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 w as studied at 533 K and 20 bar total pressure. A bimolecular reaction pathway of n-heptane was found on HZSM5. In hydrogen atmosphere a dire ct hydrogenation of alkenes and a higher activity in comparison to He atmosphere was observed. 2-Methylhexane, propane and iso-butane were f ound as primary products over metal containing HZSM5 with minor amount s of methane and ethane over CoHZSM5, resulting from hydrogenolysis. T he activity and selectivity of metal containing HZSM5 depends on the p reparation method. It was found that catalysts prepared by solid state ion exchange showed the highest overall activity and the highest sele ctivity to isomerization. (C) 1998 Elsevier Science B.V.