Oxidative polymerization of aromatic amines in aqueous solution of iron chelate

Aromatic amines, such as p‐phenylenediamine (PD) or p‐aminophenol (AP) have been found to polymerize oxidatively at room temperature, catalyzed by ferric chelates, e.g., the Fe(III)‐salt of ethylenediaminetetraacetic acid, in aqueous solution. The polymers from PD or AP are black and do not melt below 300°C. They have paramagnetic and electroconductive properties (ca. 10−10 Ω−1 ċ cm−1). They have also reversible oxidation and reduction properties; in methanolic solution the polymer is reduced by an aqueous sodium hydrosulfite solution, resulting a light yellow solution, which is re‐oxidized by air to the original black polymer. The structures of the polymers are also presented.