By adding BF3·OEt2 (B) and its derivatives to the MoCl3 (C7H15 COO)2-(i-Bu)2 AlO- (Mo-Al) two-component catalyst system of synthesizing 1

2-polybutadi-ene with hydrogasoline as solvent

the catalytic activity was influenced remarkably. By addingthe product of HO -/BF3·OEt2 = 1. 0 to the catalyst system

the highest catalyt-ic activity of molybdenum carboxylate system was obtained for the first time. A conversion of more than 70% butadiene (Bd) was achieved with Mo/Bd = 8. 0×10-5(molar ratio) at 50℃ for 5hr. The conditions to produce the gel were preliminarily thrashed out in synthesizing 1

2-polybutadiene with molybdenum catalyst system

and the reasons of producing the gel was inferred. The influence of the polymerization conditions on catalytic activity

molecular weight and microstructure was also investigated.