直接法合成HZSM-5型分子筛的B酸和L酸中心的NMR,EPR研究  

NMR AND EPR STUDIES ON B AND L ACID SITES OF HZSM-5 SYNTHESlSED BY DIRECT METHOD

作　　者：王敬中[1] 王者福[1] 郭振亚[1] 周达明[1] 李赫咺[1] 

机构地区：[1]南开大学

出　　处：《石油学报（石油加工）》1991年第1期109-114,共6页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中国科学院自然科学基金资助项目

摘　　要：用EPR实验证实直接法合成分子筛原粉经酸交换(HZSM-5),150℃烘干(不焙烧)样品骨架存在L酸中心。随着焙烧温度升高,L酸中心数量增长,且在600％～700％焙烧温域有突变上升。对不同温度焙烧的HZSM-5样品的NMR观察证实,随预焙烧温度升高,B酸中心数量减少,也在600℃～700℃焙烧温域有突变式的骤降。研究L酸中心的增加和B酸中心数量的减少之间的关联有助于深化对分子筛酸中心认识,并提供分子筛改性的依据。It has been verified by experiments that the Lewis acid sites(LA) exist in the framework of the zeolite which has been synthesized without template reagent and then acid exchanged(HZSM-5) and dried at 150℃. The number of LA increases with the increase of precalcining temperature and increases acutely when the precalcining temperature reaches 600～700℃. It has also been verified by NMR observations for samples calcined at different temperatures that the number of the Bronsted acid sites(BA)decreases with the increase of the precalcining temperature while a steep decrease occurs at 600～700℃. The investigation of the correlation between the increase of LA and the decrease of BA are helpful to the deep understanding of the acid sites and provides informations for the modifications of zeolites.

关 键 词：HZSM-5 分子筛 B酸 L酸 NMR EPR 

分 类 号：TQ424.25[化学工程]