02138nas a2200241 4500008004100000022001400041245009000055210006900145260007300214300001200287490000700299520131000306653001801616653002201634653001201656653001601668653001601684653002101700100001901721700001701740700001801757856012101775 2006 eng d a1566-736700aSites for CO2 activation over amine-functionalized mesoporous Ti(Al)-SBA-15 catalysts0 aSites for CO2 activation over aminefunctionalized mesoporous TiA aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR a314-3260 v903 a

{Activation of CO and its utilization in the synthesis of chloropropene and styrene carbonates over functionalized, mesoporous SBA-15 solids, have been investigated. The surface basicity of SBA-15 was modified with nitrogen-based organic molecules of varying basicity viz., alkyl amines (-NH2), adenine (Ade), imidazole (Im) and guanine (Gua). The surface of SBA-15 was also functionalized with Ti4+ and Al3+ species. The acid-base properties of these modified SBA-15 materials were investigated by temperature-programmed desorption (TPD) and diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy. NH3 and pyridine were used as probe molecules for acid sites, while CO, was used to characterize the basic sites. CO was activated at the basic amine sites forming surface carbamate species (IR peaks: 1609 and 1446 cm(-1)). The latter reacted further with epoxides adsorbed on the acid sites forming cyclic carbonates. A correlation between the intensity of the IR peak at 1609 cm(-1) and cyclic carbonate yield has been observed. The cyclic carbonate yields were higher when both the acid and base functionalities were present on the surface. The Ti- and Al-SBA-15 functionalized with adenine exhibited the highest catalytic activity and selectivity. There is an optimal dependence (''

10aaromatization10aGa-based zeolites10apropane10aSi/Al ratio10aSi/Ga ratio10azeolitic factors1 aSrivastava, R.1 aSrinivas, D.1 aRatnasamy, P. uhttps://library.ncl.res.in/content/sites-co2-activation-over-amine-functionalized-mesoporous-tial-sba-15-catalysts-101626nas a2200265 4500008004100000022001400041245013300055210006900188260010600257300001400363490000700377520063300384653001501017653003101032653001701063653002201080653002701102653001101129653001901140653001801159100001901177700001701196700001801213856012901231 2006 eng d a0040-403900aSyntheses of polycarbonate and polyurethane precursors utilizing CO2 over highly efficient, solid as-synthesized MCM-41 catalyst0 aSyntheses of polycarbonate and polyurethane precursors utilizing aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUN a4213-42170 v473 a

As-synthesized MCM-41 was used as a reusable, heterogeneous catalyst for the eco-friendly synthesis of cyclic carbonate precursors of polycarbonates via a cycloaddition reaction of CO2 with epoxides. This catalyst is also efficient for the synthesis of alkyl and aryl carbamate precursors of polyurethanes via the reaction of amines, CO2 and alkyl halides. Both these reactions were carried out under mild conditions and without using any solvent or co-catalyst. CO2 is utilized as a raw material replacement for toxic phosgene in the conventional synthesis of these chemicals. (c) 2006 Elsevier Ltd. All rights reserved.

10acarbamates10acarbon dioxide utilization10aCO2 fixation10acyclic carbonates10aeco-friendly processes10aMCM-4110apolycarbonates10apolyurethanes1 aSrivastava, R.1 aSrinivas, D.1 aRatnasamy, P. uhttps://library.ncl.res.in/content/syntheses-polycarbonate-and-polyurethane-precursors-utilizing-co2-over-highly-efficient-002595nas a2200253 4500008004100000022001400041245011600055210006900171260007300240300001200313490000800325520158500333653003301918653002001951653003201971653001602003653005302019653003502072653003902107653003002146100001702176700001802193856013002211 2007 eng d a1387-181100aSpectroscopic and catalytic properties of SBA-15 molecular sieves functionalized with acidic and basic moieties0 aSpectroscopic and catalytic properties of SBA15 molecular sieves aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP a170-1800 v1053 a

SBA-15, grafted with Lewis acidic Ti4+ ions and basic amines (imidazole, guanine or adenine) exhibited high catalytic activity in the cycloaddition of CO2 to epoxides yielding selectively cyclic carbonate precursors of polycarbonates. In the second class of materials, the surface of SBA-15 was grafted with thiol or sulfonic acid functionalities. Mn(Salen)Cl was, then, covalently bound to these acidic groups. The resulting catalysts show enhanced chemo-, regio- and stereo-selective catalytic activity in the epoxidation of terpenes such as R-(+)limonene, alpha-pinene and Delta-carene with molecular oxygen. The acid-base properties of these modified SBA- 15 materials were investigated by temperature-programmed desorption and diffuse-reflectance infrared Fourier transform spectroscopy. Ammonia and pyridine were used as probe molecules for acidic sites and CO2 for basic sites. Acidic Ti sites activated epoxides and the grafted basic amines activated CO2. The simultaneous presence of both acidic and basic sites on amine/adenine-functionalized Ti-SBA-15 enabled synergistic enhancement in catalytic activity in the cycloaddition reaction of CO2 to epoxides. When Mn(Salen)Cl was immobilized on thiol or sulfonic acid-functionalized SBA-15, the oxidation state of Mn decreased from +3 to +2. The organo-acidic functional groups (thiol or sulfonic acid) axialk, coordinated to Mn ions modified the electronic structure of Mn ions enhancing the activity and selectivity of Mn(Salen) complexes in aerial oxidation reactions. (C) 2007 Elsevier Inc. All rights reserved.

