Reactions of alkoxy and peroxy radicals with carbon monoxide

Experimental rate constants of the reactions HO· + CO → H· + CO2, RO· + CO → R· + CO2, HO 2 · + CO → HO· + CO2, and RO 2 · + CO → RO· + CO2 are analyzed in the framework of the intersecting-parabolas model. The transition states of the additions of the methoxy and methylperoxy radicals to carbon monoxide were calculated by quantum-chemical methods. The reactions occur in two consecutive steps: first the HO· (RO·, RO 2 · ) radical adds to CO and then the resulting unstable intermediate radical decomposes to evolve CO2. The kinetic parameters of these reactions are calculated by two methods (using the intersecting-parabolas model and the quantum-chemical method). The activation energies and rate constants of a series of R i O· + CO and R i O 2 · + CO reactions are calculated. A comparison of the kinetic parameters suggests close similarity between the transition states in the additions of the O-centered radicals to CO and olefins.