反应精馏合成氯乙酸甲酯新工艺过程研究

摘要

提出了反应精馏合成氯乙酸甲酯的一种新工艺.首先运用化工软件对反应精馏过程进行模拟优化,其结果为:精馏段理论板数为6块板,反应段理论板数为10块板,回流比为0.6,水相回流率为0.15,釜酸质量分数在22％-37％左右,塔顶得到质量分数为93.3％的氯乙酸甲酯.再对脱水塔进行优化,精制后氯乙酸甲酯质量分数为99.98％.在模拟基础上,进行反应精馏小试实验,最终确定回流比为1,水相回流率为0.2,釜酸质量分数在28％-40％,塔顶有机相中氯乙酸甲酯质量分数为93.74％,后续对粗酯进行简单脱水,即可得到质量分数高于99.5％的氯乙酸甲酯.将精馏塔小试结果与模拟结果相比较,误差均小于10％,验证了模拟计算的可靠性.%A new technology for the synthesis of methyl chloroacetate by reactive distillation was presented.Firstly,the chemical software was used to simulate and optimize the reaction distillation process,the results are as follows:theoretical plates numbers of distillation section is 6,theoretical plates numbers of reaction section is 10,the reflux ratio is 0.6,the reflux ratio of water phase is 0.15,the mass fraction of chloroacetic acid is about 20 percent to 35 percent,and the mass fraction of methyl chloroacetate in the top of the column is 93.3 percent.And then the dehydrating tower is optimized,the purity of methyl chloroacetate after purification is 99.98 percent.On the basis of simulation,the reaction distillation experiment was carried out.And finally it is determined that the reflux ratio is 1,the reflux ratio of water phase is 0.2,the mass fraction of chloroacetic acid is about 28 percent to 40 percent,the mass fraction of methyl chloroacetate in the organic phase from the top of the column is 93.74 percent.After the crude ester is simply dehydrated,the mass fraction of methyl chloacetate is higher than 99.5 percent.The experimental results of the distillation column were compared with the simulation results,and the errors were less than 10％,which verified the reliability of the simulation.