Method for preparing L-(+)-lactic acid

Abstract

The invention discloses a method for preparing L-(+)-lactic acid, relates to an enzyme method for synthesizing the lactic acid, and is a technology for producing the L-(+)-lactic acid by catalyzing asymmetric hydrolytic ethyl lactate in the enzyme method in an organic phase. The method has the steps that the ethyl lactate and water are taken to be added into a reactor, and then organic solvent and lipase catalyst are added, wherein, the materials has the compounding ratio that the mass ratio of the ethyl lactate and the water is 3 to 15:1, the dosage of the lipase catalyst is 0.4 to 1 percent of the mass of the ethyl lactate, and the volume of the water is 1 to 10 percent of the volume of the organic solvent. After being sealed, the reactor is put into a thermostat water bath shaker, the number of revolution of the shaker is 220 to 50 revolution / minute, the reaction temperature is 30 to 70 DEG C, the reaction time is 3 to 28 hours, and after the reaction is finished, the product, namely, the L-(+)-lactic acid can be obtained by distilling the molecules of the resultant. The invention has simple method for preparing the L-(+)-lactic acid, the reaction condition is mild and the environmental pollution is small; the stereo selectivity of the obtained product is high, the ee value of the L-(+)-lactic acid is 50 to 94 percent, and the yield rate thereof is 10 to 40 percent.

Description

technical field

[0001] The technical solution of the present invention relates to the technical field of synthesizing lactic acid using an enzyme method, specifically the preparation method of L-(+)-lactic acid. Background technique

[0002] The lactic acid used in the food industry is about 50% spinolactic acid. Due to the different metabolic pathways of D-(-)-lactic acid and L-(+)-lactic acid in the human body, the human body can only metabolize L-(+)-lactic acid, and the ingested D-(-)-lactic acid will be in the human body Accumulation, too much D-(-)-lactic acid can cause an increase in the uric acid value of the human body. Therefore, the World Health Organization has stipulated that only L-(+)-lactic acid is allowed to be used in baby food. In addition, highly optically isomerized poly-L-(+)-lactic acid (L / (L+D) > 92%) has good application prospects in orthopedic surgery, artificial surgical sutures, vascular surgery and drug release materials. In addition, L-(+)...