DE102004001600A1 - Production of glycerol mono(meth)acrylate for use as comonomer in adhesive, lacquer or contact lenses, involves hydrolysis of glycidyl (meth)acrylate in presence of cationic ion exchange resin and reactive solvent - Google Patents

Abstract

A method for the production of glycerol mono(meth)acrylate (I) with a low color index, involves the hydrolysis of glycidyl (meth)acrylate in presence of a cationic ion exchange resin, a reactive solvent, a stabiliser and water.

Description

The The invention relates to a process for the preparation of glycerol mono (meth) acrylate in the presence of cationic ion exchangers and reactive solvents.

Glycerol mono (meth) acrylate is a much used functional comonomer in adhesives, Paints and optical materials. There are different manufacturing methods for glycerol mono (meth) acrylate known.

Glycerol mono (meth) acrylate let yourself by the transesterification of methyl (meth) acrylate or the esterification of (meth) acrylic acid with glycerol. The result is a product mixture of mono-, di- and trifunctionalized alcohol due to its good water solubility the products only with great Effort can be separated.

you choose the Synthesis path over a protected Alcohol, the ketalized glycerin or the related Glycidol or the corresponding (meth) acrylate to obtain the monoester.

In US 4056496 the acid-catalyzed hydrolysis of 2,3-O-Isopropylidenglycerylmethacrylat is described. In JP 60215650 the acid-catalyzed hydrolysis of glycidyl methacrylate is described. In JP 07278054 the preparation is acid-catalyzed from glycidyl methacrylate in the presence of an inert organic solvent / water mixture.

All Process with acid catalysis have the disadvantage that subsequently a neutralization step carried out must become.

In JP 08277245 describes the acid-catalyzed hydrolysis of glycidyl methacrylate, including with ion exchangers. However, the reaction is carried out at high temperature (85-90 ° C), as well as the dehydration (65 ° C). This product load leads to an increased color number (APHA 50), which is an optical application, eg in contact lenses in the way.

task of the invention was glycerol mono (meth) acrylate in high purity, produce with low color number and high yields.

The Task has been solved by a process for the preparation of glycerol mono (meth) acrylate, in which glycidyl (meth) acrylate in the presence of a cationic ion exchanger and a reactive solvent as well a stabilizer and water is hydrolyzed. As a reactive solvent one understands a reagent which acts as a solvent on the one hand, i. the solubility or homogeneity the reaction mixture and on the other with glycidyl (meth) acrylate to be able to react.

Surprised was found to be through the use of a cationic ion exchanger can be worked under very mild conditions. Prefers become sulfonic acid Ion exchanger used. Hydrolysis in the presence of cationic Ion exchangers take place at 20-50 ° C, preferably at 40 ° C.

cationic Ion exchangers are preferred in amounts of 1-40% by weight, especially preferably from 10 to 20% by weight, based on the total weight of the batch, used.

in the Unlike homogeneous catalyst systems is in the inventive method the product easily separated from the solid catalyst. Advantageous is thus the reaction simplified. In addition, the catalyst is used repeatedly.

It was found to be the use of a reactive solvent the reaction accelerates. Preference is given to aldehydes and ketones aliphatic, aromatic or cycloaliphatic nature, more preferably Aldehydes from the group of aliphatic aldehydes and ketones the group of aliphatic ketones such as acetone used.

Particularly advantageous is the saving of neutralization steps. The methods listed in the prior art all work in the acidic range. The necessary neutralization step is expensive and leads to losses in the yield, since the glycerol mono (meth) acrylate is readily soluble in water. In addition, the amount of solvent is reduced, which reduces costs and protects the environment.

Advantageous in the method according to the invention is also that only work with a small excess of water got to. The thermal load of the polymerizable product gets through a shorter one Distillation time during drainage reduced.

It was also found that the product with high yields and in high purity can be produced. Yields over 80% are achieved, with purities the product of over 90%. By the obtained purities can be on a consuming distillative Cleaning can be dispensed with.

One Another advantage is the colorlessness of the product produced. There are significantly lower by the inventive method Achieved aphas. There are color numbers <50, in particular <30, achieved. The inventively prepared Glycerol mono (meth) acrylate with a low color number is thus suitable for applications in optics. It can e.g. in optical materials as a comonomer used in the manufacture of contact lenses.

at The preparation of glycerol mono (meth) acrylate are stabilizers added a radical polymerization of the (meth) acrylic groups during the Prevent reaction. The notation (meth) acrylate means here both methacrylate, e.g. Methyl methacrylate, ethyl methacrylate etc., as well as acrylate. These stabilizers are in the art well known.

