(1) take 1 portion of L-tartaric acid and appropriate amount of organic solvent into the reactor by weight, add 0.1-0.001 portion of catalyst to the reactor under stirring condition, after that, add 1~3 portions of benzoyl chloride to the reactor at a drop acceleration rate of 1-10 mL/min, and then continue the reaction for 4h after the drop is completed, and then, transfer the reaction mixture into a centrifuge for centrifugal separation. Centrifugal separation was carried out to obtain solid L-(-)-dibenzoyltartaric anhydride, standby; said catalyst was copper sulfate or ferrous sulfate;
(2) L-(-)-dibenzoyltartaric anhydride prepared in step (1) was put into the reaction kettle, to which was added an equal weight of toluene and water, and heated and refluxed at 100 for 2-4h, and after that, it cooled down to the ambient temperature, and the resulting mixture was transferred to the centrifuge for the reaction, and then, the mixture was transferred to the centrifuge for the reaction, and then the reaction was continued for 4h. The mixture was transferred to a centrifuge for centrifugal separation to obtain solid L-(-)-dibenzoyltartaric acid.
