CATALYSTS BASED ON NixFe1-xO4 FOR THE OXIDATIVE DEHYDROGENATION OF ETHANE TO ETHYLENE

Abstract

Catalysts based on mixed oxide of type NixFe1-xO4 (x=0,5 a 0,9) were prepared by coprecipitation for oxidative dehydrogenation (ODH) of ethane and were characterized by X-ray diffraction (XRD), sorption of N2 (BET’s method), temperature programmed reduction (TPR) and laser Raman spectroscopy (LRS). The ODH of ethane has been performed in a fixed bed reactor for a constant W/F ratio of 0.48 g.s/mL. The substitution of introduction of Ni+2 by Fe+3 into NiO framework allowed the formation of spinels detected by XRD analysis, dealing to a substantial increasing of specific surface, lesser pore and cristallite size compared with the values corresponding to simples samples (NiO y Fe2O3). The selectivity improved drastically at temperatures ranging from 250 to 400°C, taking into count that CO2 and ethylene were the final products. The maximum selectivity to ethylene was 84% which was obtained with samples Ni0.8Fe0.2O4 at 300 ºC as a consequence of multifactor contribution of higher surface area in relation to simple samples, major tendency to decrease the reduction temperature with the enrichment of Ni in the mixed composition and the presence of spinel species in crystal structures which were detected by Raman spectra.