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1.
G.Ya. Popova Yu.A. Chesalov T.V. Andrushkevich E.S. Stoyanov 《Reaction Kinetics and Catalysis Letters》2002,76(1):123-129
Decomposition of formic acid over V-Ti-O catalysts was studied by in situ IR spectroscopy. Four surface compounds, among which are H-bonded acid, one mono- and two bidentate formates (BF1 and BF2), were identified in the temperature range of 100-190°C. The activation energy and rate of the BF2 decomposition were found equal to those for the CO formation. This equality points to the involvement of BF2 in the HCOOH decomposition into carbon monoxide. 相似文献
2.
V.M. Bondareva T.V. Andrushkevich O.B. Lapina A.A. Vlasov L.S. Dovlitova 《Reaction Kinetics and Catalysis Letters》2003,79(1):165-173
Vanadium-titanium catalysts modified with phosphorus additives (1-15 wt.% of P2O5) have been studied in methylpyrazine ammoxidation. Introduction of high amounts of the additive (≥ 10 wt.% of P2O5) results in a decrease in activity and selectivity of the catalysts due to formation of low active phase - a ternary compound
with the component ratio V : P : Ti ≈ 1 : 1 : 1 with only one type of slightly distorted tetrahedral vanadium (5+) bound via
oxygen to phosphorus (5+). The nature of the active sites of the samples modified with 1-5 wt.% of P2O5, similarly to that in the V-Ti-O catalyst, was found to include the V5+ cations strongly bound with TiO2 and located in the significantly distorted octahedral oxygen environment.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
Bondareva V. M. Andrushkevich T. V. Lapina O. B. Khabibulin D. F. Vlasov A. A. Dovlitova L. S. Burgina E. B. 《Kinetics and Catalysis》2004,45(1):104-113
Oxide vanadium–titanium catalysts modified by phosphorus additives (20V2O5–(80 –n)TiO2–nP2O5, n = 1, 3, 5, 10, and 15 wt %) are studied in methylpyrazine ammoxidation. Two regions of compositions are found corresponding to radically different catalytic properties, namely, catalysts with a low (5 wt % P2O5) and high (10 wt % P2O5) concentration of the additive. In the first case, the introduction of phosphorus is accompanied by a gradual increase in the activity. In the second case, an increase in the additive concentration results in a decrease in the activity and selectivity to the target product, pyrazineamide, and a simultaneous increase in the selectivities to by-products, pyrazine and carbon oxides. The catalysts are characterized by X-ray diffraction analysis, differential dissolution, IR, and NMR spectroscopic data. As in the binary system, the active sites of the samples with a low concentration of phosphorus contain V5+ cations in a strongly distorted octahedral oxygen environment, which are strongly bound to a support due to the formation of V–O–Ti bonds. The catalytic properties of the samples containing 10 wt % P2O5 are due to the presence of the phase of a triple V–P–Ti compound with an atomic ratio V : P : Ti approximately equal to 1 : 1 : 1. The V5+ cations in this compound occur in a weakly distorted tetrahedral oxygen environment and are bound to the tetrahedral P5+ cations. 相似文献
4.
G. Ya. Popova T. V. Andrushkevich G. A. Metalkova 《Reaction Kinetics and Catalysis Letters》1979,12(4):469-473
Acrolein is oxidized to acrylic acid over a V–Mo catalyst by lattice oxygen, while the formation of CO2 also involves gas phase oxygen. The steady state of catalyst reduction is about 5% monolayer and is characterized by an oxygen binding energy of 61 kcal/mol.
V–Mo- , CO2 . 5% 61 /.相似文献
5.
J. Tichy M. M. Andrushkevich G. K. Boreskov A. A. Davidov L. M. Plyasova V. D. Sokolovskii 《Reaction Kinetics and Catalysis Letters》1976,5(4):407-413
The products of selective oxidation are shown to be formed via a stepwise mechanism with participation of surface allylic complexes. A successive transformation of -allyl to -allyl and further to acrolein is possible. The products of complete oxidation may be formed through surface carbonate-carboxylate complexes via either a stepwise mechanism involving the catalyst's oxygen, or a concerted mechanism with the participation of molecular oxygen.
, . - -, . - , .相似文献
6.
V. M. Bondareva T. V. Andrushkevich Yu. D. Pankratiev V. M. Turkov 《Reaction Kinetics and Catalysis Letters》1986,32(2):371-376
Adsorption heats of acrolein and acrylic acid on promoted V–Mo–O catalysts for selective oxidation of acrolein have been measured by the calorimetric technique. It has been established that modification changes the energy characteristics of the interaction of acrolein and acrylic acid with catalyst surface.
- . , .相似文献
7.
T. G. Kuznetsova G. K. Boreskov T. V. Andrushkevich Yu. A. Grigorkina N. G. Maksimov I. P. Olenkova L. M. Plyasova T. P. Gorshkova 《Reaction Kinetics and Catalysis Letters》1982,19(3-4):405-409
A solid solution of vanadium in MoO3 with a solubility limit of about 3 mol.% V2O5 is shown to be formed. Its catalytic properties are discussed.
MoO3 3 . % V2O5 .相似文献
8.
G. Ya. Popova T. V. Andrushkevich G. A. Zenkovets L. M. Plyasova N. V. Grebenyuk 《Reaction Kinetics and Catalysis Letters》1990,41(1):21-25
Catalytic properties of V-Sb-O systems in acrolein oxidation have been studied. It has been established that the changes in the activity and selectivity of the catalysts are due to the phase and chemical properties of the system.
-- . , .相似文献
9.
G. A. Zenkovets G. N. Kryukova S. V. Tsybulya E. M. Al’kaeva T. V. Andrushkevich O. B. Lapina E. B. Burgina L. S. Dovlitova V. V. Malakhov G. S. Litvak 《Kinetics and Catalysis》2000,41(4):572-583
The formation of vanadia-titania catalysts was studied with a complex of physicochemical methods. The use of highly dispersed
anatase with a defect structure results in the formation of coherent boundaries of coalescence of the V2O5 and TiO2 crystallites with the ratio V : Ti =1 : 1 in a wide range of vanadium and titanium concentrations. The catalysts containing
coherent boundaries are active and selective in Β-picoline oxidation to nicotinic acid. 相似文献
10.