Proma P. Phengsy

Bio: Proma P. Phengsy is an academic researcher from California State University. The author has contributed to research in topics: Catalysis & Benzyl alcohol. The author has an hindex of 1, co-authored 1 publications receiving 35 citations.

Kinetic study of 2‐propanol and benzyl alcohol oxidation by alkaline hexacyanoferrate(III) catalyzed by a terpyridyl ruthenium complex

Abstract: The complex (Trpy)RuCl3 (Trpy = 2,2′:6′,2″-terpyridine) reacts with alkaline hexacyanoferrate(III) to form a terpyridyl ruthenium(IV)-oxo complex that catalyzes the oxidation of 2-propanol and benzyl alcohol by alkaline hexacyanoferrate(III). The reaction kinetics of this catalytic oxidation have been studied photometrically. The reaction rate shows a first-order dependence on [RU(IV)], a zero-order dependence on [hexacyanoferrate(III)], a fractional order in [substrate], and a fractional inverse order in [HO−]. The kinetic data suggest a reaction mechanism in which the catalytic species and its protonated form oxidize the uncoordinated alcohol in parallel slow steps. Isotope effects, substituent effects, and product studies suggest that both species oxidize alcohol through similar pericyclic processes. The reduced catalytic intermediates react rapidly with hexacyanoferrate(III) and hydroxide to reform the unprotonated catalytic species. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 760–770, 2000

Kinetics and Mechanism of the Oxidation of Vanillin by Hexacyanoferrate(III) in Aqueous Alkaline Medium

Abstract: The title reaction was investigated in aqueous alkaline medium. A first-order dependence in hexacyanoferrate(III) concentration and a fractional order in both vanillin and alkali were obtained at the concentrations studied. The added product, hexacyanoferrate(II), had a retarding effect on the rate of reaction. Ionic strength and dielectric constant of the reaction medium have little effect on the reaction rate. The effect of temperature on the rate of reaction has also been studied and activation parameters have been evaluated. A mechanism based on the experimental results is proposed and the rate law is derived. The reaction constants are calculated and used to regenerate the kobs values, which are compared with the experimental values.

Kinetics and Mechanism of Ruthenium(III) Catalyzed Oxidation of LProline by Hexacyanoferrate(III) in Aqueous Alkali

Abstract: Kinetics of ruthenium(III) catalyzed oxidation of L-proline by hexacyanoferrate(III)(HCF) in alkali was studied spectrophotometrically at 30 0 C. A reaction was found to be independent upon (L-proline). The reaction was occurred without intervening free radical. Since unit order each in (Ru(III)) and (HCF), the oxidation follows an outer-sphere mechanism. A suitable mechanism was proposed and rate law was derived as kobs = kK

Osmium(VIII) Catalyzed Oxidative Cleavage of Pyrrolidine Ring in l-Proline by Hexacyanoferrate(III) in Alkaline Media

Abstract: Kinetics of oxidation of l-proline by hexacyanoferrate(III) catalyzed by osmium(VIII) in alkaline medium was studied at 30 °C. A mechanism involving free radical path was proposed. Rate law of the reaction was derived as rate=kK1K2[HCF][L-proline][OH−][Os(VIII)]1+K1[OH−]+K1K2[L-proline][OH−] The rate constant k and equilibrium constants K1 and K2 were evaluated as 3.79 × 103 dm3 mol−1 s−1, 0.52 dm3 mol−1, and 3.78 × 103 dm3 mol−1, respectively. The main reactive species of the catalyst appears to be OsO5(OH)3−. The oxidative product of l-proline was identified as l-glutamic acid which is different from the earlier reports. The literature reveals that 4-amino butyric acid, 4-amino butaraldehyde and keto acids were the oxidative products. Activation parameters were evaluated as Ea = 33.5 ± 2 kJ mol−1, ΔH⧧ = 31.0 ± 0.2 kJ mol−1, ΔS⧧ = −24 ± 1.5 J K−1 mol−1, ΔG⧧ = 38.0 ± 2 kJ mol−1.