摘要
ZSM-23是一种中孔高硅沸石,由十元环构成的一维主孔遭的孔径略小于ZSM-5,酸强度略高于ZSM-5,具有优良的择形催化性能。比较了不同沸石的二甲苯异构化性能。实验结果表明,异构化的选择性顺序是HZSM-23>HZSM-5>HM,对对二甲苯的选择性顺序是HZSM-23≌HZSM-5>HM,在异构化反应过程中二甲苯损失的顺序是HZSM-23<HZSM-5<HM。在HZSM-23和HM上二甲苯的歧化反应是造成二甲苯损失的主要原因。在HZSM-5上,温度较低时歧化反应引起的二甲苯损失大于脱烷基反应,温度较高时则相反。Pt/HZSM-23对C_8芳烃的异构化具有非常高的选择性,优于Pt/HZSM-5,更优于Pt/HM。
ZSM-23 is a medium pore, high-silica zeolite. Its pore diameter of one-dimensional main channel constituted by lO-membered rings is slightly smaller than that of ZSM-5, and its ac- tivity is slightly higher than that of ZSM-5. It has superior shape selective catalytic properties. Comparison of xylene isomerization properties of different zeolites has shown that the selectivity for isomerization decreases in the order of HZSM-23>HZSM-5>HM, the selec tivity for p-xylene (to o-xylene) is in the order of HZSM-23≌HZSM-5>HM, and the loss of xylenes in the isomerization process increases in the order of HZSM-23<HZSM-5<HM. The loss of xylene over HZSM-23 and HM zeolites is mainly due to the disproportionation reactions of xylene. Over HZSM-5 zeolite, it is shown that, at lower temperature, the loss of xylene caused by the disproportionation reactions of xylene is greater than that caused by dealkylation reactions, but at the higher temperature, the contrary is observed. For the isomerization of C_8 aromatic hydrocarbons, Pt/HZSM-23 has very high selectivity which is superior to Pt/HZSM-5, and far exceeds Pt/HM.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
1994年第2期49-55,共7页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家自然科学基金
天津石化公司资助项目
