Patent ID: 7786336

Claim:
A catalyst composition for ethylene oligomerization, the composition comprising a chromium compound, ligands containing P and N, an activator and accelerator, wherein the chromium compound is selected from the group consisting of acetyl acetone chromium, THF-chromium chloride and Cr(2-ethylhecanoate) 3 ; the general formula of the ligand containing P and N is shown as: in which R 1 , R 2 , R 3 and R 4 are phenyl, benzyl, fluorenyl or naphthyl, R 5 is isopropyl, butyl, cyclopropyl, cyclopentyl, cyclohexyl or fluorenyl; the activator is selected from the group consisting of methylaluminoxane, ethylaluminoxane, propylaluminoxane and butylaluminoxane; the accelerator is selected from the group consisting of 1,1,2,2-tetrachloroethane, 1,1,2,2-tetrabromoethane, 1,1,2,2,-tetrafluoroethane and compounds having a formula of X 1 R 6 X 2 , in which X 1 and X 2 are F, Cl, Br, I or alkoxyl, R 6 is alkylene or arylene group; and the molar ratio of the chromium compound:the ligand containing P and N:the activator:the accelerator is 1:0.5-10:50-3000:0.5-10.