Reduction of tris(2,2’-bipyridine)cobalt(III) complex by thiosulphate ion in an aqueous acidic medium

The reduction of tris(2,2-bipyridine)cobalt(III) complex by thiosulphate ion in an aqueous acidic medium gave a notable outcome. The stoichiometric evaluation indicates that one mole of the reducing agent has been consumed by one mole of the oxidant, and the reaction complies with an overall equation: 2[Co(bpy)3]3+ + 2S2O32− 2[Co(bpy)3]2+ + S4O62− The kinetics study conducted under a pseudo-first-order method shows that the rate of the reaction was acid-reliant and third-order overall; zero-order in the [oxidant], second-order in the [reductant], and first-order in the hydrogen ion concentration. The empirical rate expression complies with the equation:− [Co(bpy)33+] = a [H+][S2O32−]2‘a’ = 77.82 dm6 mol−2 s−1; at [H+] = 2.0 × 10−2 mol dm−3, µ = 0.4 mol dm−3 (NaCl), T = 28 ± 1˚C and λmax = 560 nm.With increased ionic strength and decreased medium dielectric constant, the reaction rate increased. The inclusion of cations and anions accelerate and constricted the reaction rates respectively. Spectroscopic examination and kinetic evidence indicate an outer sphere mechanism, and the mechanism was therefore proposed via an outer-sphere route.

An aqueous phase TEMPO mediated electrooxidation of 2-thiophenemethanol using MnO2–Pi dispersed nanocarbon spheres on a carbon fiber paper electrode

An environmentally benign and economic method was developed for the electrocatalytic oxidation of 2-thiophenemethanol in an aqueous acidic medium.

Mechanism and Kinetics Studies of Oxidation of the Pharmaceutical Drug Amlodipine Besylate by N-bromosuccinimide in Aqueous Acidic Medium

The oxidation of the pharmaceutical drug Amlodipine besylate [AML] by N-Bromosuccinimide [NBS] was investigated aqueous acidic medium under pseudo-first-order condition. The experimental results indicated that the reaction exhibits first-order concerning N-bromosuccinimide, fractional-order concerning [AML] and sulphuric acid [H2SO4]. There was no substantial effect on the rate of the reaction with KNO3. The reaction stoichiometry shows one mole of amlodipine besylate consumes one mole of n-bromosuccinimide. The effect of temperature on the reaction rate was studied, and the activation parameters (Ea, ∆ G, ∆ H and ∆ S) are calculated and tabulated. LC-MS technique was used to identify the oxidation product of amlodipine besylate. Based on experimental results, a mechanism is proposed, and constants K1, K2 and k3 involved in the mechanism were evaluated. The observed rate constant values and the experimental value calculated by substituting the value of k3= 4.0 × 10−3 s -1, K2 = 1272 moldm-3s-1andK1= 1.96 x 10-6 in the rate equation is in good accordance with each other.