基于污染控制的双功能催化剂设计及应用于水介质一锅串联反应

Most chemical transformations rely on multiple synthetic processes to complete a reaction. This iterative synthetic strategy inevitably generates massive toxic solvents, byproducts and wastes, which is one of the major sources of environmental pollution. Water-medium one-pot cascade reactions are believed as the efficient source pollution control approach to overcome these drawbacks and also represent a substantial challenge in environmental catalysis field. To date, the major difficulties in the heterogeneous catalyzed water-medium one-pot cascade reactions are the low reactivity, the narrow reaction types and the poor compatibility between different active sites as well as the tedious catalyst preparation. This project addresses the design, synthesis and characterization of the novel Benzenesulfonic acid and Palladium nanoparticles-containing bifunctional ordered mesoporous materials with high active sites content, controlled distribution and good compatibility, designed surface chemistry as well as tunable pore structure and morphology. We propose to explore the catalytic performances of these bifunctional mesoporous materials in the acid-metal synergistically catalyzed one-pot cascade reactions for the synthesis of high value-added nitrogen-containing products and further test their durability and subsequent reusable efficiency. Meanwhile, we investigate to inquiry the structure and chemistry of the catalysts to achieve a better catalytic performance and fundamentally understanding their influence on the catalytic reactions. Based on various characterizations, the correlation of the catalytic performances to the physical structure, chemical composition, surface chemistry, active sites properties, and the interactions between the active sites and the supports of the bifunctional mesoporous catalysts will be discussed. This success of this project will provide the directed experimental evidence and the fundamental theoretical basis for the source pollution control in chemical production process.

化工生产过程往往涉及多步合成，产生大量有毒有害溶剂、副产物和废弃物，是目前环境污染的重要来源。开发水介质一锅串联反应是实现污染源头控制的有效途径，也是当前环境催化领域的难点。针对现有非均相催化水介质一锅串联反应体系中催化效率低、适用范围窄、活性位兼容性差以及催化剂合成步骤繁琐等关键科学问题，本项目拟通过分子自组装结合金属纳米粒子原位还原方法，制得具有高活性位含量、分布可控且兼容性好，表面性质可调，丰富孔结构和立体形貌的苯磺酸/钯纳米粒子双功能介孔催化剂。研究其在水介质酸催化-金属催化一锅串联反应合成高附加值含氮类化学品的催化性能和反应机理，克服活性位相互干扰，提高催化效率、扩大适用范围以及提高使用寿命。研究活性位负载量、比例、分布及其协同效应，载体形貌、孔结构和表面性质以及载体与活性物种之间的相互作用等对催化性能的影响规律，为化工生产中的污染源头控制提供实验依据和理论基础。

本文采用表面活性剂自组装结合原位还原法或后嫁接法，成功制得一系列新型固体催化剂，包括介孔酚醛树脂负载贵金属纳米粒子（钯或铜）、介孔酚醛树脂负载三氟甲磺酸镱、介孔酚醛树脂负载三氟甲磺酸镱和苯磺酸、氮化碳负载镍纳米粒子和石墨烯负载钯纳米粒子。上述催化剂在一些重要的水介质精细有机合成中包括Knoevenagel缩合，葡萄糖转化至5-羟甲基糠醛、Mukaiyama-Aldol反应、Suzuki和Sonogahisra碳-碳键偶联反应以及光催化卤代烃羟基化反应中均显示出良好的催化能力。深入研究了双功能催化剂中载体的选择、催化剂合成方法、活性物种分布位点、数量及比例、载体与活性位相互作用等若干关键因素在催化过程中的作用，探究了活性位种类、不同活性物种耦合效应以及活性位微环境（亲疏水性、孔道限域效应）等对于活性和选择性的影响，揭示了载体效应（表面积、形貌、表面功能团和吸波性能等）与催化性能之间的使役关系。通过对催化剂物化结构表征以及催化剂动力学研究，阐明了催化剂结构形貌、孔道结构和尺寸、表面化学性质、活性位性质与催化性能间的联系。通过与目前精细化学品合成过程使用的催化剂对比，课题组研制介孔负载型金属和酸催化剂在源头污染控制体现出了明显优势。综上所述，本项目的研究实现了新型催化剂的合成及其应用于精细化学品合成中污染控制，为实现减少化工生产过程中的有机溶剂介质、均相酸、金属离子以及多步反应中产生废弃物和副产物等环境污染物排放提供实验依据和理论基础。.在本项目的资助下，发表项目标注资助的SCI 收录期刊论文12篇，其中影响因子大于5.0 的科研论文9 篇，获得中国授权发明专利5项，培养博硕研究生11名，其中3名硕士生分别到德国达姆施塔特工业大学，同济大学和华东理工大学攻读博士。在该项目资助下，项目负责人还获得了一项国家自然科学基金面上项目、上海市高校特聘教授（东方学者）基金、上海青年拔尖人才和上海曙光计划资助。