Showing papers by "Nikhil R. Jana published in 1998"

Organized media as redox catalysts

Abstract: Micellar catalysis for a methylene blue (MB)−ascorbate ion (AA-) redox reaction (activation energy 114 kJ mol-1) has been observed to occur because of the binding of the substrates onto the micellar surface by hydrophobic and electrostatic interaction. This increases the encounter probability, leading to a substantially accelerated reaction. The reported study indicates that the most likely substrate solubilization sites in micelles and reverse micelles are the interfacial and Stern regions. Studies on the effect of various salting-in and salting-out agents, an increase in the hydrophobicity of the dye, and the size of the reverse micellar water pool provide no evidence of deeper penetration into the micellar core. In addition, a fascile reversible electron-transfer reaction for the MB−AA- and MB−BH4- systems has been observed with coinage metal sol particles. Metal sol-induced catalysis occurs due to the availability of a suitable substrate which acts as a mediator for the electron-transfer reaction betw...

Silver hydrosol, organosol, and reverse micelle-stabilized sol : A comparative study

Abstract: Surfactant-stabilized silver hydrosol, organosol, reverse micelle-stabilized sol, and their dry products have been prepared and characterized. The dry products can be handled as chemical compounds. Solubility and spectral study of dry products show similar microenvironments for the organo- and reverse-micellized sol. For the conversion of hydrosol into organosol, the surfactant acts as phase transfer catalyst. The study shows that a solvent–surfactant system for which the surfactant can form a reverse micelle is effective for phase transfer of particles from aqueous to organic phase.