Oxidative Dehydrogenation Of Ethyl Lactate To Ethyl Pyruvate Over Vanadium And Iron Antimonates Catalysts

The oxidative dehydrogenation of ethyl lactate to ethyl pyruvate, corresponding to the first step of a new process in the industrial production of methionine, has been investigated. Iron and vanadium antimonates were developed as catalysts, and were optimized to reach 87 % conversion of ethyl lactate, with 88 % selectivity to ethyl pyruvate, at only 275 ?C. The catalysts were characterized before and after catalytic testing, and in situ using various techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and XANES spectroscopy. The results show that neither the Sb3+/Sb5+ nor the Fe2+/Fe3+ redox couple were involved in the dehydrogenation of ethyl lactate, or in the catalysts re-oxidation. The active and selective catalytic sites correspond to surface V5+ species. These species should not be considered as part of the bulk oxide, but as suprasurface species whose surface content is monitored with the bulk composition.