02147nas a2200217 4500008004100000022001400041245016000055210006900215260000800284300001600292490000800308520134400316653001701660653002301677653001101700653002101711653002901732100002201761700002201783856012401805 2020 eng d a2468-823100aUnderstanding the influence of alumina supported ruthenium catalysts synthesis and reaction parameters on the hydrodeoxygenation of lignin derived monomers0 aUnderstanding the influence of alumina supported ruthenium catal cJAN aUNSP 1105250 v4803 a

Up-gradation of lignin derived monomers to value-added and fuel grade products is important to make overall bio-refinery process economical. Although, few studies are devoted on this work yet, systematic study on commercially viable (low loading of metal, recyclable catalyst, mild conditions, high selectivities etc.) is scarce and typically done under harsh conditions. Herein, we report, the methodical effect of support (SiO2, Al2O3 (acidic, basic and neutral), SiO2-Al2O3) on the hydrodeoxygenation (HDO) of lignin derived various monomers, guaiacol, veretrol, eugenol, phenol using very low loading (0.5 wt%) Ru catalyst. Very high yield (82%) of cyclohexanol from guaiacol could be achieved in presence of cyclohexane as a solvent and Ru/Al2O3-Acidic catalyst at 225 degrees C and under 1 MPa H-2 pressure. The detailed study on the effect of solvent, stability and adsorption of reactant & products etc. is done and it was observed that products are more prone to adsorb and undergo further reactions. The complete characterization of fresh and spent catalysts revealed that lower catalyst reduction temperature and presence of Ru in partially higher oxidation state proved by XPS, helps in enhancing the cyclohexanol formation. Subsequently, role of Ru particle size and support on the activity was also investigated.

10aCyclohexanol10aHydrodeoxygenation10alignin10areaction pathway10asupported metal catalyst1 aSingh, Dheerendra1 aDhepe, Paresh, L. uhttps://library.ncl.res.in/content/understanding-influence-alumina-supported-ruthenium-catalysts-synthesis-and-reaction01530nas a2200217 4500008004100000022001400041245014900055210006900204260000900273300001100282490000800293520071800301653004301019653001701062653002301079653001101102653003001113100002201143700002201165856012501187 2021 eng d a1566-736700aEfficient catalytic transfer hydrogenation-hydrodeoxygenation of lignin derived monomers: investigating catalyst properties-activity correlation0 aEfficient catalytic transfer hydrogenationhydrodeoxygenation of  cJAN  a1062200 v1493 a

Reduction of O/C ratio of lignin derived monomers via hydrodeoxygenation (HDO) pathway is conventionally furnished using molecular hydrogen under severe conditions. Nonetheless, due to a prerequisite to accomplish HDO through commercially attractive methodology we report, HDO reactions of various phenolic compounds via catalytic transfer hydrogenation (CTH) pathway using very low loading of Ru (0.5 wt%) on neutral and acidic Al2O3 under nitrogen atmosphere. With guaiacol as a substrate, 74% cyclohexanol yield at 225 degrees C in the presence of IPA is realized. Bi-functionality of metal state, acidity of support and nature of alcohol are perceived to be responsible for the variation in activity.

