Study On Homogeneous Polymerization Of Butene Oligomerization By Salen-type Metal Complexes

In this thesis,the oligomerization process of butene（n-butene and isobutylene）was studied,and the design,synthesis and oligomerization process of related process catalysts were studied.Firstly,salicylaldehyde with four different substituents（salicylaldehyde,o-vanillin,5-chlorosalicylaldehyde,3,5-di-tertbutyl salicylaldehyde）and 1,2-diamines with two different framework structures（ethylenediamine,o-phenylenediamine）as raw materials,Salen ligands were obtained by aldehyde amine condensation reaction,and eight kinds of Salen-Ni were synthesized by the coordination reaction of Salen ligand and nickel acetate.the structure of the ligands and complexes were characterized by elemental analysis,FT-IR,Uv-vis and TG-DTG.The results showed that high yield of synthesized ligands and complexes,and the obtained complexes have good thermal stability.Secondly,the oligomerization process of n-butene was studied in this condition of the synthesized Salen-Ni complex as the main catalyst,toluene as solvent,and sesquiethyl aluminum chloride as co-catalyst.The influences of the Al/Ni molar ratio of catalyst and reaction conditions（catalyst concentration,polymerization temperature,polymerization time）on the reactivity of Salen-Ni complex were studied.The highest catalytic activity of8.44×10⁵g·mol^-1·h^-1 was obtained on the catalyst with the complex 1c under the optimal reaction conditions of 40°C,reaction time 90 min,n（Al）/n（Ni）=300,and the conversion of n-butene was 63.44%.We further studied the isobutene oligomerization process.Under the condition of complex 1c as the main catalyst,toluene as solvent and sesquiethylaluminum chloride as co-catalyst,The influence of polymerization temperature and polymerization time on isobutene conversion,polymer product selectivity and polymer relative molecular mass and their distribution were investigated.The results showed that the conversion of isobutylene is as high as 92.68%under the conditions of polymerization temperature of 60°C and reaction time of 1 h.The polymerization products are mainly composed of trimerization and polymerization.The relative molecular mass of the polyisobutylene obtained in the reaction is 2000-6000g·mol^-1,the relative molecular mass is between 2.1 and 5.6.