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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 Sb 3+ /Sb 5+ nor the Fe 2+ /Fe 3+ 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 V 5+ species. These species should not be considered as part of the bulk oxide, but as supra-surface species whose surface content is monitored with the bulk composition.

NdPO 4 has been studied as a model rare earth phosphate catalyst for the dehydration of 2,3-butanediol (2,3-BDO) to butadiene (BD), in order to understand the influence of structure and morphology on its catalytic properties. Rhabdophane and monazite polymorphic types of NdPO 4 were shown to have similar catalytic properties. Transmission electron microscopy revealed that rhabdophane nanorods have a core−shell structure, with a rhabdophane core surrounded by monazite. This favors the exposure of the same sites, on the predominant lateral facets of the nanorods, to the catalytic gas mixture, thus explaining the observed similarities in catalytic properties. The specific catalytic properties of the tips and side facets of the nanorods were revealed through the use of silylation, followed by breakage of the SiO 2 -covered nanorods, showing that the formation of BD took place preferentially on the side facets. Angle-resolved X-ray photoelectron spectroscopy and infrared spectroscopy revealed that the side facets had excess of phosphorus, corresponding to the (H 2 PO 4 ) − species. The absorption of these species at the strongest, coordinatively unsaturated Lewis acid sites helps produce a suitable balance between the Lewis basic and acid sites, which is needed to dehydrate 2,3-BDO to 3butene-2ol, and also leads to the creation of Brønsted acid sites responsible for the next step involving the dehydration of 3-butene-2ol to BD.

Reaction of 3-hydroxybutanone in air has been studied with and without a catalyst under atmospheric pressure and at temperatures between 523 and 673 K.

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