Effect of zeolite amount on the properties of Pt/(AlSBA-15+Beta zeolite) micro-mesoporous catalysts for the hydroisomerization of n-heptane

The composite (AlSBA-15 + Beta zeolite) materials were prepared using a simple one-step hydrothermal synthesis, aiming to investigate the effect of the ratio AlSBA-15 : zeolite on their physicochemical properties. The resulting micro-mesoporous materials (SBB) containing from 14 to 25 wt% of zeolite were used as supports for Pt catalysts in hydroisomerization of n- heptane (n-C-7). Obtained catalysts were characterized by means of nitrogen sorption, XRD, Py-IR, Al-27 MAS NMR, CO chemisorption, TEM and SEM. It was found, that the textural properties of the micro-mesoporous materials were comparable to pure AlSBA-15. It also appeared that the introduction of zeolite into AlSBA-15 at the synthesis stage affected the total acidity of the composite materials. Both the total acidity and strength of acid sites depended on AlSBA-15: zeolite ratio. The results of n-C-7 hydroconversion showed that catalysts containing 14 and 25 wt% of zeolite provided the highest yield of the most desired, high-octane number products. The most promising Pt/AlSBA-15 + BEA catalysts (i.e. containing 14 and 25 wt% of Beta) allows to improve research octane number from 0 to the 65-70 points.