02449nas a2200229 4500008004100000022001400041245009600055210006900151260011700220300000900337490000800346520152700354653001301881653004301894653002501937653002401962653002001986653004102006100002002047700002102067856013102088 2009 eng d a0920-586100aSelective oxidations over zeolite- and mesoporous silica-based catalysts: selected examples0 aSelective oxidations over zeolite and mesoporous silicabased cat aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbCatalysis Soc India; Petrotech Soc; Indo US Sci & Technol ForumcMAR a3-110 v1413 a

Selective oxidation of hydrocarbons/terpenes in the liquid phase are reported over three categories of zeolite- and mesoporous silica-based catalysts: (1) transition metal complexes (metal phthalocyanines, copper acetate dimers and Co/Mn acetate trimer) encapsulated in zeolite-Y, (2) transition metal complexes (Mn-Salen), grafted on SBA-15, and (3) transition metal ions in framework positions of zeolites and mesoporous molecular sieves like Ti-silicates. Upon heterogenization, the metal complexes exhibited enhanced catalytic acitivity/selectivity. The causes for the enhanced catalytic activity/product selectivity have been explored. Dimer formation (copper acetate) or geometric distortion in the zeolite cavities (metal phthalocyanines) and consequent changes in energy levels and redox potentials are shown to modify the catalytic activity (in the selective oxidation of hydrocarbons) of the encapsulated metal complexes. In the case of Mn-Salen grafted on SBA-15, increasing the acidity of the siliceous surface (by -SO(3)H groups, for example) leads to a more facile reduction of the Mn ions and, thereby, enhanced catalytic activity in the selective epoxidation of limonene. When Ti ions are introduced in framework positions, reactive metal-oxo species are formed on contact with H(2)O(2) or O(2), Which influence the mode of O-O cleavage (heterolytic/homolytic) and product selectivity. The structure-function relationships in these catalysts are reported. (c) 2008 Elsevier B.V. All rights reserved.

10aMn-Salen10aOxidation of hydrocarbons and limonene10aReactive oxo species10aSelective oxidation10aTitanosilicates10aZeolite-encapsulated metal complexes1 aRatnasamy, Paul1 aSrinivas, Darbha uhttps://library.ncl.res.in/content/selective-oxidations-over-zeolite-and-mesoporous-silica-based-catalysts-selected-examples-000982nas a2200157 4500008004100000022001400041245011300055210006900168260011000237300001400347520027500361100001600636700002100652700002000673856013100693 2009 eng d a1359-734500aSynthesis of framework Ti-substituted, 3-D hexagonal, mesoporous Ti-SBA-12 for selective catalytic oxidation0 aSynthesis of framework Tisubstituted 3D hexagonal mesoporous TiS aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcSEP a6484-64863 a

Framework Ti-substituted, 3-D hexagonal mesoporous, Ti-SBA-12, obtained for the first time by direct hydrothermal synthesis, oxidises bulky molecules such as cyclohexene and cyclooctene to the epoxides with >96% selectivity at high conversion levels (>60%).

1 aKumar, Anuj1 aSrinivas, Darbha1 aRatnasamy, Paul uhttps://library.ncl.res.in/content/synthesis-framework-ti-substituted-3-d-hexagonal-mesoporous-ti-sba-12-selective-catalytic-002000nas a2200241 4500008004100000022001400041245014400055210006900199260007300268300001000341490000800351520108600359653003401445653002501479653002101504653002401525653001401549653001401563653002001577100001601597700002101613856012401634 2012 eng d a0920-586100aSelective oxidation of cyclic olefins over framework Ti-substituted, three-dimensional, mesoporous Ti-SBA-12 and Ti-SBA-16 molecular sieves0 aSelective oxidation of cyclic olefins over framework Tisubstitut aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC a59-680 v1983 a

Framework Ti-substituted, three-dimensional, mesoporous titanosilicates, Ti-SBA-12 and Ti-SBA-16, were prepared by direct hydrothermal synthesis method. These catalysts showed catalytic activity higher than the hitherto known titanosilicates for the oxidation of cyclic olefins (cyclohexene and cyclooctene) with tert.-butyl hydroperoxide. An epoxide selectivity of 100% and olefin conversion greater than 92% were obtained. Cubic Ti-SBA-16 with interconnected cage-like mesopore structure was more active than hexagonal Ti-SBA-12. X-ray diffraction and diffuse reflectance UV-vis, Fourier transform infrared, Raman and electron paramagnetic resonance spectroscopies provided evidence for the substitution of Ti4+ (for Si4+) in the framework locations. The catalytic activity correlated with the concentration of framework-substituted, tetrahedral Ti4+ ions. Easy accessibility of the active sites and the three-dimensional mesoporous structure are the possible causes for the superior activity of these titanosilicate catalysts. (C) 2012 Elsevier B. V. All rights reserved.

