DE10117273A1 - Production of hydroxyalkyl carboxylate ester for use, e.g. as raw material for varnish, involves reacting carboxylic acid, e.g. acrylic acid, with alkylene oxide in presence of iron-containing multi-metal cyanide catalyst - Google Patents

Abstract

Special multi-metal cyanide compounds in which at least one of the metals is iron(II) or iron(III) (other than the usual alkali or alkaline earth metal or quaternary ammonium ion) are used as catalysts in a method for the production of hydroxyalkyl esters by reacting carboxylic acids with alkylene oxides. A method for the production of hydroxyalkyl esters of carboxylic acids involves reacting carboxylic acids with alkylene oxides in presence of multi-metal cyanide catalysts of formula (I); M<3>zM<1>a(M<2>(CN)b(A)c)d.fM<1>gXn.mM<3>pYq.h(H2O).eL.kP (I); M<1> = metal ion(s) selected from Zn<2+>, Fe<2+>, Fe<3+>, Co<3+>, Ni<2+>, Mn<2+>, Co<2+>, Sn<2+>, Pb<2+>, Mo<4+>, Mo<6+>, Al<3+>, V<4+>, V<5+>, Sr<2+>, W<4+>, W<6+>, Cr<2+>, Cr<3+>, Cd<2+>, Hg<2+>, Pd<2+>, Pt<2+>, V<2+>, Mg<2+>, Ca<2+>, Ba<2+> and Cu<2+>; M<2> = metal ion(s) selected from Fe<2+>, Fe<3+>, Co<2+>, Co<3+>, Mn<2+>, Mn<3+>, V<4+>, V<5+>, Cr<2+>, Cr<3+>, Rh<3+>, Ru<2+> and Ir<3+>, where M<1> and M<2> may be the same or different and at least one of these is Fe<2+> or Fe<3+>; M<3> = metal ion(s) selected from Li<+>, Na<+>, K<+>, Rb<+>, Cs<+>, Mg<2+>, Ca<2+>, Sr<2+> and Ba<2+> or ammonium ions of formula R<1>R<2>R<3>R<4>N<+>; R<1>-R<4> = 1-6C hydrocarbyl A, X, Y = halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, nitrate, nitrosyl, hydrogen sulfate, phosphate, dihydrogen phosphate, hydrogen phosphate or hydrogen carbonate ions; L = a water-miscible ligand selected from alcohols, aldehydes, ketones, polyethers, esters, polyesters, polycarbonate, ureas, amides, prim., sec. and tert. amines, ligands with pyridine nitrogen, nitriles, sulfides, phosphides, phosphites, phosphanes, phosphonates and phosphates; e, f, k, h, m = 0 or more (fraction or integer); P = an organic additive; a, b, c, d, g, n, p, q, z = numbers compatible with the electroneutrality of (I), where c or z or c and z may be zero.

Description

The present invention relates to a process for the preparation of hydroxyal kylcarboxylic acid esters from carboxylic acids and alkylene oxides, where for the implementation a multimetal cyanide compound is used as a catalyst, and the use of the hydroxyalkyl carboxylic acid prepared according to the invention reester than paint raw materials.

Process for the preparation of hydroxyalkyl carboxylic acid esters using of catalysts are known per se. The type of catalysts used varies greatly.

DE 12 48 660, for example, describes a process for the preparation of Gly colmonoesters of carboxylic acids and alkylene oxides in the presence of thi described ether.

US 4,970,333 describes the preparation of esters via the reaction of a Epoxy with a carboxylic acid in the presence of a strongly basic ion exchange shear resin. In particular, acrylic resins are used.

US 4,910,329 relates to a process for the preparation of hydroxyalkyl esters acrylic and methacrylic acid using heterogeneous amorphous catalysts,  where the catalysts used here are Metallphos phate acts.

DE 12 55 104 describes a process for the preparation of β-hydroxyalkyl monoesters of acrylic and methacrylic acid using iron acrylate or iron methacrylate catalysts.

According to US 3,059,024, β-hydroxyalkyl monoesters of acrylic and Me thacrylic acid also from the carboxylic acid and ethylene or propylene oxide under Use of tetraalkylammonium salts as a catalyst.

