The chemistry of pernitrites. Part I. Kinetics of decomposition of pernitrous acid

Abstract

The kinetics of decomposition of pernitrite in excess of alkali have been studies at several temperatures. These show that decomposition occurs through the pernitrous acid molecule, HO·ONO, with ΔH^‡= 12·5 kcal. mole^–1 and ΔS^‡= 26 e.u. The value of ΔH^‡ is not consistent with the accepted view that pernitrous acid decomposes via homolytic fission of the O–O link. This problem is discussed and other, non-homolytic, mechanisms suggested. An upper limit for the pK_A of pernitrous acid at 2° of 8·3 has been calculated. The first isolation of a solid pernitrite is reported. The extinction coefficient of the pernitrite anion at 302 mµ(λ_max.) has been redetermined as 1670 ± 50.