Chlorination method for sucrose-6-ethyl ester

Abstract

The invention relates to a chlorination method for sucrose-6-ethyl ester. The chlorination method comprises the following steps: (1) respectively preparing a chlorination reagent and a solution of sucrose-6-ethyl ester from a polar non-proton solvent; (2) chlorinating the sucrose-6-ethyl ester solution by a chlorination reagent solution; (3) refluxing under reduced pressure; and (4) evaporating the polar non-proton solvent by distilling, recycling, neutralizing the sucrose-6-ethyl ester solution in a distillation kettle, removing the solvent, adding water to dissolve, discoloring and crystallizing to obtain a sucrose-6-ethyl ester crude product, wherein the recycled a polar non-proton solvent is used for the chlorination reagent solution prepared in the step (1). According to the chlorination method, generated hydrogen chloride and sulfur dioxide are discharged by refluxing under reduced pressure to promote reaction to positively perform, and the final reaction temperature is reduced to 105 DEG C which is lower than the highest holding temperature in the existing chlorination technology by 10 DEG C, so that the defects generated by carbonization in the chlorination process are completely avoided; and the used polar non-proton solvent can be recycled for a next-batch chlorination reaction process, and therefore, the chlorination method is especially suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of food additives, and in particular relates to a chlorination method of sucrose-6-ethyl ester. Background technique [0002] Sucralose is a new sweetener developed by Tate&Lyle in the 1970s. Its sweetness is 600 times that of sucrose, and it is one of the most outstanding sweeteners at present. Sucralose-6-ethyl ester is the most important intermediate for the synthesis of sucralose by the single-group protection method. It is prepared by reacting sucralose-6-ethyl ester with a chlorination reagent under suitable conditions. Reagents mainly include thionyl chloride, pyridine, chlorinated hydrocarbon system (see US Patent 5136031) and Vilsmeier reagent system (see US Patent 4380476). Among them, the Vilsmeier reagent system has the advantages of large steric hindrance, strong selectivity and high yield, and is suitable for industrial production. Domestic sucralose manufacturers basically use the Vilsmeier ...

AI Technical Summary

Problems solved by technology

The reaction of Vilsmeier reagent and sucrose-6-ethyl ester has been reported since Mufti (see U.S. Patent 4380476), and there have been improved patent reports, such as Chinese patents CN102964397, CN101619083, etc. have reported improved methods for chlorination, but these methods all need to be When chlorination, a large amount of solvents with a polarity much weaker than N,N-dimethylformamide are added to accelerate the release of sulfur dioxide gas generated by the reaction and promote the positive progress of the reaction, and these weakly polar solvents will reduce the sucrose- The solubility of 6-ethyl ester and Vilsmeier reagent complex in the reaction system, the final reaction temperature must exceed 110 ° C, resulting in a large amount of carbonization, which affects the final yield of sucralose-6-ethyl ester