电子级碳酸二甲酯提纯工艺的优化研究

Optimization of Purification Process of Electronic Grade Dimethyl Carbonate

以反应精馏与熔融结晶耦合法制备的电子级碳酸二甲酯为反应原料,采用3A分子筛对该电子级碳酸二甲酯进行再次脱水提纯,从而制备水质量分数小于20μg·g^(-1)的电子碳酸二甲酯,同时降低醇类及其他微量杂质含量。考察连续进料量、脱水停留时间和分子筛吸水情况对脱水效果的影响,优化脱水工艺条件,确保在低能耗的情况下达到电子级碳酸二甲酯脱水提纯的目的,提高产品质量。结果表明:当连续进料量为0.5 mL·min^(-1)、料液停留时间为2.5~3.0 h、初始分子筛吸水量≤1%时,可以将熔融结晶排出的DMC料液中的水质量分数降至20μg·g^(-1)以下。

The electronic dimethyl carbonate prepared by the coupling method of reactive distillation and melt crystallization was dehydrated and purified by 3A molecular sieve,so as to prepare the electronic dimethyl carbonate with water mass fraction less than 20μg·g^(-1) and reduce the alcohol content and other trace impurities.By investigating the effects of continuous feed amount,dehydration residence time and water absorption of molecular sieve on the dehydration effect,the optimal reaction conditions of the dehydration process were optimized to ensure that the purpose of dehydration and purification of electronic grade dimethyl carbonate under the condition of low energy consumption,and the product quality was improved.The results showed that when the continuous feed rate was 0.5 mL·min^(-1),the residence time of the feed liquid was about 2.5~3.0 h,and the initial water absorption of the molecular sieve was less than 1%,the water mass fraction in the DMC feed liquid discharged by molten crystallization was reduced to less than 20μg·g^(-1).