01967nas a2200229   4500008004100000022001400041245010400055210006900159260007300228300001000301490000800311520116300319653001401482653001101496653001501507653001401522653001301536100001601549700002601565700001801591856012801609       2005                        eng d  a1381-116900aInfluence of silica source in the catalytic activity and heterogenity of mesoporous vanadosilicates0 aInfluence of silica source in the catalytic activity and heterog  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP  a57-630 v2393 a<p>Vanadium-substituted ordered mesoporous silicates (V-OMS) were synthesized hydrothermally using two common silica sources, viz. fumed silica and tetraethyl orthosilicate, and their surface properties and catalytic activities were evaluated in the liquid phase oxidation of 1-napthol using aqueous H2O2 as an oxidant. The catalysts were characterized by XRD, N-2, adsorption-desorption, DRUV-vis and TPR to evaluate the mesostructural ordering and the local environment of vanadium in the MCM-41 matrix. Characterization data of the fresh calcined catalysts reveal a more ordered hexagonal structure for the V-MCM-41 catalyst prepared by using tetraethyl orthosilicate as the silica source while spent catalyst showed that the material is less stable than the V-MCM-41 catalyst prepared by using fumed silica as the silica source. Further, the observed differences in the selectivity behavior of extracted and calcined forms of both vanadium catalysts shows that the treatment conditions had a decisive role in the formation of extra framework metal species and further in the mesoscopic structural ordering. (c) 2005 Elsevier B.V. All rights reserved.</p>10a1-napthol10aMCM-4110aMesoporous10aOxidation10aVanadium1 aShylesh, S.1 aMirajkar, Subhash, P.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/influence-silica-source-catalytic-activity-and-heterogenity-mesoporous-vanadosilicates-002063nas a2200217   4500008004100000022001400041245012500055210006900180260007300249300001000322490000800332520124800340653001901588653002301607653001401630653002601644100001901670700001601689700001801705856012201723       2005                        eng d  a1381-116900aSynthesis, characterization and catalytic activity of Mn(III)- and Co(II)-salen complexes immobilized mesoporous alumina0 aSynthesis characterization and catalytic activity of MnIII and C  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcNOV  a79-870 v2413 a<p>Mn(III) and Co(II)-schiff base complexes were immobilized over mesoporous alumina through the reaction of mesoporous alumina functionalized 3-aminopropyl triethoxy silane (3-APTES) and salicylic aldehyde via schiff base condensation. The surface properties of the functionalized catalysts were analyzed by a series of characterization techniques like elemental analysis, PXRD, FTIR, N(2) adsorption-desorption, TG-DTG, DR UV-vis, XPS, etc. PXRD and adsorption-desorption analysis shows that the mesostructure of alumina remains intact after various modifications, while spectral technique show the successful anchoring of the neat complexes inside the porous alumina support. The catalytic activity of the functionalized metal-salen complexes examined in the liquid phase oxidation of styrene and cyclohexene shows that the functionalized salen complexes are more active and selective than the corresponding neat metal complexes. Further, the catalyst (Mn-S-NH(2)-MA) was recycled three times in the oxidation of styrene and no major change in the conversion and selectivity is observed, which shows that the immobilized metal-salen complexes are stable under the present reaction conditions. (c) 2005 Elsevier B.V. All rights reserved.</p>10aImmobilization10aMesoporous alumina10aOxidation10aSchiff base complexes1 aChaube, V., D.1 aShylesh, S.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/synthesis-characterization-and-catalytic-activity-mniii-and-coii-salen-complexes-002290nas a2200217   4500008004100000022001400041245012600055210006900181260007300250300001200323490000700335520143400342653003201776653002701808653002401835653002401859100001601883700002401899700001801923856013101941       2006                        eng d  a1387-181100aAssembly of hydrothermally stable ethane-bridged periodic mesoporous organosilicas with spherical and wormlike structures0 aAssembly of hydrothermally stable ethanebridged periodic mesopor  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP  a364-3700 v943 a<p>Hydrothermally stable periodic mesoporous organosilicas with spherical as well as wormlike frame structures were synthesised by two different synthesis routes using the silsesquioxane precursor, 1,2-bis (triethoxy silyl) ethane (BTEE) and surfactant octadecyl trimethyl ammonium (ODTA), under basic conditions. The materials were characterized by PXRD, SEM, TEM, N-2 adsorption-desorption, FT-IR, Si-29 MAS NMR, C-13 CP MAS NMR and TG-DTA techniques. Characterization techniques revealed that the morphology of the hybrid material prepared from pure silsesquioxane precursor resulted in spherical particles while a combination of tetra ethyl orthosilicate and 1,2-bis (triethoxy silyl) ethane (90:10 ratio) resulted in materials having wormlike structures. Hydrothermal stability of the hybrid material was evaluated by refluxing the sample under boiling water for various time periods and was compared with that of a periodic mesoporous silica material, Si-MCM-41. Results showed that the hybrid material is stable up to 100 h in boiling water, with the existence of d(100) peak, while the mesopore structure of Si-MCM-41 get destroyed even after a 12 h reflux time. The improved hydrothermal stability of the hybrid material is related to the more hydrophobic environment induced inside the pore channels, due to the presence of integrating ethane groups in the wall channels. (c) 2006 Elsevier Inc. All rights reserved.</p>10ahybrid mesoporous materials10aHydrothermal stability10aspherical particles10awormlike structures1 aShylesh, S.1 aJha, Ratnesh, Kumar1 aSingh, A., P.  uhttps://library.ncl.res.in/content/assembly-hydrothermally-stable-ethane-bridged-periodic-mesoporous-organosilicas-spherical-002031nas a2200241   4500008004100000022001400041245016300055210006900218260007300287300001200360490000800372520113200380653001101512653001701523653000801540653001701548653001401565100002601579700001601605700001901621700001801640856013101658       2006                        eng d  a1381-116900aCobalt-containing hexagonal mesoporous molecular sieves (Co-HMS): Synthesis, characterization and catalytic activity in the oxidation reaction of ethylbenzene0 aCobaltcontaining hexagonal mesoporous molecular sieves CoHMS Syn  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAUG  a123-1300 v2553 a<p>Cobalt-containing hexagonal mesoporous materials (Co-HMS and Co/HMS) with different cobalt content were synthesized for the first time by direct hydrothermal and post-synthesis (grafting) method. The materials were characterized in detail by X-ray diffraction, BET surface area, N-2 sorption isotherms, SEM, TEM, UV-vis and XPS techniques. Powder X-ray diffraction pattern, N2 adsorption-desorption analysis and TEM analysis show the presence of hexagonal mesoporous structure, having Type W isotherms and reveals the typical wormhole-like morphology. Spectroscopic techniques like UV-vis and XPS reveal cobalt in +2 oxidation state and tetrahedrally coordinated. Liquid phase oxidation of ethylbenzene using TBHP (70 wt%) as an oxidant shows that the catalysts are highly active, under solvent free conditions as well as under lower cobalt concentrations. Leaching studies performed by hot filtration experiments show that the cobalt catalysts prepared by hydrothermal methods are stable, while the grafted catalysts show the leaching of cobalt under the reaction conditions. (c) 2006 Elsevier B.V. All rights reserved.</p>10aCo-HMS10aethylbenzene10aHMS10ahydrothermal10aOxidation1 aBhoware, Shrikant, S.1 aShylesh, S.1 aKamble, K., R.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/cobalt-containing-hexagonal-mesoporous-molecular-sieves-co-hms-synthesis-characterization-002480nas a2200217   4500008004100000022001400041245020600055210006900261260009500330300001000425490000800435520158100443653001102024653002202035653001402057653001502071653001302086100001602099700001802115856012902133       2006                        eng d  a0021-951700aHeterogenized vanadyl cations over modified silica surfaces: a comprehensive understanding toward the structural property and catalytic activity difference over mesoporous and amorphous silica supports0 aHeterogenized vanadyl cations over modified silica surfaces a co  a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcNOV  a52-640 v2443 a<p>Using a postsynthesis grafting method, 3-aminopropyltriethoxysilane (3-APTS) was functionalized over silica gel and mesoporous silica materials like SBA-15 and MCM-41. Vanadyl cations were then immobilized over the functionalized amino groups of the silica samples and used as a catalyst in the liquid-phase oxidation reaction of cyclohexane. Elemental analysis, PXRD, TEM, N-2 adsorption-desorption isotherms, FTIR, C-13 and Si-29 MAS NMR, UV-vis, and EPR techniques were used to characterize the developed materials. Characterization results suggest that the percentage of 3-APTS grafting depends on the number