@article { ISI:000231018800006, title = {Immobilization of metallporphyrins on polystyrene: efficient catalysts for aerobic oxidation of alcohols}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {238}, number = {1-2}, year = {2005}, month = {SEP}, pages = {46-50}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Metalloporphyrins of iron and cobalt have been successfully encapsulated for the first time using polystyrene matrix, exhibiting high activity for aerobic oxidation of alcohols mimicking cytochrome P-450 dependent mono oxygenases. This communication provides a simple and environmentally friendly protocol for immobilization of metalloporphyrins (MPs) on to polystyrenes in general, which gives stable,I reusable (see Footnote 1) and efficient catalysts for aerobic oxidation of alcohols. These catalysts were characterized by UV-vis as well as diffuse reflectance FT-IR spectroscopy. These catalysts not only have high turnover frequencies but also could be recovered quantitatively by simple filtration and reused without loss of activity. Considering their high dispersing capacity in organic solvents, they will definitely find broad spectrum of applications in the electronic as well as optical fields. This methodology will lead to a potential model to mimic the catalytic action of metalloporphyrins in the niche areas such as catalytic oxidations, drug metabolism, DNA cleavage, photodynamic therapy and many others. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {aerobic oxidation, Immobilization, metalloporphyrins, micro-encapsulation, Polystyrene, turnover frequency}, issn = {1381-1169}, doi = {10.1016/j.molcata.2005.04.041}, author = {Naik, R. and Joshi, P. and Deshpande, R. K.} } @article { ISI:000326900600015, title = {Mixed Co-Mn oxide-catalysed selective aerobic oxidation of vanillyl alcohol to vanillin in base-free conditions}, journal = {Chempluschem}, volume = {78}, number = {11}, year = {2013}, month = {NOV}, pages = {1384-1392}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Manganese-doped cobalt mixed oxide (MnCo-MO) catalyst was prepared by a solvothermal method. The as-prepared catalyst was characterised by X-ray photoelectron spectroscopy, H-2 temperature-programmed reduction, O-2 temperature-programmed oxidation and XRD. This catalyst gave 62\% conversion with 83\% selectivity to vanillin in 2hours for the liquid-phase air oxidation of vanillyl alcohol without using base. Three different types of metal oxides were observed in the prepared catalyst, which could be identified as Co3O4, Mn3O4 and CoMn2O4. Among these, the tetragonal phase of CoMn2O4 was found to be more active and selective for vanillyl alcohol oxidation than Co3O4 and Mn3O4. High-resolution TEM characterisation revealed the morphology of MnCo-MO nanorods with a particle size of 10nm. Successful recycling of the catalyst was also established in this oxidation reaction.

}, keywords = {aerobic oxidation, cobalt, heterogeneous catalysis, manganese, spinel phases}, issn = {2192-6506}, doi = {10.1002/cplu.201300247}, author = {Jha, Ajay and Patil, Kashinath R. and Rode, Chandrashekhar V.} } @article {45887, title = {Selective aerobic oxidation of alcohols over Au-Pd/sodium titanate nanotubes}, journal = {Catalysis Communications}, volume = {58}, year = {2015}, month = {JAN }, pages = {149-153}, type = {Article}, abstract = {

catalytic application of Au-Pd nanoparticles supported on sodium titanate nanotubes (NaTNTs) for liquid-phase aerobic oxidation of alcohols is reported, for the first time. This reaction occurs at 80-120 degrees C, 1 atm and solvent-/alkali-free conditions yielding the corresponding carbonyls in high selectivity. This catalyst was reusable and found to be more active/selective than the corresponding monometallic Au and Pd catalysts and Au-Pd/TiO2. Higher dispersion, smaller particle size and higher amount of electron density at gold are the causes for the superior activity of Au-Pd/NaTNT catalyst. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {aerobic oxidation, Alcohol, Bimetallic Au-Pd catalyst, Sodium titanate nanotubes, TiO2}, issn = {1566-7367}, doi = {10.1016/j.catcom.2014.09.018}, author = {Nepak, Devadutta and Darbha, Srinivas} } @article {47057, title = {Synergistic nanostructured MnOx/TiO2 catalyst for highly selective synthesis of aromatic imines}, journal = {ChemCatChem}, volume = {13}, year = {2021}, month = {APR}, pages = {1990-1997}, type = {Article}, abstract = {

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.

}, keywords = {Acid-redox properties, aerobic oxidation, Nanostructured catalyst, Selective catalysis, Synergistic metal-oxide interaction}, issn = {1867-3880}, doi = {10.1002/cctc.202001870, Early Access Date = FEB 2021}, author = {Sudarsanam, Putla and Kockritz, Angela and Atia, Hanan and Amin, Mohamad Hassan and Bruckner, Angelika} }