The oxidation kinetics of fluorene (Fl) and its halogenated derivatives, namely, 2,7-dichlorofluorene (Fl-Cl), 2,7- dibromofluorene (Fl-Br) and 2,7-diiodofluorene (Fl-I), using potassium permanganate in alkaline medium has been studied spectrophotometrically at a constant ionic strength of 0.1 mol dm-3 and at 25°C. A first order kinetics has been observed in these reactions with respect to [permanganate]. Fractional-first order dependences of the reactions on the [reductants] and [alkali] were revealed. No significant effect on the reaction rates by increasing ionic strength was recorded. Intervention of free radicals was observed in the reactions. The reactions mechanism describing the kinetic results has been proposed which involves formation of 1:1 intermediate complexes between fluorene derivatives and the active species of permanganate. The final reactions products were identified by GC/MS and FT-IR analyses in all cases as the corresponding ketones (9Hfluorenone derivatives). Under comparable experimental conditions, the order of the oxidation rate of fluorine derivatives was: Fl > Fl-I > Fl-Br > Fl-Cl. The reactions constants involved in the different steps of the reactions mechanism have been evaluated. With admiration to rate-limiting step of these reactions, the activation parameters were recorded and discussed

The kinetics of oxidation of L-glutamine (Gln) by permanganate ion has been investigated in alkaline medium at a constant ionic strength of 0.2 mol dm-3 and at 25o C using spectrophotometric technique. A first order kinetics with respect to [permanganate] and less than unit order dependences on [Gln] and [OH- ] were revealed. No pronounced effect on the reaction rate by increasing either ionic strength or solvent polarity of the medium was recorded. Intervention of free radicals was observed in the reaction. The reaction mechanism describing the kinetic results was suggested. The final oxidation products of L-glutamine were identified as formyl propanamide, ammonia and carbon dioxide. The rate-law expression for the oxidation reaction was deduced and the reaction constants have been evaluated. The activation parameters associated with the rate-limiting step of the reaction, along with the thermodynamic quantities of the equilibrium constants have been calculated and discussed

Oxidations of two aliphatic α-amino acids (AA), namely, leucine and isoleucine by hexachloroplatinate (IV) as an anticancer platinum (IV) complex has been studied using a spectrophotometric technique in perchlorate solutions in the presence of palladium (II) catalyst at a constant ionic strength of 1.0 mol dm-3 and at 25°C. The reactions did not proceed in the absence of the catalyst. The reactions of both amino acids showed a first order dependence on both [PtIV] and [PdII], and less than unit order dependences with respect to both [AA] and [H+ ]. Increasing ionic strength and dielectric constant of the reactions medium increased the rates of the reactions. A probable oxidations mechanism has been suggested and the rate law expression has been derived. Both spectral and kinetic evidences revealed formation of 1:1 intermediate complexes between AA and PdII before the rate-controlling step. The oxidation products of the investigated amino acids were identified as the corresponding aldehyde, ammonium ion and carbon dioxide. The activation parameters of the second order rate constants were evaluated and discussed

The kinetics of oxidations of two aliphatic α-amino acids (AA), namely, alanine and valine by platinum (IV) has been investigated spectrophotometrically in perchloric and sulfuric acids solutions in the presence of silver (I) catalyst at a constant ionic strength of 1.0 mol dm-3 and at 25°C. The reactions were very slow to be measured in the absence of the catalyst. The reactions in both acids showed a first order dependence on both [PtIV] and [AgI ], and less than unit order dependences with respect to both [AA] and [H+ ]. Increasing ionic strength was found to decrease the oxidation rates. Under comparable experimental conditions, the oxidation rates of alanine and valine in perchloric acid solutions were found to be about five times higher than those obtained in sulfuric acid solutions and the oxidation rates of alanine in both acids were found to be higher than those recorded with respect to valine. A plausible oxidations mechanism has been proposed and the rate law expression has been derived. Both spectral and kinetic evidences revealed formation of 1:1 intermediate complexes between AA and AgI in both acids before the rate-controlling step. Then the formed complexes react with the oxidant (PtIV) by an inner-sphere mechanism to give rise to the oxidation products of the amino acids which were identified as the corresponding aldehyde, ammonium ion and carbon dioxide. The activation parameters of the second order rate constants were evaluated and discussed.

The kinetics of oxidations of α-aminobutyric acid (ABA) by platinum(IV) has been investigated spectrophotometrically in perchloric and sulfuric acids solutions in the presence of silver(I) catalyst at a constant ionic strength of 1.0 mol dm-3 and at 25o C. The reactions were very slow to be measured in the absence of the catalyst. The reactions in both acids showed a first order dependence on [PtIV] and less than unit order dependences with respect to [ABA], [H+] and [AgI ]. Increasing ionic strength and dielectric constant was found to decrease the oxidation rates. Under comparable experimental conditions, the oxidation rate of α-aminobutyric acid in perchloric acid solutions was approximately found to be twice that recorded in sulfuric acid solutions. A plausible oxidations mechanism has been proposed and the rate law expression has been derived. Both spectral and kinetic evidences revealed formation of 1:1 intermediate complexes between ABA and AgI in both acids before the rate-controlling step. Then the formed complexes react with the oxidant (PtIV) by an inner-sphere mechanism to give rise to the oxidation products of ABA which were identified as the corresponding aldehyde (propionaldehyde), ammonium ion and carbon dioxide. The activation parameters of the second order rate constants were evaluated and discussed

