ZSM-5分子筛酸位分布及其甲醇制烯烃催化性能的定向管理与调控

ZSM-5分子筛在甲醇制烯烃(MTO)过程中的催化性能和反应机理与其孔道中酸位点分布位置紧密相关. 本文证明在水热合成过程中加入适量的钠离子(Na⁺)可以增加ZSM-5分子筛交叉腔酸位点比例; 从而促进高级甲基苯的生成并加速芳烃循环, 有利于乙烯生成. 相反, 在合成过程中不添加钠离子, 所制备的ZSM-5分子筛直孔道和正弦孔道酸位点比例明显提高, 有利于促进烯烃循环并提高丙烯和C₃₊烯烃选择性.

Regulating the Acid Sites Distribution in ZSM-5 Zeolite and Its Catalytic Performance in the Conversion of Methanol to Olefins

The catalytic performance and reaction mechanism of ZSM-5 zeolite in the conversion of methanol to olefins（MTO） is closely related to the distribution of acid sites in framework. In this work， it was demonstrated that adding proper content of Na⁺ ions during synthesis can increase the proportion of acid sites in the intersection cavity of ZSM-5； the concentration of acid sites in the intersection cavity can promote the formation of higher polymethylbenzene（polyMBs） and the propagation of aromatic cycle， forming more ethene. In contrast， in the Na⁺ ions free synthesis system， more acid sites are distributed in the sinusoidal and straight channels of ZSM-5， which is more encouraging for the alkene cycle and conduces to producing more propene and higher alkenes（C₃₊）.