Main catalyst component for olefin polymerization, a process for preparing the same and a catalyst comprising the same

Abstract

The present invention provides a main catalyst component for olefin polymerization, which is prepared by a process comprising the steps of: (i) reacting a magnesium compound in nascent state having a rational formula (RMgX)(MgX), in which R is an alkyl having from 3 to 12 carbon atoms, X is a halogen, and y is a value of from 0.02 to 1, with an alcohol having a formula ROH, in which Ris an alkyl having from 2 to 12 carbon atoms, to form a homogeneous solution; (ii) reacting an alkyl magnesium compound having a formula R'MgR″, in which R′ and R″ are independently an alkyl having from 1 to 20 carbon atoms, with the homogeneous solution formed in the step (i) to form a magnesium complex; (iii) reacting the magnesium complex with a halogenating agent in the presence of a silica, to form a magnesium halide-containing intermediate product; and (iv) reacting the magnesium halide-containing intermediate product from the step (iii) with a titanium compound having a formula Ti(OR)Cl, in which Ris an alkyl having from 1 to 10 carbon atoms and m is an integer of from 0 to 4, to form a titanium-containing main catalyst component. The main catalyst component of the invention, when used together with an orgaoaluminium cocatalyst component in a single polymerization stage in one reactor to catalyze the polymerization of ethylene to polyethylene, gives a polyethylene having a molecular weight distribution of from 6 to 10.