Laser induced fluorescence and computational studies on the tropospheric photooxidation reactions of methyl secondary butyl ether initiated by OH radicals

Abstract

The kinetics of the reaction of methyl secondary butyl ether with OH radicals was investigated experimentally using the pulsed laser photolysis-laser induced fluorescence technique (PLP-LIF) over temperatures ranging from 268 to 363 K. The rate coefficient value at 298 K was measured to be (1.09 ± 0.02) × 10^-11 cm³ molecule^-1 s^-1 and the deduced Arrhenius expression is [Formula: see text]= (2.21 ± 0.29) × 10^-12 exp ((471.71 ± 38.50)/T) cm³ molecule^-1 s^-1. To complement the experimental data, the kinetic study of the title reaction was performed computationally at CCSD(T)/cc-pVTZ//M06-2X/6-311 + G(d,p) level of theory with the incorporation of tunnelling correction from 200 to 400 K. The end products formed were qualitatively analyzed by using gas chromatography equipped with mass spectrometry (GC-MS) as detection technique and the mechanism for degradation was proposed. Thermochemical parameters were evaluated to determine the feasibility of individual reaction pathways. Atmospheric implications were evaluated and discussed in this manuscript.

Keywords: Atmospheric lifetime; Methyl secondary butyl ether; OH radicals; Photochemical ozone creation potential; Pulsed laser photolysis-laser induced fluorescence technique; Rate coefficients.