Development of hierarchical zeolites of different dimensions with potential for bulk hydrocarbon processing.
Zeolites, porosity, dimensionality, bulky hydrocarbons, accessibility.
The evaluation of the influence of secondary porosity, the dimensionality of zeolitic structures with 1D, 2D and 3D pore systems exert on the accessibility of voluminous hydrocarbons to active sites were evaluated in the present work. Y, ZSM-5 and mordenite zeolites underwent different top-down treatments to introduce secondary porosity. The analysis of X-ray diffraction (XRD), X-ray fluorescence (FRX), Fourier Transform infrared spectroscopy (FTIR), infrared spectroscopy of pyridine adsorption and desorption (IR-Pyridine), textural analysis by adsorption and nitrogen desorption, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) confirm the changes. The zeolites Y and ZSM-5 had a high increase in the specific area, reaching values of 858 m2/g with the maintenance of the volume of intrinsic micropores, as well as the increase in the concentration of Brönsted acid sites, reaching values of 625.4 and 892 .7, respectively. The mordenite zeolite showed an increase in the volume of mesopores and high retention values, and subsistence of Brönsted acidity. The materials were applied in the cumene cracking reaction and evaluated against the catalytic accessibility and influence of acidity. The synthesized zeolites Y, ZSM-5 and mordenite proved to be efficient catalysts, reaching values of 100% cumene conversion practically throughout the reaction time. The hierarchy factor (FH) is used to study the influence of the implemented secondary porous network, as well as its hierarchical structural organization.