02209nas a2200217 4500008004100000022001400041245009400055210006900149260007500218300001200293490000700305520136100312653003101673653003001704653003201734653002401766653003301790100002101823700001901844856012801863 2008 eng d a1571-101300aFunctionalized SBA-15 and its catalytic applications in selective organic transformations0 aFunctionalized SBA15 and its catalytic applications in selective a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScJUN a114-1300 v123 a

Ordered, mesoporous SBA-15 functionalized with organic and inorganic moieties exhibits efficient catalytic activity in a variety of organic transformations. In this account, reviewing our own work, three-sets of surface-modified SBA-15 materials have been investigated. The first-set of materials consists of SBA-15 modified with organo-acidic (propyl thiol and propyl sulfonic acid) and basic (propyl amine and propyl adenine) moieties. The second-set of materials was prepared by grafting Mn complexes to the organo-functionalized SBA-15. The third-set composes of nanocrystalline metal oxides supported on SBA-15. All these catalysts have been characterized by structural and spectroscopic techniques. Catalytic activities of the first-set of solid materials have been investigated in acid/base-catalyzed reactions viz., ring-opening of epoxides with amines (producing beta-amino alcohols), esterification, three-component-Mannich reactions and cycloaddition of CO(2) to epoxides. The Mn complexes grafted on organofunctionalized SBA-15 are efficient catalysts for the chemo-, regio- and stereoselective aerial oxidation of monoterpenes at ambient conditions. TiO(x), VO(x), MoO(x) and WO(x) supported on SBA-15 catalyzed biomimetic oxyhalogenation of aromatic compounds. In all these reactions, the functionalized SBA-15 showed high selectivity.

10agrafted Mn-Salen complexes10aOrdered mesoporous silica10aorganofunctionalized SBA-1510aoxidation catalysts10aOxyhalogenation of aromatics1 aSrinivas, Darbha1 aSaikia, Lakshi uhttps://library.ncl.res.in/content/functionalized-sba-15-and-its-catalytic-applications-selective-organic-transformations-001304nas a2200241 4500008004100000022001400041245010700055210006900162260005700231300001200288490000800300520042400308653002800732653003000760653003300790653001100823653002700834100001900861700001500880700002100895700001800916856012800934 2010 eng d a1011-372X00aRegiospecific oxyhalogenation of aromatics over SBA-15-supported nanoparticle group IV-VI metal oxides0 aRegiospecific oxyhalogenation of aromatics over SBA15supported n a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcJUL a190-2010 v1373 a

TiO(x), VO(x), MoO(x) and WO(x) supported on SBA-15 exhibit efficient catalytic activity for oxyhalogenation of aromatics with the H(2)O(2)-halide ion system. Unlike the hitherto known solid catalysts, these reusable catalysts yield the para-halogenated product with 100% selectivity at 298 K and moderate acidic pH (3-5). The catalytic activity was enhanced by five orders of magnitude when supported on SBA-15.

10aHaloperoxidase activity10aOrdered mesoporous silica10aOxyhalogenation of aromatics10aSBA-1510aSupported metal oxides1 aSaikia, Lakshi1 aRajesh, M.1 aSrinivas, Darbha1 aRatnasamy, P. uhttps://library.ncl.res.in/content/regiospecific-oxyhalogenation-aromatics-over-sba-15-supported-nanoparticle-group-iv-vi-001852nas a2200217 4500008004100000022001400041245013200055210006900187260000800256490000800264520105300272653001601325653002401341653003601365653003001401653001801431100002401449700002001473700002201493856011901515 2023 eng d a1387-181100aEfficient olefin epoxidation with high turnover rates over ordered mesoporous silica nanoparticles with uniform manganese sites0 aEfficient olefin epoxidation with high turnover rates over order cDEC0 v3623 a

Olefin epoxidation has been studied over a series of mesoporous manganese silicate nanoparticles and tBuOOH. Partial substitution of Si by Mn in silica framework leads to highly dispersed, distorted Mn(III) sites, confirmed by various physicochemical analyses. High conversion and stable styrene oxide, stilbene oxide and epoxy cyclohexane yield have been achieved with MS75 with 1:1.5 ratio of olefin: oxidant. However, at faster reaction rates lower styrene oxide yield is observed at lower Mn-containing catalyst (MS100). High TON, TOF over manganese sites shows accessible monomeric Mn sites. Attributed to high reactant density at redox-active Mn silicate sites due to facile diffusion across shallow pore depth channels of nanoparticulate om-MSx and surface hydrophobic characteristics. The catalysts were found to be stable under recycling and filtration experiments. The excellent stability against leaching of active manganese species indicates stable sites and good textural properties in om-MSx, essential for extended activity.

10aepoxidation10aManganese silicates10aMesoporous silica nanoparticles10aOrdered mesoporous silica10apH adjustment1 aNegi, Sanjay, Singh1 aKhatri, Prateek1 aSingh, Anand, Pal uhttps://library.ncl.res.in/content/efficient-olefin-epoxidation-high-turnover-rates-over-ordered-mesoporous-silica