Computational study of metathesis degradation of rubber. distributions of products for the ethenolysis of 1,4-polyisoprene

Abstract

The molecular modeling of the product distributions for the ethenolysis of 1,4-polyisoprene at 25 °C using the B3LYP/6-31G(d,p) level of theory reveals that chain–ring and chain–chain equilibria are completely shifted toward the formation of 2-methyl-1,5-hexadiene. The amount of cyclic oligomers at equilibrium with linear molecules is small. The concentration of 2-methyl-1,5-hexadiene at equilibrium with linear isoprene oligomers is of 90 mol%. The value of 1,5-hexadiene at equilibrium with butadiene oligomers for the ethenolysis of 1,4-polybutadiene corresponds to 46 mol%. These results are in agreement with experimental data.