Polymerization of Isoprene by Means of Titanium Alkoxide-Organoaluminum Catalyst Systems

Abstract

The polymerization of isoprene by means of catalyst systems consisting of titanium alkoxide and organoaluminum compound was studied in benzene solution. Effects of synthetic conditions of several catalysts on the yield, the microstructure and the molecular weight of the polymer were investigated.
In the case o f titanium tetrabutoxide [Ti(OBu)₄], the cis-1, 4-polymerization occurs in the presence of diethylaluminum chloride [AlEt₂Cl] or ethylaluminum sesquichloride as [AlEt_1.5Cl_1.5] a cocatalyst.
Besides, when butoxytitanium chloride combines with organoaluminum compound having appropriate numbers of chlorine atom, it showes an activity for the cis-1, 4-polymerization. In conclusion, the present results suggested that the optimum Cl/Ti mo le ratio for the cis 1, 4-polymerization of isoprene remains constant being 9-12, although the optimum Al/Ti mole ratio changes in each catalyst system.