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• Facile Co@5% Zr-TiO 2 through sol-gel synthesis method. • Synergistic effect between co and zr into TiO 2 increased catalytic transfer hydrogenation performance toward GVL synthesis. • Co@5% Zr-TiO 2 exibited higher catalytic stability than single-metallic catalyst. Co doped into 5% Zr-TiO 2 (Co@5% Zr/-TiO 2) was prepared by a simple, facile sol-gel method, and employing in the catalytic transfer hydrogen (CTH) process starting from ethyl levulinate (EL) to γ-valerolactone (GVL). Lewis/Brønsted acid ratio and BET surface area increased with the incorporation of Co into Ti-Zr-O support. In addition, the synergistic effect between Co-Zr in TiO 2 enhanced the strong acid strength sites. Co@5% Zr-TiO 2 exhibited the highest catalytic performance (EL conversion 95%, GVL yield 88%) under optimum condition (0.2 M EL, 15 mL 2-PrOH, 190 °C, 11 h). Noticeably, Co@5% Zr-TiO 2 exhibited higher stability in 4th recycling experiments as compared to 5% Zr-TiO 2 under identical condition. From computational calculation, EL adsorption process was more spontaneous with ΔEad= -8.240 eV. The protonation process made the reactants get close to the surface with a bonded O12-Ti2.179 Å and O6-Zr of 2.376 Å. Finally, GVL showed a strong leaving trend after the formation. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Liquid phase furfural catalytic transfer hydrogenation into furfuryl alcohol. • 6% Ru/mZrH is an efficient acid catalyst system for the synthesis of furfuryl alcohol. • Continuous flow process for the furfuryl alcohol production. • Bio-based ethanol as both H-donor and solvent in continuous flow. Catalytic transfer hydrogenation is gaining increasing attention as a promising alternative to conventional hydrogenation with H 2. In present work, a series of modified Zr-based catalysts were synthesized and tested for furfural catalytic transfer hydrogenation into furfuryl alcohol (FA). The results indicated that more than 13 % of furfural conversion and furfuryl alcohol yield could be achieved with modified zirconium hydroxide (mZrH) at 140 °C when compared with zirconium hydroxide (ZrH) using ethanol as H-donor and solvent in continuous flow regime, and the activity could be further enhanced by increasing the reaction temperature or Ru loading on the catalyst. The best result of 92 % furfural conversion with ∼99 % FA selectivity was obtained at 150 °C with 6% Ru/mZrH as catalyst, and the productivity of FA is 5.5 mmol g−1 h−1 which is 2 times higher than that reported with ZrH in batch. Moreover, long-term stability study of the catalysts indicated that 6% Ru/mZrH not only performs a better activity, but also a better stability than 6% Ru/ZrH. Characterizations of the catalysts by BET, XRD, EA, IR, SEM-EDS, XPS and CO 2 adsorption indicated that zirconium hydroxide (ZrH) was successfully modified with hydroxylamine, leading to significantly change of its morphology and basic sites. And the deactivation of the catalysts was due to both the leaching of Ru and the deposition of side-products on its surface. [ABSTRACT FROM AUTHOR]

Furfural is a platform molecule obtained from hemicellulose. Among the products that can be produced from furfural, furfuryl alcohol is one of the most extensively studied. It is synthesized at an industrial scale in the presence of CuCr catalyst, but this process suffers from an environmental negative impact. Here, we demonstrate that a non-noble metal catalyst (Co/SiO2) was active (100% conversion of furfural) and selective (100% selectivity to furfuryl alcohol) in the hydrogenation of furfural to furfuryl alcohol at 150 °C under 20 bar of hydrogen. This catalyst was recyclable up to 3 cycles, and then the activity decreased. Thus, a comparison between batch and continuous flow reactors shows that changing the reactor type helps to increase the stability of the catalyst and the space-time yield. This study shows that using a continuous flow reactor can be a solution to the catalyst suffering from a lack of stability in the batch process. [ABSTRACT FROM AUTHOR]

Furfural has been considered as one of the most promising platform molecules directly derived from biomass. The hydrogenation of furfural is one of the most versatile reactions to upgrade furanic components to biofuels. For instance, it can lead to plenty of downstream products, such as (tetrahydro)furfuryl alcohol, 2-methyl(tetrahydro)furan, lactones, levulinates, cyclopentanone(l), or diols, etc. The aim of this review is to discuss recent advances in the catalytic hydrogenation of furfural towards (tetrahydro)furfuryl alcohol and 2-methyl(tetrahydro)furan in terms of different non-noble metal and noble metal catalytic systems. Reaction mechanisms that are related to the different catalytic materials and reaction conditions are properly discussed. Selective hydrogenation of furfural could be modified not only by varying the types of catalyst (nature of metal, support, and preparation method) and reaction conditions, but also by altering the reaction regime, namely from batch to continuous flow. In any case, furfural catalytic hydrogenation is an open research line, which represents an attractive option for biomass valorization towards valuable chemicals and fuels. [ABSTRACT FROM AUTHOR]

[Display omitted] • Continuous flow process for the g-valerolactone production. • Levulinic acid (LA) or alkyl levulinates (AL) as starting material for the continuous flow production of g-valerolactone. • 5% Ru/C is an efficient acid catalyst system for the synthesis of g-valerolactone. • The reusability of the catalyst was efficient during 9 h. • Application to other alkyl levulinates than methyl levulinate gave lower yield of g-valerolactone. The present work explored a catalytic transfer hydrogenation process with several supported noble metal on carbon as catalysts for the production of γ-valerolactone (GVL) from methyl levulinates (ML) in iso-propanol (2-PrOH) and the performance of the commercial 5%Ru/C in continuous flow were investigated, GVL yields up to 83% at 150 °C (40 bar) using a high load (0.4 M ML) feed at 0.8 mL/min flow rate. The catalyst productivity (Pr) equal to 0.99 mol g−1 h−1. Methyl 4-hydroxypentanoate (MHP) were produced as major side product in lower amounts in continuous flow mode. Long-term (9 h) catalyst stability experiment showed good stability under optimum condition. The yield of GVL obtained from ethyl levulinate, butanol levuliante and levulinate acid were ca. 21%, 54% and 26% less than ML in 2-PrOH and Pr were 0.43, 0.73 and 0.48 less respectively. There is no obvious hydrogenation process when changed 2-PrOH to ethanol and 1-butanol. [ABSTRACT FROM AUTHOR]