Oxidation of aspirin by N-sodio-N-bromobenzene sulphonamide (bromamine-B) in acid medium; a kinetic and mechanistic study

The kinetics of the oxidation of aspirin (ASP) by bromamine-B (BAB) has been studied in aqueous perchloric acid at 303 K. Decarboxylation, bromination and loss of acetic acid gave the reaction product 2,4,6-tribromophenol and was identified by GC-MS. The rate shows first order dependence on BAB, fractional order in ASP and inverse fractional order in H +. The rate decreased with decreasing dielectric constant of the medium. The variation of ionic strength and the addition of the reaction product (benzene sulphonamide) and halide ions had no significant effect on the reaction rate. Thermodynamic parameters were evaluated. The solvent isotope effect was studied using D 2O

Ruthenium(III) catalyzed oxidation of aliphatic primary amines by bromamine-T in hydrochloric acid medium: A kinetic study

The kinetics of the ruthenium(III) catalyzed oxidation of the aliphatic primary amines n-propylamine, n-butylamine and isoamylamine, by sodium N-bromo-p-toluenesulfonamide or bromamine-T (BAT) in HCI medium has been studied in the temperature range 298-313 K. The reaction rate shows a first-order dependence each on BAT, amine, and ruthenium(III). The reaction also shows an inverse fractional-and inverse first-order dependence on acid at low and high HCl] ranges, respectively. Added halide ions and p-toluenesulfonamide (reduction product of BAT), and variation of ionic strength of the solvent medium have no effect on the rate. The activation parameters have been evaluated. Mechanisms consistent with the kinetic data have been proposed. The protonation constant of monobromamine-T has been evaluated to be 29 +/- 2. A Taft LFE relationship is observed for the ruthenium(lll) catalyzed reaction with p* = -4.6 indicating that the electron donating groups enhance the reaction rate. An isokinetic relationship is observed with B = 355 K indicating that enthalpy factors control the rate

MOSSBAUER STUDIES OF CORROSION OF METALLIC GLASSES Fe//8//1B//1//3//. //5Si//3//. //5C//2 AND Fe//6//7Co//1//8B//1//4Si//1 IN AMMONIUM NITRATE SOLUTION.

The corrosion of metallic glasses Fe//8//1B//1//3//. //5Si//3//. //5C//2 (Metglas 2605 SC) and Fe//6//7Co//1//8B//1//4Si//1 (Metglas 2605 CO) in 45 ammonium nitrate solution has been followed at room temperature and higher temperatures to 90 degree C for periods of time between 15 minutes to 1 day. Moessbauer spectroscopy at RT and at liquid nitrogen temperature (79K) and X-ray diffraction were used to follow the formation and transformation of products formed. During the initial stage of corrosion, hydroxides and oxides are formed in their superparamagnetic state. The corrosion proceeds in both types of metglasses in the same way except that Fe//6//7Co//1//8B//1//4Si//1 is more corrosion resistant. Morphology of corrosion products was studied using optical and scanning electron microscopy