Xavier Sécordel

Direct conversion of methanol into 1,1-dimethoxymethane: remarkably high productivity over an FeMo catalyst placed under unusual conditions

We report here the highest productivity ever observed in the direct conversion of methanol into 1,1-dimethoxymethane (ca. 4.6 kgDMM h−1 kgcat−1 at 553 K), this result being obtained over an FeMo catalyst. This catalyst is industrially used to selectively convert methanol into formaldehyde but has never before been applied to the present reaction. Placing this FeMo catalyst under unusual reaction conditions, i.e., using a feed rich in methanol, completely changed its behaviour in terms of selectivity: the massive production of 1,1-dimethoxymethane, instead of formaldehyde, was observed.

Applications in materials science of combining Raman and X-rays at the macro- and micrometric scale

Simultaneous combination of Raman with X-ray Absorption Spectroscopy (XAS) has become of great interest in Materials Science. Four applications are reviewed in this article that reflect the large range of possibilities offered by such coupling at the macro and micrometer scales. Special emphasis was laid on the macrometer scale on time-resolved studies of physico-chemical transformations, either for providing more complete analysis of structural changes or for looking at the sample integrity. The capability of Raman and XAS to provide complementary chemical and structural information was also pointed out for discriminating and characterizing chemical phases in heterogeneous materials at the micrometer scale.

Selective oxidation of ethanol towards a highly valuable product over industrial and model catalysts

Background: Industrial production of a highly versatile chemical derived from biomass valorization, 1,1-diethoxyethane (DEE), is practically carried out via two consecutive steps involving ethanol partial oxidation followed by condensation/dehydration of ethanol with previously obtained acetaldehyde. Developing a selective bifunctional catalyst for a one-pot synthesis of DEE is of considerable interest, helping to economize production costs and minimize environmental impacts. Activities of the model rhenium (Re) catalysts supported on TiO2 and Al2O3 with those of two industrial catalysts (amorphous Mo12V3W1.2Cu1.2Sb0.5Ox and crystalline MoO3-Fe2 (MoO4)3) in the single-step gas-phase selective oxidation of ethanol were evaluated. Results: A comparison of chosen catalytic performances is reported. The effects of the reaction parameters, including the gas hourly space velocity, oxygen-to-ethanol ratio and temperature on the catalytic activities over the amorphous Mo-based catalyst were also discussed. The Re supported on TiO2 and amorphous Mo-based catalysts exhibited promising catalytic performances, resulting in the best productivity ever reported by far in the literature of 0.7 kgDEEkgcat-1h-1. Conclusion: Besides the remarkable productivity achieved from the model Re-based and industrial Mo-based catalysts, the results obtained from this study can be used as a basis for an improvement in the percentage yield in DEE or its productivity, by optimizing both the catalyst formulations, analogous to what have been chosen here, and the catalytic conditions which are adaptable to industrial scales.