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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid-base properties on the oxidation of isopropanol

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Author(s):
D. M. Meira [1] ; G. G. Cortez [2] ; W. R. Monteiro [3] ; J. A. J. Rodrigues [4]
Total Authors: 4
Affiliation:
[1] Faculdade de Engenharia Química de Lorena. Departamento de Engenharia Química. Laboratório de Catálise II - Brasil
[2] Faculdade de Engenharia Química de Lorena. Departamento de Engenharia Química. Laboratório de Catálise II - Brasil
[3] Instituto Nacional de Pesquisas Espaciais. Laboratório Associado de Combustão e Propulsão - Brasil
[4] Instituto Nacional de Pesquisas Espaciais. Laboratório Associado de Combustão e Propulsão - Brasil
Total Affiliations: 4
Document type: Journal article
Source: Brazilian Journal of Chemical Engineering; v. 23, n. 3, p. 351-358, 2006-09-00.
Abstract

Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K2CO3 as precipitant. The decomposition of these hydrotalcite precursors at 450°C yielded homogeneous MgyAlOx mixed oxides that contain the Al+3 cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR) and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V+5 decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene. (AU)