Hydrogenation of levulinic acid with and without external hydrogen over Ni/SBA-15 catalyst

Abstract

A series of Ni/SBA-15 catalysts were prepared by impregnation method for the hydrogenation of levulinic acid (LA) to γ-valerolactone in a fixed bed reactor at atmospheric pressure. The catalysts were characterized by XRD, TPR, AAS, Pulse chemisorption, SEM-EDAX, TEM, BET Surface area and XPS. The catalyst 30 wt% Ni/SBA-15 exhibited excellent catalytic performance (97% yield) at 250 °C due to the presence of superior number of active surface Ni species. While 30 wt% Ni/ SiO 2 catalyst showed lower catalytic activity (87% yield) at about similar conversion. The co-feeding of formic acid (FA) and water (impurities) with levulinic acid was also evaluated over 30 wt% Ni/SBA-15 which yielded excellent levulinic acid conversion. The noteworthy results were obtained at a molar ratio of FA/LA = 5. The constant catalytic activity during 10 h experiment with an external H 2 flow has showed the sturdiness of the Ni/SBA-15 catalyst. On the other hand, a slight decrease in conversion as well as yield during the time-on-stream in the absence of external H 2 flow was attributed to the accumulation of carbon species on the catalyst surface.

Life cycle net energy assessment of sustainable H2 production and hydrogenation of chemicals in a coupled photoelectrochemical device

“…Future assessments regarding environmental impact and techno-economic performance should also be investigated to fully quantify the benefit of the coupled approach. Finally, other hydrogenation reactions possible to be performed at conditions relevant to that of PEC devices (e.g., near-atmospheric pressure, ambient temperature), such as levulinic acid to γ-valerolactonate 37 or acetone to isopropanol 38 , need to be explored to determine the optimum reaction and/or identify the general applicability of the coupled device concept. Although some of these hydrogenation reactions may also be performed through electrochemical processes directly on suitable dark electrodes 39 , 40 , the coupled concept proposed here introduces an important flexibility advantage in that the hydrogenation rate and the type of hydrogenation reactions performed can be controlled on demand using the same device without the need to change any components by simply changing the concentration and/or the types of feedstocks and homogenous catalysts.…”

Cooperative Catalytic Transfer for One-Pot Hydrolysis/Hydrogenation of Refined Palm Oil Using Formic Acid as a Hydrogen Source

“…Additionally, it is crucial to consider that an equivalent amount of CO 2 is produced as hydrogen is generated, suggesting that CO 2 might obstruct active sites on the catalyst, potentially influencing catalyst deactivation. Varkolu et al noted that the activity of nickel catalysts, when using FA as a hydrogen donor, decreases due to the formation of carbon species through the condensation of reaction intermediates on the catalyst surface . Furthermore, some nickel catalysts exhibit sensitivity to water in the reaction medium, which can lead to catalyst poisoning …”

“…Varkolu et al noted that the activity of nickel catalysts, when using FA as a hydrogen donor, decreases due to the formation of carbon species through the condensation of reaction intermediates on the catalyst surface. 31 Furthermore, some nickel catalysts exhibit sensitivity to water in the reaction medium, which can lead to catalyst poisoning. 32 3.5.…”

Solar-driven upgrading of biomass by coupled hydrogenation using in situ (photo)electrochemically generated H2

“…We also emphasize that the hydrogenation of IA to MSA, despite being energetically attractive, is only used here as a model reaction. The coupled PEC + hydrogenation concept offers great flexibility towards a variety of hydrogenation reactions (e.g., levulinic acid to -γ-valerolactonate 41 , acetone to isopropanol 42 ) since the hydrogenation reaction itself can be done by homogeneous catalysis and does not need to be performed (photo)electrochemically. This also enables enantioselectivity towards specific chiral products, by introducing the appropriate homogeneous catalysts.…”