SU1666459A1 - Method for obtaining carboxymethyl ester of chitin - Google Patents

Abstract

The invention relates to the field of chemistry and technology of polysaccharide derivatives, in particular, to a method for producing chitin esters containing, together with N - acetyl carboxyl groups, and being alkaline soluble polyelectrolytes, which can be used in medicine, food and chemical industries. The invention allows shortening and simplifying the process, increasing the yield of the target product due to the fact that chitin carboxymethyl ester is obtained by activating chitin with an aqueous solution of sodium hydroxide in the presence of isopropanol at a mass ratio of chitin, sodium hydroxide, isopropanol and water 1: (1.04 - 1 , 1): (9.4 - 10.6): (1.1 - 1.3), respectively, 2.5 - 3.0 hours at 23 - 30 ° C, followed by alkylation of monochloroacetic acid in the presence of isopropanol at a mass ratio of chitin , monochloracetic acid, sodium hydroxide and isoprop lovogo alcohol of 1: (1.12 - 1.20): (0.81 - 2.40), respectively of 1.5 - 2.0 hours at 70 - 80 ° C. 1 tab.

Description

The invention relates to the field of chemistry and technology of polysaccharide derivatives, in particular, to a method for producing chitin esters containing, together with M-acetyl carboxyl groups, and alkaline-soluble polyelectrolytes that can be used in medicine, food and chemical industries.

The aim of the invention is to simplify the process and increase the yield of the target product.

Example 1. To 1.0 wt.h. chitin (Xt) (10% moisture), a water-isopropanol solution of alkali is added at a ratio of NaOH to isopropanol-water of 1.04: 9.4: 1.1, the mixture is stirred for 2.5 hours at 23 ° C. Then, 2.12 wt.h. monochloroacetic acid (MCAA), 0.81 parts by weight, isopropanol

(IPA) and continue stirring for 1.5 hours at 70 ° C. At the end, the product is filtered, dissolved in 20 ml of 0.1 N. HCl solution, and the solution is dialyzed to remove inorganic impurities. At the end of dialysis, the polymer does not precipitate. The purified polymer is freeze-dried, analyzed for ionic chlorine content, solubility and degree of substitution. The properties of the obtained chitin esters and examples of their preparation are presented in the table.

Example 6 (by a known method). Chitin 1 wt.h. (humidity 10%) process 22 wt.h. dimethyl sulfoxide for 24 h at room temperature, then the mixture is filtered and washed with 155 wt.h. ethyl alcohol, dried. Dried chitin is treated with 20 wt.h. 65%

WITH

oh oh

4. SL O

AON for 1 h, after which it is squeezed from an excess of alkali, the mass of the pressed one is 3.5 wt.h. 1.4 wt.h. was added to the squeezed mercerized chitin. monochloroacetic acid to 9.8 wt.h. isopropyl alcohol and continue stirring for an hour. Isolation of the product is carried out as in Example 1. The product characteristics are shown in the table.

Claims (1)

(Makeup 9. Illustrates the fundamental impossibility of using the proposed method without the use of isopropyl alcohol (under analogue conditions). Invention Method for producing chitin carboxymethyl ester, including chi activation five Tin with an aqueous solution of sodium hydroxide followed by alkylation with monochloroacetic acid in the presence of isopropanol, characterized in that, in order to simplify the process and increase the yield of the target product, activation is carried out in the presence of isopropanol at a mass ratio of chitin, sodium hydroxide, isopropanol and water 1: {1,04-1,10) :( 9.4-10.6) :( 1.1-1.3), respectively, 2.5-3.0 hours at 23-30 ° C, and alkylation carried out at 70-80 ° C for 1.5-2.0 hours with the additional addition of 1.12-1.20 wt.h to the reaction mixture. monochloracetic acid and 0.81-2.40 wt.h. isopropanol on 1 ma.ch. chitin.