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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]

Zeolite–zeolite composites composed of Y zeolite cores and polycrystalline β zeolite shells were prepared, in which Y zeolite was overgrown with a thin layer of nano-β zeolite. The incompatibility of the cores and the shells with different zeolite structure types, chemical compositions and crystallization conditions was circumvented by using Y zeolite as the nutrients for the growth of β zeolite crystals since the dissolution of the core zeolites was inevitable during the formation of the shell layers. The structural, crystalline, and textural properties of the as-synthesized samples were characterized by XRD, SEM, TEM, EDS, SAED, N 2 adsorption–desorption, FT-IR, in situ IR spectra of pyridine and di -tert-butyl pyridine. The performances of the as-synthesized zeolite–zeolite composite supported by Ni–Mo active components were investigated during the hydrocracking of Iran VGO oil. The results displayed that the core–shell structured composites with a high-silicon β zeolite shell displayed a better performance in terms of conversion of VGO oil and yield of jet fuel, middle distillate yields and middle distillate selectivity than the reference catalyst and the composite catalyst with a low-silicon β zeolite shell. [ABSTRACT FROM AUTHOR]

Highlights: [•] Asymmetric chiral Ru(II) complexes were encapsulated in zeolite MY. [•] The complex encapsulated in LiY has higher ee selectivity than the homogenous. [•] The alkali metal cation exchanged Y has different host effect to the complex. [•] The reactivity was supported by DFT calculation and UV–vis spectra ananlysis. [Copyright &y& Elsevier]

Abstract: A series of Ru(III) tetrahydro-Schiff base complexes (denoted as Ru[H4]-Schiff base with Schiff base=salen, salpn and salcn, see ) were encapsulated in the supercages of zeolite Y by flexible ligand method. The prepared catalysts were characterized by X-ray diffraction, diffuse reflectance UV–Vis spectroscopy, Infrared spectroscopy, elemental analysis, as well as N2 adsorption techniques. It was shown that upon encapsulation in zeolite Y, Ru(III) tetrahydro-Schiff base complexes exhibited higher activity for the hydrogenation of benzene than the corresponding Ru(III)-Schiff base complexes. This indicates that hydrogenation of the C the Schiff base ligands led to a modification of the coordination environment of the central Ru(III) cations. The stability of the prepared catalysts has also been confirmed against leaching of the complex molecule from the zeolite cavities, as revealed by the result that no loss of catalytic activity was observed within three successive runs with regeneration. [Copyright &y& Elsevier]

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]

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]