Permanganate ion oxidations. 13. Soluble manganese(IV) species in the oxidation of 2,4(1H,3H)-pyrimidinediones (uracils)

Freeman, Fillmore; FUSELIER, C. O.; Armstead, Charles R.; Dalton, Charlotte; Davidson, Pamela A.; Karchesfski, Elaine M.; Krochman, Deborah E.; JOHNSON, M. N.; Jones, N. K.

doi:10.1021/ja00395a026

Cited by 91 publications

(38 citation statements)

References 3 publications

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“…Kinetic data support formation of such oxidation states during the course of reaction have been reported by many workers [3][4][5][6][7][8]. In alkaline or weakly acidic solution Mn(VII) changes to Mn(IV) [9][10][11][12]. PerezBenito et al and Freeman et al observed the formation of a relatively stable water soluble colloidal manganese(IV) species (MnO 2 ) during the permanganate ion oxidation of organic substrates (formic acid [13], triethanalamine [14]) and carbon-carbon double bonds [15] at 420 nm.…”

Section: Introductionsupporting

confidence: 74%

Oxidation of acetanilide by MnO 4 − in the presence of HClO4. A kinetic study

Kumar

Khan

2007

Transition Met Chem

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The permanganate ion oxidation of acetanilide was studied spectrophotometrically by measuring the changes in absorbance at 525 nm in perchloric acid solutions. At lower [H + ], the formation of an intermediate was observed whereas at higher [H + ], the nature of reaction-time curve was sigmoid. The reaction rate increases with [H + ] and the kinetics reveals complex order dependence in [H + ]. The kinetic data for the oxidation of acetanilide indicate that the mechanism involves two steps. The order in [acetanilide] was found to be one. Water soluble Mn(IV) has been identified as an intermediate in the reduction of MnO 4 ) by acetanilide. The hydrogen ions have been found to decrease the stability of the Mn(IV). Externally added Mn(II) (a product of the reaction) has a composite effect (inhibition and catalysis). The addition of F ) in the form of NaF has no effect on the reaction rate. The Arrhenius equation was valid for the reaction between 40 and 60°C. The energy of activation, enthalpy and entropy of activation have been evaluated. Mechanisms consistent with the observed kinetics results have been suggested.

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Section: Introductionsupporting

confidence: 74%

Oxidation of acetanilide by MnO 4 − in the presence of HClO4. A kinetic study

Kumar

Khan

2007

Transition Met Chem

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“…The inverse secondary isotope effects that are observed when the olefinic hydrogens are sequentially replaced by deuterium ( (12). The activation entropy for the reaction (Table 4) is, in fact, very similar to that for the oxidation of cinnamate ion by permanganate, which is known to proceed by way of a cyclic manganate(V) diester (13). The larger enthalpy of activation for the ruthenate reaction is probably a consequence of the fact that the cyclic diester, 5, formed in the permanganate reaction (eq.…”

Section: Introductionmentioning

confidence: 58%

“…2.1 eu) as would be expected for a fragmentation reaction (12). A large enthalpy of activation (31.0 + 0.7 kcal/mol) for this step is indicative of similar reactions in which a-bonds are cleaved (12,13 observed that 9 is the only intermediate which accumulates as the reaction proceeds (Fig. 3).…”

Section: Introductionmentioning

confidence: 79%

“…The values k5 and k6 were also assumed to be much larger than k2 or k, and were arbitrarily set at 50 M-' s-'. Reactions [12] and [13] are the product-forming steps and in all likelihood refer to the oxidation of benzaldehyde and glyoxylate ion (which would be formed by the oxidative cleavage of the double bond) to give the corresponding carboxylic acids. Since such reactions were qualitatively found to be extremely fast under these conditions, the assumption that k5 and k6 would be large seems justified.…”

Section: Introductionmentioning

confidence: 99%

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Oxidation of hydrocarbons. 12. Kinetics and mechanism of the oxidation of trans-cinnamic acid by ruthenate and perruthenate ions

Lee¹,

Helliwell²

1984

Can. J. Chem.

