REACTIONS INVOLVING COPPER(I) IN PERCHLORATE SOLUTION . A KINETIC STUDY OF REDUCTION OF IRON(3) BY COPPER(I)

Rate studies were carried out on the oxidation-reduction reaction of iron(III) and copper(I) ions in perchlorate solutions which produces quantitative yields of iron(II) and copper(II). The rate law is first order in each metal ion, with an inverse dependence on hydrogen ion concentration. The values (sec-1 × 10-4, μ = 1.00 M) are 2.48 ± 0.11 (1.6°), 7.67 ± 0.38 (15.8°), and 16.1 ± 0.3 (25.0°), with activation parameters ΔH≠ = 12.4 ± 0.2 kcal/mol and Δs≠ = 6.7 ± 0.7 eu. The reactions of FeN32+ and FeF2 + with Cu+ are immeasurably rapid by the techniques used, the lower limits at 1.6° and at μ = 1.00 M being 108 and 5 × 106 M-1 sec-1, respectively. The mechanism is discussed in comparison with related reactions, and it is concluded that an inner sphere process is probably involved. © 1969, American Chemical Society. All rights reserved.