No. 2,484,487 describes a process for the preparation of glycol monoesters described that the reaction of an alkylene oxide with acrylic or methac ryl acid in the presence of a tertiary amine as a catalyst.

In the known methods, there are a number of disadvantages, such as wise unsatisfactory sales, too low selectivity, polymers of the car bonic acid, if it is unsaturated carboxylic acids, as well as side crack tion when processing the products. In addition, some become volatile Catalyst components used and the catalyst-containing distillation back stands are difficult to dispose of.

Metal cyanide compounds are known from the prior art as catalysts for Polyadditions, especially for ring-opening polymerizations of alkylene oxides known, such as in EP-A 0 892 002, EP-1 0 862 977 and in EP-A 0 755 716.

WO 99/10407 describes a process for the preparation of polyethers Hydroxy functionality and unsaturated groups are described. The synthesis he follows the reactive water by oxyalkylation of an unsaturated monomer has fabric. The reaction takes place in the presence of a double metal cyanide  Catalyst, the production of which is described in more detail in US Pat. No. 5,545,601. in the Unsaturated carboxylic acid can also be used in the process described there be used as a monomer in the reaction with an alkylene oxide.

WO 99/10407 is on the synthesis of multiple alkoxylation products directed. Using the catalyses described there in the examples tors are polyethers and not the corresponding monoalkoxylation pro products of the starter molecules obtained. Another alkoxylation is easier rather than as the monoalkoxylation so that the monoalkoxylation product does not can be obtained selectively.

The object of the present invention was based on the prior art based, suitable catalysts for the reaction of carboxylic acids with Al Provide kylene oxides with which the desired hydroxyalkyl carboxylic acid reester, ie the monoalkoxylation products, with higher selectivity and under Avoidance of unwanted by-products can be produced.

According to the invention, this object is achieved using a method a multimetal cyanide compound of the general formula I as a catalyst solved.

Accordingly, the invention relates to a process for the preparation of hydroxyalkyl carboxylic acid esters comprising the reaction of at least one carboxylic acid with at least one alkylene oxide, a multimetal cyanide compound of the general formula I being used as catalyst for the reaction:

M ³ _z M ¹ _a [M ² (CN) _b (A) _c ] _d .fM ¹ _g X _n .mM ³ _p Y _q .h (H ₂ O) .eL.kP (I),

in the

• M ¹ at least one metal ion selected from the group consisting of Zn ²⁺ , Fe ²⁺ , Fe ³⁺ , Co ³⁺ , Ni ²⁺ , Mn ²⁺ , Co ²⁺ , Sn ²⁺ , Pb ²⁺ , Mo ⁴⁺ , Mo ⁶⁺ , Al ³⁺ , V ⁴⁺ , V ⁵⁺ , Sr ²⁺ , W ⁴⁺ , W ⁶⁺ , Cr ²⁺ , Cr ³⁺ , Cd ²⁺ , Hg ²⁺ , Pd ^{2 +} , Pt ²⁺ , V ²⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Cu ²⁺ ,
• M ² at least one metal ion selected from the group consisting of Fe ²⁺ , Fe ³⁺ , Co ²⁺ , Co ³⁺ , Mn ²⁺ , Mn ³⁺ , V ⁴⁺ , V ⁵⁺ , Cr ²⁺ , Is Cr ³⁺ , Rh ³⁺ , Ru ²⁺ , Ir ³⁺ ,
• M ¹ and M ^{2 are} identical or different and at least M ¹ or M ^{2 is} Fe ²⁺ or Fe ³⁺ ,
• - M ³ at least one metal ion selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Sr ²⁺ , ammonium ions of general formula R ¹ R ² R ³ R ^{4 is} N ⁺ , where R ¹ , R ² , R ³ and R ^{4 are} H or a hydrocarbon radical having 1 to 6 carbon atoms,
• - A, X and Y independently of one another are selected from the group Group consisting of halide, hydroxide, sulfate, carbonate, cy anide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, nitrate, Nitrosyl, hydrogen sulfate, phosphate, dihydrogen phosphate, hydro are gene phosphate or hydrogen carbonate,
• - L is a water-miscible ligand selected from the group pe, consisting of alcohols, aldehydes, ketones, ethers, polyes thern, esters, polyesters, polycarbonate, ureas, amides, pri mary, secondary and tertiary amines, ligands with pyridine Nitrogen, nitriles, sulfides, phosphides, phosphites, phosphines, Phosphonates and phosphates,  
• - k is a fractional or whole number greater than or equal to zero, and
• - P is an organic additive,
• - a, b, c, d, g, n, p, q and z are selected so that the electroneut rality of the compound (I) is guaranteed, wherein c or z or c and z can be 0,
• - e the number of ligand molecules a broken or whole Number is greater than 0 or 0,
• - f, k, h and m independently of one another a broken or whole Number greater than 0 or 0.

