论文部分内容阅读
维生素 C(抗坏血酸 H_2 A)的氧化反应与生理过程密切相关.在 Cu~(2+)离子催化下氧气氧化 H_2 A 的反应动力学已有不少报道.一般认为在反应过程中会有 H_2 O_2 出现,因此 H_2 O_2对 H_2 A 的氧化作用就引起了人们的兴趣.Mario 与 Pispisa 用生物学上酶催化模式对H_2 O_2 氧化 H_2 A 的反应进行了研究,而对其反应动力学方程和机理讨论得不多.Skurlatov在酸性条件下得到如下的反应速率方程.Υ=k[Cu~(2+)][H_2 A]~(1/2)[H_2 O_2]~(1/2)/[H~+](1)并讨论了相应的反应机理.由于生物体的体液大多近于中性,我们在弱酸性条件下,对 H_2 O_2-Cu~(2+)-磷酸体系中 H-2 A 的氧化反应动力学进行研究,得到与式(1)不同的反应速率方程:Υ=k[Cu~(2+)]~(1/2)[H_2 A][H_2 O_2]~(1/2)[H~+](2)对相应的反应机理亦进行了讨论.
The oxidation reaction of vitamin C (ascorbic acid H 2 A) is closely related to the physiological process. There are many reports on the reaction kinetics of oxygen oxidation of H 2 O catalyzed by Cu 2+ ions. It is generally believed that H 2 O 2 , So the oxidation of H 2 O 2 by H 2 O 2 has aroused people’s interest.Mario and Pispisa studied the reaction of H 2 O 2 oxidation of H 2 A with the model of biological enzyme catalysis and discussed the reaction kinetics equation and mechanism Is not much .Skurlatov get the following reaction rate equation under acidic conditions: Y = k [Cu ~ (2 +)] [H_2A] ~ (1/2) [H_2O_2] ~ (1/2) / [H ~ +] (1) and discussed the corresponding reaction mechanism.As the body fluids of most organisms are nearly neutral, we studied the effect of H-2 A in H 2 O 2-Cu 2+ The kinetics of the oxidation reaction was studied and the reaction rate equation different from that in equation (1) was obtained: Υ = k [Cu ~ (2 +)] ~ (1/2) [H_2A] [H_2O_2] ) [H ~ +] (2) The corresponding reaction mechanism is also discussed.