Study On The Preparation Technology Of DL-homocysteine Thiolactone Hydrochloride

DL-Homocysteine thiolactone hydrochloride is a sulfur-containing cyclic amino acid derivative and an important intermediate in chemical medicine and material synthesis.In view of the great application value and wide application range of DLhomocysteine thiolactone hydrochloride,it is very important to carry out research and industrial production of DL-homocysteine thiolactone hydrochloride.This article uses DL-methionine,concentrated sulfuric acid,hydrobromic acid,hydrochloric acid,tin powder,etc.as raw materials to synthesize DL-homocysteine thiolactone hydrochloride.The research contents and conclusions are as follows:Firstly use DL-methionine,concentrated sulfuric acid,and hydrobromic acid as the main raw materials to synthesize DL-homocystine.First carry out a single factor experiment to investigate the influence of factors,Then the orthogonal experiment is carried out.The result of the orthogonal experiment show that the order of the factors affecting the yield of the DL-homocystine reaction is: reaction temperature>neutralization pH of the reaction solution>hydrobromic acid amount>concentrated sulfuric acid amount.Optimal process parameters: the molar ratio of DL-methionine to concentrated sulfuric acid and hydrobromic acid is 1:2:3,the reaction time is 12 h,the reaction temperature is 130 ℃,the pH of the reaction solution is adjusted to 6.00,and the reaction solution is neutralized.The base is 10%(mass fraction)KOH aqueous solution.Under these conditions,the yield of DL-homocystine is 81.01%,and the product is confirmed by hydrogen nuclear magnetic resonance spectroscopy,infrared absorption spectroscopy,and high performance liquid chromatography.DL-homocysteine thiolactone hydrochloride is prepared with DL-homocystine,tin powder and hydrochloric acid as raw materials.Preliminary screening of the synthesis process conditions is conducted through a single factor,Then,the process conditions are optimized by response surface method.The results of response surface experiments show that the order of factors affecting the yield of DL-homocysteine thiolactone hydrochloride reaction is: reaction temperature>reaction time>hydrochloric acid amount.Optimal process parameters: the reaction temperature is 30 ℃,the reaction time is 3 h,the amount of hydrochloric acid is 24 m L(6 mol/L),and the amount of tin powder is 0.50 g.Under these conditions,the yield of DLhomocysteine thiolactone hydrochloride is 64.25%,the purity is above 96%,and the melting range is 201.5-202.5 ℃.It has passed the hydrogen nuclear magnetic resonance spectrum,infrared absorption spectrum,and high performance liquid chromatography,Melting point instrument,etc.to confirm the product.The scale-up experiment of the synthesis reaction of DL-homocysteine thiolactone hydrochloride is carried out,and the process is optimized.The total yield is 46-48%,the purity is 96%,and it is DL-homocysteine thiolactone hydrochloride.The industrial production of ester provides the basis.