Hydroisomerization of n-hexadecane over bifunctional Pt-HBEA catalysts. Influence of Si/Al ratio on activity selectivity

International audiencen-Hexadecane (n-C-16) transformation was carried out at 220 A degrees C and 30 bar on bifunctional PtHBEA catalysts, using HBEA zeolites with different Si/Al ratios (11, 16 and 26). An "ideal" bifunctional catalyst both active and selective for the hydroisomerization of n-hexadecane was obtained using a HBEA zeolite with a 26 Si/Al ratio and a metal content of 1 wt%. On this catalyst, the balance between the two functions was enough to allow that the bifunctional process is limited by the acid steps. The number of acid sites encountered by the alkene intermediates during their diffusion between two Pt sites is 1. Moreover, this "ideal" catalyst yielded a quite interesting cracking distribution with a high formation of heavy products (C-9 (+))