Half-titanocenes catalysts containing phosphine nitrogen ligands for ethylene and ethylene-propylene polymerization

Two novel half-titanocenes catalysts containing phosphine nitrogen ligands were synthesized. The impact of the complex concentration, feedstock composition, molar ratio of Al/Ti, reaction time and pressure were investigated on ethylene polymerization and ethylene-propylene(E/P) copolymerization catalyzed by half-titanocenes/methyl aluminoxane/[Ph₃C][B(C₆F₅)₄] catalytic system as well as on the composition, relative molecular mass and distribution of the polymers. The results show that the catalysts prepared exhibit high activity of 0.62×10⁶ g/(mol·h)in ethylene polymerization, moreover, the activity of the catalysts is similar to metallocene catalyst in E/P polymerization. The E/P copolymer prepared by the catalyst system feature single cite catalyst of high molecular mass with narrow molecular mass distribution. The research on the sequence of the copolymer indicates that r_E×r_P is about 1, the copolymers prepared are random.