10aaerial oxidation of terpenes10aCO2 utilization10acyclic carbonates synthesis10aepoxidation10afunctionalization with acidic and basic moieties10aimmobilization of Mn complexes10aorgano-functionalization of SBA-1510asolid acid-base catalysts1 aSrinivas, D.1 aRatnasamy, P. uhttps://library.ncl.res.in/content/spectroscopic-and-catalytic-properties-sba-15-molecular-sieves-functionalized-acidic-and-001909nas a2200217 4500008004100000022001400041245009100055210006900146260005700215300001200272490000800284520113100292653002601423653000801449653001101457653004201468653002801510100001401538700001701552856012201569 2009 eng d a1011-372X00aSelective oxidation of benzyl alcohol over copper phthalocyanine immobilized on MCM-410 aSelective oxidation of benzyl alcohol over copper phthalocyanine a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcMAR a434-4420 v1283 a

Copper phthalocyanine (CuPc) complexes immobilized on ``neat'' and Ti(4+) and Al(3+) containing MCM-41 mimic the functionality of metalloenzymes. These novel materials catalyze the oxidation of benzyl alcohol to selectively benzaldehyde at moderate temperatures using peroxides and molecular oxygen as oxidant. Electron paramagnetic resonance and X-ray photoelectron spectroscopic studies revealed that the acidity of the support (MCM-41) influences the electronic structure of the immobilized CuPc. On acidic supports a part of copper in CuPc got reduced from a ``formal'' +2 to +1 oxidation state. This reduction of copper in its oxidation state on different supports decreased in the order: Al-MCM-41 (Bronsted and strong Lewis acid sites) > MCM-41 (silanol sites) > Ti-MCM-41 (weak Lewis acid sites). A linear variation in catalytic activity with the concentration of Cu(1+) ions in different catalyst samples was observed. The study reveals that by suitably modifying the acidic properties of the support one can, in principle, fine-tune the electronic and catalytic properties of the active oxidation sites.

10aCopper phthalocyanine10aEPR10aMCM-4110aSelective oxidation of benzyl alcohol10aUV-visible spectroscopy1 aHamza, A.1 aSrinivas, D. uhttps://library.ncl.res.in/content/selective-oxidation-benzyl-alcohol-over-copper-phthalocyanine-immobilized-mcm-41-001865nas a2200241 4500008004100000022001400041245009700055210006900152260007300221300001200294490000800306520098500314653004401299653001401343653001601357653001601373653002501389653001501414653001801429100002801447700001701475856013101492 2011 eng d a0926-860X00aSelective epoxidation of methyl soyate over alumina-supported group VI metal oxide catalysts0 aSelective epoxidation of methyl soyate over aluminasupported gro aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL a189-1980 v4013 a

Epoxidation of methyl soyate (biodiesel), soybean oil and oleic acid with tert.-butyl hydroperoxide (TBHP) was investigated over gamma-alumina-supported group VI metal oxides (CrOx/Al2O3, MoOx/Al2O3 and WOx/Al2O3) prepared by impregnation method. The studies revealed that 15 wt% MoOx on gamma-Al2O3 was the most active catalyst (conversion >90 mol% under optimized conditions). While MoOx/Al2O3 is selective mainly for epoxidation, the other catalysts are active for epoxidation as well as for decomposition of TBHP. The active species on the catalyst surface were investigated using in situ UV-visible spectroscopy. A linear correlation was observed between epoxidation activity and surface acidity of the catalyst. A new H-1 NMR method was developed to monitor the progress of epoxidation reaction which was found to be superior to gas chromatographic method in estimating the conversion of double bonds of fatty compounds. (C) 2011 Elsevier B.V. All rights reserved.

10aAlumina-supported group VI metal oxides10aBiodiesel10aepoxidation10aFatty acids10aH-1 NMR spectroscopy10aMoOx/Al2O310aVegetable oil1 aSatyarthi, Jitendra, K.1 aSrinivas, D. uhttps://library.ncl.res.in/content/selective-epoxidation-methyl-soyate-over-alumina-supported-group-vi-metal-oxide-catalysts-0