Impact of Pore Architecture on the Hydroconversion of Long Chain Alkanes over Micro and Mesoporous Catalysts

n-Hexadecane hydroconversion has been investigated in a series of bifunctionnal metal/acid catalysts featuring distinct well-defined pore architectures. The acidic components were prepared from dealuminated Y zeolites with Si/Al of 15 and 30 post treated in alkaline medium to generate ordered or non-ordered secondary networks of mesopores and from aluminated ordered mesoporous materials MCM-41, MCM-48, KIT-6 type materials and amorphous silica gel. Activity relates linearly to the strength and number of strong Bronsted acid sites, while selectivity, more precisely the yield in isomerization products, scales directly with the mesopore volume of the catalyst. The architecture of the mesoporous network, namely the ordering, interconnectivity, homogeneity of the mesopores, affects little catalytst behavior. Confrontation of catalytic data with diffusion measurements suggests the existence of an optimal mesopore size above which the number of strong Bronsted sites and the mesopore volume are the only parameters governing catalytic performance.