The kineties and mechanism of oxidation of α-alanine by diperiodatocuprate (Ⅲ) ion was studied by spectrophotometry in alkaline medium. The reaction rate showed first order dependance in oxidant and 1.25 order depen...The kineties and mechanism of oxidation of α-alanine by diperiodatocuprate (Ⅲ) ion was studied by spectrophotometry in alkaline medium. The reaction rate showed first order dependance in oxidant and 1.25 order dependance in α-alamne. It was found that the pesudo first-order ([Ala].》 [Cu(Ⅲ)].) rate constant kobs increases with the increases in [OH] and decreases with the increases in [IO]. The hnear relationships between [Ala/kobs and 1/[Ala] and between 1/kobs and [IO] were observed in our experiment. There is a positive salt effect. Under the protection of nitrogen gas, the reaction system can induce polyn1erzation of acrylamide. A plausible mechanism involving free redicals has been proposed. The rate equations derived from the mechanism explained all the experimental results satisfactorily. The rate constant activation paIameters of rate determing step have been calculated.展开更多
The kinetics of okidation of ethanolaInine by potassium diperiodatocupate (Ⅲ) was studied spectrophotometrically in alkallne medium at 293-2-303.2K. The reaction rate showed first order dependance on Cu(Ⅲ) and posit...The kinetics of okidation of ethanolaInine by potassium diperiodatocupate (Ⅲ) was studied spectrophotometrically in alkallne medium at 293-2-303.2K. The reaction rate showed first order dependance on Cu(Ⅲ) and positive fractiona order dependance on ethanolndne. It was fou-nd that the pesudo first-order([EA]. X[Cu(Ⅲ)].) rate constan k.b. increases with the increase of [OH-] and decreases with the increase of [IO-4].There is a negative salt effect of addtion of KNO3. The active species and a plausible mechedsm involing free redical have been proposed. All the experimental phenomena can be explaimed by the rate equation derived from the mechanism. The rate constant of the rate-determing step together with the activation paraments haye also been evaluated.展开更多
The title reactions with R=Me, Et, n-Pr were studied in a temperature range of 298-313K by spectrophotometry. lt was fOund that the rate with respect to [complex] is unity and that to [amine] is fractional. A linear r...The title reactions with R=Me, Et, n-Pr were studied in a temperature range of 298-313K by spectrophotometry. lt was fOund that the rate with respect to [complex] is unity and that to [amine] is fractional. A linear relationship between [amine]/kobs and [amine] was observed, where kobs stands for pseudo-first-order rate constant. The rate increases with the increase in water content of the solvent. A mechanism involying a preequllibrium of an adduct formation between the complex and aAnne was proposed. The equation derived from the mechanism explained all the experimental results and the preequllibrium constants, rate constants of the rate-determing step along with the activation parameters were evaluated.展开更多
文摘The kineties and mechanism of oxidation of α-alanine by diperiodatocuprate (Ⅲ) ion was studied by spectrophotometry in alkaline medium. The reaction rate showed first order dependance in oxidant and 1.25 order dependance in α-alamne. It was found that the pesudo first-order ([Ala].》 [Cu(Ⅲ)].) rate constant kobs increases with the increases in [OH] and decreases with the increases in [IO]. The hnear relationships between [Ala/kobs and 1/[Ala] and between 1/kobs and [IO] were observed in our experiment. There is a positive salt effect. Under the protection of nitrogen gas, the reaction system can induce polyn1erzation of acrylamide. A plausible mechanism involving free redicals has been proposed. The rate equations derived from the mechanism explained all the experimental results satisfactorily. The rate constant activation paIameters of rate determing step have been calculated.
文摘The kinetics of okidation of ethanolaInine by potassium diperiodatocupate (Ⅲ) was studied spectrophotometrically in alkallne medium at 293-2-303.2K. The reaction rate showed first order dependance on Cu(Ⅲ) and positive fractiona order dependance on ethanolndne. It was fou-nd that the pesudo first-order([EA]. X[Cu(Ⅲ)].) rate constan k.b. increases with the increase of [OH-] and decreases with the increase of [IO-4].There is a negative salt effect of addtion of KNO3. The active species and a plausible mechedsm involing free redical have been proposed. All the experimental phenomena can be explaimed by the rate equation derived from the mechanism. The rate constant of the rate-determing step together with the activation paraments haye also been evaluated.
文摘The title reactions with R=Me, Et, n-Pr were studied in a temperature range of 298-313K by spectrophotometry. lt was fOund that the rate with respect to [complex] is unity and that to [amine] is fractional. A linear relationship between [amine]/kobs and [amine] was observed, where kobs stands for pseudo-first-order rate constant. The rate increases with the increase in water content of the solvent. A mechanism involying a preequllibrium of an adduct formation between the complex and aAnne was proposed. The equation derived from the mechanism explained all the experimental results and the preequllibrium constants, rate constants of the rate-determing step along with the activation parameters were evaluated.
