HYDROCONVERSION OF N-HEPTANE OVER DEALUMINATED ZEOLITE OMEGA-CATALYSTS

The hydroconversion of n-heptane was carried out as a probe reaction for the study of zeolite OMEGA catalysts. Various samples were tested, differing in their framework aluminum content, the amount of extra-framework aluminium species (EFAL) and the mesopore volume. A fraction of the EFAL species is catalytically active. As a consequence, for the same silicon/aluminium ratio in the lattice, the total activity and the selectivity for cracking go through a maximum value for a given amount of EFAL species. This behaviour results from a compromise between the positive influence of EFAL species on activity and the negative effect of limiting access to the active sites due to pore blockage by EFAL species.