循环伏安法研究显影剂的电化学行为

A CYCLIC VOLTAMMETRIC STUDY OF THE ELECTROCHEMICAL BEHAVIOR OF COLOR DEVELOPERS

本文用循环伏安法对几种显影剂及其类似物DEPPD、DEPAP和TEPPD的电化学进行了研究。实验结果证明,DEPPD经一步氧化成醌二亚胺(QDI),而TEPPD则分两步氧化;DEPAP在pH<7时一步氧化成醌亚胺(QMI),pH>7时分两步氧化。在碱性条件下,各氧化产物可发生明显的脱氨反应。由实验测得的E 1/2与pH的关系,估算了它们的去质子化常数。

The electrochemical behavior of some color developers were studied using cyclic voltam-metry. DEPPD, DEPAP and TEPPD were chosen to represent different structural types. It was shown that DEPPD can be oxidized to QDI in one step, whereas TEPPD to QDI in two steps, DEPAP can be oxidized to QMI in one step at pH<7 and in two steps at pH>7. The deamination of the oxidized developers can occur apparently in the alkaline solution. The relation between El/2 and pH for the above color developers were established, and the deproto-nation constants were estimated.