METHOD FOR OBTAINING CRYSTALLINE FORM OF CALCIUM CIS-2,3-EPOXYSUCCINATE Russian patent published in 2021 - IPC C07B61/00 C07D303/48 C07D301/12 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for obtaining a crystalline form of calcium cis-2,3-epoxysuccinate using a seed, which is the crystalline form of calcium cis-2,3-epoxysuccinate, crystals of which belong to a spatial group P21/n, wherein parameters of a crystal lattice at 22°C are a=15.1916(2), Å, b=8.9121(1), Å, c=7.4724(1), Å, beta=103.309(1)°. The resulting crystalline form of calcium cis-2,3-epoxysuccinate can be used as raw material for the production of L-(+)-tartaric acid. The method for obtaining a crystalline form of calcium cis-2,3-epoxysuccinate includes following stages: a) addition to a maleic acid or maleic anhydride solution of a seed in the amount from 0.01 to 20.0 wt.% of the weight of precipitated calcium cis-2,3-epoxysuccinate; b) incomplete neutralization of maleic acid by the first portion of a calcium compound to produce acid calcium maleate; c) epoxidation of acid calcium maleate with hydrogen peroxide in the presence of an epoxidation catalyst to produce acid calcium cis-2,3-epoxysuccinate; d) neutralization of acid calcium cis-2,3-epoxysuccinate by adding the second portion of the calcium compound; where the crystalline form of calcium cis-2,3-epoxysuccinate is used as a seed, crystals of which belong to the spatial group P21/n, wherein parameters of the crystal lattice at 22°C are a=15.1916(2), Å, b=8.9121(1), Å, c=7.4724(1), Å, beta=103.309(1)°.

EFFECT: obtaining a crystalline form of calcium cis-2,3-epoxysuccinate.

41 cl, 5 dwg, 4 tbl, 5 ex