焙烧温度对草酸二甲酯加氢制乙二醇Cu/SiO_2催化剂性能的影响

Effect of calcination temperature on Cu/SiO_2 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

以氨水(w=28%)作为沉淀剂,十六烷基三甲基溴化铵(CTAB)为改性剂,采用沉淀沉积法(蒸氨法)制备了Cu/SiO2催化剂,采用BET、XRD、H2-TPR等对催化剂结构进行表征,考察了焙烧温度对催化剂草酸二甲酯加氢制备乙二醇反应性能的影响。结果表明焙烧温度影响催化剂晶体结构、孔结构和活性组分的还原性能,从而影响了Cu/SiO2催化剂对草酸二甲酯加氢制备乙二醇的催化性能。当焙烧温度为400℃时催化剂表现出较好的催化性能。在固定床反应器中,当反应温度为200℃,反应压力为2.1MPa,n(H2)/n(DMO)为90,LHSV为0.8h-1,草酸二甲酯的转化率达到100%,乙二醇的选择性为97.3%。

Cu/SiO2 catalysts were prepared using aqueous ammonia （w（NH3）=28%） as precipitant and cetyl trimethyl ammonium bromide （CTAB） as modifier by one of deposition-precipitation techniques--the ammonia evaporation method. The effect of calcination temperature on the performances of catalysts for hydrogenation of dimethyl oxalate to ethylene glycol was investigated by means of XRD, BET and H2-TPR. The results showed that calcination temperature affected the crystal structure, pore structure and active component reducibility of the catalysts, thus influenced the catalytic performances of the catalysts on hydrogenation of dimethyl oxalate （DMO） to ethylene glycol （EG）. The catalyst calcined at 400℃ showed the best catalytic performance, and DMO hydrogenation over this catalyst in the fixed-bed reactor under the reaction conditions of 200℃, 2.1MPa , n （H2）：n （DMO）=90 and LHSV=0.8h-1 gave 100% DMO conversion and 97.3% EG selectivity.