亚胺醌水解反应动力学参数的测定

DETERMINATION OF KINETIC PARAMETERS OF HYDROLYSIS OF“QUINOIMINE”

对-氨基酚(P-Aminophenol PAP)氧化反应的历程,在本世纪初就有一些作者进行过研究,Conant和Pratt还提出了PAP的氧化历程为:

The kinetics of the hydrolysis of “quinoimine” arising from the anodic oxidation of p-aminophenol (PAP)has been studied with cyclic voltammetry. Hydrolysis rate constants of quinoimine (kf) in various buffer media have been determined. It was found that there is a maximum of kf at pH=2.30. In solutions of pH0.40--2.30 the hydrolysis reaction is in negative first-order with respect to hydrogen ion concentration whereas at pH 2.3--4.75 the reaction order becomes 0.2.The activation energies of the hydrolysis at vari- ous pHs have also been determined. The experimental results show that at pH>2.30 the activation energy decreases as the pH increases. It is apparent that the reactions are more complicated in the more basic media.