Articles written in Proceedings – Section A
Volume 62 Issue 1 July 1965 pp 56-66
A systematic study of the kinetics of photosensitized polymerization of vinyl monomers with the system Dye (erythrosin or acriflavine)-reducing agent (ascorbic acid), in the presence of oxygen and under buffered conditions (pH 6) in aqueous solution has been made. The determinations of the monomer disappearance, dye disappearance and of chainlengths of the polymers obtained against the different variables like light intensity, concentrations of monomer, dye, ascorbic acid, etc., have been made. A kinetic mechanism proposed for the overall reaction is discussed in the light of the experimental results and certain rate constants have also been evaluated.
Volume 62 Issue 3 September 1965 pp 150-158
The kinetics of the polymerization of methyl acrylate initiated by the ceric perchlorate-formaldehyde redox system has been investigated. The rate of monomer disappearance has been found to be proportional to (
Volume 64 Issue 3 September 1966 pp 128-140
Polymerization of Acrylamide initiated by cobaltic ions in aqueous solution at 15° C. and 20° C. in HClO4 and H2SO4 media have been studied. Kinetics have been followed by determining the rate of cobaltic ion disappearance as well as monomer disappearance with variations in cobaltic, monomer and hydrogen ion concentrations, temperature, ionic strength, etc. Besides polymer reaction it has been observed that side reactions like water oxidation and monomer oxidation also contribute to rate of cobaltic ion disappearance. Certain anomalous results in H2SO4 medium have been observed. A reaction scheme involving CoOH2+ and Co3+ as initiators in HClO4 and H2SO4 media respectively and mixed termination—mutual and linear—has been suggested. Certain rate parameters involving rate constants for initiation, propagation, termination and the corresponding activation energies have been evaluated.
Volume 64 Issue 6 December 1966 pp 345-358
Results on the oxidation of primary alcohols (methanol, ethanol,
Volume 65 Issue 2 February 1967 pp 124-135
The effect of tert. butyl alcohol on the polymerization of Methylmethacrylate initiated by cobaltic ions in aqueous perchloric acid medium was tried. Rates of cobaltic ion disappearance and rates of polymerization were measured with variables, [M], [A], [Co3+], [H+], etc. at constant ionic strength. From the experimental results it was concluded that at low [A], initiation and termination of polymerization was by Co3+ species. At higher [A], initiation was still by Co3+ species but termination was found to change over to mutual type. At very high [A], Co3+ + tert. butyl alcohol reaction was found to function as a red-ox system for polymerization of monomer. An appropriate kinetic scheme was proposed and the various rate constants under different [A] regions evaluated.
Volume 65 Issue 3 March 1967 pp 155-169
Studies on oxidation of water by cobaltic ions in perchloric, nitric and sulfuric acid media in the temperature range 20–30° C. at constant ionic strength of 2·2 M were carried out. An overall order of 3/2 for cobaltic ion concentration was observed in perchloric, nitric acid media and at low [Co3+]<4×10−3 M in sulfuric acid medium. At high [Co3+] in sulfuric acid medium an order 2 was observed. In all the three acid media an inverse dependence of the rates on [H+] was noticed. From the experimental results, an acid-independent reaction path was inferred in perchloric and nitric acid media. The effect of ionic strength, HSO4− and initially added cobaltous ions as well as temperature was studied. Suitable reaction schemes were suggested to explain the experimental results and activation energy values for some of the rate parameters were evaluated. Kinetic studies on oxidation of tertiary amyl and tertiary butyl alcohols in sulfuric acid medium and that of the former in perchloric acid medium were carried out. The reaction rates were found to vary linearly with [Co3+] and [Alcohol]. From the effect of acidity and of [HSO4−] in H2SO4 medium on the reaction rates it was concluded that in HClO4 medium CoOH2+ species were the active entities while in H2SO4 medium Co3+ as well as CoOH2+ species were the active entities. The influence of ionic strength, temperature, etc., on the raction rates were studied and activation energy values for some rate constants were evaluated.