The following organic additives P are mentioned: polyether, polyester, polycarbonate te, polyalkylene glycol sorbitan esters, polyakylene glycol glycidyl ether, polyacryla mid, poly (acrylamide-co-acrylic acid), polyacrylic acid, poly (acrylamide-co- maleic acid), polyacrylonitrile, polyalkyl acrylates, polyalkyl methacrylates, polyvi nylmethyl ether, polyvinyl ethyl ether, polyvinyl acetate, polyvinyl alcohol, poly-N- vinyl pyrrolidone, poly (N-vinyl pyrrolidone-co-acrylic acid), polyvinyl methyl ketone, Poly (4-vinylphenol), poly (acrylic acid-co-styrene), oxazoline polymers, polyalkyls nimine, maleic and maleic anhydride copolymers, hydroxyethyl cellulo se, polyacetates, ionic surface and surface-active compounds, Bile acid or its salts, esters or amides, carboxylic acid esters more polyvalent Alcohols and glycosides.

The process according to the invention succeeds in hydroxyalkyl carboxylic acid esters starting from carboxylic acids and alkylene oxides by means of a vote of Temperature and pressure on a corresponding catalyst system in high To produce purity and with great selectivity without further alkoxylation of the products occurs.  

In a preferred embodiment, the invention relates to a process for the preparation of hydroxyalkyl carboxylic acid esters, one or more of the following properties being fulfilled:

• A) M ¹ is selected from the group Zn ²⁺ , Fe ²⁺ , Fe ³⁺ , Co ³⁺ , Ni ²⁺ , Mn ²⁺ , Co ²⁺ ;
• B) M ² is selected from the group Fe ²⁺ , Fe ³⁺ , Co ³⁺ ;
• C) M ³ is selected from the group Na ⁺ ; K ⁺ , ammonium ion of the general formula R ¹ R ² R ³ R ⁴ N ⁺ ;
• D) M ¹ or M ² is Fe ²⁺ or Fe ³⁺ .

In a further preferred embodiment of the present invention, both M ¹ and M ^{2 are} Fe ²⁺ or Fe ³ , in particular together with the further preferred metal ions mentioned under (A) to (C).

Particularly suitable as a catalyst in the context of the present invention For example, the following multimetal cyanide compounds have been found sen: iron blue pigments, iron cyan blue, Vossen-Blau®, Prussian blue, Berliner Blue, Bull blue, Milori blue, Paris blue.

By using the multimetal cyanide compounds according to the invention in which at least M ¹ or M ^{2 is} Fe ²⁺ or Fe ³⁺ , the desired monoalkoxylation products can be prepared with high selectivity. If multimetal cyanide catalysts which do not contain Fe ²⁺ or Fe ³⁺ are used under otherwise identical reaction conditions, multiple alkoxylation occurs.

The multimetal cyanide compounds are usually min least a metal salt with at least one cyanometal compound. Salts or acids, for example, can be used as the cyanometal compound become. In the method according to the invention, impurities interfere with Alkaline or alkaline earth metal salts are not, so that a complex and costly Cleaning of the catalysts is not necessary.

In a preferred embodiment, the invention relates to a method for Production of hydroxyalkyl carboxylic acid esters, the being used as a catalyst set multimetal cyanide compound is crystalline or partially amorphous.

