Kinetics and Mechanistic Study of the Methanol Homologation with Cobalt–Ruthenium Mixed Catalyst

The role of each catalyst was examined in detail in the methanol homologation with cobalt–ruthenium mixed catalyst. Cobalt catalyst showed much higher activity for the hydrocarbonylation of methanol than ruthenium. On the other hand, the hydrogenation of acetaldehyde proceeded much more rapidly by ruthenium catalyst. The rate of methanol homologation in 1,4-dioxane with cobalt–ruthenium mixed catalyst system was found to be of the first order with respect to the partial pressure of CO. The in situ IR spectra indicated that [Co(CO)4]− was an active species for the hydrocarbonylation of methanol and that [Rulx(CO)y] existed under the reaction conditions. On the basis of both the kinetic studies and in situ IR spectral observations, the reaction mechanism of methanol homologation was fully discussed.