10aEpoxidation of cyclic olefins10amesoporous materials10aMolecular sieves10aSelective oxidation10aTi-SBA-1210aTi-SBA-1610aTitanosilicates1 aKumar, Anuj1 aSrinivas, Darbha uhttps://library.ncl.res.in/content/selective-oxidation-cyclic-olefins-over-framework-ti-substituted-three-dimensional-001879nas a2200217 4500008004100000022001400041245011700055210006900172260007300241300001000314490000800324520104600332653002101378653002801399653001701427653002201444653002301466100002101489700002101510856013001531 2016 eng d a0926-860X00aSpectroscopy and catalytic activity study of gold supported on barium titanate nanotubes for styrene epoxidation0 aSpectroscopy and catalytic activity study of gold supported on b aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG a61-720 v5233 a

Gold (0.5-5 wt.%) supported on barium titanate nanotubes (Au/BaTNT) were prepared, characterized and for the first time, investigated as catalysts for selective oxidation of styrene with oxygen (O-2 or H-2 + O-2) and peroxides (H2O2 or TBHP). Conversion of styrene enhanced when H-2 was co-added to O-2 in the reactions. Au/BaTNT activated O-2 and H-2 and produced H2O2 in situ for use in oxidations. Peroxides were found better oxidants than O-2. At optimized conditions, styrene oxide selectivity of 80.1 wt.% at styrene conversion of 60.5 wt.% was achieved over Au(1 wt.%)/BaTNT using TBHP. Au particles (5.0-7.4 nm) were dispersed and decorated on the walls of BaTNT. They exhibited superior performance to the known Au catalysts in styrene oxidation. Reactive oxygen species formed during oxidation reactions were followed with in situ spectral characterizations (diffuse reflectance UV-vis and FT -Raman). Au/BaTNT was reusable in four recycles with little loss in catalytic activity. (C) 2016 Elsevier B.V. All rights reserved.

10aAu Nanoparticles10areactive oxygen species10aspectroscopy10aStyrene Oxidation10aTitanate nanotubes1 aNepak, Devadutta1 aSrinivas, Darbha uhttps://library.ncl.res.in/content/spectroscopy-and-catalytic-activity-study-gold-supported-barium-titanate-nanotubes-styrene01786nas a2200217 4500008004100000022001400041245013300055210006900188260000800257300001200265490000800277520101600285653001301301653001801314653003001332653001601362653001601378100002201394700002101416856013101437 2017 eng d a0920-586100aSelective and reusable Pt-WO x /Al 2 O 3 catalyst for deoxygenation of fatty acids and their esters to diesel-range hydrocarbons0 aSelective and reusable PtWO x Al 2 O 3 catalyst for deoxygenatio cJUN a219-2260 v3093 aTungsten oxide promoted platinum catalysts (Pt-WOx/Al2O3) of varying composition were prepared by wet impregnation method and reduced in hydrogen atmosphere. X-ray powder diffraction and photoelectron spectroscopy revealed that Pt is completely reduced to metallic state while tungsten is in +6 and +5 oxidation state. Pt crystallite and particle sizes increased (from 1.2 to 1.4 nm and 2.5 to 3 nm, respectively) in presence of WOx (CO-chemisorption and transmission electron microscopy). Tungsten addition augmented strong acid sites. It enhanced significantly the catalytic activity of Pt/Al2O3 in deoxygenation of fatty acids and their methyl esters. Tungsten altered the reaction pathway from decarbonylation/decarboxylation to hydrodeoxygenation. A catalyst with 4 wt% Pt and 8 wt% W exhibited high catalytic performance. Complete conversion of oleic acid and octadecane product selectivity in the range 67.1 − 80.8% was obtained. Pt-WOx/Al2O3 is a stable and reusable fatty acid deoxygenation catalyst.10abiofuels10aDeoxygenation10aDiesel-range hydrocarbons10aFatty acids10aPt catalyst1 aJanampelli, Sagar1 aSrinivas, Darbha uhttps://library.ncl.res.in/content/selective-and-reusable-pt-wo-x-al-2-o-3-catalyst-deoxygenation-fatty-acids-and-their-esters