Piotr Michorczyk, Jan Ogonowski, Jolanta Sroka CATALYTIC ACTIVITY OF MCM-41-SUPPORTED VANADIUM OXIDE CATALYSTS IN THE DEHYDROGENATION OF PROPANE IN THE PRESENCE AND ABSENCE OF CO2 (Institute of Organic Chemistry and Technology, Cracow University of Technology) E-mail: pmichor@usk.pk.edu.pl The dehydrogenation of propane to propene in the presence and absence of CO2 over MCM-41-supported vanadium oxide catalysts has been studied. <...> The effect of vanadium content and feed composition on the dehydrogenation of propane has been investigated. <...> It has been found that these materials exhibit a moderate catalytic activity and an excellent selectivity in dehydrogenation of propane. <...> Moreover, it has been found that the introduction of CO2 to the reaction zone promotes the dehydrogenation of propane over the catalysts with V content above 5% of V2O5. <...> INTRODUCTION Vanadium oxide supported on siliceous materials (SiO2 and mesoporous materials: MCM-41, SBA-15) have been considered as promising catalysts for oxidation of methane to formaldehyde [1,2] and in the selective oxidative dehydrogenation of alkanes to alkenes by oxygen [3,4] or by mild oxidants like: N2O or CO2 [5, 6]. <...> Recent reports have shown that the catalytic activity of V-containing materials depends strongly on the content of vanadium load. <...> The isolated tetrahedral V5+ species containing terminal V=O groups have been suggested as the most selective ones in the oxidation reactions [1-3]. <...> These species predominate at low vanadium content, while at higher loading, polymeric and crystalline V2O5 species are formed also on the surface of supports. <...> The latter species contain V-O-V groups, which are responsible for over oxidation reactions. <...> Taking into account above, in order to prepare more active and selective vanadium oxide based catalysts for the dehydrogenation of propane in the presence of CO2, a high dispersion of vanadium oxide at vanadium loading as high as possible should be achieved. <...> We have used siliceous mesoporous MCM-41 material (SBET=1085 m2g-1 and with 2.4 nm pore diameter) as support for dispersing vanadium oxide species. <...> The V/MCM-41 catalysts with V2O5 loading in the range of 1-20 wt% were prepared by impregnation, characterized by H2TPR technique and tested in the dehydrogenation of propane to propene in the presence and absence of CO2. <...> EXPERIMENTAL MCM-41 was prepared under basic conditions using n-hexadecyltrimethylammonium chloride (HTMACl) as the surfactant and tetraethyl orthosilicate (TEOS) as the silica source <...>