Volume 66 Issue 3 September 1967 pp 174-183
The oxidation of aliphatic unsymmetrical ketones-
Volume 66 Issue 5 November 1967 pp 287-299
Vinyl monomer [methyl methacrylate (MMA), or ethyl methacrylate (EMA) or methyl acrylate (MA)] was polymerized in benzene solution with benzoyl peroxide as catalyst and in the presence of varying amounts of bromopoly (styrene) (Br PS). Branching occurred by chain transfer reaction of the growing polymer radicals with bromine atoms of the bromopoly (styrene) backbone, followed by initiation of polymerization by the Br PS radicals thus obtained. The chain transfer constants of the branching reaction and the degree of grafting were determined and by suitable correlation of the two,
Volume 67 Issue 2 February 1968 pp 78-89
The results on the kinetics of oxidation of HCHO and some alcohols,
Volume 67 Issue 4 April 1968 pp 175-183
1:1 Poly (styrene-co-ethylmethacrylate) (PSEM) was prepared by bulk polymerization and fractionated using methylethyl ketone/petroleum ether system. IR and NMR analyses of the copolymer substantiated the composition kinetically expected. As the composition heterogeneity of the compolymer was narrow, the characterization of the copolymer was effected in a single solvent by light scattering as well as viscosity measurements at 35° C. The molecular weight dependence of [
Volume 68 Issue 1 July 1968 pp 47-52
Oxidation of light and heavy water by peroxy disulphate was studied at 60–70° C. The acid independent and acid dependent rate constants and respective ΔE values were computed. An attempt is made to explain the kinetic isotopic effect observed. A probable mechanism is proposed.
Volume 68 Issue 4 October 1968 pp 186-194
A systematic study of the kinetics of photo-chemical polymerisation of acrylamide using the system anthraquinone sulphonate-NaCl-HClO4 under deaerated condition in aqueous solution has been done. The determinations of the monomer disappearance (bromometry), the sensitiser disappearance (spectrophotometry) and chainlengths of polymers with respect to light intensity, concentration of monomer, light absorption fraction (
Volume 69 Issue 1 January 1969 pp 7-17
Uncatalysed oxidation of malonic, maleic, succinic, malic, mandelic and lactic acids by peroxydisulphate have been studied at 60°–80°C. Rates of oxidation and E values are reported. Probable mechanisms are proposed.
Volume 69 Issue 3 March 1969 pp 117-128
Kinetics of oxidation of hydrazine sulphate and hydroxylamine by Co3+ in nitric and sulphuric acid media at 10–15° C. were studied. In H2SO4 medium, kinetic evidence was obtained for complex formation between Co3+-Substrate for both substrates whereas no such evidence was found in HNO3 medium. The effects of [H+], μ [HSO4−], [SO4=], [Co2+] and temperature on the reaction rates were studied. An inverse dependence of the rates on [H+] was noticed in both media with both substrates but decreasing effect of [HSO4−] was observed only with NH2OH in H2SO4 medium. Conclusions were drawn as to the nature of the active species: In H2SO4 medium for hydrazine sulphate, Co3+ (aq.) was concluded to be the active species; similarly for NH2OH, CoOH2+ was the active species. In HNO3 medium for both substrates CoOH2+ was the active oxidant. Nitrogen and Ammonia were found to be the products of oxidation with both substrates in both media. Stoichiometries were established and suitable mechanisms were proposed. The rate laws were formulated and the various equilibria and rate constants were evaluated.
Volume 69 Issue 5 May 1969 pp 284-290
A systematic study of the kinetics of photopolymerization of vinyl monomers initiated by the complex azidopentamminecobalt (III) chloride in aqueous solution has been made. The determinations of monomer disappearance, complex disappearance, chainlengths of polymers, obtained against the different variables like light intensity, concentrations of monomer, light absorption fraction, etc., have been made. A kinetic mechanism proposed for the overall reaction is discussed in the light of the experimental results and certain rate constants have also been evaluated.
Volume 71 Issue 3 March 1970 pp 111-118
Volume 71 Issue 4 April 1970 pp 189-199
Volume 72 Issue 6 December 1970 pp 279-284
The ternary system Poly (methyl methacrylate) Fraction 1/Fraction 2/n-butyl bromide has been studied. A viscometric method is proposed for the estimation of the individual polymer concentration in the two conjugate phases in equilibrium.
Volume 73 Issue 2 February 1971 pp 51-58
The thermodynamic interaction parameters of the systems, poly (ethyl methacrylate) /