Kinetics and Mechanism of Oxidation of n--Propanolamine by Dihydroxydiperiodatonickelate(IV) in Alkaline Medium

Authors: JIN-HUAN SHAN, JING QIAN, MING-ZHU GAO, SHI-GANG SHEN, HAN-WEN SUN

Abstract: The kinetics of oxidation of n--Propanolamine (n-PA) by dihydroxy diperiodato-nickelate(IV) (DPN) in alkaline medium was studied with spectrophotometry in a temperature range of 293.2-308.2 K. The reaction was found to be pseudo first-order with respect to DPN and fractional order to n-PA. The rate conatant k_{obs}, rose with an increase in the concentration of OH^{-} and a decrease in the concentration of IO_{4}^{-}. Added salts did not affect the rate and no free radical was detected. From the evaluation of linear data, a reaction mechanism is proposed which involves a pre-equilibrium of an adduct formation between n-PA and dihydroxymonoperiodatonickelate(IV) (MPN), and the activation parameters of the rate-determining step have been calculated.

Keywords: Dihydroxydiperiodatonickelate(IV), n--Propanolamine, Redox reaction, Kinetics and mechanism

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