Preparation Of Cross-linked Hydrogen-containing Polysiloxane And Its Supported Nano-silver Or Palladium Catalyst And Its Catalytic Reaction

Silver nanoparticles,among the metal-based nanoparticles,have been of great interest in organic synthesis and has expanded rapidly in the past ten years because of nanosilver catalysts’ unique reactivity and selectivity,stability,as well as recyclability in catalytic reactions.Especially in recent years,the application of heterogeneous silver-based nanoparticles in organic reactions has been proven to be an effective strategy in the development of highly efficient silver-catalyed organic transformations in terms of efficiency and selectivity.In this paper,on the basis of the development of a novel containing Si-H functional silicone semi-interpenetrating network that the organosilicon precursor material containing hydropolysiloxane co-polymenzed with another polymer,we have successfully developed an organosilicon-supported nanosilver,and investiganted its new application in the catalytic hydrosenation,cross-coupling,reactions addition and other reactions.For example,the Ag nanomaterials could be applied to the reduction reaction of primary alkynes and ketones,with achieved good catalytic effect.Therefore,this thesis revealed the strong potential of nanosilver catalysis in organic reactions,the total synthesis of natural products and pharmaceutical molecules.In the first charpter,we summaried and discussed the nanosilver catalysis.Silver nanoparticle catalysis has been applied successfully in organic synthesis in the past ten years.Especially in the last few years,synthetic interest in nanosilver-mediated organic synthesis has increased spectacularly as a result of the novelty of the concept of nanocatalysis and several advantages from an atom-economic and environmentally benign point of view.Undoubtedly,the future direction is to continue to expand the scope of nanosilver-catalyzed organic reactions with unique nanostructural features through investigation of potential methods for the synthesis of supported silver nanoparticles.Secondly,we have described the catalytic synthesis of PMHS-based semi-interpenetrating networks with SiH and other functional groups under mild and solvent-free conditions.The detailed procedure and mechanistic analysis for the synthesis of PMHS-based semi-interpenetrating networks(PMHSSIPNs)with SiH and other functional groups under mild reaction conditions was summarized in this thesis.In addition,similar to the previous reported strategy that with the concept of titanium-promoted reduction of ester with hydrosilane for well-distributed dispersion of titanium and nanosilver on crosslinked PMHS-SIPNs supporter(Ag@TiO2@PMHSIPN),and as a continuous part of previous reports on the catalytic utility of nanoAg@TiO2@PMHSIPN in heterogeneous catalysis,the SiH-containing organosilicon materials was further proved to be an effective support in the construction of nanosilver catalyst.Furthermore,an additional and highly efficient method for the synthesis of primary propargylic alcohols has been developed using PMHS-based semi-interpenetrating networks-supported nanosilver(Ag@TiO2@PMHSIPN)as catalyst.The nanoAg@TiO2@PMHSIPN was also found to be effectively in the oxidation reaction of aniline and hydrosilane,which provided a complementary method for the synthesis of corresponding azobenzene and silanol respectively.We believed that SiH-containing organosilicon materials would be an important support in heterogeneous catalysis.Notably,present work provided a good example for the organosilicon-mediated organic synthesis(SiMOS).Thirdly,the multifunctional SiH group-containing organosilicon materials was proved to be a useful reducing agent and palladium support in the conjugate reductions of various α,β-unsaturated ketones,providing a direct and effective route to a variety of substituted ketones,in which the resulting heterogeneous palladium catalyst also featured with easy preparation,facile recovery and reuse,and high selectivity.Thus the SiH group-containing PMHS-based SIPN material was proved to a multifunctional and important reducing agents and catalyst support in heterogeneous catalysis,in which the PMHSSIPN-derived palladium catalyst was also shown to be recyclable up to 5 times without any observable decrease in yield and efficiency,and it exhibited low metal leaching under the mild reaction conditions.