氨水量对草酸二甲酯加氢制乙二醇Cu/SiO_2催化剂的影响

Effect of amount of ammonia on preparation of Cu/SiO_2 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

以氨水(w(NH3)为28%)为沉淀剂,采用共沉淀法制备了Cu/SiO2催化剂,并用TPR、BET、XRD进行了表征。研究了该催化剂催化草酸二甲酯(DMO)加氢合成乙二醇(EG)的反应性能,考察了制备过程加入的氨水量对DMO转化率、EG选择性的影响。结果表明,氨水量40mL制备的催化剂具有较好的催化性能,在210℃,2.1MPa,n(H2)/n(DMO)为90,LHSV为1.0 h-1的反应条件下,DMO转化率达到100%,EG选择性97.33%。采用40mL氨水制备的Cu/SiO2催化剂具有较高的比表面积、较低的CuO还原温度,还原后的Cu/SiO2催化剂中同时存在Cu+和C0活性中心。

Cu/SiO2 catalysts were prepared by coprecipitation with a 28% by mass aqueous ammonia as precipitator,and characterized by XRD,BET and H2-TPR.The catalytic performances of the catalysts in hydrogenation of dimethyl oxalate（DMO） to ethylene glycol（EG） were investigated,and the effects of the adding amount of aqueous ammonia precipitator on DMO conversion and EG selectivity were discussed.The results showed that the catalyst prepared with 40 mL aqueous ammonia precipitator had the best catalytic performance,over which the conversion of DMO was 100% and the selectivity to EG was 97.33% under the reaction conditions of 210℃,2.1MPa,H2/DMO molar ratio of 90 and LHSV of 1.0h-1.The catalyst prepared with 40mL aqueous ammonia had larger specific surface area and lower reduction temperature,and the Cu＋ and C0 coexisted in the catalyst reduced.