02150nas a2200337 4500008004100000022001400041245009600055210006900151260007700220300001400297490000600311520104700317653001101364653002801375653001501403653002001418653001301438100001901451700001501470700001801485700001801503700002101521700001601542700002001558700002301578700002801601700001601629700001401645700002401659856012901683 2012 eng d a1867-388000aOne-pot sol-gel preparation for efficient cobalt-molybdenum-titania hydrotreating catalysts0 aOnepot solgel preparation for efficient cobaltmolybdenumtitania  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcDEC a2112-21200 v43 a

Titania-based hydrodesulfurization catalysts were prepared by using a one-pot solgel method with the titanium peroxo complex as titanium precursor and molybdenum and cobalt precursors dissolved in the aqueous hydrogen peroxide solution used during synthesis. Catalysts with MoO3 loadings varying from 5 to 40 wt?% and a Co/Mo atomic ratio of 0.5 were prepared. Solids with molybdenum loadings below 20 wt?% MoO3 demonstrated poor hydrodesulfurization activity for the model compound thiophene. This was attributed to the presence of a large amount of embedded cobalt and molybdenum species in the titania matrix. A significant increase in the catalytic activity was observed for solids containing 20 and 25 wt?% of MoO3 on which active species appeared to be accessible on the titania surface. Furthermore, the highest conversion obtained on these solgel solids was superior to the highest conversion obtained on reference catalysts prepared through the impregnation of ammonium heptamolybdate and cobalt nitrate on commercial titania.

10acobalt10aheterogeneous catalysis10aMolybdenum10asol-gel process10atitanium1 aNguyen, D., L.1 aGillot, S.1 aSouza, D., O.1 aBlanchard, P.1 aLamonier, Carole1 aBerrier, E.1 aKotbagi, T., V.1 aDongare, Mohan, K.1 aUmbarkar, Shubhangi, B.1 aCristol, S.1 aPayen, E.1 aLancelot, Christine uhttps://library.ncl.res.in/content/one-pot-sol-gel-preparation-efficient-cobalt-molybdenum-titania-hydrotreating-catalysts-001686nas a2200325 4500008004100000022001400041245008800055210006900143260007700212300001400289490000600303520057400309653002800883653001600911653001400927653002200941653002400963100002000987700002201007700002401029700002101053700003101074700001501105700002001120700003101140700002801171700002301199700002201222856011601244 2012 eng d a1864-563100aTransesterification of diethyl oxalate with phenol over sol-gel MoO3/TiO2 catalysts0 aTransesterification of diethyl oxalate with phenol over solgel M aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUL a1467-14730 v53 a

The transesterification of diethyl oxalate (DEO) with phenol to form diphenyl oxalate (DPO) has been carried out in the liquid phase over very efficient MoO3/TiO2 solid-acid solgel catalysts. A selectivity of 100?% with a remarkable maximum yield of 88?% were obtained, which opens the route to downstream phosgene-free processes for the synthesis of polycarbonates. Interpretation of the results of various acidity measurements (NH3 and pyridine desorption, methanol oxidation as a probe reaction) allowed us to identify the catalytic sites as Lewis acid sites.

10aheterogeneous catalysis10aLewis acids10aOxidation10asol-gel processes10atransesterification1 aKotbagi, Trupti1 aNguyen, Duy, Luan1 aLancelot, Christine1 aLamonier, Carole1 aThavornprasert, Kaew-Arpha1 aWenli, Zhu1 aCapron, Mickael1 aJalowiecki-Duhamel, Louise1 aUmbarkar, Shubhangi, B.1 aDongare, Mohan, K.1 aDumeignil, Franck uhttps://library.ncl.res.in/content/transesterification-diethyl-oxalate-phenol-over-sol-gel-moo3tio2-catalysts-002485nas a2200241 4500008004100000022001400041245014800055210006900203260007700272300001400349490000600363520154400369653002901913653002801942653001501970653001201985653002201997100002402019700002402043700002802067700002302095856012502118 2013 eng d a1867-388000aIsolation, characterization, and identification of catalytically active species in the MoO3/SiO2 catalyst during solid acid catalyzed reactions0 aIsolation characterization and identification of catalytically a aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUN a1531-15370 v53 a

