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<p>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.</p>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-thiol01943nas 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<p>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.</p>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