二甲基甘氨酸盐酸盐的合成

Synthesis of dimethyl glycine hydrochloride

目的 探索氯乙酸路线合成二甲基甘氨酸盐酸盐的方法。方法 用氢氧化钙中和氯乙酸水溶液制得氯乙酸钙 ,过滤去除不溶性杂质 ,然后和二甲氨缩合 ,料液经浓缩 ,酸化 ,过滤制得二甲基甘氨酸盐酸盐。并通过正交实验确定该工艺路线的最佳反应条件。结果 当氯乙酸投料量为 0 3mol时的最佳反应条件为二甲胺 0 . 4 2mol,缩合温度 4 0℃左右 ,缩合时间 2h ,稀释水量 5 0ml。所得产品mp 189～ 192℃ ,w(DMG·HCl)≥ 96 % ,以氯乙酸计收率 5 4 .7%。结论 氯乙酸路线合成二甲基甘氨酸盐酸盐工艺简单 ,原料易得 ,安全性高 ,适合进行产业化。

Objective: To investigate the method of synthesizing Dimethyl glycine hydrochloride (DMG·HCl). Method: Calcium chloroactate may be get by neutralizing monochloroactic acid with the base calcium hydroxide. The filtration containing calcium chloroactate was reacted with dimethylamine. Then the reactant solution was vaporized,acidified and filtrated to get the product DMG·HCl. The preferable conditions were given by orthogonal tests. Results: When the quantity of monochloroacetic acid was 0.3 mol, The preferable reaction conditionds were 0.42 mol dimethylamine, reaction temperature about 40 ℃,2 -hour reacton time and 50 ml dilute water. The yield of product DMG·HCl was 54.7%(based on monochloroactic acid),m.p.189～192 ℃.Conclusion: The process of synthesizing DMG·HCl with monochloroacetic acid as the starting material was simple and safte and the raw materials were easily obtained. It was suitable for industry.