Quantum Chemical Investigation of OH-Initiated Oxidation Kinetics of Ethyl 2-Chloroacetoacetate in the Atmosphere

Abstract

Anthropogenic sources release ethyl 2-chloroacetoacetate (CH₃C(O)CHClC(O)OCH2CH₃, E2CAA), a family of organic volatile chemicals, into the environment from the paper industry. Concerns over its effects on the environment are raised by its widespread use in industrial activities. Using the M06-2X functional, we carried out a thorough theoretical analysis of the atmospheric oxidation processes of E2CAA that are started by OH radicals. At room temperature, the most thermodynamically stable conformer of E2CAA was found. Four primary hydrogen abstraction pathways were characterized, each proceeding through the formation of reaction complexes, indicating that the reactions follow an indirect hydrogen abstraction mechanism. Canonical Transition State Theory (CTST) was used to compute and analyze the reaction coefficients and product branching ratios for H-abstraction channels in the temperature range of 250–450 K. Based on these kinetic results, the atmospheric lifetime of E2CAA was estimated to be approximately 4.41 hours.