Oxidative dehydrogenation of light hydrocarbons over vanadium and magnesium substituted apatite

The oxidative dehydrogenation of n-butane over 4 vanadium and magnesium substituted apatites, i.e., Whitlockite, CaHAp, CaHAp-V, and CaHAp-V/P, was studied at 450°-530°. The stability of these catalysts with time on run was very good, which indicated that activities and selectivities were strongly dependent on the degree of PO43^- anions and calcium cations substitution. The Whitlockite, which was obtained by the simultaneous partial substitution of PO43^- anions by VO43^- and of Ca⁺⁺ cations by Mg⁺⁺ showed superior results than those of the other three solids. The activity was in the order: Whitlockite ≫ CaHAp > CaHAp-V > CaHAp-V/P with a value of 50% for the first one. The selectivity at iso-conversion, toward C₄ dehydrogenated hydrocarbon, followed the order: Whitlockite > CaHAp-V > CaHAp CaHAp-V/P, with the first one reaching a value of 54.2%. This is an abstract of a paper presented at the 8th World Congress of Chemical Engineering (Montréal, Quebec, Canada 8/23-27/2009).