Abstract
A mechanistic approach to the influence of Mn(II) catalyzed
oxidative deamination of an anti-convulsant drug [GP] by
peroxomonosulphate (PMS) at a constant ionic strength of
1.0 mol dm
–3 have been studied,
spectrophotometrically. The reaction shows first order dependence on
[PMS] and [Mn(II)] and apparent less than unit order dependence
each in [GP] and alkali concentrations. Influence of dielectric
constant and ionic strength of the medium on the reaction rate have
been evaluated. It was observed that the added sulphate ion, the
reduction product of the oxidant, had insignificant effect on the
reaction rate. The reaction stoichiometry and oxidation products
deprotonated GP, SO4
2− and MnO2 have
been identified and a suitable mechanism has been proposed. The
reaction fails to initiate polymerization in the presence of
acrylonitrile under the experimental conditions employed. In
a composite equilibrium step, deprotanated GP binds to catalyst and
form a complex C that subsequently decomposes with oxidant to yield
the products. Investigations of the reaction at different temperatures
allowed the determination of the activation parameters and a tentative
reaction mechanism in good consistency with the kinetic results is discussed.
摘要:本研究采用机械方法研究了Mn(II)催化
过氧单硫酸盐(PMS)在恒定离子强度为1.0 mol dm
–3的条件下对抗惊厥药物[GP]的氧化脱
氨作用,通过光谱法进行了研究。反应对[PMS]和[Mn(II)]呈一级依赖关系,对[GP]和碱浓度的依赖程度均小于单位阶。评估了介质的介电常数和离子强度对反应速率的影响。观察到氧化剂还原产物
硫酸根离子对反应速率影响微乎其微。已确定反应的
化学计量和氧化产物去质子化的GP、SO
42−和MnO
2,并提出了一个合适的机制。在实验条件下,反应未能在
丙烯腈存在的情况下引发聚合反应。在一个复合平衡步骤中,去质子化的GP与催化剂结合形成一个复合物C,随后与氧化剂分解产生产物。在不同温度下对反应的研究允许确定活化参数,并讨论了与动力学结果一致的初步反应机制。