Preparation method of phenylalanine lactate

The invention discloses a preparation method of phenylalanine lactate from phenylalanine and lactic acid, which comprises the following steps: reacting phenylalanine and thionyl chloride to generate phenylalanine acyl chloride, carrying out esterification reaction on the amphetamine acyl chloride with hydroxy group of lactic acid to generate phenylalanine lactate hydrochloride, removing the hydrochloride by saturated sodium carbonate solution precipitation, dichloromethane extraction, saturated washing, distilled water washing, desiccant drying and rotary evaporation desolventization, and finally, purifying the phenylalanine lactate by a secondary molecular distillation technique, wherein the purity of the product is up to 95%. The method has the advantages of mild reaction conditions, higher yield of target product, simple preparation process, environment friendliness, wide raw material sources, advanced separation and purification means and high product purity, and can easily implement industrialized mass production.