Kinetic studies of OH reactions with propylal, butylal and 1,3-dioxolane

Abstract

Rate coefficients have been measured for the gas phase reactions of hydroxyl (OH) radicals with three acetals, di-n-propoxymethane (n-C₃H₇OCH₂On-C₃H₇), di-n-butoxymethane (n-C₄H₉OCH₂On-C₄H₉) and 1,3-dioxolane. The experiments were carried out using the pulsed laser photolysis - laser induced fluorescence technique over the temperature range 243–372 K and the kinetic data were used to derive the following Arrhenius expressions (in units of cm³ molecule⁻¹ s⁻¹): di-n-propoxymethane, k₁ = (4.39 ± 1.06) × 10⁻¹² exp[(563 ± 74)/T]; di-n-butoxymethane, k₂ = (5.15 ± 0.66) × 10⁻¹² exp[(590 ± 38)/T]; and 1,3-dioxolane, k₃ = (6.70 ± 0.86) × 10⁻¹² exp[(154 ± 36)/T]. At 298 K, the rate coefficients obtained (in units of 10⁻¹² cm³ molecule⁻¹ s⁻¹) are: k₁ = (27.6 ± 2.3), k₂ = (37.0 ± 5.2) and k₃ = (11.1 ± 0.9). The results are discussed in terms of structure–activity relationships and used to derive atmospheric lifetimes for these acetals.