of isolated and genlinal silanol sites of the support material, the solvents used during the grafting reactions, and the sample pretreatment conditions. We found that using toluene as the dispersing medium and Si-MCM-41 as a support provides the maximum amount of amine functionalization, and thereby the highest percentage of vanadium immobilization. Catalytic activity and metal leaching studies show that vanadium-immobilized mesoporous solids are more active and stable than the silica gel-functionalized vanadium catalyst and a framework-substituted V-MCM-41 catalyst. The enhanced activity and stability of the immobilized vanadium catalysts compared with the V-MCM-41 and silica gel samples are attributed to the active metal site isolations, as well as to the spatial restrictions imparted from the concave silica surfaces of the mesoporous solids rather than the convex silica surfaces of the silica gel sample. (c) 2006 Published by Elsevier Inc.</p>10a3-APTS10amesoporous solids10aOxidation10aSilica gel10aVanadium1 aShylesh, S.1 aSingh, A., R.  uhttps://library.ncl.res.in/content/heterogenized-vanadyl-cations-over-modified-silica-surfaces-comprehensive-understanding-002025nas a2200229   4500008004100000022001400041245016600055210006900221260007300290300001200363490000700375520113600382653002101518653001801539653001101557653001401568100002401582700001601606700002601622700001801648856012901666       2006                        eng d  a1387-181100aOxidation of ethyl benzene and diphenyl methane over ordered mesoporous M-MCM-41 (M = Ti, V, Cr): synthesis, characterization and structure-activity correlations0 aOxidation of ethyl benzene and diphenyl methane over ordered mes  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT  a154-1630 v953 a<p>Transition metals (M = Ti, V, Cr) were incorporated into the MCM-41 framework by surfactant-assisted direct hydrothermal (DHT) methods and were characterized in detail by XRD, N-2 adsorption-desorption, TG-DTG/DTA, SEM/TEM, DR UV-Vis, XPS and EPR. The structural regularity as well as the textural properties of the M-MCM-41 materials was confirmed by XRD, TEM and adsorption-desorption techniques. Nature of metal species and the percentage of framework as well as extra framework metal sites in the MCM-41 matrix are discussed in detail by various spectroscopic techniques. The catalytic activity as well as the selectivity of the M-MCM-41 catalysts were explored in the one-step liquid-phase oxidation reaction of ethyl benzene and diphenyl methane. Reaction data showed that the oxidation activity is more when H2O2 was used an oxidant, acetonitrile as solvent and V-MCM-41 as catalyst. However, the selectivity towards the desired keto derivatives (ethyl benzene to acetophenone and diphenyl methane to benzophenone) follows the order, Ti-MCM-41 &gt; V-MCM-41 &gt; Cr-MCM-41. (c) 2006 Elsevier Inc. All rights reserved.</p>10adiphenyl methane10aEthyl benzene10aMCM-4110aOxidation1 aJha, Ratnesh, Kumar1 aShylesh, S.1 aBhoware, Shrikant, S.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/oxidation-ethyl-benzene-and-diphenyl-methane-over-ordered-mesoporous-m-mcm-41-m-ti-v-cr-002179nas a2200217   4500008004100000022001400041245014600055210006900201260007300270300001200343490000700355520136100362653001601723653002701739653001201766653001001778653001301788100001601801700001801817856012601835       2006                        eng d  a1387-181100aVanadium-containing ethane-silica hybrid periodic mesoporous organosilicas: synthesis, structural characterization and catalytic applications0 aVanadiumcontaining ethanesilica hybrid periodic mesoporous organ  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP  a127-1380 v943 a<p>Vanadium-containing ethane-silica hybrid mesoporous silsesquioxane materials (V-HMM) with uniform hexagonal arrangement were prepared using C-18-, C-16- and C-14-alkyl trimethyl ammonium (ATMA) surfactants under basic conditions. The materials were characterized by PXRD, N-2 adsorption-desorption, UV-Visible spectroscopy, Raman, Si-29, C-13 and V-51 solid-state MAS NMR, TEM and SEM techniques. The characterization techniques revealed that the structural ordering, morphology as well as the percentage of metal incorporation depends strongly on the hydrophobic chain length of the surfactant. PXRD, electron microscopy and N-2 adsorptiondesorption analysis confirmed that the original hexagonal structure of the material is maintained after vanadium substitution. UV-Visible, V-51 NMR and Raman analysis certified that vanadium exists in a highly dispersed state and had tetrahedral coordination with the support surface. Liquid-phase epoxidation reaction of styrene using aqueous H2O2 and TBHP as oxidants, showed that the hybrid materials were highly active and more stable than conventional vanadosilicates. The high catalytic activity and improved epoxide selectivity of the V-HMM samples is related to the more hydrophobic environment inside the pore channels than the silica channels in V-MCM-41. (c) 2006 Elsevier Inc. All rights reserved.