DE2211954A1 - 4-substd bis-benzyl-sulphones - used in heat-resistant polyesters or polyamides prodn - Google Patents

Abstract

Title cpds. are of formula (in which X is COOH, CN or COOR, R being CnH2n+1 with n=1-6; and pref. R is CH3). Polyesters or polyamides having very high thermal stability can be produced from these cpds.; they can be formed into films or fibres.

Description

Bis- [4-carboxy-benzyl 2 -sulfone Win in the plastics field in addition to terephthalic and isophthalic acid, the dinuclear dicarboxylic acids are becoming more and more common in interest.

As a new binuclear dicarboxylic acid used in the production of polyesters and polyamides, bis [4-carboxy-benzyl] sulfone has been found.

From the literature (Beilstein's Handbook of Organic Chemistry, 1. Supplementary work, Volume 6, page 248) bis [4-methyl-benzyl i-sulfide is known. This compound is easily accessible from 4-methyl-1-chloromethylbenzene and Na2 5. If the bis [4-methylbenzyl J sulfide, e.g. with HNO3, terephthalic acid is obtained is the main product.

If, on the other hand, the bis-4-methyl-benzyl-sulfide is oxidized to the sulfone, then the bis- [4-carboxy-benzyl] -sulfone is obtained by further oxidation with HNO or with air in acetic acid.

is a new compound and a valuable intermediate for the Production of the dicarboxylic acid or the diester.

This connection has not yet been described in the literature.

Instead of the bis [4 -methyl-benzyl sulfide, for the inventive Process also contains bis- [4-alkyl-benzyl] sulfides containing up to 6 carbon atoms Alkyl residues are used as starting materials. Because of its better accessibility and because of the simpler oxidation, however, the bis-4-methylbenzyl] sulfide is used preferred as a starting product.

The bis- [4-carboxy-benzyl] -sulfone is also obtained by using 4-chloromethyl-benzonitrile or 4-chloromethyl-benzoic acid esters of lower alcohols are reacted with Na2S, the sulfide oxidized to the sulfone and then saponified.

The esters of bis-04-carboxy-benzyl] sulfone with R = CnH2n + 1, n = 1-6, especially CH3, are also new compounds and can, like the dicarboxylic acid are used for the production of polyesters.

Also the dinitrile of bis-4-carborcy-benzyl-sulfone To the Oxidation of bis [4-methylbenayl] sulfide or bis [4-cyano-benzyl] sulfide or the diesters of bis [4-carboxy-benzyl] sulfide are particularly suitable peroxidic ones Oxidizing agents such as hydrogen peroxide or peracetic acid. The oxidation will expediently at temperatures of approx.

50 - 120 C carried out in the liquid phase, using as a solvent a solvent inert to the reactants and the reaction product such as formic acid, acetic acid or propionic acid is used. A suitable method is the reflux oxidation, which takes about 10 to 60 minutes at normal pressure.

For the oxidation of bis [4-methyl-benzyl] -sulphone to bis-4-carboxy-benzyl -sulfone, stronger oxidizing agents are required, such as nitric acid or oxygen. This oxidation can be carried out with 1o -35 pointer nitric acid at temperatures from 140 - 200 C and under pressures from 5 - 20 atmospheres.

If oxygen or gases containing oxygen are used for the oxidation, it is advisable to use the bis [4-methyl-benzyl] sulfone in a short-chain aliphatic Carboxylic acid such as acetic acid, dissolve and oxidize at temperatures of 100 - 200 oO and under a pressure of 1 - 15 atmospheres in the presence of cobalt or To carry out manganese salts, by bromine compounds or aldehydes e.g. acetaldehyde are activated.

The bis [4-carboxy-benzyl 2 -sulfone can be used as a dicarboxylic acid or as Diesters in the esterification or transesterification with polyhydroxyl compounds for production of polyesters used in the manufacture of films and / or fibers from particularly high thermal stability are useful. Likewise, the free acid or its salts for the production of corresponding polyamides or polyester amides use with correspondingly favorable properties. The polycondensation can take place in liquid or solid phase carried out at elevated temperatures of about 150 to 300 OC will; it can also take place in two stages in a manner known per se.

