The reactions of Alkoxyl Radicals With O2. IV. n-C4H9O Radicals

Article abstract of DOI:10.1246/bcsj.60.2641

n-C4H9ONO was phtolyzed with 366 nm radiation at -8, 23, 55, 88, and 120 deg C in the presence of NO, O2 and N2.The quantum yields of n-C3H7CHO, C2H5CHO, and CH3CHO were measured as a function of reaction conditions.The primary photolytic act produces n-C4H9O^. radicals which can react with NO by two routes: n-C4H9O^. + NO --> n-C4H9ONO (2a) --> n-C3H7CHO + HNO (2b) or isomerize via an internal H-atom abstraction n-C4H9O^. --> I.^. (4) where I^. is the HOCH2CH2CH2CH2^. radical, and ln(k₄/K₂ mol dm^-3) = 1.93+/-1.60-(4014+/-509)/T.If k₂ is taken as 2.6*10¹⁰ dm³ mol^-1 s^-1, then log (k₄, s^-1) = 11.25+/-0.69(4014+/-509)/2.303T.In the presence of O2 n-C4H9O^. radicals can also react wit O2: n-C4H9O^. + O2 --> n-C3H7CHO + HO2 (6) with ln(k₆/K₂) = (-4.09+/-0.54)-(1178+/-176)/T.If k₂ = 2.6* 10-¹⁰ dm³ mol^-1 s^-1, then k₆ = 4.5*10⁸ exp <(-1178+/-176)/T> dm³ mol^-1 s^-1.The radical I^. is removed via I^. --> CH3CHO + 2CH2O + HO (12a) --> Undetected aldehydes + HO (12b) I^. + O2 --> n-C3H7CHO + HO (13a) --> C2H5CHO + HO (13b) where these reactions are composites of a series of steps.The ratio k_13a/k_13b ca. 1.3+/-0.2 nearly independent of temperature.The ratio k₁₂/k₁₃ was not found very accurately, but it is ca. 3*10^-3 mol dm^-3.There was no evidence for the oxidation of I^. leading to dioxygenated products.