Effect of alcohols and epoxides on the rate of ROMP of norbornene by a ruthenium trichloride catalyst

Abstract

RuCl3 · xH2O has been used commercially in butanol as a solvent for several decades for the ring-opening metathesis polymerization (ROMP) of norbornene. Different alcohols have now been tested as solvents and the effect of added epoxides studied. The systems using benzyl alcohol or its derivatives with RuCl3 · xH2O are up to 50 times more active than RuCl3 · xH2O/n-butanol. It has been shown that benzyl alcohol reacts with RuCl3 to yield quantitatively benzaldehyde and a ruthenium hydride, which, by reaction with the monomer leads to the ruthenium carbene initiating species. In the case of added epoxides or using tertiary alcohols as solvent, an increase in the rate of polymerization is observed which is attributed to the formation of a ruthenium carbene via an oxaruthenacycle intermediate. Such simple catalytic systems can be used with functionalized norbornenes.