改性HZSM-5分子筛催化乙醇胺合成哌嗪

Synthesis of Piperazine from Ethanolamine over Modified ZSM-5 Zeolite

利用离子交换法对HZSM-5分子筛进行改性,得到了KCl-ZSM-5,NiO-ZSM-5,ZnO-ZSM-5,KCl-NiO-ZSM-5和KCl-ZnO-ZSM-5分子筛催化剂,采用X射线衍射(XRD)和扫描电镜(SEM)对催化剂进行表征,并考察了改性HZSM-5分子筛对乙醇胺(MEA)合成哌嗪(PIP)的催化性能。结果表明:HZSM-5分子筛经KCl,NiO和ZnO改性后出现了相应的特征衍射峰,且其表面较改性前出现许多小晶粒;改性后催化剂的活性有所降低,但哌嗪的选择性明显提高。KCl-NiO-ZSM-5催化性能较好,在常压,温度360℃,NH3和MEA物质的量之比为0.7的条件下,原料MEA的转化率和PIP的选择性分别是66.34%和28.66%。

The KCI-ZSM-5, NiO-ZSM-5, ZnO-ZSM-5, KCI-NiO-ZSM-5 and KCI-ZnO-ZSM-5 catalysts were prepared through modifying HZSM-5 zeolite by ion exchange method and were characterized by means of X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The catalytic performance of modified HZSM-5 zeolites in synthesis of piperazine （PIP） from ethanolamine（MEA） were investigated. The results showed that the characteristic peaks of modified HZSM-5 zeolite appeared and many small grains appeared on the surface of the modified zeolites. The HZSM-5 modified by KCI, NiO and ZnO exhibited low reaction activity and high selectivity for PIP. The catalytic performance of KCI-NiO-ZSM-5 was better than that of other modified catalyst and the conversion of MEA and the selectivity of PIP reached 66.34% and 28.66%, respectively, under the conditions of normal pressure, 360 C, molar ratio of NH3 to MEA 0.7.