低固废氰乙酸乙酯合成工艺研究

Study on synthesis process of ethyl cyanoacetate with low solid waste

采用先酯化后氰化的方法将氯乙酸先酯化为氯乙酸乙酯,然后在相转移催化剂作用下,氯乙酸乙酯发生氰化反应制得氰乙酸乙酯。优化后的最佳反应条件为:酯化回流时间为3.5h,氯乙酸与乙醇物质的量比为1∶2.0;氰化反应时间为6.0h,反应温度为60℃,催化剂为聚乙二醇与四丁基溴化铵的复配物(m(聚乙二醇)∶m(四丁基溴化铵)=1∶0.4)。在此条件下,氰乙酸乙酯的总收率达到89.58%(以氰乙酸计)。该方法反应步骤少,氰乙酸乙酯含量高,解决了先氰化后酯化固废量大,成本较高的问题。

Using late cyanation method, chloroacetic acid was esterified into ethyl chloroacetate, and then cyanation was used to prepare ethyl cyanoacetate under phase transfer catalyst. The optimized reaction conditions were as follows., the esterification reflux reaction time was 3.5h, chloroacetic acid and alcohol mole ratio of 1 ： 2.0, cyanide for 6. Oh reaction time, reaction temperature was 60℃, the catalyst was a complex formulation of polyethylene glycol and tetrabutyl ammonium bromide （re（polyethylene glycol） ： rn（tetrabutyl ammonium bromide） is 1 ： 0.4）. The total yield of ethyl cyanoacetate was 89. 58% under optimized preparation conditions. This method solved the problem of large amount of solid waste, high cost in late esterification.