We report the isolation, characterization, and identification of the catalytically active species formed during various acid-catalyzed reactions if silica-supported MoO3 was used as a catalyst. We have reported previously the synthesis and extensive characterization of the silica-supported MoO3 catalyst prepared by the sol-gel process with ammonium heptamolybdate and ethyl silicate-40 as molybdenum and silica precursors, respectively. The TEM images showed uniformly distributed MoO3 nanoparticles on the high-surface area mesoporous silica support and high acidity (0.9mmolg-1) by using temperature-programmed desorption of ammonia (NH3-TPD) analysis. This catalyst has already shown high activity for various acid-catalyzed reactions. To understand the nature of catalytically active species formed during the reaction, the liquid-phase esterification of acetic acid and ethanol was studied as a probe reaction with very high acid conversion (83%) in 8h. During esterification, the reaction mixture turned blue, which indicated a change in the nature of the catalyst under reaction conditions. These catalytically active species formed in the reaction mixture were isolated and extensively characterized by using FTIR, Raman, powder XRD, BET surface area, NH3-TPD, energy dispersive X-ray, and TEM analysis. The characterization results revealed the insitu formation of silicomolybdic acid on the silica surface in the presence of water, which acts as catalytically active species responsible for the acid-catalyzed reactions.

10aesterification reactions10aheterogeneous catalysis10aMolybdenum10asilicon10asol-gel processes1 aKotbagi, Trupti, V.1 aBiradar, Ankush, V.1 aUmbarkar, Shubhangi, B.1 aDongare, Mohan, K. uhttps://library.ncl.res.in/content/isolation-characterization-and-identification-catalytically-active-species-moo3sio2-002299nas a2200253 4500008004100000022001400041245011800055210006900173260000800242300001400250490000600264520143200270653001201702653002801714653001801742653002401760653001401784100002301798700002401821700002301845700002001868700002801888856012901916 2014 eng d a1867-388000aPalladium nanoparticles supported on magnesium hydroxide fluorides: a selective catalyst for olefin hydrogenation0 aPalladium nanoparticles supported on magnesium hydroxide fluorid cNOV a3182-31910 v63 a

A one-pot synthesis of palladium nanoparticles supported on magnesium hydroxide fluoride has been performed with the fluorolytic sol-gel method. The prepared catalysts were characterized by using various physicochemical techniques. The sol-gel method led to high surface area (>135 m(2)g(-1)), mesoporous catalysts (pore volume=0.19-0.23 cm(3)g(-1), pore diameter=3-5 nm) with uniformly dispersed palladium nanoparticles approximately 2 nm in diameter on the surface. The catalysts synthesized by using different concentrations of aqueous hydrofluoric acid exhibited changing surface and acidic properties. Very high dispersion of palladium on magnesium fluoride (47%) was obtained with 1 wt% palladium loading. The catalysts were used for hydrogenation of various olefins in the presence of other organic functionalities at room temperature and atmospheric hydrogen pressure. Various substituted olefins were hydrogenated with almost 100% conversion and selectivity. The catalysts were recycled efficiently over five cycles without appreciable loss in catalytic activity. There was no palladium leaching under the reaction conditions, which was confirmed by inductively coupled plasma atomic emission spectroscopy analysis. Activation of olefin on the catalyst surface could not be observed by in situ FTIR studies, indicating facile activation of hydrogen on the palladium supported on magnesium hydroxide fluoride.

10aalkenes10aheterogeneous catalysis10aHydrogenation10amagnesium fluorides10aPalladium1 aAcham, Vaibhav, R.1 aBiradar, Ankush, V.1 aDongare, Mohan, K.1 aKemnitz, Erhard1 aUmbarkar, Shubhangi, B. uhttps://library.ncl.res.in/content/palladium-nanoparticles-supported-magnesium-hydroxide-fluorides-selective-catalyst-olefin02686nas a2200229 4500008004100000022001400041245011300055210006900168260007300237300001200310490000800322520181200330653002302142653002802165653001902193653002202212653002302234100001802257700002302275700002802298856013002326 2016 eng d a0926-337300aSol-gel synthesised WO3 nanoparticles supported on mesoporous silica for liquid phase nitration of aromatics0 aSolgel synthesised WO3 nanoparticles supported on mesoporous sil aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a142-1520 v1823 a

