硫代乳酸清洁化合成工艺研究

Study on Clean Synthesis Process of 2-Mercaptopropionic Acid

以2-氯丙酸为原料合成硫代乳酸2-巯基丙酸,并对反应影响因素进行探讨,通过多次实验,得到了能够达到最大收率且成本较低的最优条件.实验结果表明：反应介质pH值、取代反应时间、酸解反应时间、浓硫酸（或浓盐酸）的用量、金属粉的用量、取代反应的温度、酸解反应的温度对反应有明显影响.当控制取代反应介质pH值近中性,取代反应的时间为5h,酸解反应时间2.5 h,浓硫酸（或浓盐酸）用量为1～1.5份（摩尔比,2-氯丙酸为1份）,金属粉用量为3～5份（同上）时,2-巯基丙酸的收率高达78％,纯度大于98％（GC）.

Taking 2-ehloropropionic acid as raw material to synthesize 2-mercaptopropionic acid, discussed the influ- ence factors of the reaction. Through several experiments, obtained the optimal conditions under which the yield was maxi- mal and the cost was low. The experimental results showed that the acidity of reaction medium, the reaction time of substi- tution, file reaction time of acid hydrolysis, the amount of concentrated sulfuric acid or concentrated hydrochloric acid, tile amount of metal powder, the reaction temperature of substitution and acid hydrolysis had significant effects on the reaction. When the acidity of reaction medium was neutral, the reaction time of substitution was 5 h, the reaction time of acid hy- drolysis was 2.5 h, the molar ratio of concentrated sulfuric acid （hydrochloric acid） to 2-ehloropropionic acid was 1-1.5, the molar ratio of metal powder to 2-chloropmpionic acid was 3-5, the yield of 2-mercaptopmpionic acid reached 78%, and its gas chromatography purity was greater than 98%.