The kinetics and mechanism of the oxidation of formate ions by peroxodisulphate ions

• Main Author: O'Flynn, T. J.
• Language: en
• Published: University of Canterbury. Chemistry 2014
• Online Access: http://hdl.handle.net/10092/9394

The kinetics of -the peroxoclisulphate/formate reaction have been studied using four methods, (1) By titrating aliquots of reaction mixture, (2) By following pH changes, (3) By a manual pH-stat. (4) By an automatic pH-stat, Kinetic data was obtained at pH values from pH 4.0 to pH 8.0 at an ionic strength of 0.2M and at temperatures from 30° to 50°C, using method (4). Changes of rate constant with pH were considerable. Kintetic data at pH = 8.0, temperature = 35°C and ionic strength = 0.2M are, first order rate constant k₁ = 9.59 x 10-⁵ sec -¹, Ea = 11.9 Kcal mole -¹ PZ = 2.49 x 10⁴ sec -¹. A mechanism is postulated to explain the observed kinetics for the uncatalysed reaction. The kinetics of the cupric ion catalysed reaction were studied over a range of cupric ion concentrations from 2.5 x 10-⁴ to 6.25 x 10-⁴M at 30°C and pH 5.0 using method (4).