n-Hexane Hydroisomerization on Ni-HMFI Zeolites of Different Preparation Methods

A range of bifunctional catalysts based on MFI zeolite with 1.5 wt. % of nickel was synthesized. The aim of this research was to compare the performance of Ni-HZSM-5 zeolites of different methods of nickel loading (ion exchange and impregnation) in n-hexane hydroisomerization. Samples were characterized by XRD, TEM, and low-temperature nitrogen adsorption/desorption. It is stated that using ion exchange, it is more difficult to control nickel content in the samples. Impregnated sample demonstrates 26.1% yield of branched hexane products with 80.4% selectivity for isomers, whereas ion-exchanged sample gives only 12.5% yield with 80.5% selectivity at 513 K in micro pulse investigations. Therefore, impregnation of zeolites with nickel salt is a more suitable method for obtaining active and selective catalysts for hydroisomerization.