Study On Synthesis And Catalytic Performance Of High Efficiency Magnetic Mesoporous Catalyst

With the rapid development of economy and the progress of the society, thechemical industries bring benefit to mankind. At the same time, they also bring aseries of problems, such as energy shortage, environment pollution and ecologicaldestruction and so on, which seriously restrict the further development of humansociety and the world economy. Nowadays, through immobiling the homogeneouscatalyst, to overcome the issue that traditional homogeneous catalysts can not berecycled, reduce the consumption of energy and material resources, decline the cost ofthe catalyst and the chemical production, and decrease the pollution problems thattraditional catalysts may cause. Solvent is the medium in the chemical reactionprocess, which is one of the main sources of current chemical pollution. Therefore,loading efficient homogeneous catalysts were applied in green solvents in organicreaction and they reduce the harmful solvent pollution.How to select catalysts’ support is one of the important factors to build efficientheterogeneous catalysis system. Research of mesoporous catalysts has achieved greatprogress, but the separation of catalysts, kinds of active component and theimmobiling ways need to be further developed. Based on the above several aspects toconsider, this paper developed a magnetic mesoporous material as a carrier ofheterogeneous catalysis system, to realize the magnetic quick separation ofheterogeneous catalysts. There are rare earth organometal complexs, organic smallmolecules and precious metals gold nanoparticles as active centers, whichimmobilized on the mesoporous materials, and they realize the application in organicsynthesis. At the same time, through comprehending structure characterization andactivity of these catalysts, in-depth analysis of the structure-activity relationship,provides theoretical and practical basis to design a new efficient and reusable catalyticmaterials. This paper is divided into the following three parts:1) Using propyl sulfonic acid group and phenyl group to modify themultifunctional magnetic mesoporous silica is to be supporter, by covalent bandgrafting trifluoromethanesulfonate rare-earth compounds (Yb(OTf)3), and this catalyst (Yb(OTf)2-MCMS) shows good catalysis activity in Mukaiyama-Aldol reaction in thewater phase. At the same time, the catalysis properities are better than no mesoporousstructure, traditional MCM-41and no hydrophobic phenyl group grafting mesoporoussilica, and even homogeneous catalysts. It is contributed to radioactive short porouschannels and hydrophobic phenyl group which are in favor of absortion and diffusionof reactants to reduce obstacle of mass transferation. Furthermore, this catalyst can bequickly magnetic separated and useable in many times and it keeps almost samecatalysis properity.2) Using propyl sulfhydryl coordinating group grafting magnetic mesoporoussilica is to be supporter, and immobilize chiral organic small molecule catalyst-Quinidine to get magnetic mesoporous organc small molecule catalyst(QD-SH-MCMS) This catalyst can catalyze chiral Michael Addition reaction and getgood activity of catalysis and ee value. Compared to no mesoporous layer andtraditional magnetic mesoporous silica which are to be supporter, we find addition ofTMB to get comparative big aperture will increase the efficient of catalysis. At thesame time, we find this catalyst shows better ee value compared to homogeneoussmall molecule catalyst. Through a series of control experiment, we have thought theconfinement effect of apertures of QD-SH-MCMS is the main reason to get good eevalue. Meanwhile, there are good magnetic response effects in magnetic supporter,andrealize the quick seperation by magnet, and it keeps good properity and ee value afterusing five times.3) Using propyl sulfhydryl coordinating group grafting magnetic mesoporoussilica is to be supporter,. Then get sulfonic acid and nano-gold dual active centersmagnetic mesoporous silica, using redox reaction of sulfhydryl groups which are onthe supporters and chlorauric acid. This catalyst shows good activity in benzeneacetylene hydration reaction in water phase, and compared with no mesoporous layerand amorphous silica and MCM-41catalyst, it shows better activity in catalysis.