Chemical Engineering & Technology, Vol.22, No.2, 149-164, 1999
Comparative study of the activity, selectivity, and kinetic analysis of methylcyclopentane reaction on fresh and deactivating supported Pt catalysts
The conversion of methylcyclopentane (MCP) to benzene, cyclohexane, and hydrogenolysis products (2-methylpentane, 3-methylpentane, and n-hexane) on fresh and deactivating Pt/Al2O3 and PtRe/Al2O3 catalysts was studied in hydrogen in a Berty CSTR at four different partial pressures of MCP, 101.3 kPa total pressure, temperatures between 370-400 degrees C and W/F values up to 0.33 g min/cm(3). Two PtRe/Al2O3 catalysts with different pretreatment were used in the investigation in order to examine the effect of bimetallic interaction. PtRe(D) was dried before reduction and PtRe(W) was reduced directly without drying. The directly reduced catalyst is known to possess pronounced Pt-Re interaction. On the fresh catalysts, the activity sequence was PtRe(D) > PtRe(W) > Pt. Conversion to benzene also followed the same pattern although the conversion to cyclohexane and hydrogenolysis products was the reverse. The kinetic analysis showed different rate determining steps on the two catalysts with the activation energy being 23 kcal/gmol on the PtRe/Al2O3 catalyst and 32 kcal/gmol on the Pt/A/O-2(3) catalyst. The PtRe/Al2O3 was found to be more resistant to deactivation although the mechanism of deactivation was the same on both catalysts.