It is possible in the context of the invention that a catalyst Precursor compound is produced, which is then, for example, by oxidation, Reduction, recrystallization or other reactions in the actually catalytic active connection is transferred. It is therefore within the scope of the present Er invention, for example, also conceivable that the precursor compound in the reacti is used and the actually catalytically active compound only in the reac tion medium is generated in the presence of the components to be reacted.

There is also the possibility of adding suitable substances, such as surface-active substances, the morphology of the multimetal cyanide Control particles so that an increased activity for the catalyzed reac tion is achieved.

In the context of the present invention, catalyst amounts of 0.001 up to 30% by weight, preferably from 0.01 to 10% by weight, particularly preferably 0.1 to 5 wt .-% or 0.2 to 3 wt .-%, each based on the amount of the set carboxylic acid used.  

In particular, the invention therefore relates to a method for producing Hydroxyalkyl carboxylic acid esters, the catalyst in amounts from 0.01 to 30 wt .-%, based on the amount of carboxylic acid used becomes.

In principle, all substituted and unsubstituted branched or unbranched carboxylic acids if the functional groups of the carboxylic acid are not the catalyzed Re affect action.

In the context of the present invention, preference is given to substituted or un substituted, saturated or unsaturated monocarboxylic acids with 3 to 22 C- Atoms, substituted or unsubstituted, saturated dicarboxylic acids with 2 to 36 C atoms, substituted or unsubstituted, unsaturated dicarboxylic acids with 4 up to 36 carbon atoms and substituted or unsubstituted aromatic mono- and Dicarboxylic acids used.

In a further embodiment, the invention accordingly relates to a method ren for the production of hydroxyalkyl carboxylic acid esters, the carboxylic acid is selected from the group consisting of substituted or unsubstituted, saturated or unsaturated monocarboxylic acids with 3 to 22 carbon atoms, substi tuated or unsubstituted, saturated dicarboxylic acids with 2 to 36 carbon atoms, substituted or unsubstituted, unsaturated dicarboxylic acids with 4 to 36 C- Atoms and substituted or unsubstituted aromatic mono- and dicar acids.

Particularly preferred carboxylic acids according to the invention are: un saturated substituted or unsubstituted monocarboxylic acids with 3 to 5 C- Atoms and unsaturated substituted or unsubstituted dicarboxylic acids with 4 up to 8 carbon atoms, for example acrylic acid, methacrylic acid or crotonic acid,  Fumaric acid, maleic acid or itaconic acid; saturated substituted or unsubsti tuiert monocarboxylic acids with 1 to 5 carbon atoms and saturated substituted or unsubstituted dicarboxylic acids with 2 to 5 carbon atoms, for example ants acid, acetic acid, propionic acid, pivalic acid, oxalic acid, malonic acid or Bern stone acid; saturated or unsaturated substituted or unsubstituted mono carboxylic acids with 6 to 22 carbon atoms, which also contain cycloaliphatic structural elements may have, for example hexanoic acid, heptanoic acid, cyclohexane carbon acid, 2-ethylhexanoic acid, capric acid (C10), myristic acid (C14), palmitic acid (C16), stearic acid (C18), oleic acid, behenic acid (C22); saturated or unsaturated substituted or unsubstituted dicarboxylic acids with 6 to 36 carbon atoms, the in particular have cycloaliphatic structural elements, for example Adi pinic acid, pimelic acid (C7), azelaic acid (C9), sebacic acid (C10), dimer fat acids with 36 carbon atoms; substituted or unsubstituted aromatic mono- and dicarboxylic acids, for example benzoic acid, phthalic acid, isophthalic acid, Terephthalic acid or naphthalene carboxylic acids.

The use of acrylic acid and methacrylic acid is particularly preferred. In a preferred embodiment, the invention therefore relates to a method for the preparation of hydroxyalkyl carboxylic acid esters, the carboxylic acid Ac is acrylic acid or methacrylic acid.

