ABSTRACT
The applicability for investing and comparing two zeolites (H-ZSM-5 and H-MOR) as supports for low-platinum, less-expensive, catalysts for the hydroisomerization of n-paraffins in petroleum naphtha is investigated. n-Hexane was used as a model n-paraffin feed at temperatures of 250-500oC in a pulsed reactor in hydrogen flow at atmospheric pressure. The H-ZSM-5 zeolite acquires higher density of strong acid sites which are still less strongly acidic than H-MOR. These somewhat milder acid sites enhance hydroisomerization after incorporating 0.15%Pt. Moreover, hydrochlorination and hydrofluorination of the 0.15%Pt/H-ZSM-5 catalyst were carried out for modifying its acidity hoping to maximize its hydroisomerization activity. Furthermore, the effect of this hydrohalogenation treatment on other hydroconversion reactions (hydrocracking and dehydrocyclization) was investigated. The HCl treatment has significantly enhanced the required catalytic functions, whereas HF appears mostly deteriorative.