Effect of the Texture and Acidity of a Zeolite-Containing Support on the Activity and Selectivity of NiMoS Catalysts in Hydrogenation and Hydrocracking Reactions

Abstract

Supports based on pseudoboehmite, ultrastable zeolite Y, and ZSM-5 with different silica ratio and concentration of acid sites are prepared. NiMoS catalysts are synthesized by the incipient wetness impregnation of the prepared supports by the joint solution of H₃PMo₁₂O₄₀ and nickel citrate. The composition and properties of the supports and catalysts are studied by low-temperature nitrogen adsorption, ammonia temperature-programmed desorption, IR spectroscopy of pyridine adsorption, and high-resolution transmission electron microscopy. Catalytic properties are investigated in dibenzothiophene hydrodesulfurization (HDS), naphthalene hydrogenation (HYD), and hexadecane hydrocracking (HC) concurrent reactions in a flow unit equipped with a microreactor. It is shown that the HDS activity of the synthesized samples declines as the dispersity of active-phase particles decreases in correlation with a change in the surface area of support mesopores. It is shown that the NiMo/ZSM-5/23 catalyst exhibits a high activity in naphthalene HYD and subsequent reactions of tetralin and decalin naphthene ring opening and hexadecane HC. It is found that the activity of zeolite-containing catalysts in naphthalene HYD grows with the proportion of Brønsted acid sites.