Theoretical study on the mechanism of the gas phase reaction of methoxybenzene with ozone

Abstract

Methoxybenzene (MB), is seen as a potential air pollutant which may cause environmental issues in the troposphere. Nevertheless, our understanding of its gas phase reaction is extraordinarily limited. In this study, the quantum chemical methods [M06-2X/aug-cc-pVDZ//M06-2X/6-31+g(d,p)] and Rice–Ramsperger–Kassel–Marcus (RRKM) theory are utilized in investigating the detailed mechanisms and rate constants for the ozonolysis of MB for the first time. The results show that O₃-addition to the methoxy-substituted carbon dominates the entrance channel of MB with ozone and the total rate coefficient of the title reactions is calculated to be 2.67 × 10⁻²¹ cm³ per molecule per s at 298 K and 1 atm. The bimolecular rate constants show positive dependence on temperature (200–400 K) and negative dependence on pressure (10⁻³, 10⁻², 10⁻¹ and 1 atm). Moreover, the atmospheric lifetime of MB determined by O₃ is available concerning the typical concentration of O₃. This work aims to provide reference data for future experimental research on MB.