worin
R⁵ einen linearen oder verzweigten Alkylrest mit eins bis acht Kohlenstoffatomen, Halogen oder Aryl bedeutet, vorzugsweise einen Alkylrest mit eins bis vier Kohlenstoffatomen, besonders bevorzugt Methyl, Ethyl, n-Propyl, iso-Propyl, n-Butyl, iso-Butyl, sec-Butyl, tert.-Butyl, Cl, F oder Br;
o eine ganze Zahl im Bereich von eins bis vier, vorzugsweise eins oder zwei ist; und
R⁶ Wasserstoff, einen linearen oder verzweigten Alkylrest mit eins bis acht Kohlenstoffatomen oder Aryl bedeutet, vorzugsweise einen Alkylrest mit eins bis vier Kohlenstoffatomen, besonders bevorzugt Methyl, Ethyl, n-Propyl, iso-Propyl, n-Butyl, iso-Butyl, sec-Butyl oder tert.-Butyl.Are used mainly 1,4-dihydroxybenzenes. However, it is also possible to use differently substituted dihydroxybenzenes. In general, such stabilizers can be represented by the general formula (I),

wherein
R ^{5 is} a linear or branched alkyl radical having one to eight carbon atoms, halogen or aryl, preferably an alkyl radical having one to four carbon atoms, more preferably methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec Butyl, tert -butyl, Cl, F or Br;
o is an integer in the range of one to four, preferably one or two; and
R ^{6 is} hydrogen, a linear or branched alkyl radical having one to eight carbon atoms or aryl, preferably an alkyl radical having one to four carbon atoms, particularly preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec Butyl or tert-butyl.

worin
R⁵ einen linearen oder verzweigten Alkylrest mit eins bis acht Kohlenstoffatomen, Halogen oder Aryl bedeutet, vorzugsweise einen Alkylrest mit eins bis vier Kohlenstoffatomen, besonders bevorzugt Methyl, Ethyl, n-Propyl, iso-Propyl, n-Butyl, iso-Butyl, sec-Butyl, tert.-Butyl, Cl, F oder Br; und
o eine ganze Zahl im Bereich von eins bis vier, vorzugsweise eins oder zwei ist.However, it is also possible to use compounds with 1,4-benzoquinone as the parent compound. These can be described by the formula (II),

wherein
R ^{5 is} a linear or branched alkyl radical having one to eight carbon atoms, halogen or aryl, preferably an alkyl radical having one to four carbon atoms, more preferably methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec Butyl, tert -butyl, Cl, F or Br; and
o is an integer in the range of one to four, preferably one or two.

worin
R⁵ einen linearen oder verzweigten Alkylrest mit eins bis acht Kohlenstoffatomen, Aryl oder Aralkyl, Propionsäureester mit 1 bis 4 wertigen Alkoholen, welche auch Heteroatome wie S, O und N enthalten können, vorzugsweise einen Alkylrest mit eins bis vier Kohlenstoffatomen, besonders bevorzugt Methyl, Ethyl, n-Propyl, iso-Propyl, n-Butyl, iso-Butyl, sec-Butyl, tert.-Butyl bedeutet.Likewise phenols of the general structure (III) are used,

wherein
R ^{5 is} a linear or branched alkyl radical having one to eight carbon atoms, aryl or aralkyl, propionic acid esters having 1 to 4 valent alcohols, which may also contain heteroatoms such as S, O and N, preferably an alkyl radical having one to four carbon atoms, more preferably methyl, Ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl.

mit R⁷ = Verbindung der Formel (V),

worin R⁸ = C_pH_2p+1 mit p = 1 oder 2 ist.Another advantageous class of substances are hindered phenols based on triazine derivatives of the formula (IV),

with R ⁷ = compound of the formula (V),

wherein R ⁸ = C _p H _{2p + 1} with p = 1 or 2.

Especially successful are the compounds 1,4-dihydroxybenzene, 4-methoxyphenol, 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2,6-di-tert. butyl-4-methylphenol, 2,4-dimethyl-6-tert-butylphenol, 2,2-bis [3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl-1-oxopropoxymethyl)] 1,3-propanediyl ester, 2,2'-Thiodiethylbis- [3- (3,5-di-tert-butyl-4-hydroxyphenyl)] propionate, Octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3,5-Bis (1,1-dimethylethyl-2,2-methylene-bis- (4-methyl-6-tert-butyl) phenol, Tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) -s-triazine-2,4,6 (1H, 3H, 5H) trione, Tris (3,5-di-tert-butyl-4-hydroxy) -s-triazine-2,46- (1H, 3H, 5H) trione or tert-butyl-3,5-dihydroxybenzene, more preferably 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl, Hydroquinone, 4-methyl-2,6-di-tert-butylphenol, Hydroquinone monomethyl ether, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 4- (methacryloyloxy) -2,2,6,6-tetramethylpiperidine-1-oxyl or 2,5-di-tert-butylhydroquinone.

in the The scope of the invention may include a tocopherol compound for stabilization of ethylenically unsaturated Monomers can be used.

