NOPR Collection:

Role of trace iron(III) and equilibrium Fe(III) + Fe(CN) Fe(II) +Fe(CN) in the investigation on kinetics and mechanism of oxidation of hexacyanoferrate( II) by peroxodiphosphate in acid perchlorate solution

Mon, 01 Mar 1993 00:00:00 GMT

Title: Role of trace iron(III) and equilibrium Fe(III) + Fe(CN) Fe(II) +Fe(CN) in the investigation on kinetics and mechanism of oxidation of hexacyanoferrate( II) by peroxodiphosphate in acid perchlorate solution Authors: Mishra, Dilip Kumar; Amaladhas, T Peter; Bhargava, A P; Gupta, Y K Abstract: Oxidation of hexacyanoferrate(ll) with peroxodiphosphate(pdp) in aqueous perchloric acid solutions occurs through the catalysis by Fe(III) present in traces in the reagents and distilled water involving the equilibrium. Fe(III) + Fe(CN) Fe(ll) + Fe(CN). Fe(ll) is oxidised back to Fe(III) by pdp in the fast step. The rate law is d[Fe(CN)]/dt =((k₁ + k_d/[H⁺]) [Fe(Ill)][Fe(CN)].The values of k₁ and k_d have been found to be 5.7 x 10³dm³ mol^-1 s^-1 and 36 s^-1 respectively at I = 0.5 mol dm^{- 3}and 30°. The equilibrium constant for the above equilibrium determined spectrophotometrically is 34 ± 4 at 28°, I = 0.05 mol dm^-3 and [H⁺] = 0.01 mol dm^-3. Aquo copper(II) retards the rate of oxidation of Fe(CN) by pdp. Spectrophotometrically too the equilibrium is shifted to the left in the presence of Cu(II). Page(s): 187-194

Stoichiometry, kinetics and mechanism of the silver(I) catalysed oxidation of hyponitrous acid with peroxodisulphate ion in acid perchlorate solutions

Mon, 01 Mar 1993 00:00:00 GMT

Title: Stoichiometry, kinetics and mechanism of the silver(I) catalysed oxidation of hyponitrous acid with peroxodisulphate ion in acid perchlorate solutions Authors: Bhatnagar, Pankaj; Mittal, R K; Gupta, Y K Abstract: The title reaction provides the first indirect kinetic evidence for the well known assumed complex formation between S₂O and Ag⁺. It is also the first report of a reaction with comparable rates of oxidation of hyponitrous acid and water in the (S₂O + Ag⁺) system. Hyponitrous acid is the first reported substrate which is not oxidised by SO. Page(s): 195-200

Kinetics of oxidation of sulphur(IV) by peroxodisulphate: Relative reactivity of bisulphite and sulphite ions

Mon, 01 Mar 1993 00:00:00 GMT

Title: Kinetics of oxidation of sulphur(IV) by peroxodisulphate: Relative reactivity of bisulphite and sulphite ions Authors: Bhargava, Pinky; Gupta, K S Abstract: In the pH region 4.3-8.5, the oxidation of sulphur(IV) by peroxodisulphate (Eq. i) obeys the experimental rate law (ii).

where kSo₃ and k_HSO3 are bimolecular rate constants for the S₂O- SO- and S₂O- HSO- reactions and K_d(2) is the dissociation constant of HSO₃-· k_SO3 and k_HSO3 values are 6 x 10^{- 2} and 2.8 x 19^{- 3} dm³mol^{- 1}s ^-1 respectively at I = 1.0 mol dm ^{- 3} and 40°C. Page(s): 201-204

Separation of polar and steric effects in the oxidation of ortho-substituted benzaldehydes by ethyl chlorocarbamate

Mon, 01 Mar 1993 00:00:00 GMT

Title: Separation of polar and steric effects in the oxidation of ortho-substituted benzaldehydes by ethyl chlorocarbamate Authors: Varshney, Seema; Kothari, Seema; Banerji, Kalyail K Abstract: Kinetics of oxidation of twelve ortho-substituted benzaldehydes by ethyl chlorocarbamate (ECC) to the corresponding benzoic acids have been studied. The reaction is first order each in [aldehyde],[ECC] and [H⁺]. Addition of ethyl carbamate has no effect on the reaction rate. (EtOC(OH)NHCl)⁺ has been postulated as the reactive oxidizing species. The correlation of rates with single substituent parameter equations is poor. The correlation with Charton's equation of inductive, resonance and steric parameters is satisfactory. However, excellent correlations are obtained, when Charton's steric parameter is used along with Taft's or and σsubstituent constants. The polar reaction constants have negative values. The reaction is subject to steric hindrance by the ortho- substituents. Mechanistic aspects are discussed. Page(s): 205-209