Results 171 to 180 of about 13,522 (202)

Supported VPO Catalysts for Selective Oxidation of Butane. II. Characterization of VPO/SiO₂Catalysts

The Journal of Physical Chemistry B, 1997
SiO2-supported VPO catalysts with different P/V ratios were prepared, used in selective oxidation of butane, and characterized by X-ray diffraction (XRD), laser Raman spectroscopy (LRS), near-edge X-ray absorption spectroscopy (XANES), and 31P magic angle spinning NMR.
Kari E. Birkeland, Scott M. Babitz, Gregory K. Bethke, Harold H. Kung, George W. Coulston, Simon R. Bare   +5 more
openaire   +1 more source

Redox Properties of VPO Ammoxidation Catalysts

Chemical Engineering & Technology, 1999
The purpose of this study is to explore correlations between the molarity of V x IV/V O y proportions of (NH 4 ) 2 (V IV O) 3 (P 2 O 7 ) 2 catalysts, the vanadium valence states, and the reducibility of the vanadium on the one hand and the catalytic activity of the solids on the other. Pure (NH 4 ) 2 (V IV O) 3 (P 2 O 7 ) 2 and two ((NH 4 ) 2 (V IV
Andreas Martin, Bernhard Lücke
openaire   +1 more source

Transient n-butane partial oxidation kinetics over VPO

Applied Catalysis A: General, 2004
Abstract A novel reactor configuration is proposed to study the kinetics of heterogeneous catalytic reactions. It is based on the bubbling fluidization regime; gas velocities are sufficiently low to minimize bypassing but high enough to ensure solids backmixing and a uniform temperature gradient.
Marı́a J. Lorences, Gregory S. Patience, Fernando V. Dı́ez, José Coca   +3 more
openaire   +2 more sources

Characterization of cobalt-impregnated VPO catalysts

Catalysis Today, 2000
Abstract Cobalt-impregnated VPO catalysts containing 1–6% of the metal by weight were prepared. The catalytic tests showed that cobalt impregnation significantly increased the overall activity while slightly decreasing the maleic anhydride selectivity.
L.M. Cornaglia, C.R. Carrara, J.O. Petunchi, E.A. Lombardo   +3 more
openaire   +1 more source

?????????????? ?????????????? ???? ????????????-???????????????????? ???????????????? ?????????????????????? VPO-????????????????????????

2009
?????????????? ?????????????? ?????????????????????????? ?????????????? (????, ??i, Te, Zr, La, Ti, W, Fe) ???? ????????????-???????????????????? ???????????????? ?????????????????????? VPO-??????????????????????????. ?????????????? ?????????????????????? ???????????????? ???????????????????????????? ???????????????? ??????????????, ????????????????????
openaire   +2 more sources

Deactivation behavior on VPO and VPO-Zr catalysts in the aldol condensation of methyl acetate and formaldehyde

Catalysis Today, 2018
Abstract Improvement in activity for the Zr doped VPO catalyst appears to be a general observation in aldol condensation of methyl acetate and formaldehyde to methyl acrylate. The deactivation behavior significantly differs between VPO and VPO-Zr catalysts.
Dan Yang, Gang Wang, Hui Wu, Xinpeng Guo, Suojiang Zhang, Zengxi Li, Chunshan Li   +6 more
openaire   +1 more source

Re-oxidation kinetics of a VPO catalyst

Catalysis Today, 2002
Oxidation of vanadium pyrophosphate (VPO) to the orthophosphate was investigated by temperature programmed oxidation (TPO) and by weight gain measurements in a TGA unit as a model for the re-oxidation of a catalyst in a two-bed process in the partial oxidation of butane to maleic anhydride (MA).
Xiao-Feng Huang, Biao-Hua Chen, Bai-Jian Liu, P.L. Silveston, Cheng-Yue Li   +4 more
openaire   +1 more source

Phase transformations in mesostructured VPO/surfactant composites

Microporous and Mesoporous Materials, 2004
Abstract Mesostructured VPO phases were obtained by soft-chemistry approaches in the presence of charged surfactants. These phases underwent phase transformations to various mesostructured and amorphous VPO phases during thermal treatment in N2 at 400 °C.
Moises A. Carreon, Vadim V. Guliants, M. Olga Guerrero-Pérez, Miguel A. Bañares   +3 more
openaire   +1 more source

No x abatement over VPO catalysts

Catalysis Letters, 1993
Vanadium phosphorus oxide (P/V = 1.1) was found to be active for NO reduction by butane to N2 at 766–816 K. The conversion increased with increasing butane concentration, increasing temperature, and decreasing NO concentration. The activity per surface vanadium ion compared favorably with other active catalytic systems, but was low in the absence of ...
openaire   +1 more source

Synthesis of a novel mesoporous VPO compound

Chemical Communications, 1996
A novel mesoporous VPO compound is synthesized from VOHPO4·0.5H2O by intercalation of surfactant and subsequent hydrothermal treatment.
T. Doi, T. Miyake
openaire   +1 more source