Patent ID: 7354981

Claim:
A polyethylene catalyst consisting of a main component of catalyst and a cocatalyst, wherein the main component of catalyst is prepared by a preparation process comprising reacting the following components: (1) a magnesium-alcohol complex prepared by reacting a magnesium compound in nascent state having a formula (MgRX) y (MgX 2 ) with an alcohol compound R 1 OH and an electron donor ED, wherein R is alkyl having 3-12 carbon atoms, X is halogen, y is in a range of from 0.02 to 4, and R 1 is alkyl having 2-12 carbon atoms, and wherein molar ratio of the alcohol compound to Mg in the magnesium compound in nascent state, R 1 OH:Mg, is in a range of from 0.5:1 to 6:1; (2) an alkyl aluminum compound having a formula R 3 n AlCl 3-n supported on silica, wherein R 3 is alkyl having 1-14 carbon atoms, and n is in a range of from 1 to 3; and (3) a titanium compound having a formula Ti(OR 2 ) m Cl 4-m , wherein R 2 is alkyl having 1-10 carbon atoms, and m is in a range of from 0 to 4; and the cocatalyst is an organic aluminum compound, and molar ratio of Al in the cocatalyst to Ti in the main component is in a range of from 30:1 to 300:1, wherein the preparation process produces a catalyst that, in a slurry polymerization process, catalyzes the polymerization of ethylene to polyethylene such that, under polymerization conditions of a temperature of 85Â° C., a total pressure of 1.0MPa, a ratio of Al/Ti of 200, a polymerization time of 2 hours, hexane as diluent, and addition of hydrogen gas, the catalyst exhibits a polymerization activity that drops by no more than 61% when a ratio of hydrogen/ethylene in the polymerization process increases from 0.2/0.8 to 0.7/0.3.