Preparation of the MoVTeNbBiO catalysts for selective oxidative conversion of light alkanes

Abstract

Physicochemical properties of modified MoVTeNbО catalysts are shown to depend strongly on the preparation procedure and the source of bismuth. Addition of a pH-neutral organic bismuth-containing compound at the stage of mixing initial component solutions is accompanied by precipitation and formation of inactive phase but not the necessary phase M1. Irrespectively of the nature of the initial bismuth compound, the introduction of it to the dry MoVTeNb precursor results in destruction of the latter and, as a consequence, in a lower content of phase M1 and the formation of binary V-Mo and Te-Mo oxides. In the reaction of oxidative dehydrogenation of ethane (ODE), the maximal yield of ethylene (76.5 %) is observed with the catalyst obtained by impregnation of calcined MoVTeNb oxide catalyst with a solution of an organobismuth compound. The same catalyst provides the yield of acrylic acid of ca. 48 %. Nevertheless, a more practicable method for preparation of bismuthcontaining catalysts is the addition of bismuth nitrate to the solution of the initial components; such an ODE catalyst provides the maximal yield of ethylene of ca. 76 %.