01884nas a2200253 4500008004100000022001400041245009800055210006900153260011000222300001000332490000700342520096700349653001701316653001601333653002001349653002201369653001401391100002201405700002501427700001901452700001501471700001801486856012601504 2010 eng d a0971-457X00aGas-phase oxidant-free oxidation of cyclohexanol over V2O5-MoO3-M2O (M = Na, K, Cs) catalysts0 aGasphase oxidantfree oxidation of cyclohexanol over V2O5MoO3M2O  aDR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIAbNATL INST SCIENCE COMMUNICATION-NISCAIRcJAN a43-490 v173 a

Oxidant-free oxidation (dehydrogenation) of cyclohexanol is carried out in a down-flow integral laboratory scale reactor using different alkali doped catalysts. The effect of reaction temperature, contact time (W/F) and doping of alkali metals is studied to check its effect on nature of prominent products of the reaction (cyclohexanone and cyclohexene). At lower temperature the cyclohexanone prevails whereas at higher temperature cyclohexene is observed in prominence. Acid-modified catalysts (with boron and phosphorous) facilitated cyclohexene selectivity whereas alkali modified catalysts facilitated cyclohexanone selectivity. Calcination of sodium modified catalyst at different temperatures under static condition affect characteristic phase intensity and cyclohexanone selectivity. XRD investigation showed formation of different inorganic phases as the characteristic of dopant. Cesium modified catalyst showed better dehydrogenation activity.

10aCyclohexanol10adehydration10aDehydrogenation10aElectronegativity10aV2O5-MoO31 aVyawahare, Y., K.1 aChumbhale, Vilas, R.1 aPardhy, S., A.1 aSamuel, V.1 aAswar, A., S. uhttps://library.ncl.res.in/content/gas-phase-oxidant-free-oxidation-cyclohexanol-over-v2o5-moo3-m2o-m-na-k-cs-catalysts-002221nas a2200265 4500008004100000022001400041245011700055210006900172260000800241300001400249490000700263520134800270653001701618653001701635653002001652653001501672653001501687100002801702700002101730700002201751700001601773700002201789700001301811856013101824 2018 eng d a1533-488000aCyclohexylation of resorcinol with cyclohexanol catalyzed by tungstophosphoric acid supported zirconia catalysts0 aCyclohexylation of resorcinol with cyclohexanol catalyzed by tun cAPR a2986-29920 v183 a

We demonstrate a highly active and reusable heterogeneous catalyst system, tungstophosphoric acid (TPA) supported on zirconia (ZrO2), for the cyclohexylation of resorcinol by cyclohexanol to produce value added chemicals such as 2-cyclohexyl resorcinol, 4-cyclohexyl resorcinol and 3-Hydroxy cyclohexyl phenyl ether under liquid phase reaction condition. TPA/ZrO2 catalysts prepared with different TPA loadings (5-30 wt.%) by wet impregnation method and calcined in the temperature range of 650-850 degrees C were characterized by Nitrogen sorption analysis, XRD, FTIR, DTG and DTA, and P-31 MAS NMR spectroscopy. Among the catalysts studied, 15 wt.% TPA/ZrO2 catalyst calcined at 750 degrees C gave the highest conversion of resorcinol (51.2%) with the selectivities for 3-Hydroxy cyclohexyl phenyl ether (53.9%) and 2-cyclohexyl resorcinol and 4-cyclohexyl resorcinol together (46.1%) under optimum reaction conditions. However, the selectivity of the products were controlled by varying the reaction conditions. At higher conversion of resorcinol (78.9%), only C-alkylated products were formed at 200 degrees C with 15 wt.% TPA/ZrO2 catalyst calcined at 750 degrees C. The combination of TPA and ZrO2 coupled with calcination temperature offered an excellent platform for the conversion of resorcinol into O- or C-alkylated products.

10a15% TPA/ZrO210aCyclohexanol10aCyclohexylation10aKeggin TPA10aResorcinol1 aBalasubramanian, V., V.1 aDevassay, B., M.1 aHalligudi, S., B.1 aDeepika, R.1 aUmbarakar, S., B.1 aVinu, A. uhttps://library.ncl.res.in/content/cyclohexylation-resorcinol-cyclohexanol-catalyzed-tungstophosphoric-acid-supported-zirconia02473nas a2200265 4500008004100000022001400041245008800055210006900143260000800212300001600220490000600236520163300242653001701875653001801892653003101910653002501941100001801966700001901984700001802003700002002021700002402041700001602065700001802081856010802099 2019 eng d a2168-048500aMechanistic insights into the pathways of phenol hydrogenation on Pd nanostructures0 aMechanistic insights into the pathways of phenol hydrogenation o cOCT a17126-171360 v73 a

Product selectivity in aqueous phase phenol hydrogenation on well-defined supported Pd nanostructures (spheres, cubes, and octahedra) was studied using defined experiments and density functional theory (DFT) simulations. On Pd spheres and octahedra, the reaction initially showed high selectivity (in the first 3 h, at 363 K and 5 bar H-2 pressure) toward the partially hydrogenated product cyclohexanone. On prolonged operation (>20 h of reaction time), a shift in the product selectivity (up to 100%) toward the completely hydrogenated product cyclohexanol was observed on Pd spheres and octahedra. In contrast, the reaction on Pd cubes, which only had {100} facets, showed a high selectivity (similar to 90%) toward the product cyclohexanone even after 40 h, at the same reaction conditions. Since the {111} facets are expected to be the majority sites on a spherical particle, we attribute the selectivity trend observed on spherical Pd particles to be primarily controlled by the selectivity trend on the Pd{111} facets. This observation was further confirmed on performing the hydrogenation reaction on a mixture of Pd cube and Pd octahedron particles in a ratio of 25:75 (representing the site ratio of a spherical particle). DFT simulations provided a mechanistic insight into the reactivity of the two different facets ({100} and {111}) toward phenol hydrogenation. The calculations revealed that the selectivity significantly depended on the activation barriers involved in cyclohexanone hydrogenation on the Pd{111} facets (77 and 57 kJ/mol) as compared to those on the Pd{100} facets (97 and 101 kJ/mol).