A series of WO3/SiO2 catalysts have been prepared by sol-gel method using ammonium metatungstate and ethyl silicate-40 (ES-40) as WO3 and SiO2 precursors respectively. The sol-gel method has led to the formation of WO3 nano-particles of 2-5 nm well dispersed on mesoporous silica along with some WO3' agglomerates. Formation of monoclinic WO3 was seen on the catalysts above 5 wt% WO3 loading by XRD analysis. Silica has shown very high surface area of 606 m(2)/g which decreased gradually upto 368 m(2)/g with 20 wt% WO3 loading. 20 wt% WO3/SiO2 catalyst has shown maximum acidity (0.56 mmol NH3/g) with presence of both Lewis and Bronsted acidity. UV-vis DRS analysis showed formation of polytungstate species along with WO3 on silica surface. The prepared catalysts were used for liquid phase nitration of aromatics using 70% nitric acid as nitrating agent without using any sulfuric acid. Very high conversion (99%) was obtained for p-cresol nitration with very high selectivity (99%) for 2-nitro p-cresol. The water formed during the reaction was removed azeotropically using ethylene dichloride as solvent. In case of o-xylene 74% conversion was obtained with 54% selectivity for 4-nitro o-xylene. The effect of different WO3 precursors on nitration efficiency was studied using sodium tungstate and tungstic acid as precursors. However,ammonium metatungstate showed the highest acidity. Sodium tungstate showed formation of dimer of sodium tungstate which did not show any acidity and hence no activity for nitration. The mechanism for nitration using WO3/SiO2 has been proposed based on polarisation of water on tungsten centre generating Bronsted acidity which can further generate nitronium ion giving subsequently nitration of the aromatic ring. (C) 2015 Elsevier B.V. All rights reserved.

10aAromatic nitration10aheterogeneous catalysis10aRegioselective10aSol-gel synthesis10aWater polarization1 aKulal, A., B.1 aDongare, Mohan, K.1 aUmbarkar, Shubhangi, B. uhttps://library.ncl.res.in/content/sol-gel-synthesised-wo3-nanoparticles-supported-mesoporous-silica-liquid-phase-nitration-001796nas a2200253 4500008004100000022001400041245013300055210006900188260000800257300001200265490000600277520091200283653002401195653001601219653002801235653002701263653000901290100002401299700002801323700002301351700001701374700002401391856012701415 2017 eng d a2168-048500aEnvironmentally benign bioderived carbon microspheres-supported molybdena nanoparticles as catalyst for the epoxidation reaction0 aEnvironmentally benign bioderived carbon microspheressupported m cJAN a904-9100 v53 a

A one pot synthesis of molybdenum oxide nanoparticles (NPs supported on bioderived carbon microspheres is reported. The catalyst was synthesized by the low temperature hydrothermal (LTH) method using D-glucose and bagasse as the carbon source. The carbonization of bagasse resulted in the formation of nonuniform carbon microspheres while glucose resulted in uniform carbon spheres. SEM and STEM elemental mapping show the uniform distribution of molybdenum oxide NPs over the carbon microspheres. XPS spectroscopy confirmed that molybdenum was in the Mo6+ oxidation state. The 1% MoO3 supported on carbon microspheres derived from D-glucose showed excellent catalytic activity up to 100% olefin conversion with 100% epoxide selectivity using organic tent-butyl hydroperoxide as an oxidant. The catalyst was successfully used for up to five cycles without losing substantial activity and selectivity.

10aCarbon microspheres10aepoxidation10aheterogeneous catalysis10aHydrothermal synthesis10aTBHP1 aDoke, Dhananjay, S.1 aUmbarkar, Shubhangi, B.1 aGawande, Manoj, B.1 aZbori, Radek1 aBiradar, Ankush, V. uhttps://library.ncl.res.in/content/environmentally-benign-bioderived-carbon-microspheres-supported-molybdena-nanoparticles