Preparation method of high-substitution-degree acetylated sodium hyaluronate

Abstract

The invention discloses a preparation method of high-substitution-degree acetylated sodium hyaluronate. The preparation method is characterized by being prepared from hyaluronic acid through I activation separation, II dehydration reaction and III acylation reaction, wherein the I activation separation is carried out by virtue of an acetone solution of triethylamine; the II dehydration reaction iscarried out through cobalt-60 radiation auxiliary dehydration of acetic anhydride at a low-temperature condition; and the III acylation reaction is carried by virtue of a catalyst and an acylation enhancer. The preparation method has the beneficial effects that by utilizing the I activation separation operation, the acylation degree is increased, and the introduced impurities are reduced during the activation; by utilizing low-temperature cobalt-60 radiation auxiliary dehydration, the temperature of the dehydration reaction is reduced, acetic anhydride is taken as a dehydration agent, and substances generated through the water absorption of acetic anhydride can take part in the III acylation reaction in the later procedure, so that the introduced impurities are reduced, and the environmental pollution caused by acid gas when materials are added in the subsequent process is avoided by virtue of acetic anhydride; and by adding a catalyst and an enhancer into the III acylation reaction,the acylation degree is substantially increased.

Description

Technical field: [0001] The invention belongs to the field of organic chemical synthesis, and more specifically relates to a preparation method of acetylated hyaluronic acid with a high degree of substitution. Background technique: [0002] Hyaluronic acid (Hyaluronic acid, HA), also known as hyaluronic acid, is composed of (1-3)-2-N-acetylamino-2-deoxy-D-glucose-(1-4)-O-β-D-glucose An acidic straight-chain polymucopolysaccharide formed by the repeated arrangement of disaccharides of aldehyde acid, which has strong hydrophilicity and very good moisturizing properties, and widely exists in the cytoplasm of animal tissue cells and the membrane of some bacteria. In medicine, cosmetics and food, it is also recognized as the most ideal natural moisturizing factor by the international cosmetics industry. [0003] There are mainly the following ways to prepare HA: one is to separate and extract from animal tissues; the other is to obtain it through microbial fermentation. The ani...

AI Technical Summary

Problems solved by technology

[0009] The first technical problem to be solved is: the existing amide reaction lacks activation or the activation principle is unreasonable, resulting in a low degree of acetylation and a large loss of products;

Images