10aCatalytic transfer hydrogenation (CTH)10aCyclohexanol10aHydrodeoxygenation10alignin10aSupported metal catalysts1 aSingh, Dheerendra1 aDhepe, Paresh, L. uhttps://library.ncl.res.in/content/efficient-catalytic-transfer-hydrogenation-hydrodeoxygenation-lignin-derived-monomers02878nas a2200277 4500008004100000022001400041245014900055210006900204260000800273300001600281490000600297520188700303653003702190653001702227653000802244653002302252653001302275653002002288653003002308100002502338700002202363700002902385700002602414700002902440856013102469 2021 eng d a2168-048500aMechanistic investigations on the catalytic transfer hydrogenation of lignin-derived monomers over Ru catalysts: theoretical and kinetic studies0 aMechanistic investigations on the catalytic transfer hydrogenati cOCT a14040-140500 v93 aThe hydrodeoxygenation (HDO) reaction of oxygenated compounds such as lignin-derived phenolics is well studied using molecular H-2 as a hydrogen source, yet the use of high pressures discourages its use on an industrial scale. As an alternative, the catalytic transfer hydrogenation (CTH) pathway provides in situ hydrogenation species, which reduces the need for the high-pressure infrastructure required when molecular hydrogen is used. Nevertheless, this strategy is scantly studied, and in lieu with this, herein we report the kinetic and mechanistic investigations of the CTH strategy for the HDO of guaiacol, phenol, anisole veratrole, and eugenol to their respective products. For potential commercialization purposes, low loading of metal, milder reaction conditions, and high selectivity toward desired products with a high H/C ratio were considered while designing catalysts (0.5 wt % Ru on SiO2-Al2O3, SiO2, Al2O3-acidic, Al2O3-basic, and Al2O3-neutral) for these reactions. As high as 74% cyclohexanol yield from guaiacol was achieved at 225 degrees C in the presence of isopropyl alcohol (IPA) as the hydrogen source and over the Ru/Al2O3-acidic catalyst reduced at 150 degrees C. A detailed kinetic study is carried out to understand the interaction of the substrate and intermediates with the catalyst and the influence of reaction parameters on the product formation. It was observed that the cisisomer of 2-methoxycyclohexanol rapidly undergoes further conversion than the trans-isomer. The experimental observations are substantiated through density functional theory (DFT) studies on Ru(0001) and guaiacol molecule complexes. DFT studies indicate that the adsorption of the cis-isomer is more exothermic as compared to that of the trans counterpart, and the underlying electronic factors are elucidated using charge density difference and density of states plots.10acatalytic transfer hydrogenation10aCyclohexanol10aDFT10aHydrodeoxygenation10akinetics10alignin monomers10aSupported metal catalysts1 aKhan, Tufeil, Sartaj1 aSingh, Dheerendra1 aSamal, Pragnya, Paramita1 aKrishnamurty, Sailaja1 aDhepe, Paresh, Laxmikant uhttps://library.ncl.res.in/content/mechanistic-investigations-catalytic-transfer-hydrogenation-lignin-derived-monomers-over-ru01967nas a2200229 4500008004100000022001400041245013600055210006900191260000800260490000700268520116500275653002501440653001101465653001301476653001701489653001101506100002201517700002801539700001801567700002201585856013001607 2025 eng d a1867-388000aContinuous flow hydrodeoxygenation of lignin-derived guaiacol to cyclohexanol over durable Al2O3 hollow fiber supported co catalyst0 aContinuous flow hydrodeoxygenation of ligninderived guaiacol to  cSEP0 v173 a

The drive to decarbonize the chemical, oil, and gas industries through use of bio-derived resources is intensifying. This study focuses on converting lignin-derived phenolic compounds into cyclohexanol, a precursor for adipic acid production. The alumina hollow fiber supported cobalt catalyst (5Co/AHF@capillary) prepared by capillary action method was found to consist cobalt in both metallic and +delta oxidation states. Initial tests in a batch-mode reactor showed promising results, with 5Co/AHF@capillary catalyst demonstrating catalytic activity comparable to Ru/Al2O3 systems (225 degrees C, 1 MPa H-2, 4 h), achieving similar to 86% cyclohexanol yield in guaiacol hydrodeoxygenation reactions. The catalytic system was then adapted for continuous flow reactors under milder conditions (300 degrees C, 2.5 MPa H-2, 18 mL min(-1)), resulting in 83% guaiacol conversion and 74% cyclohexanol yield. The durability of the catalyst was checked for >80 h and results claim that catalyst was active in yielding consistent results. The roles of catalyst preparation method, hydrogen pressure, solvent, WHSV were thoroughly checked and discussed.

10abiomass valorization10aCarbon10aCo/Al2O310aCyclohexanol10alignin1 aSingh, Dheerendra1 aJogdand, Shunottara, M.1 aDevi, Nandini1 aDhepe, Paresh, L. uhttps://library.ncl.res.in/content/continuous-flow-hydrodeoxygenation-lignin-derived-guaiacol-cyclohexanol-over-durable-al2o3