01978nas a2200241   4500008004100000022001400041245011100055210006900166260009500235300001200330490000800342520104800350653002701398653002301425653003101448653002101479653004101500653001401541653001401555100001601569700002101585856013001606       2012                        eng d  a0021-951700aAminolysis of epoxides catalyzed by three-dimensional, mesoporous titanosilicates, Ti-SBA-12 and Ti-SBA-160 aAminolysis of epoxides catalyzed by threedimensional mesoporous   a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcSEP  a126-1400 v2933 a<p>The application of three-dimensional, mesoporous titanosilicates (Ti-SBA-12 and Ti-SBA-16) as reusable, solid catalysts for the synthesis of a range of beta-amino alcohols in high yields and selectivity through ring-opening of epoxides with amines at ambient and solvent-free conditions is reported, for the first time. These mesoporous titanosilicates (Si/Ti = 20-80) were prepared by a direct hydrothermal synthesis route adjusting the concentration of HCl (0.05-2 M) used in the synthesis. Ti ions in these catalysts were mostly substituted for Si in the framework. Water adsorption and Si-29 magic-angle spin nuclear magnetic resonance spectroscopy revealed that Ti-SBA-16 is more hydrophobic than Ti-SBA-12. Mesoporosity, three-dimensional architecture, surface hydrophobicity and easy access of Lewis acidic, framework-substituted Ti sites are the factors responsible for the superior activity of Ti-SBA-16 compared to Ti-SBA-12 and the hitherto known solid catalysts for this reaction. (C) 2012 Elsevier Inc. All rights reserved.</p>10aAminolysis of epoxides10abeta-Amino alcohol10aMesoporous titanosilicates10aMolecular sieves10aRing opening of epoxides with amines10aTi-SBA-1210aTi-SBA-161 aKumar, Anuj1 aSrinivas, Darbha  uhttps://library.ncl.res.in/content/aminolysis-epoxides-catalyzed-three-dimensional-mesoporous-titanosilicates-ti-sba-12-and-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<p>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.</p>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-001819nas a2200229   4500008004100000022001400041245008800055210006900143260007300212300001200285490000800297520095700305653005101262653002101313653003901334653003701373653001401410653001401424100001601438700002101454856011401475       2013                        eng d  a1381-116900aHydroxylation of phenol with hydrogen peroxide catalyzed by Ti-SBA-12 and Ti-SBA-160 aHydroxylation of phenol with hydrogen peroxide catalyzed by TiSB  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR  a112-1180 v3683 a<p>We report here, for the first time, the application of ordered, three-dimensional, mesoporous titanosilicates, Ti-SBA-12 and Ti-SBA-16, as reusable solid catalysts, for hydroxylation of phenol, an industrially important organic transformation. The reactions were conducted using 30% aqueous H2O2 as oxidant. The catalysts of this work are more efficient than the hitherto known mesoporous Ti-silicates. They are more para-product selective than TS-1 and other titanosilicates. Ti-SBA-12 exhibited higher activity and hydroquinone/catechol selectivity (by nearly two times) than Ti-SBA-16. H2O2 efficiency of similar to 90 mol% was obtained. Our study reveals that framework substituted Ti with pseudo-tetrahedral geometry, three-dimensional mesoporosity as well as surface structure are the unique features responsible for the high catalytic activity and selectivity of these titanosilicate catalysts. (C) 2012 Elsevier B.V. All rights reserved.</p>10aCatalytic liquid-phase hydroxylation of phenol10aMolecular sieves10aOrdered mesoporous titanosilicates10aOxidation with hydrogen peroxide10aTi-SBA-1210aTi-SBA-161 aKumar, Anuj1 aSrinivas, Darbha  uhttps://library.ncl.res.in/content/hydroxylation-phenol-hydrogen-peroxide-catalyzed-ti-sba-12-and-ti-sba-16-0