A green route to conducting polyaniline by copper catalysis

摘要

The oxidative polymerization of N-(4-aminophenyl)aniline (AD) to the conducting emeraldine salt (2.6 × 10~(-2) S cm~(-1)) has been investigated using dioxygen or hydrogen peroxide as the oxidant in aqueous solution under mild conditions. The spontaneous oxidation by O_2 takes place with a modest yield (13%) while H_2O_2 allows a better result (43% yield). On adding acetonitrile as a co-solvent, the polymerization is completely suppressed with both the reagents. A strong catalytic effect has been detected by using Cu, CuCl, and CuCl_2, being all these simple copper compounds similarly efficient using either O_2 or H_2O_2 reagents, thus allowing yields up to 86-93% of emeraldine. The poisoning effect of acetonitrile has been observed also in the case of the copper-catalyzed reactions but with a minor impact (5-14% decrement).