Formation of organic nitro-compounds in flowing H2O2+ NO2+ N2+ organic vapour systems. Part 3.—Effects of O2 addition on H2O2+ NO2+ N2+ alkane systems

Abstract

The effects of oxygen on the product distribution from the surface-initiated reactions in flowing mixtures of H₂O₂, NO₂, N₂ and RH, where RH = ethane, propane, n-butane and n-pentane, at 298 K have been studied. In the absence of O₂, the principal products are the corresponding nitroalkane, alkyl nitrite and alkyl nitrate. In the presence of sufficiently large concentrations of O₂, the predominant product is the alkyl nitrate and the only other products of significance, in some cases, are the corresponding carbonyl compounds.

The variation of the product yields with [O₂]/[NO₂] gives values for the rate-constant ratios k₈/(k₃+k₄) for reaction at both primary and secondary radical sites: R + NO₂(+ M)→ RNO₂(+ M)(3), R + NO₂(+ M)→ RONO_*(+ M)(4), R + O₂(+ M)→ RO₂(+ M). (8) Possible mechanisms by which the products are formed are discussed.