Abstract:

A new process of reactive distillation in the dividing-wall column is proposed for the preparation of ethyl methyl carbonate (EMC). In addition to the interesterification between dimethyl carbonate (DMC) and ethanol, the effect of the anti-disproportionation reaction between dimethyl carbonate and diethyl carbonate (DEC) was also considered. The above reactions were integrated into an reactive distillation dividing-wall column to optimize the production process of methyl ethyl carbonate. Firstly, anti-disproportionation reaction between dimethyl carbonate and diethyl carbonate was conducted in laboratory, and the reaction kinetic model is established, experiments verified the reliability of the established process calculation results. Subsequently, the new process was simulated and optimized in Aspen plus, stage number of esterification reaction section, anti disproportionation reaction section, common stripping section, and product rectification section, the optimum feeding position, the optimum technical parameters such as reflux ratio was determined. Compared with traditional reaction distillation three column process, bottom product diethyl carbonate was returned to column in new process, an anti disproportionation reaction zone was added. Which improved product quality and yield obviously, avoided the output of low value by-products, also reduced equipment investment and energy consumption effectively.

Key words: reactive divided wall column, ethyl methyl carbonate, anti disproportionation, process simulation

摘要：

提出了隔壁反应精馏合成碳酸甲乙酯的新工艺，除考虑碳酸二甲酯与乙醇酯交换反应外，还考虑了碳酸二甲酯与碳酸二乙酯反歧化反应的影响，并集成上述反应于一台隔壁反应精馏塔中，优化了碳酸甲乙酯的生产过程。首先，进行了碳酸二甲酯与碳酸二乙酯反歧化反应动力学实验，建立反应动力学模型，并验证了该工艺流程中此模型计算结果的可靠性。然后，运用Aspen Plus对隔壁反应精馏新工艺进行了流程模拟和优化设计，分别确定了酯交换反应段、反歧化反应段、产品精馏段和公共提馏段的理论塔板数，最佳进料位置、回流比等主要操作参数。隔壁反应精馏新工艺与常规反应精馏三塔工艺相比，新工艺将塔釜产品碳酸二乙酯返回隔壁塔内，增加了反歧化反应区，显著提高了碳酸甲乙酯选择性和收率，避免了低价值副产物碳酸二乙酯的产生，并有效减少了设备投资和运行能耗。

关键词: 隔壁反应精馏, 碳酸甲乙酯, 反歧化, 过程模拟