Aerobic oxidation of 1,6-hexanediol to adipic acid over Au-based catalysts: the role of basic supports

1,6-Hexanediol is a relevant building blocks that could be obtained from biomass and transformed under base free conditions into adipic acid used for polymer synthesis

Raman Spectroscopy Applied to Monitor Furfural Liquid-Phase Oxidation Catalyzed by Supported Gold Nanoparticles

International audienceIn this paper, Raman spectroscopy is used as a tool to study the mechanism of furfural oxidation using H2O2 as a reagent on gold nanoparticles (NPs) supported on hydrotalcites (HTs). This reaction was repeated, under the same conditions, but with different reaction times in a parallel multireactor system. The reaction media were analyzed using a macro device associated with a multipass cell permitting us to enhance the Raman signal by reflecting the laser beam 3 times. The Raman spectra showed the conversion of furfural to furoic acid without any chemical intermediates, thus privileging a direct pathway. Combining the results of the catalytic tests with those of the Raman study, the mechanism of furfural oxidation to furoic acid using gold NPs supported on HTs is proposed. The key points of this mechanism were found to be as follows: (i) the in situ formation of a base, originating from the Mg leaching from the HT support, initiates the oxidation of furfural by deprotonation; (ii) H2O2 used as a reagent in the solution increases the catalytic activity by its dissociation to form hydroxide ions; and (iii) the oxidation of furfural occurs on the surface of gold NPs and leads to higher furoic acid yield

Structure–performance correlations in the hybrid oxide-supported copper–zinc SAPO-34 catalysts for direct synthesis of dimethyl ether from CO2

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Study of the Direct CO2 Carboxylation Reaction on Supported Metal Nanoparticles

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Hybrid monometallic and bimetallic copper–palladium zeolite catalysts for direct synthesis of dimethyl ether from CO 2

International audienceLow palladium content in the hybrid bimetallic copper-palladium zeolite catalysts is beneficial for the dimethyl ether production from CO 2

Influence of Pd and Pt Promotion in Gold Based Bimetallic Catalysts on Selectivity Modulation in Furfural Base-Free Oxidation

Furfural (FF) has a high potential to become a major renewable platform molecule to produce biofuels and bio-based chemicals. The catalytic performances of AuxPty and AuxPdy bimetallic nanoparticulate systems supported on TiO2 were studied in a base-free aerobic oxidation of furfural to furoic acid (FA) and maleic acid (MA) in water. The characterization of the catalysts was performed using standard techniques. The optimum reaction conditions were also investigated, including the reaction time, the reaction temperature, the metal ratio, and the metal loading. The present work shows a synergistic effect existing between Au, Pd, and Pt in the alloy, where the performances of the catalysts were strongly dependent on the metal ratio. The highest selectivity (100%) to FA was obtained using Au3-Pd1 catalysts, with 88% using 0.5% Au3Pt1 with about 30% of FF conversion at 80 °C. Using Au-Pd-based catalysts, the maximum yield of MA (14%) and 5% of 2(5H)-furanone (FAO) were obtained by using a 2%Au1-Pd1/TiO2 catalyst at 110 °C

Heterogenization of Complexes by Encapsulation in Solid Micelles for Aqueous-Phase Catalysis

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Efficient Promoters and Reaction Paths in the CO₂Hydrogenation to Light Olefins over Zirconia-Supported Iron Catalysts

Hydrogenation into light olefins is an attractive strategy for CO2fixation into chemicals. In this article, high throughput experimentation and extended characterization were employed to identify the most efficient promoters and to elucidate structure-performance correlations and reaction paths in the CO2hydrogenation to light olefins over zirconia-supported iron catalysts. K, Cs, Ba, Ce, Nb, Mo, Mn, Cu, Zn, Ga, In, Sn, Sb, Bi, and V were added in the same molar concentrations to zirconia-supported iron catalyst and evaluated as promoters. The CO2hydrogenation proceeds via intermediate formation of CO followed by surface polymerization. Over the iron catalysts containing alkaline promoters, initially higher selectivity to light olefins shows a significant decrease with the CO2conversion, because of further surface polymerization and the formation of longer chain hydrocarbons. A relatively low selectivity to light olefins over the promoted catalysts, without potassium, is not much affected by the CO2conversion. Essential characteristics of iron catalysts to obtain a higher yield of light olefins seem to be a higher iron dispersion, a higher extent of carbidization, and optimized basicity. The strongest promoting effect is reported for the alkaline metals. A further increase in the light olefin selectivity is observed after simultaneous addition of potassium with copper, molybdenum, gallium, or cerium.Instrumenten groe

Efficient Promoters and Reaction Paths in the CO 2 Hydrogenation to Light Olefins over Zirconia-Supported Iron Catalysts

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Efficient Promoters and Reaction Paths in the CO 2 Hydrogenation to Light Olefins over Zirconia-Supported Iron Catalysts

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