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, 1085 (1984). Recent theoretical calculations by RappC and Goddard have pointed to the importance of spectator 0x0 groups in stabilizing intermediates produced during thc reduction of high-valent transition metal oxides; intermediates which contain triply-bonded metal 0x0 groups are predicted to be unusually stable. In an attempt to test these conclusions experimentally, the rates of oxidation of cinnamate ion by ruthenate and permthenate ions have been studied. Since the most likely intermediate formed from permthenate ion (but not ruthenate ion) would contain a stabilizing, triply-bonded spectator 0x0 group, it would be expected to react faster if the calculations are correct. In agreement with these predictions, it was found that the activation energy (AG*) for the ruthenate reaction was about 7 kcal/mol higher than for the corresponding permthenate reaction. DONALD G. LEE et STUART HELLIWELL. Can. J . Chem. 62, 1085 (1984) Les recents calculs thCoriques de RappC et Goddard ont mis en Cvidence I'importance des groupes 0x0 spectateurs dans la stabilisation dcs intermediaires obtenus lors de la riduction d'oxydes de mCtaux de transition de valence ClevCe; d'apres ces calculs, les intermCdiaires qui contiennent les groupes 0x0 triplement liCs au metal seront particulierement stables. Dans le but de verifier expCrimentalement cette hypothkse, on a CtudiC les vitesses d'oxydation de I'ion cinnamate par les ions ruthenate et permthCnate. Puisque l'intermtdiaire le plus communtment form6 a partir de I'ion permthenate (mais non B partir de I'ion ruthhate) contiendrait le groupe spectateur 0x0 triplement liC, on pourrait s'attendre 21 ce qu'il soit plus rkactif si les calculs sont corrects. En accord avec ces prkvisions, on a trouvC que I'tnergie d'activation (AG*) de la rCaction du ruthhate est d'environ 7 kcal/mol plus ClevCe que celle de la rCaction correspondante du permthCnate.[Traduit par le journal] Introduction Transition metal oxides and oxyanions have been used extensively as oxidants in both inorganic and organic chemistry (1). The driving force in most such reactions is generally considered to be a lowering of the oxidation number of the oxidant, which may formally be considered as a flow of electrons into the d orbitals of the metal. Since many of the high-valent do, d l , and d2 oxidants are capable of accepting several electrons before reaching a stable oxidation state, these reactions usually proceed in several steps with the formation of a number of intermediates of greater or lesser stability. The reactions are consequently of interest from both a practical and a theoretical point of view.RappC and Goddard (2) have recently described results, obtained from a theoretical study, that are extremely useful for predicting which intermediates are most likely to be formed during the course of several of these reactions. By use of ab initio methods they found that the metal-0x0 bonds present substantially influenced the stability of an intermediate. Metal-0x0 groups which have triple bond character were f...

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“…The obtained large negative values of ∆S ≠ (Table 2) suggests that the more plausible mechanism is one-electron transfer of inner-sphere nature [36][37][38]. Also, the large negative values of ∆S ≠ indicate that there is a randomness decrease during the oxidation reaction which leads to formation of a compacted intermediate complex.…”

Section: Reaction Mechanismmentioning

confidence: 94%

A Study of the Kinetics and Mechanism of Oxidation of Fluorene by Alkaline Hexacyanoferrate(III)

Fawzy¹

2017

AJPC

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Kinetics of hexacyanoferrate (III) (HCF) oxidation of fluorene (Fl) in organic alkaline medium has been studied by spectrophotometric technique at a constant ionic strength of 0.15 mol dm -3 and at a temperature of 25°C. The reaction showed a first order kinetics with respect to [HCF] and fractional-first order dependences on both [Fl] and [OH -]. The oxidation rate was increased with the increase in the ionic strength of the reaction medium. The oxidation mechanism was suggested which involves formation of a 1:1 intermediate complex between fluorene and HCF species in a pre-equilibrium step. The final oxidation product of fluorene was identified by spectroscopic and chemical tools as 9H-fluorenone. The appropriate rate law expression was deduced and the reaction constants involved in the mechanism were evaluated. The activation parameters of the rate constant of the slow step along with the thermodynamic quantities of the equilibrium constants were evaluated and discussed.

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Permanganate ion oxidations. 13. Soluble manganese(IV) species in the oxidation of 2,4(1H,3H)-pyrimidinediones (uracils)

Cited by 91 publications

References 3 publications

Oxidation of acetanilide by MnO 4 − in the presence of HClO4. A kinetic study

Oxidation of acetanilide by MnO 4 − in the presence of HClO4. A kinetic study

Oxidation of hydrocarbons. 12. Kinetics and mechanism of the oxidation of trans-cinnamic acid by ruthenate and perruthenate ions

A Study of the Kinetics and Mechanism of Oxidation of Fluorene by Alkaline Hexacyanoferrate(III)

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