Method for recycling and reusing L-(+)-tartaric acid in production of D-p-methyl sulfone phenyl ethyl serinate

Abstract

The invention discloses a method for recycling and reusing L-(+)-tartaric acid in production of D-p-methyl sulfone phenyl ethyl serinate. The method comprises the following steps: (1), a L-(+)-calcium tartrate dihydrate crystal is recovered from L-ethyl ester mother liquor; (2), an L-(+)-tartaric acid double brine solution is recovered from D-p-methyl sulfone phenyl ethyl serinate mother liquor; (3), L-(+)-tartaric acid double hydrochlorination is performed; (4), L-(+)-tartaric acid is recovered through L-(+)-tartaric acid single hydrochlorination; and (5), processes of vacuum concentration, crystallization, separation, drying and the like are performed. An insert organic solvent is used for replacing a conventional water phase method to recover L-(+)-tartaric acid, the possibility of side reaction is avoided, the purity and specific rotation of a product can both reach the raw material quality standard, and L-(+)-tartaric acid can be directly and circularly applied to chiral resolution of D-p-methyl sulfone phenyl ethyl serinate. Different recovery processing technologies are adopted for different mother liquor of two components in the production process of D-p-methyl sulfone phenyl ethyl serinate, the product quality is improved remarkably, the whole recovery condition is mild, and the operation is simpler and easy to control.

Description

technical field [0001] The invention belongs to the technical field of chemistry and relates to a method for recovering and applying L-(+)-tartaric acid in the production of D-ethyl ester. Background technique [0002] D-(+)-p-thymphenylphenylserine ethyl ester (referred to as D-ethyl ester) is obtained from DL-(±)-p-thymphenylphenylserine ethyl ester through L-(+)-tartaric acid optical resolution Obtained, the intermediate is an important intermediate for the synthesis of thiamphenicol and florfenicol, especially florfenicol is an excellent broad-spectrum antibiotic for veterinary use, with low toxicity, no residue, and no drug resistance. Because the rapid growth of the amount of florfenicol has driven the growth of the demand for intermediates, therefore, a large amount of L-(+)-tartaric acid needs to be consumed in the D-(+)-ethyl ester generation process. [0003] The chiral substance L-(+)-tartaric acid was used to resolve DL-(±)-p-thiamphenicyl phenylserine ethyl est...

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Problems solved by technology

[0015] It has been reported in the literature that methanol and ethanol are used as organic solvents to prepare L-(+)-tartaric acid, but the added calcium chloride reacts with the solvent to form CaCl2 ·4CH3OH, CaCL2·4C2H5OH and other complex impurities , even under strong acid catalysis and a certain temperature, impurities such as L-(+)-dimethyl tartrate and L-(+)-diethyl tartrate are formed. Then most of the impurities are always present in the L-(+)-tartaric acid, causing the quality of the recovered L-(+)-tartaric acid product to fail to meet the resolution requirements

[0016] In the reaction process of the above-mentioned water phase method and the alcohol solvent method, there are many difficult problems, if not handled properly, it will cause the recovered L-(+) - Unqualified quality of tartaric acid, HPLC content <98.0%, specific rotation [a] D20: <+12° (C=20, aqueous solution) (generally +9.0°~+11.5°), recovered L-(+) - The quality of tartaric acid products is poor, basically not up to the quality standard of L-(+)-tartaric acid raw materials, and cannot be directly applied to the production of D-ethyl ester

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