Long-Term Deactivation of Supported Pt Catalysts in the Dehydrogenation of Methylcyclohexane to Toluene

The kinetics of methylcyclohexane (MCH) dehydrogenation over supported Pt catalysts was successfully described by a non-Langmuirian/noncompetitive Horiuti-Polanyi model (Ind. Eng. Chem. Res., in press). The daily reversible and irreversible deactivation, associated with activity tests, was satisfactorily included in the dehydrogenation model. The objective of this work is to incorporate the long-term deactivation of Pt catalysts, associated with life or deactivation tests, in the kinetic model. This has been successfully achieved by assuming that the long-term deactivation is the sum of two exponential decay processes, one rapid and completed in a few days, while the other is slow with a half-life of weeks to months.