对比SSZ-13和SAPO-34分子筛在甲醇制烯烃中的研究进展

发布时间：2018-02-25 18:14

本文关键词： SSZ- SAPO- 分子筛甲醇制烯烃　出处：《化工进展》2017年01期 　论文类型：期刊论文

【摘要】：SSZ-13和SAPO-34是性能优异的甲醇制烯烃(methanol to olefins,MTO)催化剂。本文从酸性、积炭、烃池物种及其反应途径等方面介绍了SSZ-13和SAPO-34的酸强度和酸中心密度的差异及其对MTO反应催化性能的影响,综述了SSZ-13和SAPO-34在MTO中的催化反应机理和失活机理的研究进展。总结显示,尽管SSZ-13和SAPO-34都是CHA型拓扑结构,但SSZ-13的酸性强于SAPO-34,更有利于碳正离子的生成;与修边机理相比,侧链烷基化机理是更主要的反应途径,且SSZ-13的甲基化速率比SAPO-34高3个数量级;SSZ-13和SAPO-34的积炭速率和积炭物种存在差异,积炭行为受温度影响较大。从催化剂的角度,指出合理调控酸强度和酸中心密度、研制出能够抑制反应失活的催化剂结构、发展高产乙烯或者丙烯的特色MTO催化剂是以后的研究方向;从反应机理的角度,认为SSZ-13和SAPO-34在MTO反应中活性中间体的形成以及转化途径、活性物种到积炭物种的演变有待进一步研究。此外,如何在MTO反应过程中观察到高活性的反应中间体是今后研究的难点。
[Abstract]:SSZ-13 and SAPO-34 are excellent catalysts for the preparation of olefins from methanol. In this paper, the difference of acid strength and acid center density between SSZ-13 and SAPO-34 and their effects on the catalytic performance of MTO reaction were introduced from the aspects of acidity, carbon deposition, hydrocarbon cell species and their reaction pathways. In this paper, the mechanism of catalytic reaction and deactivation of SSZ-13 and SAPO-34 in MTO is reviewed. The results show that although both SSZ-13 and SAPO-34 are CHA topologies, the acidity of SSZ-13 is stronger than that of SAPO-34. The alkylation mechanism of side chain is the main reaction pathway, and the methylation rate of SSZ-13 is three orders of magnitude higher than that of SAPO-34. The charring rate and charring species of SSZ-13 and SAPO-34 are different, and the charring behavior is greatly affected by temperature. It is pointed out that it is the future research direction to control the acid strength and the acid center density, to develop the characteristic MTO catalyst which can inhibit the deactivation of the reaction and to develop the characteristic MTO catalyst with high yield of ethylene or propylene. It is suggested that the formation and transformation of active intermediates of SSZ-13 and SAPO-34 in MTO reaction and the evolution from active species to charred species need to be further studied. How to observe high activity intermediate during MTO reaction is a difficult point in the future.
【作者单位】：天津工业大学环境与化学工程学院;
【基金】：国家自然科学基金(21176187) 天津市科技特派员项目(14JCTPJC00559)
【分类号】：O643.36;TQ221.2

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