In principle, all alkylene oxides can be used for the process according to the invention are set that are known to the expert. In particular, are substituted or unsubstituted alkylene oxides with 2 to 24 carbon atoms, especially alkyls noxides with halogen, hydroxy, non-cyclic ether or ammonium substance tuenten. The following should be mentioned in particular: aliphatic 1,2-alkylene oxides with 2 to 4 C atoms, for example ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3- Butylene oxide or isobutylene oxide, aliphatic 1,2-alkylene oxides with 5 to 24 C Atoms, cycloaliphatic alkylene oxides, for example cyclopentene oxide, cyclo hexene oxide or cyclododecatriene (1,5,9) monoxide, araliphatic alkylene oxides, for example styrene oxide.  

Preferred substituted alkylene oxides are, for example, epichlorohydrin, E. pibromohydrin, 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 chloride.

For the process according to the invention, 1,2- Alkylene oxides with 2 to 4 carbon atoms used, in particular ethylene oxide or Propylene oxide.

In a preferred embodiment, the invention therefore relates to a method for the preparation of hydroxyalkyl carboxylic esters from a carboxylic acid and an alkylene oxide, the alkylene oxide being a 1,2-alkylene oxide with 2 to 4 carbon atoms Atoms.

Ethylene oxide or propylene oxide is particularly preferred as the alkylene oxide set.

According to the carboxylic acid and the alkylene oxide in one mole ratio of 1 to 0.4 to 1 to 10 used. One mole is particularly advantageous ratio of 1 to 1 to 1 to 1.5, in particular 1 to 1.03 to 1 to 1.2.

The reaction of the carboxylic acid with the alkylene oxide can be carried out as part of the lying invention are carried out at 20 to 200 ° C. A is preferred Temperature range from 40 to 150 ° C, especially from 50 to 100 ° C. The implementation tongue can be at atmospheric pressure or vacuum, as well as at high pressure, for example at a pressure of 0.8 to 50 bar, in particular be carried out at a pressure of 1 to 10 bar.  

The invention therefore also relates to a process for the preparation of hydroxyal kylcarboxylic acid esters, the temperature during the reaction of the carboxylic acid with the alkylene oxide is 50 to 100 ° C.

In a further embodiment, the invention relates to a method for manufacturing position of hydroxyalkyl carboxylic acid esters, wherein in the implementation of the Car bonic acid with the alkylene oxide there is a pressure of 1 to 10 bar.

In the process according to the invention, the implementation can be carried out in the sense of Batch process or carried out continuously. It can be in one Stirred reactor, tubular reactor, loop reactor, in a fixed bed reactor or in an egg be carried out in a fluidized bed reactor.

When reacting the carboxylic acid with an alkylene oxide, the subject known auxiliaries and additives can be added. In a preferred one Embodiment is the reaction of the carboxylic acid with the alkylene oxide in In the presence of at least one polymerization inhibitor. As a polyme Risk inhibitors can, for example, hydroquinone, hydroquinone mono methyl ether, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, nitrosoverbin such as isoacrylonitrite, nitrosodiphenylamine or N-nitroso cyclohexylhydroxylamine, methylene blue, phenothiazine, tannic acid or dipheny be used lamin. It is also within the scope of the present invention possible that two or more of these polymerization inhibitors are used the. The polymerization inhibitors are used in amounts of 10 to 10,000 ppm, in particular from 100 to 1000 ppm, in each case based on the carbon used acid, used.

Furthermore, within the scope of the present invention, additional small, safe proportionally acceptable proportions of molecular oxygen or nitrogen mo noxide can be used.  

It is not necessary for the process according to the invention to use solvents for the Implementation of the carboxylic acid to use with the alkylene oxide. But it is e equally possible, the process according to the invention in the presence of water or organic solvents such as aliphatic, cycloaliphatic or aromatic hydrocarbons, alcohols, ethers, acetals, ketones, Perform esters or cyclic carbonates.

The hydroxyalkyl carboxylic acid ester can be used in the context of the ver driving isolated for example by distillation from the reaction mixture the. The catalyst can then be in the form of the distillation residue or after Separation from the distillation residue can be used again. However, it is it is also possible to separate the catalyst before the distillation. The Separation can take place, for example, by filtration, in particular depths filtration, cross-flow filtration, membrane filtration or ultrafiltration.

