01866nas a2200265 4500008004100000022001400041245012600055210006900181260007300250300001200323490000800335520080500343653003301148653003701181653001101218653004101229653003201270653002901302653004401331653004001375100001901415700001701434700002001451856012901471 2006 eng d a0926-860X00aChemo-, regio- and stereo-selective aerial oxidation of limonene to the endo-1,2-epoxide over Mn(Salen)-sulfonated SBA-150 aChemo regio and stereoselective aerial oxidation of limonene to  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJUL a144-1540 v3093 a

Mn(Salen) complexes immobilized on sulfonic acid-functionalized SBA-15 molecular sieves (SBA-15-pr-SO3-Mn(Salen)) catalyze the Mukaiyama-type oxidation of R-(+)-limonene selectively to the 1,2-epoxide with molecular oxygen at 298 K (Salen = N,N-ethylenebis(salicylidenaminato)). The endo-diastereomer is formed with a diasteromeric excess of 39.8%. This catalyst exhibited higher catalytic activity than ``neat'' Mn(Salen) complexes directly supported on SBA-15 or zeolite-Y. A change in the oxidation state of Mn from +3 in the ``neat'' complex to +2 when immobilized on the sulfonated surface is a probable cause for the observed enhancement of catalytic activity. A part of the Mn complexes was leached out of the solid phase during the reaction. (c) 2006 Elsevier B.V. All rights reserved.

10aaerial oxidation of limonene10acatalysis by Mn(Salen) complexes10achemo-10aimmobilized Mn Schiff base complexes10aMesoporous molecular sieves10aMukaiyama-type oxidation10aregio- and stereo-selective epoxidation10asulfonic acid-functionalized SBA-151 aSaikia, Lakshi1 aSrinivas, D.1 aRatnasamy, Paul uhttps://library.ncl.res.in/content/chemo-regio-and-stereo-selective-aerial-oxidation-limonene-endo-12-epoxide-over-mnsalen-101968nas a2200157 4500008004100000245017700041210006900218260000800287300001300295490000800308520130400316100001901620700002101639700002001660856013001680 2007 eng d00aComparative catalytic activity of Mn(Salen) complexes grafted on SBA-15 functionalized with amine, thiol and sulfonic acid groups for selective aerial oxidation of limonene0 aComparative catalytic activity of MnSalen complexes grafted on S cAUG a 225-2350 v1043 aSBA-15 molecular sieves were functionalized with propylamine, propylthiol and propylsulfonic acid groups. Mn(Salen)Cl complexes were grafted on these organo-functionalized SBA-15. The support and the type of organo-functional group influenced the electronic structure (oxidation state and redox behavior) and chemo selectivity of the Mn-complexes in the oxidation of limonene. The Mn ions were reduced from +3 to +2, the extent of this reduction on different supports decreasing in the order: SBA- 15-pr-SH > SBA- 15-prSO(3)H > SBA-15-pr-NH2- Mn(Salen)Cl supported on propylthiol-functionalized SBA-15 yielded the 1,2-limonene epoxide with 100% chemo- and regioselectivity. Higher electron density at the site of Mn ions and the consequent lower redox potential of the Mn-complexes on immobilization are the probable causes for their efficient and selective catalytic activity. Solvents, additives (N-MeIm) and co-reagents (iso-butyraldehyde), which facilitated formation of Mn2+ ions, enhance the catalytic activity. A part of the Mn complexes was leached out of the solid phase during the reaction and the extent of this with different catalysts decreased in the order: SBA-l5-pr-NH2-Mn(Salen)Cl > SBA- 15-pr-SO3H-Mn(Salen)Cl > SBA- 15-pr-SH-Mn(Salen)Cl. (C) 2007 Elsevier Inc. All rights reserved1 aSalkia, Lakshi1 aSrinivas, Darbha1 aRatnasamy, Paul uhttps://library.ncl.res.in/content/comparative-catalytic-activity-mnsalen-complexes-grafted-sba-15-functionalized-amine-thiol01655nas a2200169 4500008004100000022001400041245009600055210006900151260007100220300001400291490000700305520098800312100002801300700001701328700002001345856012001365 2009 eng d a0887-062400aEstimation of free fatty acid content in oils, fats, and biodiesel by (1)H NMR spectroscopy0 aEstimation of free fatty acid content in oils fats and biodiesel a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a2273-22770 v233 a

