02372nas a2200241 4500008004100000022001400041245014100055210006900196260007300265300001200338490000700350520148000357653001401837653001101851653001601862653003201878653001401910100001601924700002001940700001801960700002101978856013101999 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

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.

10aCr-MCM-4110aCr-PMO10aCyclohexane10ahybrid mesoporous materials10aOxidation1 aShylesh, S.1 aSrilakshmi, Ch.1 aSingh, A., P.1 aAnderson, B., G. uhttp://library.ncl.res.in/content/one-step-synthesis-chromium-containing-periodic-mesoporous-organosilicas-and-their-catalytic01906nas a2200241 4500008004100000022001400041245012600055210006900181260007300250300001200323490000800335520103600343653001701379653001801396653001801414653001901432100001601451700002401467700002001491700001901511700001801530856011601548 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

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.

10acondensation10aethane-silica10aheterogeneity10asulfonic acids1 aShylesh, S.1 aSamuel, Prinson, P.1 aSrilakshmi, Ch.1 aParischa, Renu1 aSingh, A., P. uhttp://library.ncl.res.in/content/sulfonic-acid-functionalized-mesoporous-silicas-and-organosilicas-synthesis-002067nas a2200241 4500008004100000022001400041245010400055210006900159260009200228300001200320490000600332520118900338653001401527653002501541653002701566653001801593100001601611700002501627700002101652700002001673700001801693856011401711 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

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.

10aAluminium10aCationic Surfactants10aHydrothermal stability10aOrganosilicas1 aShylesh, S.1 aKapoor, Mahendra, P.1 aJuneja, Lekh, R.1 aSrilakshmi, Ch.1 aSingh, A., P. uhttp://library.ncl.res.in/content/synthesis-and-characterization-bifunctional-ethenylene-bridged-mesoporous-0