The kinetics of oxidation of vanillin (VAN) by hexachloroplatinate(IV) has been investigated in perchloric acid solutions in the presence of ruthenium(III) catalyst at a constant ionic strength of 1.0 mol dm-3 and at 25°C. The progress of the reaction was followed spectrophotometrically. The reaction was not proceeding in the absence of the catalyst. The reaction exhibited first order kinetics with respect to both [HCP] and [Ru(III)] and less than unit order with respect to both [VAN] and [H+ ]. Increasing ionic strength and dielectric constant were found to increase the oxidation rate. The reaction mechanism adequately describing the kinetic results has been proposed. Both spectral and kinetic evidences revealed formation of an intermediate complex between vanillin substrate and ruthenium(III) catalyst 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 which were identified by both spectral and chemical analyses as vanillic acid and tetrachloroplatinate(II). 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 associated with the rate-limiting step of the reaction, along with the thermodynamic quantities of the equilibrium constant have been evaluated and discussed.

The kinetics of oxidation of vanillin (VAN) by chromium(VI) in sulfuric acid medium was studied by a spectrophotometric technique. The reaction exhibited a first order dependence with respect to [Cr(VI)] and fractionalfirst orders with respect to [VAN] and [H+]. Varying ionic strength or dielectric constant of the reaction medium had no significant effect on the oxidation rate. The proposed mechanism includes an intermediate complex formation between vanillin and chromium(VI) before the rate-determining step. The final oxidation product of vanillin was identified by both spectral and chemical analysis as vanillic acid. The suitable rate law has been deduced. The reaction constants included in the various steps of the suggested mechanism have been evaluated. The activation parameters of the rate constant of the rate-determining step of the mechanism and the thermodynamic quantities of the equilibrium constant have been evaluated and discussed.

The kinetics of oxidation of vanillin (VAN) by permanganate ion in neutral medium has been investigated spectrophtometrically. The stoichiometry of the reaction was found to be 3:2 (VAN: MnO4 - ). The oxidation reaction exhibited a first order dependence in [MnO4 - ] and less than unit order dependence with respect to vanillin concentration. Addition of small amounts of Ag(I), Co(II) and Ru(III) catalysts increased the oxidation rate and the catalytic efficiency increased in the order: Ru(III) > Ag(I) > Co(II). The proposed oxidation mechanism involves formation of a 1:1 intermediate complex between vanillin and permanganate ion in pre-equilibrium step. The final oxidation product of vanillin was identified by both spectral and chemical analysis as vanillic acid. The appropriate rate law was deduced. The reaction constants involved in the different steps of the mechanism were evaluated. The activation parameters associated with the rate constant of the slow step of the proposed mechanism along with the thermodynamic quantities of the equilibrium constant have been evaluated and discussed.

The kinetics of oxidation of one of the formamidine derivatives, namely, methylaminopyrazole formamidine (MAPF) by cerium(IV) has been investigated in aqueous perchlorate solutions at a constant ionic strength of 1.2 mol dm-3 and at 25°C. The progress of the reaction was followed spectrophotometrically. The reaction exhibited a first order kinetics with respect to [Ce(IV)], whereas the order with respect to [MAPF] was found to be less than unity. The reaction rate decreased with the increase in acid concentration with a negative less than unit order. The rate of reaction was not affected by increasing either ionic strength or dielectric constant of the medium. Furthermore, addition of cerium(III) product did not affect the reaction rate. The plausible oxidation mechanism involves formation of an intermediate complex between MAPF substrate and the kinetically active species of cerium(IV) in a pre-equilibrium step which decomposes in the slow step to give free radical derived from the substrate and Ce(III). The free radical is attacked by another Ce(IV) species to yield the final oxidation products which were identified by spectral and chemical analyses as methylaminopyrazole, dimethylamine and carbon dioxide. The activation parameters have been evaluated and discussed. The rate law associated with the reaction mechanism was derived.

The of kinetics of oxidation of a pyrimidine derivative, N,N-dimethyl-N’-(pyrimidin-2-yl) formamidine (Pym-F), by hexacyanoferrate(III) (HCF) was studied in aqueous alkaline medium in the presence of palladium(II) catalyst. The reaction did not proceed in the absence of Pd(II) catalyst. The progress of the catalyzed reaction was followed spectrophotometrically. The reaction showed a first order kinetics in both [HCF] and [Pd(II)], and less than unit orders with respect to both [Pym-F] and [OH- ]. Increasing ionic strength and dielectric constant of the medium increased the reaction rate. A mechanistic scheme for the catalyzed oxidation reaction has been proposed. The final oxidation products are identified as 2-aminopyrimidine, dimethylamine and carbon dioxide. The rate law expression associated with the reaction mechanism is derived and the reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect to the ratedetermining step have been computed and discussed.