The tocopherol compounds which can be used in the context of the invention are chroman-6-ols (3,4-dihydro-2H-1-benzopyran-6-ols) substituted in the 2-position by a 4,8,12-trimethyltridecyl radical , The tocopherols preferably used according to the invention include alpha-tocopherol, beta-tocopherol, gamma-tocopherol, delta-tocopherol, zeta2-tocopherol and eta-tocopherol, all of which are present called compounds each in the (2R, 4'R, 8'R) form, as well as alpha-tocopherol in the (all-rac) form. Preference is given to alpha-tocopherol in the (2R, 4'R, 8'R) form (common name: RRR-alpha-tocopherol) and also the synthetic racemic alpha-tocopherol (all-rac-alpha-tocopherol). Of these, in turn, the latter is particularly interesting because of the relatively low price.

Based on the weight of the total reaction mixture is the proportion the stabilizers individually or as a mixture generally 0.001 to 0.50 wt .-%, wherein the Concentration of the stabilizers preferably selects that the color number according to DIN 55945 not impaired becomes. Many of these stabilizers are commercially available.

Glycerol mono (meth) acrylate can in the crosslinking with difunctional isocyanates in paint formulations or adhesives.

The Examples given below are for better illustration of the present invention, but are not suitable to limit the invention to the features disclosed herein.

example 1

58 g (1.0 mol) acetone, 58 g Dowex cationic ion exchanger M-31 (Dow, Stade), 36 g (2.0 mol) deionized water (demineralized Water) and 0.008 g of 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl (Tempol) are presented. Within 1.4 hours, 142 g (1.0 mol) glycidyl methacrylate was added dropwise. The approach will be 4.0 hours at 40 ° C stirred. The reaction mixture is cooled. Subsequently the reaction mixture is over separated a filter. The ion exchanger is washed out with acetone. The organic phase is concentrated.

The Yield is 85% at a purity of 95%. The product is colorless and has the color number 25.

Comparative Example 1

200 ml (2.0 mol) of toluene, 100 ml of 5% sulfuric acid and 1.2 g of hydroquinone submitted. Within 13 minutes, 60.0 g (0.42 mol) of glycidyl methacrylate dropwise. The reaction mixture is stirred for 1.5 hours at 40.degree.

The reaction mixture is separated in a separating funnel. The aqueous phase is neutralized with an 8% NaHCO ₃ solution. Then it is shaken out with ethyl acetate. The organic phase is concentrated at about 60 ° C.

The Yield is 63% with a purity of 94%. The product is reddish, the Color number> 50, however, became not determined.

Comparative Example 2

23.2 g Dowex M cation exchanger M-31.14.4 g DI water and 0.032 g of hydroquinone monomethyl ether are introduced. Within 0.2 Hours 56.8 g of glycidyl methacrylate are added dropwise. The reaction mixture is 4.0 hours at 60 ° C stirred.

The Reaction mixture is cooled. Subsequently the reaction mixture is over separated a filter. The ion exchanger is washed out with acetone. The organic phase is concentrated.

The Yield is 74% with a purity of 95%. The product is yellowish, the color number> 50, but did not certainly.

Claims (10)

A process for the preparation of glycerol mono (meth) acrylate having a low color number, characterized in that glycidyl (meth) acrylate is hydrolyzed in the presence of a cationic ion exchanger and a reactive solvent and a stabilizer and water. Process for the preparation of glycerol mono (meth) acrylate with low color number, characterized in that the cationic Ion exchanger a sulfonic acid-containing Ion exchanger is. Process for the preparation of glycerol mono (meth) acrylate having a low color number, characterized in that as a reactive solvent Aldehydes or ketones are used. Process for the preparation of glycerol mono (meth) acrylate with low color number, characterized in that the reaction at 20-50 ° C he follows. Process for the preparation of glycerol mono (meth) acrylate with low color number, characterized in that the cationic Ion exchangers in amounts of 1-40 wt .-%, based on the total weight of the approach is used. Process for the preparation of glycerol mono (meth) acrylate with low color number, characterized in that the cationic Ion exchangers in amounts of 10-20 wt .-%, based on the total weight of the approach is used. Process for the preparation of glycerol mono (meth) acrylate with low color number, characterized in that stabilizers in amounts of 0.001-0.50 wt .-% are used. Process for the preparation of glycerol mono (meth) acrylate with low color number, characterized in that the cationic Ion exchanger can be used repeatedly. Use of glycerol mono (meth) acrylate prepared according to claim 1 as a functional comonomer in adhesives and paints. Use of glycerol mono (meth) acrylate prepared according to claim 1 in optical materials.