Abstract: Dimethyl carbonate(DMC)was prepared by transesterification of propylene carbonate and methanol with sodium methoxide as catalyst.Based on the traditional process,transformation of floate valve tray was made.The pilot test was carried on the novel reactive distillation column.Effects of tray liquid height,reflux ratio on the product purity were studied.The result shows that the dimethyl carbonate content improved and became stable with the reflux ratio increased;with the tray liquid height increases,the dimethyl carbonate content increased and gradually stable;propylene glycol content decreased as the reflux ratio increased.When the reflux ratio was 0,tray liquid height was 5.2 cm,the content of product can reach 26% or so,content of propylene glycol was less than 0.5%.Comparison of new and traditional process energy consumption was made.The result shows that the new process can save 0.46 t of standard coal per ton of products.

Key words: Dimethyl carbonate,    , Transesterification,    , Reactive distillation column,    , Tray liquid height,    , Reflux ratio

摘要： 以甲醇钠为催化剂,碳酸丙烯酯和甲醇为原料酯交换生产碳酸二甲酯。在传统工艺基础上对浮阀塔塔盘进行了改造,在新型反应精馏塔上进行了中试并考察了塔盘液位高度、回流比等因素对塔顶产品纯度的影响。结果表明,随着回流比增大,塔顶碳酸二甲酯含量开始增加并逐渐趋向稳定;随着塔盘液位高度增加,塔顶碳酸二甲酯含量增加并逐渐稳定;塔顶丙二醇含量随着回流比的增大而降低。在保证塔顶产品含量满足工业要求的前提下,在回流比为0,塔盘液位高度为5.2cm 的工艺条件下,塔顶产品质量分数可达到26%,塔底丙二醇质量分数在0.5%以下。对比了新老工艺的能耗,结果表明新工艺平均每吨产品节能0.46t标准煤。

关键词: 碳酸二甲酯,    , 酯交换,    , 反应精馏塔,    , 塔盘液位高度,    , 回流比