树形聚合物表面大环载双金属纳米粒子催化二烯类聚合物氢化改性

This project is based on the characteristic of synergistic electronic effect in bimetallic nanoparticles that can be more beneficial to the catalytic reaction of substrate having a double bond. Accordingly, a series of bimetallic RuRh and PdPt dendrimer-templated nanoparticles (DTNs), stabilized by hybrid dendrimers containing a poly(propyleneimine) core and 15-membered triolefinic macrocycles in periphery, will be prepared by using the simultaneous ligand-exchange reaction between the macrocycles and two transition-metal complexes (Ru(PPh3)3/Rh(PPh3)4, Pd2(dba)4/Pt2(dba)4 or Pd(PPh3)4/Pt(PPh3)4). The relationships between formation process and structure of the bimetallic DTNs will be discussed. The hydrogenation degree, catalytic activity, hydrogenation selectivity, and cycle times of the process for hydrogenating diene polymers with the bimetallic DTNs as catalysts will be investigated. The change regularity and mechanism of catalytic hydrogenation of the C=C in diene polymers, as well as the physical and chemical performance of the hydrogenated products will also be researched. It can be expected to provide the theory basis for not only the establishment of novel surface-loaded type of bimetallic DTN catalytic systems, which are of high selectivity, high catalytic activity, good stability, easy recovery, and reuse, but also the hydrogenation modification of catalytic diene polymers.

本项目拟基于双金属纳米粒子的协同电子效应更有利于含双键底物催化反应的特性，利用聚丙烯亚胺为核、表面含十五元三烯大环配体的杂化树形聚合物载体和过渡金属络合物（Ru(PPh3)3、Rh(PPh3)4、Pd2(dba)4、Pt2(dba)4、Pd(PPh3)4、Pt(PPh3)4），通过两种过渡金属络合物配体与大环配体的同步交换反应制备出一系列杂化树形聚合物表面负载的双金属RuRh 和PdPt纳米粒子(DTNs)。探讨双金属DTNs形成过程和结构的关系，考察双金属DTNs催化剂在二烯类聚合物氢化反应过程中的氢化度、催化活性、选择性和循环使用次数，研究二烯类聚合物中碳碳双键催化加氢反应的变化规律、作用机理及其氢化二烯类聚合物的物理化学性能。为建立高选择性、高催化活性、稳定性好、易于回收和循环使用的新型表面负载型双金属DTNs催化体系及其催化二烯类聚合物氢化改性提供理论依据。

氢化是降低二烯类聚合物不饱和度，以改善其耐热性和抗氧化降解性的重要化学改性方法之一。本项目基于双金属的协同电子效应更有利于含双键底物催化反应的特性，利用聚丙烯亚胺为核、表面含十五元三烯大环配体的杂化树形聚合物载体和过渡金属（Rh、Ru、Pd、Pt）化合物，通过两种过渡金属化合物与大环配体的同步交换反应或络合-还原反应制备了一系列杂化树形聚合物表面负载的双金属纳米粒子（或双金属离子）催化剂。探讨了双金属催化剂的形成过程和结构的关系以及催化氢化作用机理。研究了双金属催化剂在二烯类聚合物氢化过程中的氢化度、催化活性、选择性和循环使用效果等，实验结果表明：双金属催化剂的催化活性顺序为Gn-M(Ph7Ru3)＞Gn-M(Rh7Pd3)＞Gn-M(Pd7Pt3)(n = 2,3,4)，且其具有氢化选择性高和较低的产物总金属残留量等优点，这为进一步研发新型表面负载型双金属催化体系及其催化二烯类聚合物氢化改性提供了理论依据。