http://nopr.niscpr.res.in/handle/123456789/20970 2026-10-17T23:48:42Z http://nopr.niscpr.res.in/handle/123456789/20992 Title: Adsorption behaviour of N-haloarene sulphonamidates on activated carbon at 303 K Authors: Ramachandran, Jaya; Vivekanandan, S; Lakshmi, S Abstract: By batch studies adsorption behaviour of some sodium-N-haloarene sulphonamidates (NHAS) such as chloramine-B (CAB) and bromamine-B (BAB), chloramine- T (CAT) and its bromo analogue (BAT) on activated carbon (AC) is studied at 303 K. Langmuir adsorption isotherm (LAI), Freundlich adsorption isotherm (FAI) and Temkin adsorption isotherm (TAI) are well obeyed while Harkins Jura adsorption isotherm (HJAI) is poorly obeyed. The constants of these adsorption isotherms have been evaluated and their variation with adsorbate is analysed. The sorption capacity for different NHAS has been arrived and it is more for CAT than for CAB. Similarly it is more for BAT as compared to that of BAB. The specific surface area determined with these four adsorbates is almost the same. The dimensions of the adsorbates have been calculated. Page(s): 115-118 2001-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/20991 Title: Mechanism of oxidation of isoniazid by hypohalites in alkaline medium: A kinetic study Authors: Ramalingaiah, Hulivana; Puttaswamy; Mohan, K Abstract: Kinetics of oxidation of isoniazid (INH) by sodium hypohalites NaOX (X=Cl or Br) has been investigated at 303 K in NaOH medium. Under comparable experimental conditions the oxidation behaviour is similar with both the oxidants with first order dependence of rate each on [NaOX] and [INH] and fractional order on [OH^-]. Variation of ionic strength or dielectric constant of the medium does not have any effect on the reaction while the addition of halide ions slightly retards the rate. The reaction fails to induce polymerisation of acrylonitrile. The rate increases in D₂O medium and the inverse solvent isotope effect <i>k</i>(D₂O)/<i>k </i>(H₂O) is around 1.52. Proton inventory studies have been made in H₂O - D₂O mixtures. Activation parameters for the reaction have been computed from the Arrhenius plots. lsonicotinic acid has been identified as the oxidation product of INH, by GC-MS. Under identical experimental conditions the rate of oxidation of INH is found to be higher with NaOBr than NaOCl by a factor of 3. The proposed reaction mechanism and the derived the law arc consistent with the observed kinetics. Page(s): 110-114 2001-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/20990 Title: Kinetic and thermodynamic aspects of chloramine - T adsorption on different adsorbents at different temperatures Authors: Ramachandran, Jaya; Vivekanandan, S; Lakshmi, S Abstract: The rate constants for the attainment of adsorption equilibria at s 298, 303, 308 and 315.5K have been determined for the adsorption of chloramine-T (CAT) on solid adsorbents such as activated carbon (AC), rice husk carbon (RHC), Salem bentonite (SB) silica gel (SG) and acidic alumina (AA). The energy of activation for chemisorption and Elovich parameters have been evaluated. The calculated pore and film diffusion coefficients have been used to ascertain the rate determining step in each case. The thermodynamic activation parameters for the adsorption of CAT on the different matrices have been evaluated. The calorimetric enthalpies have been experimentally determined. The isosteric, isochoric and Semenov Shilov enthalpies have been calculated. The probable causes for the difference in the different enthalpy values and the variation of free energy of adsorption with temperature have been discussed. Page(s): 105-109 2001-01-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/20989 Title: Viscometric and volumetric studies of some transition metal chlorides in glycine water solution Authors: Mishra, A P; Gautam, S K Abstract: Viscosity and density data for nickel (II), copper (II), cobalt (II) and zinc (II) chlorides in glycine-water mixture at different concentrations and temperatures have been analysed using the Jones-Dole equation. The activation parameters of viscous flow have been obtained to throw light on the mechanism of viscous flow. The values of apparent molar volume and relative viscosity have been deduced from the density and viscosity data. Structure making/breaking capacities of these transition metal chlorides have been inferred from the sign of <i>d</i>B<i>/d</i>T<i>. </i>All the electrolytes behave as structure makers/promotors. Page(s): 100-104 2001-01-01T00:00:00Z