采用浸渍法制备了不同Cs质量分数的Cs/SiO₂催化剂,并利用XRD、氮气物理吸附、CO₂-TPD和NH₃-TPD等技术对其进行表征。在固定床反应器中,优化了Cs/SiO₂催化丙酸甲酯与甲醛缩合制备甲基丙烯酸甲酯(MMA)的反应条件,并初步进行了动力学分析。结果表明,Cs质量分数为10%的Cs/SiO₂催化剂性能最优,在反应温度为370℃、反应空速为1.2 h^-1、酯醛摩尔比为1∶1的优化条件下,丙酸甲酯的转化率为46.3%,MMA的选择性接近100%。动力学分析显示丙酸甲酯与甲醛缩合制备MMA的表观活化能为39.1 kJ/mol,非常接近理论值。

Cs/SiO₂ catalysts with different Cs contents are prepared via the impregnation method,and characterized by means of XRD,nitrogen physical adsorption,CO₂-TPD and NH₃-TPD.The reaction conditions for the Cs/SiO₂-catalyzed condensation between methyl propionate and formaldehyde to methyl methacrylate (MMA) are optimized in a fixed-bed reactor,and the reaction kinetics is also briefly explored.It is proved that the Cs/SiO₂ catalyst with a Cs content of 10 wt% is the optimal for the condensation,over which the conversion of methyl propionate reaches 46.3% and the selectivity of MMA reaches nearly 100% under the optimized conditions as follows:the reaction temperature is 370℃,n(MP)/n(HCHO)=1/1,and WHSV=1.2 h^-1.It is shown from additional kinetic analysis that the apparent activation energy for the reaction is 39.1 kJ·mol^-1,close to the theoretical value.

贾鑫(1998-),男,硕士生,研究方向为工业催化,1206380325@qq.com。