The kinetic behaviour of polymerization of butadiene with Ti(n-C4H9O)4-xClx-Al(i-C4H9)3 systems in hexane with variable X values has been studied. The results showed that both the catalyst activity and the apparent activation energy decrease as the chlorine content of the system increases. In the range of AI/Ti value from 15 to 90 (mole ratio)

the polymerication rate is first order with respect to the concentration of both monomer and Ti catalyst

but is not much effected by the concentration of Al cocatalyst. The efficiency of the catalysts is only 0.5-1.5%

increasing slightly with increase of the X value

while the relevant propa-gation rate constants decrease greatly. Therefore the polymerization rate reduces as the chlo-rine contents of the systems increase.