The kinetics of oxidation of fluorene (Fl) and its halogenated derivatives, namely, 2,7-dichlorofluorene (Fl-Cl), 2,7-dibromofluorene (Fl-Br) and 2,7-diiodofluorene (Fl-I), by permanganate ion in neutral organic medium in the presence of phosphate buffer solution has been investigated at a constant temperature of 25°C. The progresses of the reactions were followed spectrophotometrically. The stoichiometry of the reactions was found to be 3:4 (fluorene: permanganate). The oxidation reactions exhibited a first order dependence in [permanganate] and less than unit order dependences with respect to fluorenes concentrations. Under comparable experimental conditions, the order of the oxidation rate of the fluorene derivatives was: Fl-Cl > Fl > Fl-I > Fl-Br. The final oxidation products of fluorene derivatives were identified by GC/MS, FT-IR and chemical tools as the corresponding ketones (9H-fluorenone derivatives). The proposed oxidation mechanism involves formation of 1:1 intermediate complexes between fluorene derivatives and permanganate ion in pre-equilibrium step. The ratelaw expression was deduced. The reactions constants involved in the different steps of the mechanism were evaluated. The activation parameters associated with the second order rate constants were calculated and discussed.

Kinetics of oxidation of cadaverine by chromium(VI) in aqueous perchloric and sulfuric acids media has been investigated spectrophotometrically at fixed ionic strength and temperature. In both acids the reactions showed a first order dependence on [Cr(VI)], less than unit order dependence with respect to cadaverine concentration. The effect of hydrogen ion concentration on the oxidation rates showed that the oxidation reactions in both acids were acid-catalyzed with fractional-second order dependences with respect to [H+ ]. The oxidation rates were not affected significantly by variation of ionic strength or dielectric constant of the reactions media. Addition of Mn(II) was found to decrease the oxidation rates. In both acids, the final oxidation products of cadaverine were identified as 5-aminopentanal and ammonia. Under comparable experimental conditions, the oxidation rate of cadaverine in sulfuric acid was found to be higher than that in perchloric acid. The plausible oxidation mechanism were proposed and the rate-law expression was derived. The activation parameters with respect to the second order rate constants were evaluated.

The kinetics of oxidation of N,N-dimethyl-N’-(1H-benzimidazol-2-yl) formamidine (BIF) and N,N-dimethyl-N’-(benzthiazol-2-yl) formamidine (BTF) by permanganate ion in diluted sulfuric acid medium has been investigated spectrophotometrically at a constant ionic strength of 0.2 mol dm-3 and at a temperature of 25°C. The reactions of both organic reductants with permanganate ion showed a first order dependence with respect to [MnO4 − ] and fractional-first order dependences with respect to both hydrogen ion and reductants concentrations. Increasing either ionic strength or dielectric constant of the reactions media had no significant effect on the oxidation rates. Manganese(II) ion was found to auto-catalyze the oxidation reactions with less than unit order dependences. The final oxidation products of BIF and BTF were identified by both spectroscopic and chemical tools as 2-aminobenzimidazole and 2-aminobenzthiazole, respectively, in addition to dimethylamine and carbon dioxide. Under comparable experimental conditions, the oxidation rate of BIF was higher than that of BTF. A plausible reactions mechanism has been suggested and the reaction constants involved in the mechanism have been evaluated. The activation parameters with respect to the second order rate constants have been computed and discussed

Oxidation of methylaminopyrazole formamidine (MAPF) by permanganate ion was studied spectrophotometrically in neutral medium in the presence of phosphate buffer solution. The stoichiometry of the reaction was found to be 3: 2 (MAPF: MnO4 - ). The oxidation reaction showed a first order kinetics with respect to [MnO4 - ] and a fractionalfirst order dependence with respect to [MAPF]. Addition of small amounts of some metal ions increased the oxidation rate and the order of catalytic efficiency was: Ag(I) > Cu(II) > Al(III). The suggested oxidation mechanism involves formation of a 1:1 intermediate complex between permanganate ion and MAPF. The formed complex decomposes in the rate-determining step to yield a free radical derived from MAPF and an intermediate Mn(VI). The free radical is attacked by Mn(VI) species to give rise to the final oxidation products which were identified by both spectroscopic and chemical tools as methylaminopyrazole, dimethylamine and carbon dioxide. The rate-law expression was deduced and the reaction constants involved in the different steps of the suggested mechanism were evaluated. The activation parameters of the rate constant of the slow step along with the thermodynamic quantities of the formation constant of the intermediate complex were evaluated and discussed.

