Ammoxidation of methylaromatics over vanadium phosphate catalysts. II. Catalyst formation, active sites and reaction mechanism

Abstract The interactions of VOHPO 4 · 0.5H 2 O and (VO) 2 P 2 O 7 with the ammoxidation feed and the single components such as ammonia, oxygen, water and component mixtures were studied in detail using XRD and temperature-programmed reaction spectroscopy. The aim of this work was to improve the knowledge of the formation of the active phases or active sites of the catalysts from their precursors under the condition of the ammoxidation reaction. Similar catalytic properties of various applied VPO materials were discussed in terms of the presence of similar structure elements (domains of adjacent edge-sharing VO 6 octahedra-units and P-O-NH 4 groups).