ANALYSIS OF GOLDbecomes contaminated with anionic impurities, derived mainly from the side reactions of the KCN with water and air. Moreover, a comparison of the results of this work and those of a previous work (1) would indicate that electrolysis has an effect on the relative concentrations of the H.COO-and CO3 = ions present within a KCN/KAu(CN)2 electroplating solution.The ratio of CO3 = ion to H.COO-ion in Table VIII is approximately 0.65. Yet, in an aqueous KCN solution maintained at 70~ and exposed to air (1), in which no electrolysis is being conducted, the ratio is closer to 0.2. The higher CO3=/H.COO -ratio observed for the used electroplating solution probably results from the electrolytic oxidation of the H.COOion at the anode to CO2 (8, 9), which is retained in the alkaline KCN solution. ConclusionDibasic ammonium citrate/KAu(CN)2 and KCN/ KAu(CN)2 electroplating solutions are both susceptible to metallic impurity contamination. These impurities do not plate out of the KCN/KAu (CN)2 solution with the gold as readily as they do from the dibasic ammonium citrate/KAu (CN) 2 solution. However, the H.COO-and CO3 = ionic impurities build up to a high concentration in the KCN/KAu(CN)2 electroplating solution, but are barely present in the dibasic ammonium citrate/KAu(CN)2 electroplating solution. FOILS FOR IMPURITIES 743There is evidence that some of the H.COO-ion is oxidized at the anode to CO2, which is retained in the alkaline electroplating solution.

The electrolytic reductive coupling of a variety of diactivated olefins, XCH‒CHY , has been studied. The reduced dimeric products have been isolated and carefully identified. Both symmetrical and unsymmetrical dimers were observed. The dimeric products are formed by two paths: the first involves the attack of the electrochemically generated anion radical on unreduced olefin; the second involves the protonation of the anion radical followed by reduction to an anion and subsequent attack on the olefin. The isomer distribution in the dimeric product obtained by the first route is rationalized on the basis of the relative anion stabilizing ability of the activating groups in the acceptor molecule and the relative ability toward stabilizing a radical site in the donor molecule. The possibility of forming cross‐coupled products (between a diactivated olefin and a Michael acceptor) is limited to systems in which the electrochemically generated anion radical is relatively stable toward its parent olefin or in which the reduction potentials of the pair are similar, i.e., normalΔE½<0.4normalv .

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