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A new method for the synthesis of molybdovanadophosphoric heteropoly acids and their catalytic activities

ZHANG Fumin, GUO Maiping, GE Hanqing, WANG Jun

《化学科学与工程前沿（英文）》 2007年第1卷第3期页码 296-299 doi: 10.1007/s11705-007-0054-0

摘要： An environmentally benign method for the synthesis of heteropoly acids HPMoVO·HO (PMoV, = 1−3) was developed by the reaction of an aqueous slurry which contained stoichiometric amounts of MoO, VO and HPO. Characterization of the as-synthesized catalysts with inductively coupled plasma (ICP) elemental analysis, thermogravimetry (TG), X-ray diffraction (XRD) and infrared (IR) spectroscopy indicated that V ions substituted for Mo ions in Keggin-type phosphomolybdic acid. The as-synthesized samples were found to be an efficient catalyst for the hydroxylation of benzene which was carried out in a mixed solvent of acetonitrile and acetic acid with aqueous hydrogen peroxide as oxidant. PMoV exhibi ted the highest benzene conversion of 34.5% with phenol selectivity of 100%.

关键词： conversion heteropoly Characterization efficient catalyst Keggin-type phosphomolybdic

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Transition metal-doped heteropoly catalysts for the selective oxidation of methacrolein to methacrylic

Yanxia Zheng,Heng Zhang,Lei Wang,Suojiang Zhang,Shaojun Wang

《化学科学与工程前沿（英文）》 2016年第10卷第1期页码 139-146 doi: 10.1007/s11705-015-1548-9

摘要： Heteropoly compounds with the general formula Cs M H P Mo VO (M= Fe, Co, Ni, Cu or Zn) and Cs Cu H P Mo VO ( = 0.1, 0.3 or 0.7) were synthesized and then used as catalysts for the selective oxidation of methacrolein to methacrylic acid. The effects of the transition metals on the structure and activity of the catalysts were investigated. FTIR spectra showed that the transition metal-doped catalysts maintained the Keggin structure of the undoped catalysts. X-ray diffraction results indicated that before calcination, the catalysts doped with Fe and Cu had cubic secondary structures, while the catalysts doped with Co, Ni or Zn had both triclinic and cubic phases and the Co-doped catalyst had the highest content of the triclinic form. Thermal treatment can decrease the content of the triclinic phase. NH temperature-programmed desorption and H temperature-programmed reduction results showed that the transition metals changed the acid and redox properties of the catalysts. The addition of Fe or Cu had positive effects on the activities of the catalyst which is due to the improvement of the electron transfer between the Fe or Cu and the Mo. The effects of the copper content on structure and catalytic activity were also investigated. The Cs Cu H P Mo VO catalyst had the best performance for the selective oxidation of methacrolein to methacrylic acid.

关键词： heteropoly compounds transition metals selective oxidation methacrolein