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A tetracycline antibiotic doxycycline hydrochloride (DOX) has been oxidized by N-chlorosuccinamide (NCS) in sulphuric acid medium at 303 K and the kinetics have been investigated. The stoichiometry of the reaction was found to be 1:1 where one mole doxycycline reacted with one mole of NCS and the product of oxidation of doxycycline, 1,4,4a,5,5a,6,11,12a-octahydro-3,5,10,12,12a-pentahydroxy-6-methyl-1,4,11-trioxotetracene-2-carboxamide is identified by the spot tests and confirmed by LC-MS spectral analysis. The titled reaction exhibited first-order kinetics with reference to concentration of NCS and doxycycline a fractional order kinetics was observed with respect to [H2SO4] and doxycycline. The changes in the reaction rate on the addition of halide ions and reduction product was studied. The influence of added product, p-toluene sulfonamide was studied and found no significant effect. The influence of ionic strength (NaClO4) and dielectric constant of the medium was investigated on the reaction rate. All the experimental values were compiled together and a mechanism was proposed. The temperature effect was studied for calculating the activation parameters with reference to the rate determining step in the mechanism and the thermodynamic parameters were also discussed.

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.

Ferrate (Fe (VI)) is a potential water treatment chemical due to its dual functions as an oxidant and a subsequent coagulant/precipitant as ferric hydroxide. Hence, an application of Fe (VI) to wastewater could achieve both oxidative elimination of various micro pollutants and reduction in the COD, BOD, Total hardness, Chloride, Fluoride can be achieved.