分子筛骨架铝分布和落位对其甲醇制丙烯催化性能的影响本质研究

分子筛骨架铝分布和落位与其甲醇制丙烯(MTP)催化性能密切相关，近年来在铝分布/落位的研究进展，使得通过调变分子筛铝存在状态改进其催化性能成为可能。本项目首次提出研究ZSM-5等分子筛铝分布/落位对MTP反应的“烃池”结构及作用机制的影响。通过Co2+交换后的UV-Vis、27Al MQ MAS NMR及EXAFS等多种表征技术手段，结合量子化学计算/分子模拟的方法确定不同方法合成分子筛的骨架铝分布/落位；通过in situ 13C MAS NMR、in situ IR、同位素追踪、脉冲反应、模型实验并结合动力学数据和DFT计算结果研究不同铝分布/落位的分子筛上甲醇活化、中间体转变及烯烃生成过程，认识“烃池”物种演变、催化剂失活原理；通过调变分子筛合成原料、加入晶化调节剂、改进合成工艺等环节实现分子筛铝落位的可控合成。项目的实施对定向调控铝分布和落位，设计高性能MTP催化剂具有重要意义。

In recent years encouraging progress has been made in understanding the aluminum (Al) distribution and Al siting in zeolite framework; on the other hand, coal to methanol process is mature, improving the catalytic performance of methanol to propylene (MTP) catalyst and developing MTP technology help to realize the economic transformation in coal dependent regions. In this project, attempts will be for the first time made to investigate the effects of Al distribution/siting in framework of zeolites on their “hydrocarbon pool” mechanism in MTP process, so as to design and prepare high performance MTP catalyst. Combination of UV-Vis spectra of Co2+ exchanged zeolite, 27Al MQ MAS NMR spectra and extended X-ray absorption fine structure (EXAFS) analysis supported by DFT-based molecular dynamics simulations will be used to discriminate individual Al atoms in zeolite framework. The formation, compositions and changes of “hydrocarbon pool” and its interaction mechanism with reactants, intermediates and products will be studied by using a series of spectroscopic techniques and GC-MS to in situ trace the reacting process combined with a variety of model reactions, isotopic experiments and theoretic calculations. Synthesis of zeolites with defined distributions of Al in framework will be achieved by using different Si, Al, Na source and structure directing agent and adjusting the sequence of mixing.