Arrhenius parameters for the reaction i-C3H7+ O2→ C3H6+ HO2

Abstract

The yields of C₃H₆ and C₃H₈ formed during the oxidation of isobutyraldehyde have been measured over the temperature range 653–773 K, and the results used to obtain values of E₃–E₂= 38.1 ± 2.4kJ mol^–1 and A₃/A₂= 10^{0.41 ± 0.14}: i-C₃H₇+ O₂→ C₃H₆+ HO₂(2), i-C₃H₇+ i–C₃H₇CHO → C₃H₈+ i–C₄H₇O. (3)

Use of the literature values of A₃ and E₃, with suitable corrections, gives A₂= 10^{7.44 ± 0.25} dm³ mol^–1 s^–1 and E₂=(–9.0 ± 5.0) kJ mol^–1, compared with A₁= 10^{7.05 ± 0.18} dm³ mol^–1 s^–1 and E₁=(–6.3 ± 3.5) kJ mol^–1 for the related reaction of C₂H₅ with O₂: C₂H₅+ O₂→ C₂H₄+ HO₂. (1)

No other data are available for reaction (2). The mechanism of reaction (2) is discussed in the light of the present results and of those from studies of reaction (1). The possibility of a cyclic intermediate of some stability is considered in an attempt to explain the negative temperature coefficient.