Studies On Kinetics And Mechanism Of Oxidation Of Some Amino Compounds By Ag(Ⅲ) Complex Ion

Kinetics and mechanism of oxidation of 2-aminoethanol,3-amino-1-propanol, 2-amino-1-butanol, glycyglycine and sodium sulfanilate by Ag(â…¢) in alkaline medium were studied by spectrophotometry in this paper. The change of kobs with different [reductant], [OH-], [IO4-] and ionic strength were studied, the determining-step rate constants at different temperatures and the activation parameters at 298.2 K were evaluated.The reactions were found to be first order with respect to DPA,3-amino-l-propanol and 2-aminoethanol and sodium sulfanilate,1.30-1.35 order to glycyglycine, fractional order to 2-amino-l-butanol. Simultaneously, the rate of 3-amino-l-propanol and 2-aminoethanol is faster than that of the glycyglycine and sodium sulfanilate. The reason is that a stable ring complex is formed in the reaction of DPA with aminoalcohol compounds. In additional, the rate constants of the slow step of 2-amino-l-butanol is much smaller than that of 2-aminoethanol, this show that steric effects is greater in this type reaction.The results show that the mechanisms of oxidation of three types of amino-compounds by DPA are similar. We put forward the main existing form of DPA is [Ag(OH)2(H2IO6)2]5- in alkaline medium, and the activation center of DPA in the reaction is [Ag(OH)2(HIO6)]3-. There is good agreement between the experimental phenomena and the mechanisms that have been suggested.The present discuss and study will provide certain theoretical foundation for the reaction route design of the organic synthesis and quantitative analysis of analytical chemistry. Form the macrosopical experimentation phenomena, we can explain the microstructure of the complex, and conjecture the stability and stucture of the transition state, it is very significative for the development of theory of coordination chemistry.