POLYMERIZATION OF BUTADIENE IN TOLUENE WITH NICKEL(II) STEARATE-DIETHYL ALUMINUM CHLORIDE CATALYST?

A bench-scale batch reactor was used to study the polymerization of butadiene with nickel(II) stearate Et₂AlCl catalyst. In particular, the effects of moisture on polymerization were investigated. The initiation reaction is sensitive to temperature. At 0°C an induction period was observed, but at room temperature initiation can be assumed instantaneous. Water enhances catalytic reactivity, however at water concentrations greater than 10 mmol/L, termination reactions become significant. Maximum conversion is obtained in the 6 to 15 mmol/L range of water. The determining step for the molecular weight of polymer is the chain transfer to monomer. At low H₂O concentration the molecular weight increases with water concentration, however it becomes independent of water concentration at high moisture content. With the help of statistical analysis of the experimental data, a two-active-species model was developed to describe the kinetics of the system and to explain certain polymerization characteristics.