Synthesis Of Phosphine (Phosphine Oxide) Ligands、Isonitrile Ligands And Their Applications In Hydrosilylation

At present,organosilicon products are widely used in our daily life,because they have many advantages,such as non-toxic,excellent weather resistance,good stability,etc.The main production method of organosilicon products in industry is the hydrosilylation reaction,which has the advantages of simpler operation,less by-products,and pure products.At present,the catalysts for hydrosilylation reaction are still precious metal catalysts.However,due to the disadvantages of expensive and difficult recovery of precious metal catalysts,non-noble metal catalysts have gradually become the research object of more and more people.It is expected that non-noble metals can slowly replace precious metal catalysts in the future.In this thesis,a series of silicon-bridged phosphine（phosphine oxide）ligands and isonitrile ligands were synthesized,and these ligands were coordinated with transition metals respectively to explore their catalytic activity for hydrosilylation of olefins.According to relevant experimental research,for the phosphine（phosphine oxide）ligand part,the catalytic effect of the complex Co（BF₄）₂/L（2-2）a is the best after the metal salts coordinate with the phosphine（phosphine oxide）ligand.When the catalytic conditions are:the molar ratio of the ligand to the metal salt is 2:1,the amount of cobalt in the catalytic system is 0.1 mol%of olefin,90°C,and reaction 8 hours,the conversion of 1-octene is the highest,reaching 98.1%,and the selectivity ofβ-addition product is 99.6%.For the isonitrile ligand part,after the coordination of various metal salts with the isonitrile ligand,the catalytic effect of the complex Fe（acac）₂/L（3-7）a is the best.When the molar ratio of the ligand to the metal salt is2:1,the amount of iron in the catalytic system is 0.1 mol%of the olefin,70°C,and reaction 8 hours,the conversion of 1-octene is the highest,reaching 99.4%,and the selectivity ofβ-addition product is 99.8%;It was found that the introduction of silicon atoms into the isonitrile complex can enhance the catalytic activity of the catalytic system.By comparing the catalytic activity of these two types of catalytic systems,it was found that using isonitrile ligands resulted in lower catalytic reaction temperatures.These two types of catalysts also have certain catalytic effects in the hydrosilylation of other linear olefins and olefins containing aromatic substituents;It was found that the conversion of 1-octene can still maintain a yield of over 80%when the catalytic cycle of the hydrosilylation reaction is carried out for four times.