Kinetics of the Gas-Phase Reaction of NO3 Radicals with 1-Butene, trans-Butene, 2-Methyl-2-butene and 2,3-Dimethyl-2-butene Using LIF Detection

Abstract

Rate constants for the gas-phase reaction of NO₃ radicals with 1-butene, trans-butene, 2-methyl-2-butene and 2,3-dimethyl-2-butene have been obtained in a flow system at 298±2 K and a pressure of 3 mbar He using NO₃ LIF measurements. NO₃ radicals were produced via thermal decomposition of N₂O₅ at ca. 400 K, i.e. N₂O₅+M → NO₃+NO₂+M.

Applying pseudo-first-order conditions, the rate constants for 1-butene and trans-butene were found to be (1.04±0.11)·10⁻¹⁴ and (3.74±0.45)·10⁻¹³, respectively. For 2-methyl-2-butene and 2,3-dimethyl-2-butene the rate constants were obtained under second-order conditions to be (1.03±0.09)·10⁻¹¹ and (5.49±0.42)·10⁻¹¹, respectively (unit: cm³ molecule⁻¹ s¹).