Hydroconversion of n-heptane over bifunctional HZSM5 zeolites - Influence of the metal concentration and distribution on the activity and selectivity

The hydroconversion of n-heptane over HZSM5 and Co-, Ni- and PtHZSM5 was studied at 533 K and 20 bar total pressure. A bimolecular reaction pathway of n-heptane was found on HZSM5. In hydrogen atmosphere a direct hydrogenation of alkenes and a higher activity in comparison to He atmosphere was observed. 2-Methylhexane, propane and iso-butane were found as primary products over metal containing HZSM5 with minor amounts of methane and ethane over CoHZSM5, resulting from hydrogenolysis. The activity and selectivity of metal containing HZSM5 depends on the preparation method. It was found that catalysts prepared by solid state ion exchange showed the highest overall activity and the highest selectivity to isomerization. (C) 1998 Elsevier Science B.V.