Study On Catalyst System For The Selective Trimerization Of Ethylene To 1-Hexene

As an important comonomer in polyethylene, 1-hexene is used in the production of high density polyethylene(HDPE) and linear density polyethylene(LLDPE). 1-Hexene modifies the processing and mechanical properties of the polymer, imparting greater strength and thoughness. Nowadays, 1-Hexene co-polymerization resin has been 55% percent of the total copolymer in many developed countries such as the United States, Europe and Japan, but it has not been produced in China.The research of ethylene trimerization to Hexene-1 was popular at the beginning of 1990s'. The catalyst systems of [Cr(2-ethylhexanoate)3 /2,5-dimethylpyrrole/triethylaluminum/tetrachloroethane] was studied respectively. This project uses the analytic method of FTIR in situ to research the component, structure and coordinate mode of the catalyst system. Preferred reactive condition is be discovered, and the best concentration of Cr in catalyst system is 0.07mmol/L. Conclusions include that the best proportion in catalyst system is N/Cr=5,Cl/Cr=15,Al/Cr=90.According the changes of coordinate bond and relating with experimental results, influence of sequence in affixion has been discussed. So that, catalyst has preferred activity and selectivity, conclusions avoid effectively cause of inactivation.This research brings forward new views on mechanism of ethylene trimerization, which reactive process of ethylene trimerization can be controlled by. A lot of value data is be provided, and actuates olefin industry. Therefore this project has important significance in olefin industry of china.