The hydroxyalkyl carboxylic acid esters produced according to the invention can be used for for example as paint raw materials or as monomers for radical homo- or Copolymerizations are used. Therefore, the present invention relates also the use of the hydroxyalkyl carboxylic acid prepared according to the invention reester as paint raw material.

The invention is explained in more detail below with the aid of examples.

Examples Production Example 1 catalyst synthesis

To 950 g of a 20% aqueous solution of potassium hexacyanoferrate (II) - Trihydrate were stirred 540 g of a 30% aqueous solution of egg Sen (III) chloride hexahydrate added dropwise. It was stirred for 30 minutes and then suctioned off via a filter funnel. The filter residue was twice  washed with water and once with methanol by an appropriate Slurry was stirred for 30 minutes and then suction filtered. To the last suction was dried at 50 ° C in a vacuum. There were 178 g of a black powder.

example 1 Synthesis of 2-hydroxyethyl acrylate

In a stirrer equipped with a dry ice cooler, under a nitrogen atmosphere of 15.2 g of catalyze enriched with 2% by volume of oxygen sator from Example 1 in 504.4 g of acrylic acid, stabilized with 200 ppm of hydroquinone monomethyl ether and 500 ppm phenothiazine, at 50 to 70 ° C over a period added in 1.5 hours with 339 g of gaseous ethylene oxide. It was 3.5 hours the stirred. Gas chromatographic analysis of the crude product showed that a mixture of 91.3% 2-hydroxyethyl acrylate, 6.0% diethylene glycol monoac rylate and 0.5% triethylene glycol monoacrylate in addition to 0.5% acrylic acid.

Comparative Example 1 catalyst synthesis

In a stirred tank with a volume of 8001, equipped with a slant blade turbine, dip tube for dosing, pH electrode, conductivity measuring cell and scattered light probe, 370 kg of aqueous hexacyanocobaltoic acid (cobalt Content: 9 g / l cobalt) and heated to 50 ° C. with stirring. Subsequently 209.5 kg of aqueous zinc acetate dihydrate were stirred (stirring power 1 W / l) Solution (zinc content: 2.7% by weight), which was also heated to 50 ° C, in added within 50 min. Then 8 kg of Pluronic PE 6200 (BASF AG) and 10.7 kg of water while stirring. Then 67.5 kg aqueous zinc acetate dihydrate solution (zinc content: 2.7% by weight) with stirring  (Stirring power 1 W / l) metered in at 50 ° C within 20 min. The suspension was stirred at 50 ° C until the pH dropped from 3.7 to 2.7 was and remained constant. The precipitate suspension obtained in this way was then used filtered off by a filter press and washed in the filter press with 400 l of water rule.

Oxethylation of acrylic acid

In an analogous procedure to Example 1, instead of a Ka according to the invention Talysators not according to the invention as described in the comparative example NEN prepared catalyst used.

The dosage of only 198 g of ethylene oxide required 3 hours before the ethylene oxide uptake stagnated. The gas chromatographic analysis showed in addition 45.2% residual acrylic acid 43.5% 2-hydroxyethyl acrylate, and - despite the low Sales - already 3.7% diethylene glycol monoacrylate and 0.3% triethylene glycol colmonoacrylat.

Claims (9)

1. A process for the preparation of hydroxyalkyl carboxylic acid esters comprising the reaction of at least one carboxylic acid with at least one alkylene oxide, a multimetal cyanide compound of the general formula I being used as the catalyst for the reaction:
M ³ _z M ¹ _a [M ² (CN) _b (A) _c ] _d .fM ¹ _g X _n .mM ³ _p Y _q. h (H ₂ O) .eL.kP (I),
in the

