Metal Induced Decarboxylation of Aliphatic Free Radicals. I. Kinetics of the Reactions of Copper(I) and Copper(II) Ions with the 2‐Methyl‐2‐Carboxylicacid‐Propyl Free Radical in Aqueous Solutions. A Pulse Radiolysis Study

CH₂C(CH₃)₂CO₂H free radicals react with Cu²⁺_aq to form Cu^III‐CH₂C(CH₃)₂CO₂H²⁺_aq, which probably is rapidly transformed into intermediate I. This intermediate decomposes into Cu⁺_aq + CO₂ + CH₂=C(CH₃)₂. This is the first system in which a metal ion induced β‐carboxyl elimination reaction was observed. ·CH₂C(CH₃)₂CO₂H free radicals react with Cu^III‐CH₂C(CH₃)₂CO₂H²⁺_aq to form Cu²⁺_aq and a mixture of (‐CH₂C(CH₃)₂CO₂H)₂, (CH₃)₃CCO₂H, and HOCH₂C(CH₃)₂CO₂H. CH₂C(CH₃)₂CO₂H reacts with Cu⁺_aq to form Cu^II‐CH₂C(CH₃)₂CO₂H⁺_aq. The latter intermediate decomposes both via homolysis and by a reaction with Cu²⁺_aq to form 2Cu²⁺_aq + (CH₃)₃CCO₂H. The spectra of the intermediates and the kinetics of reaction are reported.