A novel (1)H NMR method for the quantification of free fatty acid (FFA) content in vegetable oils, animal fats, and biodiesel is reported. Nonedible oils and animal fats, which are increasingly being explored as cheaper, renewable feed stocks for biodiesel production by transesterification with methanol, contain a significant amount of FFA along with other acidic impurities. The (1)H NMR spectroscopic method is found to be more accurate than the conventional titrimetric analysis for the estimation of FFA content especially in those cases where acidic entities other than the FFA are also present in the feedstock. The titrimetric methods provide a gross acid value which corresponds to that of FFA and other acidic impurities. Our NMR method provides the FFA content exclusively. In the case of refined edible oils (wherein the other acidic impurities are negligible), the results obtained from the (1)H NMR method are comparable with those from the titrimetic analysis.

1 aSatyarthi, Jitendra, K.1 aSrinivas, D.1 aRatnasamy, Paul uhttps://library.ncl.res.in/content/estimation-free-fatty-acid-content-oils-fats-and-biodiesel-1h-nmr-spectroscopy-002449nas 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-001673nas a2200169 4500008004100000022001400041245009800055210006900153260007100222300001400293490000700307520099800314100002801312700002101340700002001361856012201381 2010 eng d a0887-062400aInfluence of surface hydrophobicity on the esterification of fatty acids over solid catalysts0 aInfluence of surface hydrophobicity on the esterification of fat a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a2154-21610 v243 a

The relative roles of surface acidity and hydrophobicity in the methylation of fatty acids (C(8) - C(18)) to the corresponding methyl esters were investigated over three solid acid catalysts: Fe-Zn double-metal cyanide (DMC), sulfated zirconia (SZ), and Al-MCM-41. The esterification reaction was faster and the apparent activation energy was lower over SZ and Al-MCM-41 than on DMC because of their higher acid strength, specific surface area, and pore diameter. Over SZ and Al-MCM-41, the apparent activation energy for esterification increased with the chain length of the fatty acid. A reverse trend, however, was observed over DMC. The relative adsorption of methanol and fatty acids (compared to water) was higher on DMC than on SZ and Al-MCM-41. Hence, in addition to the acidic and textural properties, surface hydrophobicity and relative surface coverage by reactants/products also play an important role in reactions of long-chain fatty acids with alcohols on solid catalysts.

1 aSatyarthi, Jitendra, K.1 aSrinivas, Darbha1 aRatnasamy, Paul uhttps://library.ncl.res.in/content/influence-surface-hydrophobicity-esterification-fatty-acids-over-solid-catalysts-001943nas a2200253 4500008004100000022001400041245009700055210006900152260007300221300001000294490000700304520104600311653001901357653002201376653002201398653003601420653001001456100001501466700002101481700002701502700002001529700002401549856011601573 2013 eng d a1566-736700aCatalytic activity of ZIF-8 in the synthesis of styrene carbonate from CO2 and styrene oxide0 aCatalytic activity of ZIF8 in the synthesis of styrene carbonate aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a36-400 v323 a

The catalytic activity of ZIF-8 in the synthesis of styrene carbonate from carbon dioxide and styrene oxide is presented. ZIF-8 crystals displayed catalytic activity even at temperatures as low as 50 degrees C, with styrene carbonate yields as high as similar to 54% at 100 degrees C. In contrast to many prior-art catalysts, solvents or co-catalysts were not required. Pyridine and ammonia were used as probe molecules to estimate the type and density of acid sites in fresh and reused ZIF-8 catalysts. DRIFT spectroscopy of adsorbed pyridine revealed the presence of both Bronsted (B) and Lewis (L) acid sites. The B-sites have nearly vanished in the case of recycled ZIF-8 catalysts. The simultaneous presence of both the acid sites and the nitrogen basic moieties from the imidazole linker in ZIF-8 promoted the adsorption of the CO2 on the solid surface and its further conversion to the cyclic carbonate. The ZIF-8 catalysts could be recycled and reused without significant loss in catalytic activity. Published by Elsevier B.V.

10aCO2 conversion10acyclic carbonates10aStyrene carbonate10aZeolitic imidazolate frameworks10aZIF-81 aZhu, Minqi1 aSrinivas, Darbha1 aBhogeswararao, Seemala1 aRatnasamy, Paul1 aCarreon, Moises, A. uhttps://library.ncl.res.in/content/catalytic-activity-zif-8-synthesis-styrene-carbonate-co2-and-styrene-oxide-0