02306nas a2200277   4500008004100000022001400041245013200055210006900187260000800256300001400264490000800278520130000286653002601586653002301612653003001635653002101665653003901686653002701725100002401752700002201776700002801798700002601826700002501852700002401877856012701901       2020                        eng d  a1011-372X00aHighly dispersed MnOx nanoparticles on shape-controlled SiO2 spheres for ecofriendly selective allylic oxidation of cyclohexene0 aHighly dispersed MnOx nanoparticles on shapecontrolled SiO2 sphe  cOCT  a3023-30350 v1503 a<p>Shape-controlled metal nanomaterials are considered as a unique class of catalysts because of their synergistic size- and shape-dependent catalytic properties. This work reports the synthesis of a novel size- and shape-controlled catalyst, consisting of highly dispersed MnOx nanoparticles (average particle size of 4.5 nm) on shape-controlled SiO2 nanospheres (250-300 nm) for selective cyclohexene oxidation using air as the oxidant under solvent- and base-free conditions. The MnOx/SiO2 catalyst exhibited an excellent cyclohexene conversion (92%) with a high selectivity (96%) to the allylic products (2-cyclohexene-ol and 2-cyclohexene-one) under mild conditions, outperforming various SiO2 supported CoOx, FeOx, and CuOx catalysts. The better performance of shape-controlled MnOx/SiO2 nanocatalyst is due to high redox nature of Mn, uniform dispersion of smaller sized MnOx nanoparticles, and synergetic interaction between MnOx and SiO2 spheres, as evidenced by XPS and TEM studies. Further, the MnOx/SiO2 catalyst could be reused at least 5 times for selective cyclohexene oxidation with a negligible loss in its catalytic performance, indicating the excellent stability of shape-controlled metal nanocatalysts in organic synthesis under economically viable and mild conditions.</p>
10aCyclohexene oxidation10aMnOx nanoparticles10aShape-controlled catalyst10aSiO2 nanospheres10aStructure-performance relationship10aSynergetic interaction1 aRao, Bolla, Govinda1 aSudarsanam, Putla1 aRao, Tumula, Venkateshw1 aAmin, Mohamad, Hassan1 aBhargava, Suresh, K.1 aReddy, Benjaram, M.  uhttps://library.ncl.res.in/content/highly-dispersed-mnox-nanoparticles-shape-controlled-sio2-spheres-ecofriendly-selective02039nas a2200253   4500008004100000022001400041245010000055210006900155260000800224300001400232490000700246520115700253653002601410653002201436653002801458653002401486653004001510100002201550700002101572700001601593700002601609700002301635856012701658       2021                        eng d  a1867-388000aSynergistic nanostructured MnOx/TiO2 catalyst for highly selective synthesis of aromatic imines0 aSynergistic nanostructured MnOxTiO2 catalyst for highly selectiv  cAPR  a1990-19970 v133 a<p>This work reports the development of a synergistic nanostructured MnOx/TiO2 catalyst, with highly dispersed MnOx nanoparticles (4.5 +/- 1 nm) on shape-controlled TiO2 nanotubes (8-11 nm width and 120-280 nm length), for selective synthesis of valuable aromatic imines at industrially important conditions. Pristine TiO2 nanotubes exhibited 97 % imine selectivity at a 38.3 % benzylamine conversion, whereas very low imine selectivity was obtained over commercial TiO2 materials, indicating the catalytic significance of shape-controlled TiO2 nanotubes. The MnOx nanoparticle/TiO2 nanotube (10 wt% Mn) catalyst calcined at 400 degrees C showed the best activity with 95.6 % benzylamine conversion and 99.9 % imine selectivity. This catalyst exhibited good recyclability for four times and is effective for converting numerous benzylamines into higher yields of imines. The high catalytic performance of MnOx/TiO2 nanotubes was attributed to higher number of redox sites (Mn3+), high dispersion of Mn species, and shape-controlled structure of TiO2, indicating that this catalyst could be a promising candidate for selective oxidation reactions.</p>
10aAcid-redox properties10aaerobic oxidation10aNanostructured catalyst10aSelective catalysis10aSynergistic metal-oxide interaction1 aSudarsanam, Putla1 aKockritz, Angela1 aAtia, Hanan1 aAmin, Mohamad, Hassan1 aBruckner, Angelika  uhttps://library.ncl.res.in/content/synergistic-nanostructured-mnoxtio2-catalyst-highly-selective-synthesis-aromatic-imines