02179nas a2200229   4500008004100000022001400041245013600055210006900191260007300260300001200333490000800345520133700353653001301690653001701703653001101720653003201731653001301763100001501776700001501791700001401806856012901820       2005                        eng d  a0926-860X00aVanadium-containing ordered mesoporous silicas: synthesis, characterization and catalytic activity in the hydroxylation of biphenyl0 aVanadiumcontaining ordered mesoporous silicas synthesis characte  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG  a148-1580 v2903 a<p>A series of vanadium-containing ordered mesoporous MCM-41 materials (V-OMS) have been synthesized by direct hydrothermal (VMCM-41) and grafting (V/MCM-41) methods using hexadecyl trimethyl ammonium bromide (HDTMABr) as the structure-directing agent. The physico-chemical properties of the vanadium-containing materials were characterized in detail by ICP-OES, XRD, Fr-IR, N-2 adsorption-desorption, DRUV-VIS, TPR, XPS and SEM techniques. The redox performances of the vanadium-modified mesoporous materials were tested in the hydroxylation of biphenyl using aqueous H2O2 (30 wt.%) as oxidant. For a better exploitation of the catalytic activity, the reaction parameters are optimized in terms of temperature, solvent, oxidant, etc. A comparison between the catalytic activity values of the vanadium-containing mesoporous materials prepared by the two routes shows that vanadium-substituted (V-MCM-41) materials had increased activity and improved selectivity for mono hydroxyl products in the hydroxylation reaction of biphenyl compared to the V/MCM-41 catalysts. The heterogenity of the catalysts was verified by a series of leaching studies. Both the catalysts enhance the leaching of active vanadia species during the reaction; among them, V/MCM-41 shows the least heterogenity. (c) 2005 Elsevier B.V. All rights reserved.</p>10abiphenyl10aheterogenity10aMCM-4110aMesoporous molecular sieves10aVanadium1 aGeorge, J.1 aShylesh, S1 aSingh, AP  uhttps://library.ncl.res.in/content/vanadium-containing-ordered-mesoporous-silicas-synthesis-characterization-and-catalytic-001866nas 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-102547nas a2200205   4500008004100000022001400041245014100055210006900196260007300265300001200338490000800350520173500358653001402093653001802107653003202125653001802157100002602175700001802201856012202219       2007                        eng d  a1381-116900aCharacterization and catalytic activity of cobalt containing MCM-41 prepared by direct hydrothermal, grafting and immobilization methods0 aCharacterization and catalytic activity of cobalt containing MCM  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR  a118-1300 v2663 a<p>{Cobalt containing hexagonal mesoporous molecular sieves (MCM-41) were prepared by different methods viz., direct hydrothermal synthesis, grafting and immobilization. The calcined material was characterized by various spectroscopic tools such as powder X-ray diffraction (XRD), N-2 adsorption-desorption isotherms, Fourier transformed infra-red (Fr-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-vis and X-ray photoelectron spectroscopy (XPS). The XRD patterns show the highly intense (100) reflection peak in the range 2-3 degrees (2 theta angle), characteristic of mesoporous material. Higher order reflection peaks suggest highly ordered mesoporous structure. N2 adsorption-desorption isotherms are of type IV according to IUPAC classification and the steep rise in the isotherms in the narrow range 3.5-4.5 of relative pressure (P/P-0) is due to the condensation of N-2 gas molecules in the pores (characteristic of mesoporous structure). In FT-IR increase in the intensity of band at 960 cm(-1) with the increase of the cobalt content in Co-MCM-41 samples indicate the incorporation of cobalt ions in the framework of MCM-41. SEM and TEM reveal spherical morphology for the cobalt substituted MCM-41. UV-vis spectra demonstrate the characteristic features of framework and extraframework cobalt in MCM-41. Cobalt is in +2 oxidation state as evidenced from UV-vis and XPS. The catalysts were tested for the side chain oxidation of ethylbenzene using 70 wt.% tert-butyl hydrogen peroxide as an oxidant with and without the use of solvent. Solvents have effect in the catalytic activity and selectivity. In the absence of solvent, substituted cobalt [</p>10a2-butanol10acyclohexanone10aMesoporous molecular sieves10aMPV reduction1 aBhoware, Shrikant, S.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/characterization-and-catalytic-activity-cobalt-containing-mcm-41-prepared-direct-001532nas a2200253   4500008004100000022001400041245013100055210006900186260007300255300001000328490000800338520056900346653002100915653002800936653002700964653003200991653003301023653001401056100002101070700002001091700001701111700001801128856013201146       2009                        eng d  a0926-860X00aSynthesis, characterization and catalytic performance of Sn-MCM-48 in solvent-free Mukaiyama-type aldol condensation reactions0 aSynthesis characterization and catalytic performance of SnMCM48   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR  a88-940 v3583 a<p>The influence of various synthesis variables on the physico-chemical properties of mesoporous stannosilicate molecular sieves with MCM-48 structure (Sn-MCM-48) has been investigated. Sn-MCM48 has been used as a new heterogeneous catalyst in solvent-free Mukaiyama-type aldol reactions. Invariably, the beta-hydroxy ester selectivity was found to be 100% irrespective of the conversion level. The product yield was found to increase, to reach a maximum (70%), and then to decrease with the increase in tin content. (C) 2009 Elsevier B.V. All rights reserved.</p>10aCharacterization10aheterogeneous catalysis10aHydrothermal synthesis10aMesoporous molecular sieves10aMukaiyama-aldol condensation10aSn-MCM-481 aTaralkar, U., S.1 aKalita, Pranjal1 aKumar, Rajiv1 aJoshi, P., N.  uhttps://library.ncl.res.in/content/synthesis-characterization-and-catalytic-performance-sn-mcm-48-solvent-free-mukaiyama-type-0