10aCyclohexanol10acyclohexanone10afacet-dependent reactivity10aphenol hydrogenation1 aPorwa, Govind1 aGupta, Shelaka1 aSreedhala, S.1 aElizabeth, Joes1 aIthan, Tuhin, Suvra1 aHaider, Ali1 aVinod, C., P. uhttps://library.ncl.res.in/content/mechanistic-insights-pathways-phenol-hydrogenation-pd-nanostructures02147nas 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-ru01865nas a2200229 4500008004100000022001400041245008600055210006900141260000900210490000700219520109700226653001701323653002301340653002101363653001601384653002501400100002401425700002401449700002301473700002801496856011101524 2023 eng d a1861-472800aPhenol hydrogenation to cyclohexanol catalysed by palladium supported on CuO/CeO20 aPhenol hydrogenation to cyclohexanol catalysed by palladium supp cJUN 0 v183 a

Hydrogenation of phenol to cyclohexanone/cyclohexanol is an important reaction in production of nylon-6, nylon-66 and in petroleum industry. Liquid phase phenol hydrogenation over Pd-CuO/CeO2 was carried out under mild conditions. Palladium impregnated over CuO/CeO2 synthesized by co-precipitation method showed excellent catalytic activity for phenol hydrogenation (99% conversion with 80% cyclohexanol yield) at 90 degrees C and 10 bar H-2 pressure in water. Commercial 10%Pd/C showed only 8% phenol conversion under identical conditions. The detailed characterization revealed significant improvement in surface area of ceria after addition of CuO and decrease in crystallite size with creation of defects in CeO2 lattice. XPS analysis showed Pd loading on CuO/CeO2 to cause hydrogen spillover on the surface leading to increase in the oxygen vacancies. The interaction of phenol with catalyst surface studied by detailed FTIR analysis, revealed activation of phenol on oxygen vacancy of ceria as phenoxide ion with perpendicular orientation of aromatic ring on catalyst surface.

10aCyclohexanol10aHydrogen spillover10aoxygen vacancies10aPd-CuO/CeO210aphenol hydrogenation1 aKasabe, Mirabai, M.1 aKotkar, Vaibhav, R.1 aDongare, Mohan, K.1 aUmbarkar, Shubhangi, B. uhttps://library.ncl.res.in/content/phenol-hydrogenation-cyclohexanol-catalysed-palladium-supported-cuoceo201967nas 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-al2o302324nas a2200217 4500008004100000022001400041245011700055210006900172260000800241490000700249520155600256653001701812653001301829653002301842653001801865653002501883100002101908700002601929700002301955856012801978 2025 eng d a1867-388000aHydrodeoxygenation of guaiacol to cyclohexanol using noble metal-supported Ni-based perovskite-derived catalysts0 aHydrodeoxygenation of guaiacol to cyclohexanol using noble metal cAUG0 v173 a

This study focuses on the role of noble metal-doped Ni-based perovskites, specifically LaNiO3 and NiTiO3 catalysts in the hydrodeoxygenation (HDO) of guaiacol. The findings demonstrate that reduced Ru-LaNiO3 catalyst achieved superior performance with 100% guaiacol conversion and a 75% selectivity toward cyclohexanol, compared to reduced Ru-NiTiO3, which achieved only 43% conversion and 25% cyclohexanol selectivity under identical conditions (240 degrees C, 30 bar H2, and 4 h). High-resolution transmission electron microscopic (HR-TEM) analysis reveals that LaNiO3-supported catalysts exhibit better metal dispersion and smaller nickel nanoparticle sizes compared to NiTiO3-supported counterparts. X-ray photoelectron spectroscopy (XPS) analysis shows that the reduction of nickel and noble metals is more facile on LaNiO3. Additionally, the O 1s XPS profile for reduced Ru-LaNiO3 indicates a higher proportion of lattice oxygen (OLat similar to 79%) and a lower proportion of oxygen vacancies (OVac similar to 21%) compared to other catalyst systems. The optimized OLat/OVac ratio is shown to be critical for the effective HDO of guaiacol. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) demonstrates a high HDO reaction rate using reduced Ru-LaNiO3 than reduced Ru-NiTiO3, with cyclohexanol formation attributed to the keto-enol tautomerization pathway. Overall, this study underscores the critical roles of oxygen vacancies, metal dispersion, and metal-metal oxide interactions in the HDO of guaiacol.

10aCyclohexanol10aGuaiacol10aHydrodeoxygenation10aIn-situ DRIFT10aNi-based perovskites1 aMarimuthu, Prabu1 aRaja, Thirumalaiswamy1 aVinu, Ravikrishnan uhttps://library.ncl.res.in/content/hydrodeoxygenation-guaiacol-cyclohexanol-using-noble-metal-supported-ni-based-perovskite