Direct Conversion of Glycerol to Allyl Alcohol Over Alumina-Supported Rhenium Oxide

Strengthening the Connection between Science, Society and Environment to Develop Future French and European Bioeconomies: Cutting-Edge Research of VAALBIO Team at UCCS

The development of the future French and European bioeconomies will involve developing new green chemical processes in which catalytic transformations are key. The VAALBIO team (valorization of alkanes and biomass) of the UCCS laboratory (Unité de Catalyse et Chimie du Solide) are working on various catalytic processes, either developing new catalysts and/or designing the whole catalytic processes. Our research is focused on both the fundamental and applied aspects of the processes. Through this review paper, we demonstrate the main topics developed by our team focusing mostly on oxygen- and hydrogen-related processes as well as on green hydrogen production and hybrid catalysis. The social impacts of the bioeconomy are also discussed applying the concept of the institutional compass.

Titania-supported molybdenum oxide combined with Au nanoparticles as hydrogen-driven deoxydehydration catalyst of diol compounds

A heterogenous catalyst for deoxydehydration (DODH) reaction was developed using less expensive Mo than Re as the active center. Combination of Mo with anatase-rich TiO2 and Au as the support...

Transition metal-catalyzed deoxydehydration: missing pieces of the puzzle

Deoxydehydration (DODH) is a transformation that converts a vicinal diol into an olefin with the help of a sacrificial reductant.

Thermal exfoliation of electrochemically synthesized graphite intercalation compound with perrhenic acid

In present work, we describe the synthesis of graphite intercalation compounds with perrhenic acid (HReO4-GIC) through the anodic oxidation of graphite in aqueous perrhenic acid solution and their thermal exfoliation. Due to electrochemical treatment of graphite in perrhenic acid solution, ReO4− ions are intercalated into interlayer spaces of graphite. Anodic oxidation of graphite in HReO4 solution leads to the formation of 3-stage GIC. Simultaneously, some amount of perrhenic acid becomes deposited on the graphite surface and edges. In the next step, thermal treatment of the previously synthesized GIC was performed, causing both the exfoliation of graphitic structure and transformation of perrhenic acid into rhenium oxides on the surface of graphene layers. The yielded product was exfoliated graphite-ReO2/ReO3 composite. The obtained composite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. Additionally, specific surface area of the exfoliated materials was measured.

Influence of the pendant arm in deoxydehydration catalyzed by dioxomolybdenum complexes supported by amine bisphenolate ligands

Molybdenum complexes devoid of a strongly coordinating pendant arm result in enhanced catalytic activity.

Tungsten–zirconia-supported rhenium catalyst combined with a deoxydehydration catalyst for the one-pot synthesis of 1,4-butanediol from 1,4-anhydroerythritol

Biomass-derived 1,4-anhydroerythritol is reduced to 1,4-butanediol over a reusable mixture of heterogeneous catalysts, ReO_x–Au/CeO₂ and ReO_x/WO₃–ZrO₂.

Preparation of Highly Active Monometallic Rhenium Catalysts for Selective Synthesis of 1,4-Butanediol from 1,4-Anhydroerythritol

1,4-Butanediol can be produced from 1,4-anhydroerythritol through the co-catalysis of monometallic mixed catalysts (ReO_x /CeO₂ +ReO_x /C) in the one-pot reduction with H₂ . The highest yield of 1,4-butanediol was over 80 %, which is similar to the value obtained over ReO_x -Au/CeO₂ +ReO_x /C catalysts. Mixed catalysts of CeO₂ +ReO_x /C showed almost the same performance, giving 89 % yield of 1,4-butanediol. The reactivity trends of possible intermediates suggest that the reaction mechanism over ReO_x /CeO₂ +ReO_x /C is similar to that over ReO_x -Au/CeO₂ +ReO_x /C: deoxydehydration (DODH) of 1,4-anhydroerythritol to 2,5-dihydrofuran over ReO_x species on the CeO₂ support with the promotion of H₂ activation by ReO_x /C, isomerization of 2,5-dihydrofuran to 2,3-dihydrofuran catalyzed by ReO_x on the C support, hydration of 2,3-dihydrofuran catalyzed by C, and hydrogenation to 1,4-butanediol catalyzed by ReO_x /C. The reaction order of conversion of 1,4-anhydroerythritol with respect to H₂ pressure is almost zero and this indicates that the rate-determining step is the formation of 2,5-dihydrofuran from the coordinated substrate with reduced Re in the DODH step. The activity of ReO_x /CeO₂ +ReO_x /C is higher than that of ReO_x -Au/CeO₂ +ReO_x /C, which is probably related to the reducibility of ReO_x /C and the mobility of the Re species between the supports. High-valent Re species such as Re⁷⁺ on the CeO₂ and C supports are mobile in the solvent; however, low-valent Re species, including metallic Re species, have much lower mobility. Metallic Re and cationic low-valent Re species with high reducibility and low mobility can be present on the carbon support as a trigger for H₂ activation and promoter of the reduction of Re species on CeO₂ . The presence of noble metals such as Au can enhance the reducibility through the activation of H₂ molecules on the noble metal and the formation of spilt-over hydrogen over noble metal/CeO₂ , as indicated by H₂ temperature-programmed reduction. The higher reducibility of ReO_x -Au/CeO₂ lowers the DODH activity of ReO_x -Au/CeO₂ +ReO_x /C in comparison with ReO_x /CeO₂ +ReO_x /C by restricting the movement of Re species from C to CeO₂ .

Deoxydehydration of glycerol in presence of rhenium compounds: reactivity and mechanistic aspects

Re compounds in different oxidation states are activated during a delay time into an active Re alkoxide precipitate catalysing the DODH of glycerol.