氨基酸氧化反应的动力学研究

Kinetics and Mechanism of Oxidation of α-Aminino Acids by N-bromosuccinimiole

利用紫外吸收光谱法研究了α－氨基酸与Ｎ－溴代琥珀酰亚胺（ＮＢＳ）进行氧化反应的动力学．结果表明：反应对ＮＢＳ为一级，对α－氨基酸为正分数级，准一级反应速率常数ｋ＿（ｏｂｓ）随［ＯＨ－］增加而降低，离子强度及扩散效应对反应无影响．提出了反应的可能机理，导出的速率方程圆满地解释了实验现象，并且计算出了速控步的速率常数、前期平衡常数等动力学参数．

The kinetics of the oxidtive decarboxylation of amino acids promoted by-bro-mosuccinimole(NBS)has been studied hy spectrophotometry in aqueous acid and alkalinemedium.The reaction was first order in NBS, and fractional order in amino acids.It wasfound that the pseudo first-order([AA]0.>>[NBS]0 rate constants decreases with the in-crease of[OH-](see Fig.2), and ionic strength and diffusion have no effect on the rate con-stants. Based on the experimental results, a mechanism involving the formatin of an inter-mediate, its slow decomposition to an imine,and subsequent rapid conversion of imine toproducts is proposed and the derived rate law was in good agreement with the experimentalobservations and the preequilidrium constants, rate constant of the rate-determining step to-gether with the activation parameters were evaluated.