The reaction of ONOO^- with carbonyls: Estimation of the haft-lives ONOOC(O)O^- and O₂NOOC(O)O^-

The equilibrium constant for the formation of an adduct between a carbonyl and a hydroperoxide ion varies linearly with the acid dissociation constant of the hydroperoxide. Based on this relationship, the half-life of the adduct formed between ONOO^- and CO₂, ONOOC(O)O^-, is estimated to be shorter than 100 ns. Consequently, this adduct should not play any role whatsoever in chemical or biological systems. O₂NOO^- and CO₂ are believed to be involved in a fast equilibrium reaction forming an adduct, O₂NOOC(O)O^-. This adduct does not appear to homolyse either along the O-O or the N-O bond. Furthermore, at realistic CO₂ concentrations, the equilibrium should be shifted far to the O₂NOO^- + CO₂ side. Therefore, the rate of self-decomposition of O₂NOO^- into NO₂^- and O₂ is unaffected by the presence of bicarbonate.