Metal Ion Oxidative Decarboxylations. 13. Kinetics and Mechanisms of the Oxidation of N-Benzyliminodiacetic Acid with Cerium(IV) in Acidic Perchlorate and Acidic Sulfate Media

Article abstract of DOI:10.1021/jo00154a015

The Ce(IV)-mediated decarboxylation of N-benzyliminodiacetic acid (BIDA) produces benzaldehyde, formaldehyde, dimethylamine, benzylmethylamine, and N-benzylglycine in acidic perchlorate and acidic sulfate media.Spectrophotometric evidence of an intermediate Ce(IV)-BIDA complex is given.The data may be interpreted in terms of a mechanism which involves sequential reactions, the first of which is a reversible reaction: BIDA + Ce(IV) (k₁) <*> (k_-1) complex (k₂) <*> products.The rapid complex formation is followed by a slower oxidative decomposition to give a free radical capable of inducing free-radical polymerization.The free radical reacts rapidly with another Ce(IV) to give an iminium ion which undergoes either hydrolysis or decarboxylation.The rate constants k₁, k_-1, and k₂ were determined from kinetic data.At acidities between 0.10 and 2.0 M, the rates of both complex formation and complex decomposition are inversely dependent on +>.Activation parameters were determined in perchloric acid.Evidence is given to suggest CeSO4²⁺ as the reactive Ce(IV) species in acidic sulfate media.