</p>10aepoxidation10aorgano vanadosilicates10astyrene10aV-HMM10aV-MCM-411 aShylesh, S.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/vanadium-containing-ethane-silica-hybrid-periodic-mesoporous-organosilicas-synthesis-002407nas a2200217   4500008004100000022001400041245015100055210006900206260007300275300001200348490000800360520156700368653001301935653001601948653001401964653002301978100001602001700002402017700001802041856013002059       2007                        eng d  a0926-860X00aChromium-containing small pore mesoporous silicas: synthesis, characterization and catalytic behavior in the liquid phase oxidation of cyclohexane0 aChromiumcontaining small pore mesoporous silicas synthesis chara  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB  a128-1360 v3183 a<p>Organic-inorganic hybrid mesoporous silica materials containing chromium and various organo trialkoxysilanes (chloropropyl, vinyl, methyl) were prepared by the co-condensation method, in the presence of cetyl trimethyl ammonium surfactants. The hybrid material, containing chromium, retains one X-ray diffractogram (XRD) peak up to a molar ratio of 1: 1 between tetra ethyl orthosilicate (TEOS) and organosilane in the synthesis gel. Small pore mesoporous chromium-silica samples can be prepared from the large pore hybrid mesoporous chromium samples by calcination. By this method, the pore size of the material can be tailored into the supermicroporous region, without changing the chain length of the surfactant used in the assembly process, as judged from the XRD and N-2 sorption isotherms. The shrinkage in pore size is dependent on the nature and percentage of the organic pendant groups, such that the chloro propyl and vinyl pendant mesoporous material show more pore size shrinkage than the smaller methyl pendant units. Because of the tailorable pore size and with better textural characteristics, the chromium samples show better catalytic activity in the aerial oxidation reaction of cyclohexane than the conventional chromium-containing mesoporous material, like Cr-MCM-41, under a solvent free system. Among the porous chromium catalysts, the samples prepared using chloro propyl silane show higher cyclohexane conversion and cyclohexanone selectivity and behave as a true heterogeneous catalyst. (c) 2006 Elsevier B.V. All rights reserved.</p>10achromium10aCyclohexane10aOxidation10asmall pore silicas1 aShylesh, S.1 aSamuel, Prinson, P.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/chromium-containing-small-pore-mesoporous-silicas-synthesis-characterization-and-catalytic01809nas a2200241   4500008004100000020002200041022001400063245014400077210006900221260009900290300001400389490000800403520090400411100001601315700002401331700001901355700001801374700001001392700001201402700001201414700001101426856013001437       2007                        eng d  a978-0-444-53068-4  a0167-299100aEthane bridged hybrid mesoporous silsesquioxanes with sulfonic acid functionalities: synthesis, characterization and catalytic applications0 aEthane bridged hybrid mesoporous silsesquioxanes with sulfonic a  aSara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, NetherlandsbElsevier Science BVcAUG  a1899-19040 v1703 a<p>Periodic mesoporous organosilicas having -CH(2)-CH(2)- groups in the framewall positions and sulfonic acid groups in the pore channels were prepared using 1,2-bis(triethoxysilyl) ethane, 3-mercaptopropyltriethoxysilane and cetyltrimethylammonium surfactant, under basic conditions, by a one-pot synthesis method. XRD, N(2) sorption isotherm and TEM analysis revealed that the mesoporous structural ordering is retained after the functionalization of organic groups while solid-state NMR techniques like (13)C CP MAS NMR and (29)Si MAS NMR show the presence of sulfonic acid groups and the stability of the mesoporous framework with integrated ethane moieties as bridging groups. The hybrid material was more active, selective and stable than the conventional sulfonic acid containing mesoporous catalysts in the Claisen-Schmidt condensation of acetophenone with benzaldehyde to form chalcone.