adjust the rheological behavior. The polymers accord-ing to the invention can also be used as detergent additive to inhibit transfer of dyes during the washing process.
5 Examples Example 1 400 g of ethyl acetate, 100 g of N-vinylimidazole, 10 g of divi-10 nylethyleneurea and 1 g of tert-butyl perpivalate were stirred at 72 C in a 2000 ml flask which was equipped with a stirrer, reflux condenser, thermometer and an apparatus for working under protec-tive gas for 2 hours. The resulting product was filtered off on a suction funnel, washed with 100 g of ethyl acetate and dried in a 15 vacuum oven at 50 C for 8 hours. 111 g of a white powder with an apparent density of 67 g/100 ml and an average particle size of 124 ~m were obtained.

Example 2 600 g of cyclohexane, 100 g of N-vinylimidazole, 10 g of divinylethyleneurea and 1 g of azobisisobutyronitrile were stirred at 77 C in a 2000 ml flask which was equipped with a stirrer, reflux condenser, thermometer and an apparatus for 25 working under protective gas for 4.5 hours. The resulting product was filtered off on a suction funnel, washed with 200 g of cyclo-hexane and dried in a vacuum oven at 50 C for 8 hours. 109 g of a white powder with an apparent density of 6 g/100 ml and an average particle size of 30 ~m were obtained.
Example 3 400 g of methyl ethyl ketone, 100 g of N-vinylimidazole, 10 g of allyl methacrylate and 1 g of 2,2'-azobis(2-methylisobutyroni-35 trile) were stirred at 74 C in a 2000 ml flask which was equippedwith a stirrer, reflux condenser, thermometer and an apparatus for working under protective gas for 2.5 hours. The resulting product was filtered off on a suction funnel, washed with 100 g of methyl ethyl ketone and dried in a vacuum oven at 50 C for 40 8 hours. 106 g of a white powder with an apparent density of 10 g/100 ml and an average particle size of 11 ~m were obtained.

Example 4 45 400 g of cyclohexane, 50 g of N-vinylimidazole, 50 g of N-vinyl-pyrrolidone and 2 g of divinylethyleneurea were heated to 77 C in a 2000 ml flask which was equipped with a stirrer, reflux . BASF Aktiengesellschaft 940188 O.Z. 0050/44957 - 9 21~1770 condenser, thermometer and an apparatus for working under protec-tive gas. As soon as this temperature was reached, 0.5 g of dime-thyl 2,2'-azobisisobutyrate was added dropwise over the course of 2 hours. The mixture was then stirred at this temperature for a 5 further 4 hours. The resulting product was filtered off on a suc-tion funnel, washed with 200 g of cyclohexane and dried in a vac-uum oven at 50 C for 8 hours. 101 g of a white powder with an apparent density of 32 g/100 ml and an average particle size of 12 ~m were obtained.
Example 5 400 g of cyclohexane were heated to 77 C in a 1000 ml flask which was equipped with a stirrer, reflux condenser, thermometer and an 15 apparatus for working under protective gas. As soon as this tem-perature was reached, 70 g of 1-methyl-2-vinylimidazole and 0.7 g of mercaptoethanol were added dropwise over the course of 1 hour and, in parallel to this, 0.4 g of azobisisobutyronitrile in 20 ml of cyclohexane was added dropwise over the course of 20 2 hours. The mixture was then stirred at this temperature for a further 4 hours. The resulting product was filtered off on a suc-tion funnel, washed with 200 g of cyclohexane and dried in a vac-uum oven at 50 C for 8 hours. 68 g of a white powder were ob-tained. A solution of the polymer in water was clear and color-25 less and had a K value of 26.2 (determined by the method ofH. Fikentscher, Cellulose-Chemie 13 (1932) 58-64 and 71-74 at 25 C
and a polymer concentration of 1% by weight).

Example 6 400 g of ethyl acetate, 100 g of N-vinylimidazole and 17.3 g of stearyl acrylate were heated to 70 C in a 2000 ml flask which was equipped with a stirrer, reflux condenser, thermometer and an apparatus for working under protective gas. As soon as this 35 temperature was reached, 1 g of tert-butyl perpivalate in 20 ml of cyclohexane was added dropwise over the course of 2 hours. The mixture was then stirred at this temperature for a further 4 hours. The resulting product was filtered off on a suction funnel, washed with 200 g of cyclohexane and dried in a vacuum 40 oven at 50 C for 8 hours. 116 g of a white powder were obtained. A
solution of the polymer in ethanol had a K value of 31 (deter-mined by the method of H. Fikentscher, Cellulose-Chemie 13 (1932) 58-64 and 71-74 at 25 C and a polymer concentration of 1% by weight).

BASF Aktiengesellschaft 940188 O.Z. 0050/44957 ~` 215177~
Example 7 15 g of the polymer powder from Example 1 were dispersed in 200 g of ethanol and, at 40 C, 30 g of dimethyl sulfate were added over 5 the course of 30 minutes. The mixture was subsequently heated to 60 C and stirred at this temperature for a further 3 hours. The product was then filtered off on a suction funnel, washed with 100 ml of water, stirred twice in 400 ml of a 10~ strength aqueous NaCl solution for 15 minutes, again filtered off with 10 suction, washed with twice 100 ml of water and dried in a vacuum oven at 50 C for 8 hours. 21 g of a polymer powder with an exchange capacity of 5.8 meq/g were obtained.

Claims

1. A process for preparing polymers based on vinylimidazoles by polymerizing a monomer mixture composed of (a) 10-100% by weight of a compound of the general formula I

I

where R1, R2 and R3 are identical or different and each is hydrogen, C1-C18-alkyl or phenyl, (b) 0-90% by weight of another monoethylenically unsaturated monomer capable of free-radical copolymerization, and (c) 0-20% by weight of a monomer which contains at least two non-conjugated ethylenic double bonds, in the presence of compounds which form free radicals, wherein the polymerization is carried out in an organic solvent or solvent mixture which contains no aromatic groups and, apart from oxygen, no heteroatom and in which the resulting polymer is of low solubility or insoluble.

2. A process as claimed in claim 1, wherein the organic solvent or solvent mixture is selected from the group of saturated hydrocarbons with 5-12 carbon atoms, of dialkyl ethers with 2-12 carbon atoms, of C4-C16-alkanols, of C3-C12-ketones and of C1-C22-alkyl esters of C1-C22-carboxylic acids.

3. A process as claimed in claim 1, wherein heptane, cyclohexane or ethyl acetate is used as organic solvent.