Synthesis And Middle-scale Production Of The DL-2-Amino-△～2-thiazoline-4-Carboxylic Acid(DL-ATC)

L-Cysteine is an important biochemical product which is widely used in themedical, cosmetic and food field. DL—2—Amino—△2—thiazoline－4－Carboxylicacid(DL—ATC)is a precursor of L-Cysteine. In the biosynthesis method. From methyl acrylate, DL—2—Amino—△2—thiazoline－4－Carboxylicacid ( DL — ATC ) was prepared through chlorination, dehydrochlorination,neutralization addition and cyclization reactions. Thus, A stream of chlorine isintroduced in a mixture of 1 portion methyl acrylate and 0.03%-0.04% portion ofp-Benzoquinone inhibitor, That the temperature of the mixture is maintained between40oC and 50oC.then metuyl acryeate is chlorinated to obtain 2,3-methyldichloropropianate. Polymerization of methyl acrylate during chlorination isdecreased greatly by using such inhibitor and the incerase quantity of the solubilisedoxygea by the introduce air into the reaction vessel.Yield of methyldichloropropianate can reach 97％。 The following three steps of reaction conditionwere optimized. Thus, 1mol of 2,3-methyl dichloropropianate reacted with about1.5mol of sodium hydrochloric in water at 25~30℃ for 3 hours. Then about 2mol30% hydrochloric acid and 1mol. of thiaurea were added and stirred at 50~70℃ for 3hours and finally 1.5mol 25% ammonium hydroxide was added. Neutralization,cyclization and filtering treatment were used to get the final product. In this way, notonly the procedures are simplified, but also the yield is increased from 72%. to about75%. Beside, the process of the middle-scale production was investigated .the processfor the production of DL—ATC was designed on the results of research work. Theequipment setting and running tests were accomplished and the high quality productswere obtained.The quantitative analytical method using HPLC is also established.