</p>1 aShylesh, S.1 aSamuel, Prinson, P.1 aParischa, Renu1 aSingh, A., P.1 aXu, R1 aGao, Z.1 aChen, J1 aYan, W  uhttps://library.ncl.res.in/content/ethane-bridged-hybrid-mesoporous-silsesquioxanes-sulfonic-acid-functionalities-synthesis-002373nas a2200241   4500008004100000022001400041245014100055210006900196260007300265300001200338490000700350520148000357653001401837653001101851653001601862653003201878653001401910100001601924700002001940700001801960700002101978856013201999       2007                        eng d  a1387-181100aOne step synthesis of chromium-containing periodic mesoporous organosilicas and their catalytic activity in the oxidation of cyclohexane0 aOne step synthesis of chromiumcontaining periodic mesoporous org  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB  a334-3440 v993 a<p>Chromium-containing ethane-bridged hybrid mesoporous materials (Cr-PMO) with uniform hexagonal arrangement were synthesized by two different synthesis routes using 1,2-bis(triethoxysilyl)ethane (BTEE) and tetraethyl orthosilicate (TEOS) as silica sources and alkyltrimethyl ammonium salts (ATMA) as surfactants. Powder X-ray diffraction, TEM, N-2 adsorption-desorption, FT-IR, in situ FT-Raman, UV-ViS, XPS, Si-29 MAS NMR and C-13 CP MAS NMR were used to probe the mesoporous structure and the nature of chromium sites in the hybrid catalyst matrix. PXRD, TEM and N-2 adsorption-desorption analysis showed that the original hexagonal structure of the materials is maintained after chromium substitution, while FT-Raman, UV-Vis and XPS analysis showed that chromium atoms exist in a highly dispersed state. The catalytic performance of the chromium-containing hybrid samples was tested in the liquid-phase oxidation of cyclohexane with aqueous hydrogen peroxide (H2O2) and non-aqueous tert-butylhydroperoxide (TBHP) as oxidants. The hybrid materials exhibited better catalytic activities and were more stable than the conventional Cr-MCM-41 catalyst. The higher catalytic activity of the new chromium-containing molecular sieves is attributed to the improved hydrophobicity of the materials and to the complementary structural features that facilitates the accessibility of cyclohexane to the active framework chromium sites. (c) 2006 Elsevier Inc. All rights reserved.</p>10aCr-MCM-4110aCr-PMO10aCyclohexane10ahybrid mesoporous materials10aOxidation1 aShylesh, S.1 aSrilakshmi, Ch.1 aSingh, A., P.1 aAnderson, B., G.  uhttps://library.ncl.res.in/content/one-step-synthesis-chromium-containing-periodic-mesoporous-organosilicas-and-their-catalytic01907nas a2200241   4500008004100000022001400041245012600055210006900181260007300250300001200323490000800335520103600343653001701379653001801396653001801414653001901432100001601451700002401467700002001491700001901511700001801530856011701548       2007                        eng d  a1381-116900aSulfonic acid functionalized mesoporous silicas and organosilicas: synthesis, characterization and catalytic applications0 aSulfonic acid functionalized mesoporous silicas and organosilica  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP  a153-1580 v2743 a<p>Ethane bridged mesoporous organosilicas and MCM-41 having sulfonic acid groups in the pore channels were prepared by co-condensation method as well as grafting method, using 3-mercaptopropyltriethoxysilane (3-MPTS) as the sulfur precursor. TEM and N-2 sorption isotherm analysis revealed that the mesoporous structural ordering is retained after the functionalization and modifications of organic groups while FT-IR, Raman, XPS and solid-state C-13 CP MAS NMR shows the presence of sulfonic acid groups and the stability of the mesoporous framework. The catalytic activity of the developed materials was evaluated in the liquid phase Claisen-Schmidt condensation reaction of acetophenone with benzaldehyde, to probe the effect of mesoporous support surfaces as well as the role of preparation methods. Results showed that sulfonic acid functionalized ethane-silica samples were more active, selective and stable than the conventional sulfonic acid containing mesoporous catalysts. (c) 2007 Elsevier B.V. All rights reserved.</p>10acondensation10aethane-silica10aheterogeneity10asulfonic acids1 aShylesh, S.1 aSamuel, Prinson, P.1 aSrilakshmi, Ch.1 aParischa, Renu1 aSingh, A., P.  uhttps://library.ncl.res.in/content/sulfonic-acid-functionalized-mesoporous-silicas-and-organosilicas-synthesis-002394nas a2200217   4500008004100000022001400041245013600055210006900191260007300260300001200333490000800345520156800353653001101921653001401932653002101946653002701967100001601994700002402010700001802034856012402052       2007                        eng d  a1387-181100aSynthesis of hydrothermally stable aluminium-containing ethane-silica hybrid mesoporous materials using different aluminium sources0 aSynthesis of hydrothermally stable aluminiumcontaining ethanesil  