Catalytic hydrogenolysis of diphenyl ether over Ru supported on amorphous silicon-aluminum-TiO₂

A bifunctional catalyst of Ru₅/ASA-TiO₂ was prepared by using a novel silicon-aluminum (ASA)-TiO₂ amorphous composite, which was synthesized by a steam-assisted method, as the support. X-ray diffraction (XRD), pyridine adsorption infrared (Py-FTIR), ammonia-temperature-programmed desorption (NH₃-TPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and other methods were used to characterize the structure and the acidity of the prepared catalyst. Using diphenyl ether as the lignite-related model compound, the reaction activity of the Ru₅/ASA-TiO₂ for the catalytic hydrogenolysis of 4–O–5 type ether bonds was investigated under a mild condition. The results show that the weak acid and/or the Lewis acid rather than the strong Brønsted acid mainly contribute to improve the conversion rate and the benzene yield of the catalytic hydrogenolysis of diphenyl ether. The reaction temperature can influence the relative content of various types of acids to significantly affect the selectivity of the hydrogenolysis products of diphenyl ether. The conversion rate of diphenyl ether is greater than 98% while the benzene yield is 67.1%.