The effect of UTL layer connectivity in isoreticular zeolites on the catalytic performance in toluene alkylation

Toluene alkylation with isopropyl alcohol was used as a model reaction to investigate the effect of UTL-type layer connectivity in a series of isoreticular zeolites and related zeolitic materials. All prepared catalysts possess the same structure of the layers but their connectivity differs from amorphous pillars (IPC-1PI), double-four-rings (UTL), single-four-rings (IPC-2 = OKO, International Zeolite Association code), oxygen bridges (IPC-4 = PCR), or their combinations (IPC-6 and IPC-7). X-ray powder diffraction, scanning electron microscopy, and nitrogen adsorption isotherms were employed to characterize structural and textural properties of the studied catalysts. Deuterated acetonitrile was adsorbed on catalysts to determine the concentrations and type of individual acid sites. Toluene alkylation with isopropyl alcohol evidenced that toluene conversion increases with increasing size of zeolite channels. Simultaneously, selectivity in cymenes increased as open structure of these catalysts did not present optimum reaction volume for the bimolecular reaction of cymenes with toluene to n-propylbenzenes.