Hydrocracking of 1-methylnaphthalene/decahydronaphthalene mixture catalyzed by zeolite-alumina composite supported NiMo catalysts

Various zeolite-alumina composites supported NiMo catalysts were prepared and their properties for hydrocracking of a decahydronaphthalene (decalin) solution containing 10 wt.% of 1-methylnaphthalene (1-MN) and 0.1 wt.% of dibenzothiophene were investigated in order to estimate not only hydrocracking of hydrocarbons but also isomerization and hydrogenation of 1-MN. 1-MN was converted to 2-MN for almost all the catalysts. The hydrogenation activities to form methyltetralin decreased in the order NiMo/Beta(940)60A > NiMo/Beta(980)60A > NiMo/ HY(5.5)60A > NiMo/USY(390)60A > NiMo/USY(360)60A > NiMo/ZSM60A at 300 degrees C where Beta(940) p zeolite with SiO2/Al2O3 = 37, Beta(980) beta zeolite with SiO2/Al2O3 = 500, HY(5.5) Y zeolite with SiO2/Al2O3 = 5.5, USY(360) dealuminated Y zeolite with SiO2/Al2O3 = 14, USY(390) dealuminated Y zeolite with SiO2/Al2O3 = 400, ZSM ZSM-5 zeolite with SiO2/Al2O3 = 1500, 60A alumina content in a composite support. Hydrocracking was observed at 360 degrees C specifically for beta zeolite containing catalysts and the highest yields of benzene, toluene and xylene were obtained for NiMo/Beta(940)35A. It is elucidated that mesopore is favorable for hydrocracking and that the strength of the acid sites as well as homogeneous dispersion of metal species played an important role. 2013 Elsevier B.V. All rights reserved.