Hydrocracking of Tetrahydronaphthalene for Preparation of Benzene and Alkylbenzene Catalyzed by Mo/Beta Sulfide Catalyst

Selective hydrocracking (HDC) of aromatic hydrocarbons is an important reaction to obtain high-value monocyclic aromatic hydrocarbons (MAHs) enriched with benzene, toluene, and xylene (BTX). The equilibrium relationship between the metal and acid sites within the bifunctional catalysts typically employed in this process remains unclear. Herein, we report a Mo/beta catalyst with varying Si/Al ratio for HDC of tetrahydronaphthalene (THN) to evaluate the influence of acid site properties on the performance and stability of the HDC reaction. Mo/β-30 catalyst with a moderate Si/Al ratio exhibits optimal HDC performance and gives 36.5% of the desired C6–C10 MAHs yield at a 63.7% conversion of THN for 120 h. The promoted performance and stability of Mo/β-30 are attributed to the well-balanced state between abundant strong acid sites and the uniformly dispersed MoS2 metal sites, which enables rapid transfer and further conversion of intermediate products between the two sites, thereby inhibiting the formation of byproducts and coke deposition. Notably, the Mo/β-30 catalyst is also found to be effective for the HDC of reformed heavy oil into BTX. It achieved 77.0% BTX product selectivity at 44.0% conversion of polycyclic aromatic hydrocarbons (PAHs) over 245 h. This work will provide valuable insights into the design and preparation of efficient industrial catalysts for converting PAHs into high-value MAHs enriched with BTX.