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  • Author or Editor: Qiubin Kan x
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Abstract  

Salicylaldimine functionalized SBA-15 hybrid mesoporous material was synthesized by post-grafting of salicylaldehyde modified 3-aminopropyltriethoxysilane and followed by introducing Cu(II) ions into the hybrid material via a ligand exchange reaction. The prepared catalyst was characterized by means of XRD, N2 adsorption/desorption, SEM, FT-IR, UV–vis spectroscopy, EPR and XPS techniques as well as ICP-AES and elemental analysis measurements. The solid catalyst was evaluated in the oxidation of styrene with H2O2 as the oxidant under mild conditions, and the reaction parameters (the molar ratio of styrene/H2O2, amount of catalyst, temperatures, solvents, alkaline additive) were investigated and optimized for the oxidation of styrene. The optimal conversion (77.1%) and yield of styrene oxide (60.0%) were obtained at 80 °C using CH3CN as the solvent under basic conditions. Moreover, the covalently anchored Cu(II) salicylaldimine complex showed good recoverability and high stability against leaching of active copper(II) species.

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Abstract

Keggin-type phosphomolybdic acids with molybdenum partially substituted by vanadium and protons completely substituted by tellurium have been prepared, characterized and tested as catalysts in the partial oxidation of isobutane into methacrolein (MAL) and methacrylic acid (MAA). Characterization results showed that the structures of Te(1.5+0.5x)PMo12−xVxOn (x = 1–3) with Mo partially substituted by V can basically be preserved, while the XRD pattern of Te1.5PMo12On was different from H3PMo12O40. It is found that Te element induced a positive effect on the selectivity to MAL with slightly negative effect on the activity and selectivity to MAA.

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Abstract  

ITQ-13, a tridirectional medium-pore zeolite containing 9- and 10-member-ring pores, has been successfully synthesized by a hydrothermal method. The catalytic performance of Mo-ITQ-13 is worse than with Mo-ZSM-5 in the methane aromatization reaction. It has been shown that 9-member-ring channels favor coke and are a disadvantage in methane non-oxidative aromatization.

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Abstract

Two samples of aminopropyl-functionalized silica (APS) have been prepared by grafting an organosilane precursor 3-aminopropyl-triethoxysilane onto the SBA-15 in ethanol or toluene. Aminopropyl-functionalized silica-E (sample grafted in ethanol) and APS-T (sample grafted in toluene) were evaluated in carbon–carbon bond forming reactions such as the Knoevenagel condensation and the Claisen–Schmidt condensation. It has been found that the sample grafted in ethanol displayed better catalytic properties than the sample grafted in toluene. The surface silanol groups, which were proven to be more numerous in samples grafted in ethanol compared to those grafted in toluene, were found to be responsible for the enhanced catalytic activity in carbon–carbon bond forming reactions.

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