Design of Transition-Metal Oscillators Based on the Reduction of Permanganate Ions by Keto Dicarboxylic Acids

Abstract

Permanganate chemical oscillators with some keto dicarboxylic acids in the presence of phosphoric acid in a continuously stirred tank reactor (CSTR) are described in terms of the phase diagrams in the [ketomalonic acid]o-ko, [oxalacetic acid]o-ko, and [α-ketoglutaric acid]o-ko planes, and in the [H3PO4]o-ko , [MnO4-]o-ko , temperature-ko planes. The results show that an optimum degree of stabilization of the Mn(IV) colloid, which may serve as a reservoir of solvated Mn(IV) ions participating in the elementary reaction steps, is a prerequisite for the oscillations in the MnO4--keto dicarboxylic acid system. A skeleton mechanism for permanganate oscillators with keto dicarboxylic acids involving five reaction steps is proposed.