N-乙基哌嗪合成催化剂及工艺

采用共沉淀法制备CuZnAl复合催化剂,借助N₂吸附-脱附、TG-DTA、XRD和H₂-TPR对催化剂进行表征分析,在固定床反应器中考察反应条件对催化剂性能的影响以及在优选条件下的催化剂活性稳定性。结果表明,CuZnAl复合催化剂具有介孔特征,比表面积和孔径较大,前驱体经500 ℃活化,阴离子基团分解完全,晶体成型,热稳定性好,主活性组分以CuO和CuAl₂O₄尖晶石形式存在,250 ℃条件下经H₂还原为活性相Cu⁰粒子。合成N-乙基哌嗪的适宜条件为:反应温度180 ℃,反应压力2.5 MPa,空速0.5 h^-1,在此条件下连续运行32 d,哌嗪转化率大于85%,N-乙基哌嗪选择性大于95%。

Catalyst and process for preparing N-ethylpiperazine

CnZnAl catalyst was prepared by co-precipitation method,and characterized by N₂ adsorption,TG-DTA,XRD and H₂-TPR.Reaction conditions and stability of catalyst were evaluated in a fixed-bed reactor.The results showed that the catalyst had mesoporous characteristics and high specific surface area,as well as a large pore diameter.After catalyst precursor was activated at 500 ℃,anionic groups decomposed completely and crystal was formed to possess good thermal stability.The main active components existed in the form of CuO and CuAl₂O₄ spinel,which were reduced to active phase Cu⁰ particles by H₂ at 250 ℃.Under optimized reaction conditions which were reaction temperature 180 ℃,reaction pressure 2.5 MPa and space velocity 0.5 h^-1,conversion of piperazine and selectivity to N-ethylpiperazine reached above 85% and 95%,respectively after 32 d of reaction.