Oxidation of inositol (INOS) by hexachloroplatinate(IV) complex (HCP) in perchlorate solutions in the presence of palladium(II) catalyst was studied spectrophotometrically. The reaction rate was very slow in the absence of the catalyst. The reaction exhibited a first order dependence on [HCP], and fractional-first order dependences with respect to [INOS], [H+ ] and [Pd(II)]. Increasing ionic strength and dielectric constant was found to increase the oxidation rate. A probable oxidation mechanism has been suggested and the rate-law expression has been derived. Both spectral and kinetic evidences revealed formation of a 1:1 intermediate complex between INOS and Pd(II) prior to the rate-controlling step. The final oxidation product of inositol was identified by both spectral and chemical analyses as the corresponding monoketone derivative, namely inosose. The activation parameters of the second order rate constant were evaluated and discussed

Oxidation kinetics of inositol (INOS) by cerium(IV) has been studied spectrophotometrically in perchlorate medium at fixed ionic strength and temperature. The reaction showed a first order dependence with respect to [Ce(IV)] and less than unit order kinetics in both [H+ ] and [INOS]. Increasing both ionic strength and dielectric constant of the reaction medium increased the oxidation rate. Addition of Ce(III) product had no any significant effect on the oxidation rate. The oxidation product of inositol was identified by both spectroscopic and chemical tools as inosose. A plausible mechanistic scheme for oxidation reaction has been proposed and the rate law associated with the reaction mechanism was derived. The activation parameters of the second order rate constant were calculated and discussed.

The kinetics of oxidation of inositol (INOS) by permanganate ion in both perchloric and sulfuric acids solutions was studied using a spectrophotometric technique at a constant ionic strength of 1.0 mol dm-3 and at 25°C. In both acids, the reactions showed a first order dependence with respect to [permanganate], whereas the orders with respect to [INOS] were found to be less than unity. The effect of acids concentrations suggests that the reactions were acid-catalyzed with fractionalsecond order kinetics in [H+ ]. Variation of either ionic strength or dielectric constant of the medium had no effect significantly on the oxidation rates. The reactions mechanism adequately describing the kinetic results was proposed. In both acids, the main oxidation products of inositol were identified by spectral and chemical tools as the corresponding monoketone derivative, namely inosose. Under comparable experimental conditions, the oxidation rate in sulfuric acid was approximately three times higher than that in perchloric acid. Regarding to the second order rate constants of these reactions, the activation parameters have been evaluated and discussed.

Kinetics of oxidation of L-citrulline (Cit) by permanganate ion in both acidic and basic media has been investigated spectrophtometrically at constant ionic strengths and at 25°C. In both media the reactions exhibited first order dependence in [permanganate] and less than unit order dependences in L-citrulline concentration. A fractional-second order dependence with respect to [H+ ] and a fractional-first order dependence with respect to [OH- ] were revealed in acidic and basic media, respectively. Increasing ionic strength in basic medium increased the oxidation rate of L-citrulline, whereas it had a negligible effect on the oxidation rate in acidic medium. The rate-determining step in both media is suggested to involve a oneelectron change, but the stoichiometry (L-citrulline: permanganate) was different, being 5:2 in acidic medium and 1:2 in basic medium. The proposed oxidation mechanisms involve formation of 1:1 intermediate complexes between kinetically active species of both L-citrulline and permanganate ion in pre-equilibrium steps. The final oxidation products of L-citrulline were identified in both acidic and basic media as the corresponding aldehyde (4-(carbamoylamino) butyraldehyde), ammonia and carbon dioxide. The appropriate rate laws are deduced.

Oxidation kinetics of L-citrulline (Cit) by hexachloroplatinate(IV) (HCP) was studied spectrophotometrically in perchloric acid solutions in the presence of ruthenium(III) catalyst at a constant ionic strength of 1.8 mol dm-3 and at 20°C. The reaction rate was very slow in the absence of the catalyst. The reaction showed first order kinetics in both [HCP] and [Ru(III)] and less than unit order with respect to both [Cit] and [H+ ]. Increasing ionic strength and dielectric constant were found to increase the oxidation rate. Both spectral and kinetic evidences revealed formation of an intermediate complex between Lcitrulline and ruthenium(III) prior to the rate-determining step. The complex reacts with the oxidant (HCP) by an inner-sphere mechanism leading to decomposition of the complex in the rate-determining step to give rise to the final oxidation products of L-citrulline which were identified by both spectroscopic and chemical tools as 4-(carbamoylamino) butyraldehyde, ammonia and carbon dioxide. The rate-law expression for the catalyzed reaction was deduced. The reaction constants involved in the different steps of the reaction mechanism have been evaluated. The activation parameters of the second order rate constant have been evaluated and discussed

The kinetics of permanganate oxidation of Fluorenone Hydrazone (FH) in both perchloric and sulfuric acid solutions was studied spectrophotometrically at a constant ionic strength of 1.5 mol dm-3 and at 20oC. In both acids, the reactions showed a first order dependence with respect to permanganate ion concentration, whereas the orders with respect to fluorenone hydrazone concentration were less than unity. The orders with respect to both perchloric and sulfuric acid concentrations were found to be fractional-second. Variation of either ionic strength or dielectric constant of the medium had no any significant effect on the oxidation rates. The reactions mechanism describing the kinetic data was proposed. In both acids, the main oxidation products of fluorenone hydrazone as confirmed by GC/MS analysis and FT-IR spectroscopy as the corresponding ketone (9H-fluorenone). Under comparable experimental conditions, the oxidation rate of fluorenone hydrazone in perchloric acid was slightly lower than that in sulfuric acid. The activation parameters of the second order rate constants have been evaluated and discussed.