Preparation method of sucrose-6-acetate

Abstract

The invention relates to a preparation method of a key intermediate sucrose-6-acetate for a novel sweetener sucralose. The method including the following specific processes: (1) adding the sucrose into an organic solvent N,N-dimethyl formamide, heating to 80-100 DEG C, dissolving, then cooling to 70 DEG C, adding a non-polar organic solvent and an organic tin compound, and conducting reflux and reaction in the presence of water for 5-8 h, wherein the reflux temperature is controlled at 80-100 DEG C; (2) cooling the reactants to below 25 DEG C, then dropwise adding acetic anhydride and reacting for 2-8 h; and (3) adding an appropriate amount of water to the above reaction liquid, extracting the organic tin compound with a non-polar organic solvent, concentrating and recycling the organic tin compound, conducing azeotropy on a raffinate and a non-polar organic solvent in the presence of water to obtain a sucrose-6-acetate solution. The method avoids the problems of solid treatment and low yield in a traditional organic tin process, has the advantages of simple operation, low labor intensity, high reaction conversion rate, and direct usage of the reaction solution without refining separation into a next step of chlorination reaction.

Description

technical field [0001] The invention relates to a preparation method of chemical products, in particular to a preparation method of sucrose-6-acetate, a key intermediate of a novel sweetener sucralose. Background technique [0002] Sucralose, chemical name 4, 1', 6'-trichloro-4, 1', 6'-trideoxygalactose, was first synthesized by Tate & Lyte in the UK, and is by far the most competitive, artificially synthesized Non-nutritive intense sweetener. The synthesis of sucralose mainly includes whole-group protection method, enzyme-chemical method and single-group protection method. The synthetic route of protection method is short and the yield is high, which is the most suitable synthetic route for industrialization. The core of the single-group protection method is to protect the 6-hydroxyl in the sucrose molecule. At present, there are two methods: the trimethyl orthoacetate method and the organotin method. From the perspective of low cost and high yield, the organotin method i...

AI Technical Summary

Problems solved by technology

The synthetic method of the disclosed sucrose-6-ethyl ester of U.S. Patent No. 5,023,329 is: in a polar organic solvent such as dimethylformamide, the water in the reaction process is taken out by an organic solvent azeotropic with water such as cyclohexane, sucrose React with dialkyltin oxide to form sucrose-organotin complex (DBSS), and then react with acid anhydride acylating reagent to form sucrose-6-acetate. This process needs to recover dialkyltin oxide, and there is cumbersome solid treatment , difficult to continuous production and other shortcomings

U.S. Patent No. 4,950,746 discloses a method for reacting sucrose with 1,3-dialkoxy-1,1,3,3-tetrahydrocarbyl distannoxane to generate 1,3-di-sucrose-1,1,3,3 -Tetrahydrocarbyl distannoxane, which is then reacted with an acylating agent to generate sucrose-6-ester, and this process also requires alkoxide recovery treatment of 1,3-dialkoxy-1,1,3,3-tetrahydrocarbyl di Stannoxane, the process route is cumbersome

In addition, U.S. Patent No. 5,470,969 discloses the use of 1,3-diacetoxy-1,1,3,3-tetrabutyldistannoxane (DSDA) as a reaction reagent, and DSDA can be directly applied mechanically only by removing the solvent. The previous process omits the recovery treatment step, but the yield of DSDA recycling is unstable