02179nas 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-0