双活性中心Cu-分子筛的构筑及催化氧化羰基反应的机理研究

Dimethyl carbonate is an important eco-friendly chemical with diverse applications. Gas-phase oxidative carbonylation is a competitive technology in according with the concept of “Green Chemistry”, which has attracted much attention of scientific and industrial community. Since Cu-zeolite catalysts have exhibited good performance and stability, the relevant studies contribute to the development of this process as well as the rational design of metal-zeolite materials and analysis of their structure-performance relationship..This work focuses on the controllable fabrication of Cu-zeolite catalyst with dual active centers, which are isolated Cu+ ions bonding to the zeolitic framework and Cu2O aggregates. The main content includes the following aspects: (1) Clarifying the influence of the location, coordination environment and valence states of Cu active sites on catalytic performance. (2) Improving the accessibility of active sites and eliminating the diffusion limitation through directional regulation of zeolite composition and channel structure. (3) Elucidating the synergy between isolated Cu+ ions and Cu2O aggregates and building a complete reaction network. It is anticipated that this research will give direction and provide reference for the rational design of catalyst in organic carbonate synthesis via oxidative carbonylation.

碳酸二甲酯（DMC）是一种重要的绿色化学品，有着广泛的用途。气相氧化羰基法符合当前“绿色化学”的理念，是一条具有竞争力工艺路线，近年来已成为学术界和产业界基础研究和技术开发的热点。Cu-分子筛催化剂在该反应中表现出良好的活性和稳定性，其相关研究不仅有利于该工艺的进步，同时也对金属-分子筛催化材料的设计和构效关系解析提供了参考。.本项目拟过构筑兼具骨架Cu+离子和Cu2O双活性中心的分子筛催化剂，确定双活性位点的最优比例，明确活性中心的存在形式、位置及配位环境对催化性能的影响。通过载体组成和孔道结构的定向调控，提高活性中心的可接近性，消除内扩散的影响。结合实验和量化计算，探究Cu+和Cu2O双活性位的协同催化机制，建立包括副反应在内的完整的反应网络。为指导氧化羰基化合成有机碳酸酯的催化剂设计、开发提供实验基础及理论参考。

氧化羰基法合成烷基碳酸酯符合当前“绿色化学”的理念，是一条具有竞争力工艺路线。Cu-分子筛催化剂在氧化羰基合成烷基碳酸酯反应中表现出良好的活性和稳定性，是近年来学术研究和技术开发的热点。双活性Cu位点的调控、空间限制对催化性能的影响机制及协同催化反应机理是该工艺目前研究的难点。本项目针对上述科学问题，通过不同制备方法（蒸氨法、浸渍法）、还原方法（H2、甲醇、惰性气氛热处理）获得了Cu双活性中心的分子筛催化剂，明确了铜物种在制备过程中的演变及存在形式、配位环境、落位情况等性质，建立了不同铜物种与催化性能的定性定量关系。通过后处理和水热合成的手段调节了分子筛载体的酸位分布，实现分子筛Cu交换位点的定向调控。此外，结合原位实验及量化计算，阐明了活性铜物种对反应的促进机制，建立了包括副反应在内的完整的反应网络。本项目的研究结果有望为指导氧化羰基化合成有机碳酸酯的催化剂设计、开发提供实验基础及理论参考。