High catalytic activity at low temperature in oxidative dehydrogenation of propane with Cr-Al pillared clay

M. A. DE LEÓN, C. DE LOSSANTOS, L. LATRÓNICA, A. M. CESIO, C. VOLZONE, J. CASTIGLIONI, M. SERGIO

CHEMICAL ENGINEERING JOURNAL

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2013 vol. 241 p. 336 - 343

1385-8947

A montmorillonitic clay was pillared separately with chromium and aluminium polyoxocations, Cr-C and Al-C respectively, and also with an equimolar mixture of both polioxocations (Al-Cr-C). The resulting solids were characterized by thermal analysis, X-ray diffraction and nitrogen adsorption at -196 oC. The inclusion of polycations in the interlamellar space led to modifications in the properties of the clay. An elevenfold increase in specific surface area with respect to the calcined starting clay was found for the Al-C, whereas a twofold increase was observed for the Cr-C; the value for the Al-Cr-C was only slightly higher than that for the latter. Diffractograms of the Cr-C showed the occurrence of a Cr2O3 phase. Catalytic activity in oxidative dehydrogenation of propane was assayed in the temperature range of 350 oC to 450 oC using Ar/C3H8/O2 (80/10/10) as reactant gas mixture. Propylene selectivity was found to be temperature-dependent -showing a maximum in the temperature range studied- in assays of the catalyst containing only aluminium, whereas it remained practically constant with temperature in assays of the Cr-containing catalysts. A remarkable high yield in propylene at a such low temperature as 350 oC of 9.3% (being at 450 oC of 10.3%) was obtained with the Al-Cr-C catalyst, in which the catalytic activity of Cr is enhanced by the appropriated textural properties supplied by Al.