尿素醇解法合成碳酸二甲酯的工艺对比研究

摘要

以尿素和甲醇为原料,利用尿素醇解法直接合成碳酸二甲酯(DMC),研究对比了催化精馏法、溢流法、釜式连续法、固定床一段法、固定床两段法等不同工艺.结果表明,固定床一段法上行料工艺所得DMC收率及反应器出口DMC质量分数最佳；在进料的尿素质量分数为5％ ～ 10％,反应压力为1.0 MPa,反应温度为180 ～ 190℃,液体体积空速为0.18～0.22 h-1的适宜条件下,DMC的收率高于70％,反应器出口DMC质量分数大于5％.%Processes,such as catalytic distillation, overflowing, kettle - continuous reaction, one - stage fixed bed and two - stage fixed bed methods, were compared for the the synthesis of dimethyl carbonate ( DMC ) by direct alcoholysis of urea. The results showed that the one - stage up - flow fixed bed process had the highest DMC yield and DMC mass fraction at the outlet of reactor. Under the suitable conditions of mass fraction of stock urea 5% -10% ,pressure 1.0 MPa, temperature 180 - 190 ℃ , liquid - volume hourly space velocity 0. 18 -0.22 h-1 , DMC yield was over 70% , DMC mass fraction at the outlet of reactor was over 5% .