488-82-4Relevant articles and documents
Continuous transfer hydrogenation of sugars to alditols with bioderived donors over Cu-Ni-Al catalysts
Scholz, David,Aellig, Christof,Mondelli, Cecilia,Pérez-Ramírez, Javier
, p. 1551 - 1558 (2015)
The transfer hydrogenation of sugars to alditols with biobased alcohol donors was studied over hydrotalcite-derived Cu6-xNixAl2 catalysts prepared by coprecipitation at different pH and featuring variable Cu/Ni ratios. Their evaluation, after in situ activation in pure H2 at 773 K, in the ethanol-assisted upgrading of glucose in a continuous-flow fixed-bed reactor identified the solid synthesized at pH 9-10 and with Cu/Ni=1 as the best performer. Based on textural, structural, and redox analyses, this is related to an enhanced intermetallic interaction. Upon screening alternative donors, a sorbitol yield as high as 67 % was achieved with 1,4-butanediol. The catalytic system displayed a stable behavior during 48 h on stream and proved suitable to hydrogenate also fructose, mannose, xylose, and arabinose to the corresponding polyols (yields up to 65 %), thus standing as a more sustainable and economical alternative to Ru-based catalysts for sugar reductive upgrading. Finding the right partner: Hydrotalcite-derived Cu-Ni-Al materials efficiently catalyze the continuous transfer hydrogenation of C6 and C5 sugars with biobased alcohols as hydrogen donors with yields of up to 67 %. This technology comprises a safer and cheaper alternative to direct hydrogenation over Ru catalysts.
Room temperature versatile conversion of biomass-derived compounds by means of supported TiO2 photocatalysts
Colmenares, Juan C.,Magdziarz, Agnieszka
, p. 156 - 162 (2013)
The selective oxidation of glucose and degradation of phenol in liquid phase were studied in the presence of supported TiO2 photocatalysts. Photocatalysts were synthesized by a modified ultrasound-assisted sol-gel method. The fact of supporting TiO2 on zeolite type Y is giving more selective photocatalyst in glucose oxidation toward glucaric acid (GUA) and gluconic acid (GA) (total selectivity approx. 68%, after 10 min illumination time and 50%H2O/50%acetonitrile solvent composition) than the unsupported TiO2 and the commercially available photocatalyst Evonik P-25. Photocatalysts worked at room temperature, atmospheric pressure and very short reaction times (up to 15 min). Additionally, these photocatalysts were investigated in the mineralization of phenol as a cellulosic industries water contaminant. It was observed that fumed silica is a better option than zeolite as titania support in phenol aqueous degradation. Ultrasound-promoted sol-gel methodology is giving promising supported TiO2 photocatalysts for water purification and solar chemicals production.
Elucidating the effect of solid base on the hydrogenation of C5 and C6 sugars over Pt–Sn bimetallic catalyst at room temperature
Tathod, Anup P.,Dhepe, Paresh L.
, (2021)
Conversion of sugars into sugar alcohols at room temperature with exceedingly high yields are achieved over Pt–Sn/γ-Al2O3 catalyst in the presence of calcined hydrotalcite. pH of the reaction mixture significantly affects the conversion and selectivity for sugar alcohols. Selection of a suitable base is the key to achieve optimum yields. Various solid bases in combination with Pt–Sn/γ-Al2O3 catalysts were evaluated for hydrogenation of sugars. Amongst all combinations, the mixture (1:1 wt/wt) of Pt–Sn/γ-Al2O3 and calcined hydrotalcite showed the best results. Hydrotalcite helps to make the pH of reaction mixture alkaline at which sugar molecules undergo ring opening. The sugar molecule in open chain form has carbonyl group which can be polarized by Sn in Pt–Sn/γ-Al2O3 and Pt facilitates the hydrogenation. In the current work, effect of both; solid base and Sn as a promoter has been studied to improve the yields of sugar alcohols from various C5 and C6 sugars at very mild reaction conditions.
Unexpected reactivity related to support effects during xylose hydrogenation over ruthenium catalysts
Fongarland, Pascal,Freitas, Victoria D. S.,Paez, Ana,Philippe, Régis,Veyre, Laurent,Vilcocq, Léa
, p. 39387 - 39398 (2021/12/27)
Xylose is a major component of hemicelluloses. In this paper, its hydrogenation to xylitol in aqueous medium was investigated with two Ru/TiO2catalysts prepared with two commercial TiO2supports. A strong impact of the support on catalytic performance 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 the catalysts with ICP, XRD, FTIR, TEM, H2chemisorption, N2porosimetry, TPR and acid-base titration was performed to elucidate the role of each support. TiO2-R has a small specific surface area with large ruthenium nanoparticles in weak interaction with the TiO2support and no acidity, whereas TiO2-A is a mesoporous material with a large specific surface area that is mildly acidic, and bears small ruthenium particles in strong interaction with the TiO2support. 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 the reaction products also revealed that anatase TiO2can 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 kinetic approach, 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.
Preparation method of gamma-acetyl n-propanol
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Paragraph 0036; 0037, (2017/12/09)
The invention discloses a preparation method of gamma-acetyl n-propanol. The method includes the steps of (1) adding the hydrolysate of plant fiber or xylose and other raw materials into a reaction still, adding a two-phase reactive solvent and a catalyst, inletting hydrogen, and heating the reaction still to react for several hours; (2) carrying out standing, liquid separation and then solid-liquid separation on reaction materials in the reaction still, obtaining water phase, oil phase and the catalyst, and recycling the catalyst for reutilization; (3) concentrating water phase products, extracting 1, 4-pentanediol in the oil phase, mixing with the concentrated solution, and carrying out further separation to obtain a crude product of 1, 4-pentanediol; (4) pumping the crude product of 1, 4-pentanediol obtained from the water phase and the oil phase in step (3) to a fixed bed reactor, carrying out dehydrogenation to produce gamma-acetyl n-propanol under the action of a catalytic dehydrogenation catalyst or an oxydehydrogenation catalyst. According to the preparation method, raw materials have extensive sources, the production cost is low, no inorganic acid system is used, and the reaction process is environment-friendly.
