SU455090A1 - The method of producing esters of penta-0- / -carboxyethyl / -xylite - Google Patents

Description

one

This invention relates to a process for the preparation of complex penta-O- (p-carboxyethyl) xylitol esters, which can be used as plasticizers.

A known method for producing polyhydric alcohol esters is that the ip-cyano ethyl esters of these alcohols undergo EO interaction with monohydric alcohols at room temperature to 100 ° C in the presence of an aqueous solution of sulfuric acid as a catalyst, preferably with simultaneous distillation of water in Vnde azeotroia with benzene, toluene. The yield of 80-90%. The reaction time is 15-20 hours.

The disadvantages of this method are the high temperature of the process and the long duration of it, which leads to the tarring of the product and its contamination with various by-products, resulting in the need to clean the product, which is associated with additional costs and losses.

In order to improve the quality of the product at the same time shortening the process and maintaining the yield at the same level, it was suggested to use dry hydrogen chloride as a catalyst and carry out the process at a temperature of ± 5 ° C with subsequent treatment of the reaction mixture with water and extraction of the target product by extraction with EFPR.

Example 1. In a reaction mixture consisting of 83.4 g of crystalline ient-O- (rcyanethyl) -xylite and 115 g of hexyl alcohol, is sprinkled for 8 hours with Ivavia batch and at a temperature of + 5 ° C hydrogen chloride gas. The temperature of the reaction mixture is then brought to room temperature and 200 ml of water is gradually added to it, after which the mass is stirred for 3 hours and at room temperature. The product was extracted with ethyl ether, the ether extracts were washed with 10% sodium bicarbonate solution, then with water until neutral, and dried with calcined sodium sulfate. After distilling off the ether and an excess of hexyl alcohol, pept-O- (3β-carboxyethyl) -split hexyl ester is obtained as a light yellow, mobile oil with a yield of 150.2 g (80.5%).

Physico-chemical characteristics of the product: a pour point of 45-4b ° C; pb 1.4595; viscosity 95.7 eats, saponification number 288.4 (theoretically calculated 300.4).

In the IR spectrum of the product obtained, there is an absorption band of 1745 cm-typical for stretching vibrations of the C 0 group in esters, x, which confirms its structure.

Calculated,%: C 64.34; H 9.93.

C5H92Oi5.

Found,%: C 63.91; H 10.52.

EXAMPLE 2: In a reaction mixture consisting of 100 g of penta-O- (p-cyano-7) -xylite and 280 g of n-butyl alcohol, ip is allowed to mix for 10 hours with stirring and at a temperature of ± 5 ° C dry chloride hydrogen. Further processing of the reaction mixture is carried out as in Example 1. Peite O-O (p-carboxyethyl) xylitol butyl ester is obtained as a light yellow mobile oil.

Physico-chemical characteristics of the product: a pour point of 56 ° C; pd 1.4562; viscosity 39.4 eats; The number of saponis 348 (theoretical. Calculated - 353).

The presence in the P1K spectrum of the obtained product of the band of the absorption band 1745 characteristic of the stretching vibrations of the C O group in the esters confirms its structure.

Subject invention

A method of producing esters of penta-O (p-carboxyethyl) -xyelite by reacting penta-O- (p-cyanoethyl) -xylite with monohydric alcohols in the presence of an acid catalyst, followed by separation of the gel product, characterized in that. In order to improve product quality and speed up the process, dry hydrogen chloride is used as an acid catalyst, and the process is carried out at a temperature of ± 5 ° C, followed by treatment of the reaction mixture with water and extraction of the target product with ether.