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR  a250-2580 v1003 a<p>Aluminium-containing ethane-silica hybrid mesoporous materials having ethane groups in the frame wall positions are synthesized using aluminium isopropoxide as well as aluminium nitrate as the aluminium sources. The materials were characterized in detail using powder XRD, N-2 adsorption-desorption, SEM, TEM, TG-DTG, TPD, Si-29, C-13 and Al-27 MAS NMR techniques. Characterization techniques revealed that aluminium isopropoxide was the appropriate source for the synthesis of organo aluminosilicas on considering the structural ordering, acidity as well as the percentage of aluminium incorporation into the ethane bridge. Al-27 MAS NMR displays aluminium as tetrahedrally coordinated in both the aluminium-containing organosilicas. Unlike the conventional EtOH-HCl template extraction process, in the present studies, we had used EtOH-NH4OH as the surfactant-extracting medium and chemical analysis results suggest that using this procedure the extent of dealumination can be greatly reduced. XRD and nitrogen physisorption studies further proved that the materials are hydrothermally stable, that the ordered pore channels retains its structure even after 150 h reflux in boiling water, while the conventional Al-MCM-41 catalyst collapsed its mesostructure after 50 h reflux in water. The improved hydrothermal stability of the hybrid materials, even in presence of sodium ions, is attributed to the thick pore walls as well as due to the presence of hydrophobic bridging ethane groups in the wall positions. (c) 2006 Elsevier Inc. All rights reserved.</p>10aAl-HMM10aAl-MCM-4l10ahybrid materials10aHydrothermal stability1 aShylesh, S.1 aSamuel, Prinson, P.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/synthesis-hydrothermally-stable-aluminium-containing-ethane-silica-hybrid-mesoporous02664nas a2200241   4500008004100000022001400041245013100055210006900186260007300255300001000328490000800338520179500346653002502141653001302166653001602179653001102195653001402206100001602220700002102236700001802257700002102275856012602296       2008                        eng d  a1387-181100aBridging the gap between micropores and mesopores by the controlled transformation of bifunctional periodic mesoporous silicas0 aBridging the gap between micropores and mesopores by the control  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB  a29-400 v1083 a<p>Novel bifunctional periodic mesoporous silicas having high content of organic groups in the pore channels and chromium in the frame wall has been synthesized by direct co-condensation method, using organo trialkoxysilanes (chloro propyl, vinyl, methyl), chromium nitrate and tetraethyl orthosilicate, in presence of cetyltrimethyl ammonium surfactants. The obtained materials show one main peak in the XRD patterns up to a molar ratio of 1: 1 between TEOS and organosilane in the synthesis gel and N-2 adsorption-desorption analysis shows that the mesopore structure remains intact after the surfactant removal process. Among the organosilanes, chloro propyl and vinyl pendant chromium samples shows a shift in the main peak to higher 2-theta values with a corresponding decrease in pore volume and pore diameter, with the percentage of organosilane functionalization. Small-pore silicas and chromium silicas can be prepared from the large pore mesoporous MCM-41, by effectively removing the organic groups by calcination. By this method, the pore size of the material can be tailored into the super-microporous region, without changing the chain length of the surfactant used in the assembly process. The shrinkage in pore size is dependent on the nature and percentage of the organic pendant groups that the chloro propyl and vinyl pendant mesoporous materials show the maximum pore size shrinkage than the small chain length methyl units. Because of the tailorable pore size and with better textural characteristics, chromium-silica materials find applications in the field of shape selective heterogeneous catalysis, as demonstrated in the oxidation reaction of cyclohexane, than the conventional metal-containing mesoporous materials. (c) 2007 Elsevier Inc. All rights reserved.