Benzoquinone imines. Part I. p-Phenylenediamine–ferricyanide and p-aminophenol–ferricyanide redox systems
Benzoquinone imines. Part I. p-Phenylenediamine–ferricyanide and p-aminophenol–ferricyanide redox systems
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第一部分：对苯二胺-铁氰化物和对氨基苯酚-铁氰化物氧化还原体系。
DOI：
10.1039/j29690000207
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发表时间：
1969
期刊：
影响因子：
--
通讯作者：
J. Corbett
中科院分区：
文献类型：
--
作者：
J. Corbett
讨论了pH对对苯二胺-铁氰化钾和对氨基苯酚-铁氰化钾氧化还原体系平衡位置的影响。在所有的pH值下，平衡很快就建立起来了。在高pH(>；7)时，体系的平衡有利于苯二酮亚胺，体系的不稳定性是由于这些亚胺的水解所致。在低pH(<；4)时，平衡有利于胺，体系相对稳定。在中等pH下，胺和亚胺都大量存在，导致与有色产物的快速偶合反应。对苯二胺-铁氰化铁体系因生成大量的对苯并二喹酮双亚胺自由基阳离子而变得复杂。用平衡数据计算了亚胺的氧化电势和生成半喹酮的平衡常数。
The effect of pH on the position of equilibrium in the p-phenylenediamine–ferricyanide and p-aminophenol–ferricyanide redox systems is discussed. The equilibria are established very rapidly at all pH. At high pH (>7), the equilibria lie in favour of the quinone imine and the instability of the systems is due to hydrolysis of these imines. At low pH (<4), the equilibria lie in favour of the amines and the systems are relatively stable. At intermediate pH, both the amine and imine are present in significant amounts, resulting in rapid coupling reactions with the formation of coloured products. The p-phenylenediamine–ferricyanide system is complicated by the formation of significant quantities of the p-benzosemiquinone di-imine radical cation. Equilibrium data are used to calculate the oxidation potentials of the imines and the equilibrium constant for the formation of the semiquinone.