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Three industrially modified Y zeolites with a hierarchical structure were characterized by XRD, N2 adsorption–desorption, SEM, TEM, 27Al-/29Si-NMR, in situ pyridine-FTIR, and NH3-TPD techniques. The industrial hydrocracking catalyst of light diesel oil was prepared by kneading and extruding the mixture of 10 wt.% industrially modified zeolite, commercial alumina, nickel nitrate, and molybdenum oxide. The small amount of hierarchical Y zeolite in the hydrocracking catalyst plays a key role, resulting in selective hydrogenation of naphthalene and further ring-opening activity. The mesoporous structure of the zeolites provided an effective interface and improved the accessibility of acid sites to bulky reactants. [ABSTRACT FROM AUTHOR]

In the hydrocracking of 9, 10-dihydroanthracene, acid sites and their locations in the Y zeolites play crucial roles. Hydrogen transfer is the dominant reaction for the industrial Y zeolites with undeveloped mesopores whether at low or high temperatures. Those with developed mesopores exhibit enhanced ring-opening and cracking ability due to the improved molecular transport and accessibility of acid sites. Their ring-opening and cracking ability is crucially related to the amount of highly strong Brønsted acid sites in the high-silica Y zeolites. The reaction processes of 9, 10-dihydroanthracene hydrocracking over the industrial Y zeolites with different properties were expounded rationally. • 9, 10-DHA on various Y zeolites follows the different hydrocracking routes. • Highly strong B acid formed in supercage is key to ring-opening and cracking. • Enhanced acidic accessibility by mesopores promote the ring-opening and cracking. • Acidic and textural properties show synergetic effects on the hydrocracking. • The acidic and textural properties of Y zeolites affect the activation to H 2. [ABSTRACT FROM AUTHOR]

Abstract: A variety of transition metal (M=Cu, Co, Fe and Mn) tetrahydro-Schiff base complexes (denoted as M–[H4]Schiff with Schiff=salen, salpn and salicyhexen, see ) have been encapsulated in zeolite Y with flexible ligand method for the first time. The prepared samples were characterized with X-ray diffraction, diffuse reflectance UV–vis spectroscopy, Infrared spectroscopy, N2 adsorption/desorption at −196°C, elemental analysis, as well as thermo-gravimetry and differential-thermal analysis techniques. The formation of tetrahydro-Schiff base ligand was confirmed with 1H NMR and IR spectroscopy before complexing. The prepared M–[H4]Schiff/Y catalysts such as Cu–[H4]salen/Y showed much higher conversion in the oxidation of cyclohexane than the corresponding M–Schiff analogues encapsulated in zeolite Y as a result of the incorporation of larger amounts and the stronger oxidation ability of tetrahydro-Schiff base complexes. In addition, the M–[H4]Schiff/Y catalysts were also active for the oxidation of other cycloalkanes although their activity depended on the reaction conditions as well as the central transition metals of the complexes and the substrate molecules. It was shown that the catalytic reaction occurred via a radical mechanism. The time for the addition of H2O2 significantly affected the catalytic performance. Earlier (e.g. 20min) addition of H2O2 than substrate molecules to the reaction system led to a drastic reduction in the catalytic activity. [Copyright &y& Elsevier]