The kinetic study of butadiene polymerization with a cobalt-containing catalyst in hexane

The kinetics of butadiene polymerization in hexane initiated by a catalyst prepared through the interaction of cobalt 2-ethylhexanoate with ethylaluminum sesquichloride and isoprene in the absence of water at Co: Al: isoprene = 1: 20: 20 (mol/mol) has been studied. The reaction orders with respect to the monomer and cobalt ethylhexanoate are estimated as 1.45 ± 0.04 and 1.5 ± 0.3, respectively. The concentration of active centers of the catalyst turns out to be 60 mol % of the cobalt concentration, as determined by the fractional inhibition of polymerization with cyclopentadiene. The rate constant of chain propagation, as calculated from the kinetic data, appears to be 1700 l/(mol min). The effective activation energy is 25.1 ± 7.5 kJ/mol.