负载钯纳米颗粒催化经由C-H活化的交叉偶联反应研究

Used a variety of metal oxide supported or organically modified Kaolin supported nano palladium particles as catalysts, multiple nano palladium catalyzed cross-coupling reactions via Csp2-H, Csp3-H activation would be researched for achieving recyclable green catalysis reaction. Meanwhile, according the characterization of fresh and used catalysts, the changes of valence state, loading, particle size and dispersity of catalysts were tested and the root cause of the change of yield would be explained. Through the hot filtration test, Hg drop test and three phases test, whether the catalytic active species is homogeneous mononuclear metal or heterogeneous nano metal particles would be confirmed. The comparative studies of the catalytic performance of Pd0 nano catalyst and PdII nano catalyst for every cross-coupling reaction and the catalytic mechanism of heterogeneous catalysis and homogeneous catalysis would be performed for confirming that reaction catalytic cycle is Pd0/PdII, Pd0/PdII/PdIV or PdII/PdIV. In addition, we will apply abundant Kaolin resources of Inner Mongolia, through organic modification, to support palladium nanoparticles for finding a kind of cheap and self-developed heterogeneous catalyst. This project has profound implication to the development of heterogeneous C-H activation reaction study, and it is the only way to realize the industrialization and going green of palladium catalyzed croos-coupling reactions.

本课题拟采用多种金属氧化物或有机改性高岭土负载钯纳米颗粒做催化剂，研究探索多种纳米钯催化经由Csp2-H, Csp3-H键活化的交叉偶联新反应，实现可循环的绿色催化反应。同时通过反应前后催化剂的表征，测定催化剂的价态、负载量、粒径大小、分散度的变化，解释反应产率变化的根本原因。通过热过滤试验、滴汞试验、三相试验等方法确定催化活性物种是均相单核金属原子，还是非均相纳米金属颗粒。对比研究Pd0和PdII两种纳米催化剂在每个交叉偶联反应中的催化性能以及均相/非均相两种催化体系的催化机理，确定反应催化循环是Pd0/PdII, Pd0/PdII/PdIV或PdII/PdIV。另外，我们将应用内蒙古自治区大量的高岭土资源，进行有机改性，使之用于负载纳米钯颗粒，从而找到一种廉价的、自主研发的多相催化剂。此项目对非均相C-H活化反应的发展具有深刻的意义，是钯催化交叉偶联反应走向绿色、走向工业化的必经之路。

本课题针对均相钯催化剂价格高昂、回收利用难、环境不友好等问题，采用不同方法制备了多种以金属氧化物、稀土氧化物或有机改性高岭土为载体的纳米钯催化剂并将其应用于基于C-H活化的交叉偶联反应，实现了多种绿色、高效的非均相钯催化C-H键功能化反应。拓展负载纳米钯催化领域，实现了乙腈与苯硼酸作用制备芳香酮以及乙腈、苯硼酸与苯甲醛三组分级联反应制备吡啶环等新反应。聚焦钯催化中瞬态导向策略，报道了两例瞬态导向控制的立体发散性钯催化C-H活化反应，为非均相钯催化立体发散性C-H活化反应的研究奠定基础。