Process for preparing r-(-)-carnitine from s-(-)-chlorosuccinic acid or from a derivative thereof

摘要

A process for the preparation of S-(-)-chlorosuccinic acid comprising the reaction between S-(+)-aspartic acid and sodium nitrite in a hydrochloric acid-aqueous milieu being said S-(+)-aspartic acid suspended in demineralised water in a w/v ratio ranging from 1 kg/L to 0.5 kg/L, and concentrated hydrochloric acid being added in a ratio of S-(+)-aspartic acid to hydrochloric acid ranging from 0.35 kg/L to 0.55 kg/L, in the presence of sodium chloride, said S-(+)-aspartic acid and said sodium chloride being in a molar ratio ranging from 1:0.3 to 1:0.5, the improvement wherein consists in the isolation by precipitation of the reaction product by cooling the reaction mixture at a temperature ranging from -10 DEG C to -20 DEG C.