DE1144275B - Process for the preparation of compounds containing the phosphonic acid ester group - Google Patents

Description

Process for the preparation of compounds containing the phosphonic acid ester group The addition of dialkyl phosphites or trialkyl phosphites to compounds containing activated double bonds in the presence of alkaline catalysts is already known. So you get z. B. by adding dimethyl phosphite to maleic acid dimethyl ester in the presence of sodium alcoholate, the corresponding phosphonic acid ester of the following structural formula: (cf. AN Pudivik, Dukladi akad. SSSR. 85, p. 349 [1952]).

Attempts have also been made to use maleic acid half-esters To add trialkyl phosphites.

However, as a result of the very violent reaction, none of them could be defined Reaction products are obtained.

It has now been found that the production of defined addition products containing phosphonic acid ester groups with half-esters of α-unsaturated dicarboxylic acids is possible if half-esters containing free hydroxyl groups are obtained from α, β-unsaturated dicarboxylic acids, which are optionally substituted by 1 chlorine atom, and polyhydric alcohols with phosphites of the general formula in which R, R 'and R "denote alkyl, alkenyl or aralkyl radicals which are optionally substituted by chlorine or bromine atoms, temperatures between 0 and about 200 ° C. being maintained.

This was once more surprising in that it is usually the case with that Conversion with trialkyl phosphite to expect a transesterification with the hydroxyl function was. On the other hand, it was also known that the reaction of trialkyl phosphite with a, fl-unsaturated carboxylic acids whenever the carboxylic acid is still another Contains carboxyl group, even under special precaution took a partial Decarboxylation cannot be avoided.

Trialkyl or triaralkyl phosphites suitable for the process according to the invention are z. B. trimethyl phosphite, triethyl phosphite, tributyl phosphite, tri-ß-chloroethyl phosphite, Tri-y-bromopropyl phosphite, tridodecyl phosphite, triallyl phosphite, trimethallyl phosphite, Tribenzyl phosphite, tri- (pentachlorobenzyl) phosphite, diallyl methyl phosphite and dibenzyl p-chloroethyl phosphite.

Suitable half esters of a, fl-unsaturated dicarboxylic acids are, for. B. the free hydroxyl-containing half esters of maleic acid, fumaric acid, Methyl maleic acid, chloromaleic acid, methylene succinic acid and glutaconic acid. The half esters of maleic acid and chloromaleic acid, for example, are particularly important the ethylene glycol monochloromaleinate of the formula HO - CH2 - CH2 -O-CO - CH = G (C1) COOH and 1,4-butylene glycol monomaleinate, as their half-esters are very easily separated from the Form corresponding acid anhydrides and alcohols with ring opening.

The inventive implementation of the trialkyl, trialkenyl or triaralkyl phosphites with the half-esters of a, fl-unsaturated dicarboxylic acids containing free hydroxyl groups is carried out at 0 to approx. 200 "C. For very reactive substances are Temperatures in the range of 0 ° C are advantageous, while on the other hand, less reactive and at the same time stable connections temperatures in the range around 2000 C are applied can be. Since the addition reaction takes place with a very strong heat release, it is advisable to submit one component and the other slowly in small steps Add portions. The reaction can also be carried out in the presence of solvents, such as Benzene, toluene, chloroform or dioxane.

In all reactions, the addition products are formed in practice quantitative yield and in most cases they are colorless to light yellow in color Are oils that have characteristic hydroxyl numbers.

The addition compounds obtainable according to the invention are valuable Intermediates for. the production of phosphorus-containing polyesters and are themselves can be used as non-flammable plasticizers. They can also be used as fire retardants use for plastics.

EXAMPLE 1 The 1,3-butylene glycol monomaleinate is prepared from 980 parts by weight of maleic anhydride and 900 parts by weight of 1,3-butylene glycol (molar ratio 1: 1) It is then cooled to 60 "C. and, with thorough stirring, 2700 parts by weight of tri-β-chloroethylphosphite are added dropwise. The temperature rises depending on the dropping speed. In general, it should not exceed 90" C. After all the trichloroethyl phosphite has been added, the mixture is stirred for a further 1 hour. A light yellow oil with an acid number of 12 is obtained.

Example 2 From 1120 parts by weight of methyl maleic anhydride and 620 parts by weight of ethylene glycol (molar ratio 1: 1) are made by stirring at 1300 C represents the ethylene glycol monomethyl maleate.

2700 parts by weight of trichloroethyl phosphite are then added dropwise at 70.degree without the addition of heat.

The temperature should not exceed 80 ° C. It is then stirred another 30 minutes as the temperature falls, and a light yellow adduct is obtained an acid number of 8.

Example 3 From 980 parts by weight of maleic anhydride and 1340 parts by weight of trimethylolpropane (molar ratio 1: 1), the corresponding half-ester of the following formula is prepared at 120 "C. 2700 parts by weight of trichloroethyl phosphite are then added dropwise at 80 ° C. and the mixture is stirred for a further 112 hours. An almost colorless oily adduct with an acid number of 25 and a hydroxyl number of 220 is obtained.

Example 4 From 1330 parts by weight of chloromaleic anhydride and 1340 Parts by weight of trimethylolpropane (molar ratio 1: 1) are produced by melting at 1300C the trimethylolpropane monochloromaleinate is then added dropwise at 80 ° C 2700 Parts by weight of trichloroethyl phosphite. The dripping speed should be regulated in this way be that the temperature holds itself at 80 "C. After everything has been added is, the mixture is stirred for a further 1 hour with falling temperature. A colorless one is obtained oily adduct with acid number 18 and hydroxyl number 182.

Claims (2)

PATENT CLAIMS: 1. A process for the preparation of compounds containing the phosphonic acid ester group by reacting half-esters of unsaturated dicarboxylic acids with phosphites, characterized in that half-esters containing free hydroxyl groups are obtained from α, -unsaturated dicarboxylic acids, which are optionally substituted by 1 chlorine atom, and polyhydric alcohols with phosphites the general formula in which R, R 'and R "denote alkyl, alkenyl or aralkyl radicals, which are optionally substituted by chlorine or bromine atoms, at 0 to about 200" C. 2. The method according to claim 1, characterized in that the Reaction with one molar equivalent of half-ester and less than the equivalent amount to trialkyl or Triaralkyl phosphite, based on the half-ester groups with the a, fl-unsaturated groups. References considered: Chemical Abstracts, 1958, column 9948.