• M ¹ at least one metal ion selected from the group consisting of Zn ²⁺ , Fe ²⁺ , Fe ³⁺ , Co ³⁺ , Ni ²⁺ , Mn ²⁺ , Co ²⁺ , Sn ²⁺ , Pb ²⁺ , Mo ⁴⁺ , Mo ⁶⁺ , Al ³⁺ , V ⁴⁺ , V ⁵⁺ , Sr ²⁺ , W ⁴⁺ , W ⁶⁺ , Cr ²⁺ , Cr ³⁺ , Cd ²⁺ , Hg ²⁺ , Pd ^{2 +} , Pt ²⁺ , V ²⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Cu ²⁺ ,
• M ² at least one metal ion selected from the group consisting of Fe ²⁺ , Fe ³⁺ , Co ²⁺ , Co ³⁺ , Mn ²⁺ , Mn ³⁺ , V ⁴⁺ , V ⁵⁺ , Cr ²⁺ , Is Cr ³⁺ , Rh ³⁺ , Ru ²⁺ , Ir ³⁺ ,
• M ¹ and M ^{2 are} identical or different and at least M ¹ or M ^{2 is} Fe ²⁺ or Fe ³⁺ ,
• - M ³ at least one metal ion selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Sr ²⁺ , ammonium ions of the general Formula R ¹ R ² R ³ R ^{4 is} N ⁺ , where R ¹ , R ² , R ³ and R ^{4 are} H or a hydrocarbon radical having 1 to 6 carbon atoms,
• - A, X and Y independently of one another an anion selected from the group consisting of halide, hydroxide, sulfate, carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, nitrate, nitrosyl, hydrogen sulfate, phosphate, dihydrogen phosphate, hydro are gene phosphate or hydrogen carbonate,
• L is a water-miscible ligand, selected from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, polyesters, polycarbonate, ureas, amides, primary, secondary and tertiary amines, ligands with pyridine Nitrogen, nitriles, sulfides, phosphides, phosphites, phosphines, phosphonates and phosphates,
• - k is a fractional or whole number greater than or equal to zero, and
• - P is an organic additive,
• a, b, c, d, g, n, p, q and z are selected so that the electroneutrality of the compound (I) is ensured, where c or z or c and z can be 0,
• e the number of ligand molecules is a fractional or whole number greater than 0 or 0,
• - f, k, h and m are independently a fractional or whole number greater than 0 or 0.

2. A process for the preparation of hydroxyalkyl carboxylic acid esters according to claim 1, one or more of the following properties being fulfilled:

• A) M ¹ is selected from the group Zn ²⁺ , Fe ²⁺ , Fe ³⁺ , Co ³⁺ , Ni ²⁺ , Mn ²⁺ , Co ²⁺ ;
• B) M ² is selected from the group Fe ²⁺ , Fe ³⁺ , Co ³⁺ ;
• C) M ³ is selected from the group Na ⁺ , K ⁺ , ammonium ion of the general formula R ¹ R ² R ³ R ⁴ N ⁺ ;
• D) M ¹ or M ² is Fe ²⁺ or Fe ³⁺ .

3. A process for the preparation of hydroxyalkyl carboxylic acid esters according to one of claims 1 or 2, wherein both M ¹ and M ^{2 is} Fe ²⁺ or Fe ³⁺ . 4. A process for the preparation of hydroxyalkyl carboxylic acid esters according to a of the preceding claims, wherein the multimetal cyanide compound kri is stallin. 5. A process for the preparation of hydroxyalkyl carboxylic acid esters of the preceding claims, wherein the catalyst in amounts of 0.01 to 30 wt .-% based on the amount of carboxylic acid is used. 6. A process for the preparation of hydroxyalkyl carboxylic acid esters of the preceding claims, wherein the carboxylic acid is acrylic acid or Me is thacrylic acid.   7. Process for the preparation of hydroxyalkyl carboxylic acid esters according to a of the preceding claims, wherein the alkylene oxide ethylene oxide or Pro is pylene oxide. 8. Process for the preparation of hydroxyalkyl carboxylic acid esters according to a of the previous claims, wherein the temperature during the reaction is 50 is up to 100 ° C or in the reaction of the carboxylic acid with the Al kylene oxide there is a pressure of 1 to 10 bar or both. 9. Use of a hydroxyalkyl carboxylic acid ester, prepared according to a Method according to one of claims 1 to 8, as a coating raw material.