Synthesis And Application Exploration Of Multi-site Phosphorous Ligands

In the research field of new ethylene oligomerization and polymerization,the important direction of the study is the new type of polymer catalyst.The space steric and electronic effect in the ligand structure has important influence on the activity of the catalyst, so the molecular design of new ligands and synthesis has become the core work of the new catalyst development.In this paper, the p-phenylenediamine, o-phenylenediamine, m-phenylenediamine,N-ethylethylenediamine, N-propylethylenediamine and N-benzylethylenediamine, N,N’-dibenzylethylenediamine as the raw material, synthesized with chlorodiphenyl phosphine,then achieved seven different multilocus multi-site phosphorous ligands. Using 1H NMR to analysed the characterizs of the ligand structure, it was explored in different conditions such as the reaction temperature, reaction time, reaction solvent, the ratio of raw materials,and got the optimizing reaction of achiving the ligands.Using multi-site phosphorous ligands and metal Cr(III) synthesis the complexes, choose the best ligand L1 and using it in the reaction of the ethylene oligomerization. At the same time, the exploration of the reaction of the polymerization temperature, polymerization pressure, Al/Cr, by PNP/Cr, pre-mixing time, stirring speed and other factors,has effected the activity of the catalyst of ethylene oligomerization. The best results of the catalytic activity and selectivity of the target products were obtained by optimizing the conditions. Through the study, the activity of the catalyst in the catalytic ethylene polymerization was 7.27×106g/(mol Cr·h), and the selectivity to 1-octenes was 68.25%.