The kinetic studies on the hydrogenation of 1-octene and cyclohexene using a fluoroacrylate copolymer grafted rhodium catalyst in supercritical carbon dioxide (scCO(2)) are reported. The reactions were investigated at temperatures between 50 and 120 degreesC, and pressures ranging from 172 to 241 bar. The catalyst also deactivated at these reaction conditions. For the case of 1-octene, isomerization to (E)2-octene and (Z)2-octene also occurred as side reactions. To represent the experimental data, a kinetic model was developed on the basis of reported studies about hydrogenation and isomerization of olefins in conventional solvents. It was proposed that two hydride catalytic species are formed during the kinetic cycle. Monohydride species promoted the isomerization, and dihydride species catalyzed the hydrogenation. Deactivation of the catalyst was attributed to the formation of an unsaturated olefin complex. Statistical methods were applied to discriminate among rival models. It was found that the rate-determining steps for hydrogenation and isomerization were the formation of the alkylrhodium hydride complex and the coordination of the olefin in the monohydride catalytic species, respectively.