Preparation method of DL-sodium hydrogen malate

The invention discloses a preparation method of DL-sodium hydrogen malate and relates to the technical field of organic acid salt preparation. The DL-sodium hydrogen malate is prepared by the following steps: in the presence of little anhydrous sodium carbonate, mixing a DL-disodium malate trihydrate crystal with a solid DL-malic acid, and grinding for reaction in a solvent-free condition. According to the preparation method disclosed by the invention, the DL-sodium hydrogen malate is prepared by a solvent-free solid grinding reaction method; and the preparation method has the characteristics of simplicity and convenience in operation, high utilization rate of raw materials and high product yield, is free from environmental pollution and conforms to the idea of green chemistry.