Synthesis And Application Of Binary Rare Earth Catalysts

Polymer materials are the most important synthetic materials in modern society.They have a wide range of material properties and can be applied anywhere.The development of highly efficient and regio-or stereoselective rare earth metal catalysts for olefin polymerization offers new opportunities for the preparation of high performance synthetic materials with precisely controlled microstructures and desirable properties.In this paper,two kinds of rare earth complexes,lanthanide and lanthanide,were synthesized.The corresponding ligands and complexes were characterized by nuclear magnetic,infrared,elemental analysis and single crystal diffraction characterization.It is combined with a cocatalyst to form a binary catalytic system,which is applied to the polymerization of monoolefins and conjugated diolefins.Their effects on olefin polymerization were studied by adjusting the amount of catalyst,the amount of cocatalyst,the reaction time,and other factors.The research results are as follows:(1)Schiff base ligand is prepared by amine aldehyde condensation reaction using ethylenediamine,propylenediamine,transcyclohexanediamine with salicylaldehyde,The prepared Schiff base ligand is reacted with a Silyl scandium complex to obtain a Schiff base scandium complex.The complex catalyzes the homopolymerization of 4-fluorostyrene after activation of the cocatalyst organic boron salt.The optimal polymerization conditions are:Chlorobenzene is a solvent,and the catalyst is a Schiff base ruthenium complex with less steric hindrance,[Sc]/[B]=1:1,[p-FSt]/[Sc]=100,the binary catalyst system has the highest activity.The obtained polymer has a relative molecular weight of 2.37×104 and a molecular mass distribution of 1.45.The structure is random,no melting point,a glass transition temperature of 112.5? and starts to lose weight and decompose at a higher temperature of 375.0?.It has good hydrophobicity and a static contact angle with water of 92.495°.(2)In the absence of a procatalyst,the cocatalyst organoboron salt also has a corresponding activity for the polymerization of 4-fluorostyrene.The optimum conditions for the organoboron catalyzed Polymerization of 4-fluorostyrene are:20?,chlorobenzene as the solvent,[p-FSt]/[B]=2000,the organic boron salt has good activity.The reaction obtained a random,low molecular weight polymer(9173).having a glass transition temperature of 104.5?,starting weight loss at 375.5?,which also had hydrophobicity,and a static contact angle with water of 90.495°.(3)Synthesis of neodymium triflate with trifluoromethanesulfonic acid and neodymium oxide,and then complexing with TBP,acac,PriOH,C2H5OH to form a complex.Further,forming a binary catalytic system with the promoter aluminum alkyl,the optimum conditions for catalyzing the butadiene using the system are:when the ligand is a relatively sterically hindered tributyl phosphate,the cocatalyst is diisobutyl aluminum,Nd/Bd=0.8×10-4,Al/Nd=25,the activity of the catalytic system is the highest,The obtained polymer has a relative molecular weight of 31.1×104 and a narrow molecular mass distribution(3.06),wherein the cis-1,4 content is 99%or more.