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A series of ZSM-5 zeolites with tunable mesoporosity were synthesized by a facile ultrasound-assisted method. XRD, FT-IR and NH 3 -TPD results exhibited that as-synthesized ZSM-5 kept the MFI structure as well as the original acidity. Traced by TEM techniques, the crystallization process, especially the state of initial amorphous gel, was found notably affected by the ultrasound treatment by breaking the weak bonds, which led to formation of mesopores in crystals. The ZSM-5 catalysts with abundant mesoprores inhibited coking significantly and showed high catalytic stability for methanol to propylene reaction. The Z5-us-60 catalyst exhibited the highest catalytic stability for >600 h at a high WHSV of 4.0 h −1 . [ABSTRACT FROM AUTHOR]

Abstract: A series of boron isomorphously framework-substituted ZSM-5 (B x –Al–ZSM-5, Si/Al=200, B/Al=X) were synthesized and used to selectively transform methanol to propylene (MTP). The catalytic stability can be significantly influenced by B incorporation. In comparison with the conventional ZSM-5, the B1–Al–ZSM-5 catalyst afforded a 7-time-long catalytic life under a space velocity of WHSV 1.8h−1 (700h for B1–Al–ZSM-5 and 100h for ZSM-5, respectively). The enhancement of catalytic stability can be attributed to the increase of weak acid sites on the ZSM-5 catalysts. [Copyright &y& Elsevier]

Abstract: The effect of alkali species on performance of MnO/γ-Al2O3 catalysts for methyl benzoate hydrogenation was investigated in fixed-bed reactor. Doping alkali species on MnO/γ-Al2O3 catalysts enhanced the selectivity of benzaldehyde significantly, toluene and benzyl methyl ether were greatly suppressed. The infrared spectra of adsorbed pyridine adsorption was acquired to study the surface acid properties, the results revealed that doping alkali species weakened the acid strength of MnO/γ-Al2O3 catalysts, which lead to restrain from the formation of toluene and benzyl methyl ether. [Copyright &y& Elsevier]

Abstract: Modified high silica HZSM-5 catalysts have been used to selectively transform methanol to propylene (MTP). The HZSM-5 catalyst with a Si/Al ratio of 220 exhibited satisfying catalytic performance (space time yield of propylene is up to 18mmol/gh). The selectivity of propylene can be obviously affected by additives. P leads to a pronounced improvement of propylene selectivity up to 55.6% with complete conversion of methanol. The enhancement of propylene selectivity and catalytic life can be attributed to partial elimination of the strong acid sites on the HZSM-5 catalyst. [Copyright &y& Elsevier]

Abstract: Pt was introduced into pure and polyacrylic acid (PAA) grafting multi-walled carbon nanotubes (MWNTs) by electroless metal deposition method and used as catalysts for hydrogenation of citral. The catalysts exhibited higher activity in the hydrogenation of citral when compared with Pt impregnated active carbon (AC) catalyst, while the selectivity of the catalysts on different MWNTs supports were quite different. The catalyst characterization results reveal that the selectivity of products is related with the morphology of the MWNTs and Pt(111) facet, functionalized carbon nanotubes will orient Pt facet and facilitate its dispersion on support. [Copyright &y& Elsevier]