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Novel Cu–ZnO–ZrO2/UGSO catalysts for CO2 hydrogenation to methanol were developed using a metallurgical residue as catalytic support, focusing on (i) the synergy of Cu/Zn/Zr and UGSO composition and (ii) UGSO modification, on catalytic activity and stability.

In this study, the kinetics of the esterification of glycolic acid with ethanol homogeneously autocatalyzed and heterogeneously catalyzed are investigated.

Xylose is a major component of hemicelluloses. In this paper, its hydrogenation to xylitol in aqueous medium was investigated with two Ru/TiO2 catalysts prepared with two commercial TiO2 supports. A strong impact of support on catalytic performances was evidenced. Ru/TiO2-R led to fast and selective conversion of xylose (100 % conversion in 2 h at 120°C with 99 % selectivity) whereas Ru/TiO2-A gave a slower and much less selective transformation (58 % conversion in 4 h at 120°C with 17 % selectivity) with the formation of several by-products. Detailed characterization of catalysts with ICP, XRD, FTIR, TEM, H2 chemisorption, N2 porosimetry, TPR and acid-base titration were performed to elucidate the role of each support. TiO2-R has a small specific surface area with large ruthenium nanoparticles in weak interaction with TiO2 support and no acidity, whereas TiO2-A is a mesoporous material with a large specific surface area, mildly acidic, and bears small ruthenium particles in strong interaction with TiO2 support. The former was very active and selective for xylose hydrogenation to xylitol whereas the latter was less active and poorly selective. Moreover, careful analysis of reaction products also revealed that TiO2 anatase can catalyze undesired side-reactions such as xylose isomerisation to various pentoses, and therefore the corresponding unexpected polyols (arabitol, ribitol) were produced during xylose conversion by hydrogenation. In a first approach of the kinetics, a simplified kinetic model was built to compare quantitatively intrinsic reaction rates of both catalysts. The kinetic constant for hydrogenation was 20 times higher for Ru/TiO2-R at 120°C.

An improved method for the oxidation of benzylic and aliphatic alcohols using concentrated bleach (1.6 M NaOCl) using 2-step continuous flow microreactors is reported herein. Enhancement of the reaction rate was obtained by on-line pH adjustment. In the first step, the pH of the bleach was precisely decreased to pH 8.5 using CO2. Such pH is a compromise between oxidative properties, chemical stability and unwanted precipitation. The aqueous bleach solution was subsequently used for the oxidation of benzyl alcohols in EtOAc using catalytic amounts of TBAB (n-Bu4N+Br−) in a segmented flow microreactor. The total conversion of benzyl alcohols was obtained in less than 1 min using 2 eq. of NaOCl at r.t. without any metal catalysts. Selective benzyl alcohol oxidation (>98%) was demonstrated on primary and secondary alcohols. For aliphatic alcohols, 0.1 mol% TEMPO was used as a co-catalyst in synergy with TBAB and a total conversion with high selectivity (>98%) was achieved in less than 2 min.

The aim of this work was to design efficient mesoporous heterogeneous catalysts for the reaction of conversion of methanol to dimethyl ether (DME). Mesostructured silica and aluminosilicate solids were synthesized using an original synthesis procedure enabling the elaboration of structurally homogeneous solids at atmospheric pressure and using a food grade templating agent. The prepared solids consisted of mesoporous silica and aluminosilicates with aluminium contents of 0.76, 1.11 and 1.60 wt%. These solids were characterized by XRD, N2-physisorption and TEM. Their efficiency in the catalytic reaction of conversion of methanol to DME was subsequently correlated with their structural and acidic properties. The sample exhibiting a pore diameter of 2.2 nm for a Si/Al ratio of 27 showed remarkable performances with a methanol conversion as high as 80% at 598 K (7.5 vol% MeOH; 50 mg of catalyst; GHSV = 26,000 cm3 h−1 g−1) and a total selectivity to DME.

Due to its three hydroxyl groups, glycerol is a potential starting material for various high value fine chemicals such as dihydroxyacetone, tartronic acid and mesoxalic acid. The corresponding oxidation reactions are catalysed by various metals such as palladium, platinum, bismuth or gold. Nevertheless, the selectivity not only depends on the type of the active phase, but is also influenced by numerous parameters such as the metal particles size, the pore size of the support and the pH of the reaction medium. This review not only describes the recent developments in the field of research for new catalysts but also spotlights the role of the reaction conditions as well as the possible transport limitations in this tri-phasic system. Furthermore, an economical analysis of some processes is given, which shows that this is realistic to envision sustainable production of, e.g., dihydroxyacetone.

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.