Configurational isomerization ofcis- andtrans-1,2-, 1,3-and 1,4-dimethylcyclohexanes on Rh/SiO2 catalyst

Configurational isomerization ofcis- andtrans-1,2-, 1,3-, and 1,4-dimethylcyclohexanes has been studied on Rh/SiO2 catalyst in the range of 373–523 K and a hydrogen partial pressure range of 13.3–100 kPa. Temperature has a small effect on the isomerization rate while this rate increases with increasing hydrogen pressure. Isomers containing axial-equatorial methyl groups were converted at higher rates than those containing diequatorial methyl groups. The difference between Rh and Pt catalysts can be interpreted by assuming that on Pt the π-bonded surface intermediates play more important role than on Rh.