Kinetic Study on Stereospecific Polymerization of 1,3-Butadiene Using a Nickel Based Catalyst System in Environmentally Friendly Solvent

The present work describes the stereospecific polymerization of 1,3-butadiene catalyzed by a nickel naphthenate/triethylaluminum/boron trifluoride etherate catalytic system in a noncarcinogenic solvent mixture. The detailed study on the effect of various parameters on the polymerization and product characteristics is reported. The catalyst concentration and reaction temperature did not have any significant effect on microstructure. Moreover, the conversion was observed to be the maximum at a 1.07 boron trifluoride/alkylaluminum molar ratio. The effect of catalyst concentration showed that at lower concentrations, a lower number of active sites leads to higher molecular weight (<i>M</i>_w) while the polydispersity index (PDI) exhibited a reverse trend. The polymerization was first order with respect to monomer as well as catalyst concentration. The overall rate constant was found to be 0.032 s^–1 mol^–1 for this catalyst system. The activation energy of the polymerization was found to be 14.1 kcal mol<sup>–1