</p>10abifunctional silicas10achromium10aCyclohexane10aMCM-4110aOxidation1 aShylesh, S.1 aSrilakshini, Ch.1 aSingh, A., P.1 aAnderson, B., G.  uhttps://library.ncl.res.in/content/bridging-gap-between-micropores-and-mesopores-controlled-transformation-bifunctional-001843nas a2200229   4500008004100000022001400041245008100055210006900136260007500205300001200280490000700292520101700299653001901316653001601335653002901351653003901380100001601419700002401435700002201459700001801481856011401499       2008                        eng d  a1571-101300aPeriodic mesoporous silicas and organosilicas: an overview towards catalysis0 aPeriodic mesoporous silicas and organosilicas an overview toward  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScDEC  a266-2820 v123 a<p>Micelle-templated mesoporous and organic-inorganic hybrid mesoporous materials are important in many fields of material research, especially for hosting catalysts in confined space. Among this class, the recent discovery of periodic mesoporous organosilicas (PMOs) represent an exciting new group of organic-inorganic nanocomposites targeted for a broad range of applications ranging from catalysis to microelectronics. Compared to the earlier generation of organic-inorganic hybrid mesoporous samples, obtained by the cocondensation reaction or by the grafting reaction, PMOs represent the right combination of organic and inorganic groups in the frame wall positions. This article reviews the current state of art in organic-inorganic hybrid mesoporous material research with special emphasis over periodic mesoporous organosilica materials having various redox centers (Ti, V, Cr) suitable for oxidation reactions as well as acidic sites (Al, -SO(3)H) for the organic transformation of bulky molecules.</p>10aAcid catalysis10aepoxidation10aMesoporous organosilicas10aOrganic-inorganic hybrid materials1 aShylesh, S.1 aSamuel, Prinson, P.1 aSisodiya, Sheetal1 aSingh, A., P.  uhttps://library.ncl.res.in/content/periodic-mesoporous-silicas-and-organosilicas-overview-towards-catalysis-002083nas a2200253   4500008004100000022001400041245011500055210006900170260005700239300001200296490000800308520123300316653001401549653001601563653001801579653001801597653001401615100001801629700001501647700001601662700001401678700001301692856012401705       2009                        eng d  a1011-372X00aCatalytic aerobic oxidation of cyclohexane and ethyl benzene over chromium-containing mesoporous organosilicas0 aCatalytic aerobic oxidation of cyclohexane and ethyl benzene ove  a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcOCT  a492-4990 v1323 a<p>Chromium-containing ethane-bridged hybrid periodic mesoporous organosilicas (Cr-PMO) were synthesized using 1,2-bis(triethoxysilyl) ethane (BTEE) and tetraethyl orthosilicate (TEOS) as silica sources and alkyltrimethyl ammonium salts as surfactants by two different synthesis routes. PXRD and N(2) adsorption-desorption analysis shows that the original structure of the materials is maintained after chromium substitution while spectroscopic study proves the incorporation of chromium in the frame wall positions and show the existence of Cr(2)O(3) species in the mixed silica source (BTEE-TEOS) synthesized chromium samples. The catalytic activity of the newly developed chromium samples was evaluated in the liquid phase oxidation of cyclohexane and ethylbenzene using air as an oxidant. Further, the Cr-PMO samples exhibited better cyclohexane conversion and cyclohexanone selectivity than the conventional Cr-MCM-41 and other metal-containing MCM-41 samples. The exceptional activity of the new chromium-containing molecular sieves is attributed to the hydrophobicity of the materials and to the complementary structural features that facilitates the accessibility of substrate to the active framework chromium sites.</p>10aCr-MCM-4110aCyclohexane10aEthyl benzene10aOrganosilicas10aOxidation1 aSingh, A., P.1 aTorita, N.1 aShylesh, S.1 aIwasa, N.1 aArai, M.  uhttps://library.ncl.res.in/content/catalytic-aerobic-oxidation-cyclohexane-and-ethyl-benzene-over-chromium-containing-002106nas a2200253   4500008004100000022001400041245019400055210006900249260007300318300001200391490000800403520111100411653002601522653002201548653001701570653001401587100001601601700002501617700002101642700002401663700001901687700001801706856012801724       2009                        eng d  a1381-116900aCatalytic meerwein-ponndorf-verley reductions over mesoporous silica supports: rational design of hydrophobic mesoporous silica for enhanced stability of aluminum doped mesoporous catalysts0 aCatalytic meerweinponndorfverley reductions over mesoporous sili  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR  a118-1260 v3013 a<p>A series of aluminum isopropoxide-grafted mesoporous organosilica having ethane (-CH(2)-CH(2)-) and ethene (-CH=CH-) groups in the frame wall positions (ethane-silica, ethene-silica) as well as mesoporous silicas (MCM-41, MCM-48. SBA-15) through siloxide linkages were fabricated. The samples were used as catalysts in the Meerwein-Ponndorf-Verley reduction of ketones and aldehydes of different nature and size using secondary alcohols as the hydrogen transfer agents. Aluminum isopropoxide supported mesoporous silica samples show higher catalytic conversion and among them, the one-dimensionally channel oriented Si-MCM-41 supported aluminum isopropoxide shows better results than the three-dimensional Si-MCM-48 and the large pore Si-SBA-15. Compared to aluminum isopropoxide-grafted mesoporous silica samples, aluminum alkoxide-grafted organosilica samples shows better catalytic activity even in the presence of 10% of water and the better stability is attributed to the presence of integrated hydrophobic organic groups in the frame wall positions. (C) 2008 Elsevier B.V. All rights reserved.