CONFIGURATIONAL ISOMERIZATION OF CIS-1,2-DIMETHYLCYCLOHEXANES, CIS-1,3-DIMETHYLCYCLOHEXANES AND CIS-1,4-DIMETHYLCYCLOHEXANE AND TRANS-1,2-DIMETHYLCYCLOHEXANES, TRANS-1,3-DIMETHYLCYCLOHEXANES AND TRANS-1,4-DIMETHYLCYCLOHEXANES

Configurational isomerization (henceforth isomerization) of cis-and tr ans-1,2-, 1,3-, and 1,4-dimethylcyclohexanes (henceforth c-1,2, 1,3, 1 ,4 and t-1,2, 1,3, 1,4) has been studied under identical experimental conditions on supported Pt catalyst in the temperature range 373-548 K and partial pressure of hydrogen range 13.3-100 kPa. The effect of te mperature and hydrogen pressure on the reaction rates as well as the a ctivation energies were determined. Plotting the rates of isomerizatio n against temperature reveals maxima. The rate of isomerization of t-1 ,3, increases with increasing hydrogen pressure. Isomers containing ax ial-equatorial (henceforth a,e) methyl groups were converted at a high er rate than those containig diequatorial methyl groups (henceforth e, e). At lower temperatures the experimental data maybe interpreted by t he 'roll-over' mechanism, while at higher temperatures the pi-allyl me chanism proceeding via more unsaturated surface intermediates is invok ed.