ZnO-La_2O_3-Al_2O_3尿素醇解催化剂的研究

Study on ZnO-La_2O_3-Al_2O_3 Catalyst for Synthesis of Dimethyl Carbonate by Alcoholysis of Urea

以氧化铝为载体,制备了ZnO-La2O3-Al2O3催化剂,对活性组分负载量、焙烧温度以及锌镧比进行了考察,并在催化精馏装置上对催化剂性能进行了考察,对反应温度、进料速率、物料配备等条件进行了考察,在最佳温度下对催化剂连续运行稳定性和重复性进行了考评。结果表明,一浸催化剂最佳焙烧温度500～550℃,二浸活化温度700℃,ZnO/La2O3为1.84时,DMC收率最高。在尿素浓度5wt%～10wt%、进料速率20mL/min、反应温度170℃～175℃、反应压力0.8MPa条件下连续运行300h,DMC最高收率达到33.5%。

In this paper, Catalysts of ZnO-La2O3-Al2O3 were prepared with alumina as carrier,and the catalyst performances was studied by using catalytic distillation.As the results,Theoptimalcalcination temperaturewas 500℃～550℃,ZnO/La2O3 was 1.84. Experiment results show that the best conditions waere as follows: quality concentration of urea in methanol5～10wt%and feed rate of 20mL/min, Reaction Temperature 170℃～175℃,reaction pressure 0.8MPa, over urea alcoholysis, reaction time 300 min, the highest yield 33.5%.