Kinetics of oxidation of glycine and related substrates by diperiodatoargentate (III)

Oxidation of Aspirin by a New Oxidant Diperiodatoargentate(III) in Aqueous Alkaline Medium

The kinetics of oxidation of aspirin by diperiodatoargentate(III) (DPA) in alkaline medium at a constant ionic strength of 1.0 mol dm−3 has been studied spectrophotometrically. The reaction between DPA and aspirin in alkaline medium exhibits 1: 2 stoichiometry (aspirin: DPA). The reaction is of first order in [DPA] and has less than unit order in both [ASP] and [alkali]. However, the order in [ASP] and [alkali] changes from first order to zero order as the concentration changes from lower to higher concentration. A decrease in the dielectric constant of the medium increases the rate of the reaction. The effect of added products and ionic strength of the reaction medium have been investigated and a mechanism is proposed.

Oxidation of a Anticholinergic Drug Atropine Sulfate Monohydrate by Alkaline Copper(III) Periodate Complex: A Kinetic and Mechanistic Study

The oxidation of a anticholinergic drug, Atropine sulfate monohydrate (ASM) by diperiodatocuprate(III) (DPC) has been investigated spectrophotometrically in aqueous alkaline medium at a constant ionic strength of 0.50 mol dm-3. The reaction between diperiodatocuprate(III) and atropine sulfate exhibits1:2stoichiometry (atropine sulfate: diperiodatocuprate(III)). The main oxidation products were identified and confirmed by spectral studies including IR,1H NMR and GC-MS. A suitable mechanism is proposed. The order with respect to diperiodatocuprate(III) concentration was unity, while the order with respect to atropine sulfate concentration was less than unity over the concentration range studied. The rates increased with an increase in alkali concentration and decreased with an increase in periodate concentration. The activation parameters with respect to slow step of the mechanism were calculated and the thermodynamic quantities we are also determined. Kinetic experiments suggest that [Cu(OH)2(H3IO6)]-is the reactive species of copper(III).

Effect of CTAB Micelle on the Oxidation of L-Leucine by N-Bromophthalimide: a Kinetic Study

The effect of cationic surfactant cetyltrimethylammonium bromide (CTAB) on the oxidation of L-leucine by N-bromophthalimide (NBP) has been studied at 308 K. The reaction exhibits first order dependence on NBP and L-leucine and negative and fractional order dependence on HClO4. The effects of KCl, KBr, phthalimide and mercuric acetate have also been studied and summarized. The rate of reaction increased with an increase in dielectric constant of the medium. CTAB strongly catalyzes the reaction and typical k obs and CTAB profile was observed, i.e., with a progressive increase in CTAB, the reaction rate increased and after achieving a peak k obs decreased at higher concentrations of CTAB. The results are treated quantitatively in terms of “Piszkiewicz” and “Raghvan and Srinivasan's” models. The various activation parameters in presence and absence of CTAB have been also evaluated. A suitable mechanism consistent with the experimental findings has been proposed. The rate constant in micellar phase k M, cooperativity index (n), binding constant (K 1 and K 2) have been computed.

Kinetics and Mechanism of Oxidation of Chloramphenicol — an Antibiotic Drug by Diperiodatocuprate(III) in Aqueous Alkaline Medium

The kinetics of oxidation of chloramphenicol (CHP) by diperiodatocuprate(III) (DPC) in aqueous alkaline medium at a constant ionic strength of 0.10 mol dm-3 was studied spectrophotometrically. The reaction between DPC and CHP in alkaline medium exhibits 1:2 stoichiometry (CHP: DPC). The main oxidation products were identified by spot test, IR, NMR and GCMS spectral studies. The reaction is of first order in DPC and CHP concentrations. As the alkali concentration increases the rate of reaction increases with fractional order dependence on alkali concentration. Increase in periodate concentration decreases the rate. A suitable mechanism is proposed. The reaction constants involved in the different steps of the mechanism were calculated. The activation parameters with respect to slow step of the mechanism are computed and discussed. Thermodynamic quantities are also determined.

Kinetic and Mechanistic Aspects of Osmium(VIII) Catalyzed Oxidation of DL-ornithine by Copper(III) Periodate Complex in Aqueous Alkaline Medium

The oxidation of DL-ornithine monohydrochloride (OMH) by diperiodatocuprate(III) (DPC) has been investigated in the presence of osmium(VIII) catalyst in aqueous alkaline medium at a constant ionic strength of 0.20 mol dm−3spectrophotometrically. The reaction exhibits 1:4 stoichiometry i.e., [OMH]: [DPC]. The order of the reaction with respect to [DPC] was unity while the order with respect to [OMH] was less than unity over the concentration range studied. The rate increased with an increase in [OH–] and decreased with an increase in [IO4−]. The order with respect to [Os(VIII)] was unity. The reaction rates revealed that Os(VIII) catalyzed reaction was about nine-fold faster than the uncatalyzed reaction. The oxidation products were identified by spectral analysis. Suitable mechanism has been proposed. The reaction constants involved in the different steps of the reaction mechanism were calculated. The catalytic constant (KC) was also calculated at different temperatures. The activation parameters with respect to slow step of the mechanism and also the thermodynamic quantities were determined. Kinetic experiments suggest that [OsO4(OH)2]2−is the reactive Os(VIII) species and [Cu(H2IO6)(H2O)2] is the reactive copper(III) species.