The bis [4-cyano-benzyl J sulfone can be converted into the dicarboxylic acid in the usual way or converted into a diester and as such to form polyamide or polyester be used.

The usual conditions are used to saponify the ester or the nitrile applied; the same applies to the esterification of the acid.

Example 1 90 g of Na 2 S 5 9 H 2 O, 75 ml of water and 20 ml of methanol were added refluxed. After adding dropwise 70 g of 4-methyl-1-chloromethylbenzene was cooked for another 5 hours. On cooling, 55.5 g = 92 mol of so bis-04-methyl-benzyl crystallized 2 sulfide. M.p. 73 OC.

25 g of bis [4-methyl-benzyl] sulfide were added to a mixture of 150 ml of glacial acetic acid and 50 ml of 30% H2O2 are added and refluxed for 30 minutes. then 100 ml of water were added and, after cooling, it was filtered off. It fell 22.4 g sulfone = 79 mol%.

20 g of bis [4-methyl-benzyl] sulfone and 300 g of 20% HNO3 were Heated to 170 ° C. in the autoclave for 5 hours. After cooling, the bis [4-carboxy-benzyl ] -sulfone filtered off, washed with water and dried.

Yield: 20. 1 g = 82 mol.% Neutralization number: 328 mg EOH / g (calc. 336) The bis [4-carboxy-benzyl] -sulfon was treated with methanol at 220 ° C. in the autoclave esterified and then recrystallized.

Mp. 228-229 ° C found: 59.51% calc. 59.65 ffi H 5.12% 5, o1% 0 26.51 % 26.49% s 8.86% 8.85% The IR spectrum of the bis [4-carboxy-benzyl] sulfone is shown in FIG. 1 and that of the dimethyl ester in FIG.

Example 2 To 72 g of Na2S. 9 H20, 75 ml water and 20 ml methanol were 60 g of 4-chloromethyl-benzonitrile obtained by chlorination of p-tolunitrile and the mixture was refluxed for 5 hours. When cooling down crystallized 46 g = 88 Nol. % Bis [4-cyano-benzyl] sulfide.

The bis [4-cyano-benzyl] sulfide was dissolved in acetic acid with H 2 O 2 Sulphone oxidizes. In the IR spectrum, which is shown in Fig. 3, it can be seen that there was also a small degree of saponification of nitrile to acid amide.

The sulfone was then saponified with 10o% NaCH and acidified the bis- [4-carboxy-benzyl] -sulfone precipitated with HOl. The product obtained in this way had a neutralization number of 332 mg EOH / g.

The IR spectrum of the product obtained in this way agrees with that according to Fig. 1 match.

Example 3 The procedure was as in Example 2, but methyl 4-chloromethylbenzoate was obtained used instead of 4-chloromethyl-benzonitrile. by the IR spectrum of the thus obtained Product corresponds to that of FIG. 1.

Claims (4)

Claims C 4- substituted bis-benzyl sulfones where X = COOH, CN or COOR, with R = CnH2n + 1, n = 1-6 in particular denote -CH3. 2) Method of making where X = COOH, characterized in that where R = CnH2n + 1, n = 1-6, in particular -CH3, in a first stage by means of a peroxidic oxidizing agent to form sulfone and this is then oxidized to dicarboxylic acid in a second stage. 3) Process for the preparation of compounds of the formula where X = CN or COOR with R = CnH2n + 1, n = 1-6, in particular -CH3, characterized in that the corresponding disulfides be oxidized by means of peroxidic oxidizing agents, in particular hydrogen peroxide. 4) Method according to claim 2 or 3, characterized in that the Oxidation of the sulphide is carried out at 50 - 120 OC in the liquid phase, whereby an inert solvent such as formic acid, acetic acid or propionic acid is used will.