Method for preparing sucrose-6-ethyl ester

Abstract

The invention relates to a chemical products preparing method, especially a modified method to prepare a key intermediate sucrose-6-ethyl ester preparing food sweetener sucralose. Its concrete technical flow: (1) add sucrose to formyl compound-containing organic solvent, heat to 70-100 deg.C to dissolve, then cool to below 70 deg.C, add in nonpolar organic solvent and dibutyl tin dioxide to make reflux water reaction for 3-6 hours at 70-100 deg.C; (2) cool the above reacting substances to below 20 deg.C, then drip acetic anhydride to react for 3-10 hours; (3) add a proper amount of water to the above reacting solution, extract by nonpolar organic solvent, and then make reflux water reaction by nonpolar organic solvent to obtain sucrose-6-ethyl ester solution.

Description

technical field [0001] The invention relates to a method for preparing chemical products, in particular to an improved method for preparing the key intermediate sucrose-6-ethyl ester of the food sweetener sucralose. Background technique [0002] Sucralose is a functional sweetener, which represents the latest achievement in the development of sweeteners. It is formed by replacing the three hydroxyl groups of 4, 1' and 6' in the sucrose molecule with three chlorine atoms; and the sucrose molecule There are 8 hydroxyl groups in sucralose, which are three primary carbon hydroxyl groups (6, 1', 6' positions) and five secondary carbon hydroxyl groups (2, 3, 4, 3', 4' positions). To prepare sucralose, it is necessary Protect the 6-hydroxyl group. [0003] Utilize dibutyltin oxide to carry out the existing multiple literature report of selective esterification reaction, as: detailed dibutyl The type, process and mechanism of tin oxide reacting with hydroxyl-containing compounds a...

AI Technical Summary

Problems solved by technology

Navia etc. disclose the preparation method of sucrose-6-ethyl ester in US4950746, and the process is: (1) sucrose, dibutyltin oxide and methanol reflux reaction, concentrate to obtain 1,3-bis(6-oxo-sucrose)- 1,1,3,3-tetrabutyltin dioxide (DBSS); (2) DBSS and acetic anhydride are reacted in DMF, and then through a series of treatments, sucrose-6-ethyl ester is obtained, with a content of 63.4%; the method The disadvantage is that the sucrose-6-ethyl ester content is too low, and there are many difficulties for the next step chlorination reaction

David etc. disclose the preparation method of sucrose-6-ethyl ester in US5023329, process is: (1) sucrose, dibutyltin oxide, DMF and cyclohexane reflux 5 hours at 100 ± 1 ℃; (2) cool to- Add acetic anhydride dropwise at 4°C, the maximum temperature should not exceed -1°C, and react overnight at room temperature after the dropwise addition of acetic anhydride; (3) add appropriate amount of water, extract three times with cyclohexane, and concentrate to obtain a sticky substance; (4) Dissolve the sticky substance in methanol and process through a series of processes to obtain sucrose-6-ethyl ester with a yield of 55.3% and a content of 90.2%. The disadvantage of this method is that the yield is not high and the content is still low