Quantum calculation on night-time degradation of 2-chloroethyl ethyl ether (CH3CH2OCH2CH2Cl) initiated by NO3 radical

Abstract

A dual-level quantum chemical calculations have been carried out on the initiation of night-time degradation of 2-chloroethyl ethyl ether (CH3CH2OCH2CH2Cl) via H-abstraction by NO3 radical. Within the scope of density functional theory, the electronic structure of all the species involved in the titled reaction has been optimized at M06-2X functional along with 6-31[Formula: see text]G(d,p) basis set. A higher level of couple cluster CCSD(T) method in conjunction with 6-311[Formula: see text]G(d,p) basis set has been used for the refined energy of the species. All minima and saddle states involved in the reaction channel have been characterized on the potential energy surface (PES). From PES, it is confirmed that H-abstraction from methylene (–CH2–) of ethyl (CH3CH2–) part of CH3CH2OCH2CH2Cl follows the minimum energy path. The rate constants (individual and overall) of the titled reaction are obtained using Canonical Transition State Theory (CTST) over the temperature range of 250–350[Formula: see text]K. The atmospheric lifetime and radiative efficiency of the titled molecule have also been estimated, amounting to 0.23 years and 0.024 years, respectively. The Global Warming Potentials of the 2-chloroethyl ethyl ether in 20 years, 100 years and 500 years time horizon were found to be 0.13, 0.04 and 0.01, respectively.