Hydroisomerization of n-hexadecane on Pt/HBEA bifunctional catalysts: effect of the zeolite crystallites size on the reaction scheme

The transformation of n-hexadecane was carried out in a fixed-bed reactor at 220 degrees C under a 30 bar total pressure on bifunctional Pt-exchanged HBEA catalysts differing only by the zeolite crystallites size. The activities of the catalysts and especially the reaction scheme depended strongly on the crystallites size. Monobranched isomers were the only primary reaction products formed with the smallest crystallites, while cracking was the main reaction observed with the biggest crystallites. This was explained in terms of number of zeolite acidic sites encountered by the olefinic intermediates between two platinum particles.