</p>10aAluminum isopropoxide10aMesoporous silica10aOrganosilica10areduction1 aShylesh, S.1 aKapoor, Mahendra, P.1 aJuneja, Lekh, R.1 aSamuel, Prinson, R.1 aSrilakshmi, Ch1 aSingh, A., R.  uhttps://library.ncl.res.in/content/catalytic-meerwein-ponndorf-verley-reductions-over-mesoporous-silica-supports-rational-002068nas a2200241   4500008004100000022001400041245010400055210006900159260009200228300001200320490000600332520118900338653001401527653002501541653002701566653001801593100001601611700002501627700002101652700002001673700001801693856011501711       2011                        eng d  a1941-490000aSynthesis and characterization of bifunctional ethenylene bridged mesoporous organoaluminosilicates0 aSynthesis and characterization of bifunctional ethenylene bridge  a26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USAbAMER SCIENTIFIC PUBLISHERScAUG  a497-5020 v33 a<p>Bifunctional mesoporous organosilicas having -CH=CH- bridges and aluminium in tetrahedral coordination with tailorable pore sizes have been synthesized using a one-step templating method using cationic surfactants of different chain lengths. Unlike the conventional EtOH-HCl template extraction process, EtOH-NH(4)NO(3) was used as the surfactant-extracting medium and chemical analysis results suggest that through this procedure the mesoporous structure can be retained and dealumination can be minimized. The surfactant-extracted mesoporous solids display high surface area, pore volume and the pore size of the material varies in the range 2.6-3.6 nm, with respect to the alkyl chain length of the cationic surfactant. XRD and nitrogen physisorption studies further proved that the organosilicas are hydro thermally stable than the conventional Al-MCM-41 materials and their better stability is attributed to the thick pore walls as well as due to the presence of hydrophobic bridging ethenylene groups in the wall positions. The coupling of Al(4) with -CH=CH- bridges offer new prospects for the application of periodic mesoporous organosilicas in heterogeneous catalysis.</p>10aAluminium10aCationic Surfactants10aHydrothermal stability10aOrganosilicas1 aShylesh, S.1 aKapoor, Mahendra, P.1 aJuneja, Lekh, R.1 aSrilakshmi, Ch.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/synthesis-and-characterization-bifunctional-ethenylene-bridged-mesoporous-001728nas a2200241   4500008004100000022001400041245015700055210006900212260007300281300001200354490000700366520082600373653001601199653002701215653001501242653001701257653001401274653001101288100002201299700001601321700001801337856013101355       2011                        eng d  a1566-736700aTin incorporated periodic mesoporous organosilicas (Sn-PMOs): synthesis, characterization, and catalytic activity in the epoxidation reaction of olefins0 aTin incorporated periodic mesoporous organosilicas SnPMOs synthe  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR  a629-6330 v123 a<p>Tin incorporated mesoporous organosilicas (Sn-PMO) having uniform hexagonal arrangements were prepared using alkyl trimethylammonium bromide surfactants under basic reaction conditions. Characterization techniques revealed that the structural ordering, morphology, and the percentage of tin incorporation depend critically on the hydrophobic chain length of surfactants. The Sn-PMO samples are thermally stable up to 500 degrees C under air atmosphere and were hydrothermally stable up to 100 h in boiling water. The organotinsilicates showed excellent catalytic activity and reusability in the epoxidation of norbornene and ciscyclooctene than an Sn-MCM-41 due to organic groups in the frame wall positions and the better accessibility of reactants to the active sites. (C) 2010 Elsevier B.V. All rights reserved.</p>10aepoxidation10aHydrothermal stability10aMesoporous10aOrganosilica10aSn-MCM-4110aSn-PMO1 aSisodiya, Sheetal1 aShylesh, S.1 aSingh, A., P.  uhttps://library.ncl.res.in/content/tin-incorporated-periodic-mesoporous-organosilicas-sn-pmos-synthesis-characterization-and-0