• C Kalidas

      Articles written in Journal of Chemical Sciences

    • Polarographic behaviour of 2,4-dinitrodiphenylamine in amphiprotic media

      V John Koshy C S Venkatachalam C Kalidas

      More Details Abstract Fulltext PDF

      Two six-electron diffusion-controlled irreversible waves are obtained for the polarographic reduction of 2,4-dinitrodiphenylamine (DPA) in buffered and unbuffered media in all compositions of methanol-water mixtures. Based on the polarographic and coulometric data, it is suggested that each of the nitro groups is reduced to the corresponding amine in a single stepvia the diimine intermediate to give 2,4-diamino DPA as the final product. The influence of various factors such as structure of the depolariser, pH and composition of methanol on the reduction of the compound is also discussed.

    • Selective solvation of Ag(I) iodate in methanol-dimethyl sulphoxide mixtures

      S Janardhanan C Kalidas

      More Details Abstract Fulltext PDF

      The selective solvation of silver(I) iodate was studied in methanoldimethyl sulohoxide mixtures at 30° C by solubility and EMF measurements. The solubility of the salt increases continuously with the addition of dimethyl sulphoxide after a slight decrease into XDMSO =0.1. The Gibbs energy of transfer of silver cation (determined on the basis of ferrocene reference method) decreases continuously while that of the iodate ion increases with the addition of dimethyl sulphoxide. The solvent transport number passes through a maximum (Δ = 2.0) around XDMSO= 0.5. These results were interpreted as arising due to a heteroselective solvation of the salt, the silver ions being preferentially solvated by dimethyl sulphoxide and the iodate ion by methanol in these mixtures.

    • Determination of ionisation constants of nitrobenzidines

      S Aravamuthan C Kalidas C S Venkatachalam

      More Details Abstract Fulltext PDF

      The ionisation constants of 2-nitrobenzidine, 2,2’-dinitrobenzidine and 2,3’-dinitrobenzidine were determined spectrophotometrically in 33-3% (w/w) methanol. The low pK value obtained for 2,3’-dinitrobenzidine when compared to that of 2-nitro and 2,2’-dinitrobenzidines is explained on the basis of electron withdrawing nature of the nitrogroup and intramolecular hydrogen bonding.

    • Conductance behaviour of HCl in water-ethylene glycol, water-diethylene glycol and ethylene glycol-diethylene glycol mixtures

      P Sivaprasad C Kalidas

      More Details Abstract Fulltext PDF

      The conductance behaviour of HCl in water-ethylene glycol, water-diethylene glycol and ethylene glycol-diethylene glycol mixtures was investigated in the complete range of solvent compositions of 25°C by applying the three-parameter conductance equation. No appreciable association of the acid was observed in any of the mixed solvents. The large decrease ofΛ0 andΛ0η0 of the acid in the early and end composition region of the mixed solvents has been attributed to the drastic structural changes brought about by the addition of the organic component in the aqueous solvent mixtures and by the addition of diethylene glycol in the case of ethylene glycol-diethylene glycol mixtures.

    • Electrochemical reduction of 2-nitrobenzidine in methanol-water mixtures

      S Aravamuthan M S Sashidar C Kalidas C S Venkatachalam

      More Details Abstract Fulltext PDF

      The electroreduction of 2-nitrobenzidine (2-NB) in buffered methanol-water mixtures in the composition range 20–80% (v/v) and pH range 2.80–12.00 gave a single six-electron diffusion-controlled irreversible wave. On the basis of the results obtained, a diphenoquinone-diimine intermediate is suggested in the mechanism of 2-NB reduction in methanol-water mixtures.

  • Journal of Chemical Sciences | News

© 2021-2022 Indian Academy of Sciences, Bengaluru.