In this work, feasible mechanisms and pathways of the C₂H₅O₂ + BrO reaction in the atmosphere were investigated using quantum chemistry methods, i.e., QCISD(T)/6-311++G(2df,2p)//B3LYP/6-311++G(2df,2p) levels of theory. Our result indicates that the title reaction occurs on both the singlet and triplet potential energy surfaces (PESs). Kinetically, singlet C₂H₅O₃Br and C₂H₅O₂BrO were dominant products under the atmospheric conditions below 300 K. CH₃CHO₂ + HOBr, CH₃CHO + HOBrO, and CH₃CHO + HBrO₂ are feasible to a certain extent thermodynamically. Because of high energy barriers, all products formed on the triplet PES are negligible. Moreover, time-dependent density functional theory (TDDFT) calculation implies that C₂H₅O₃Br and C₂H₅O₂BrO will photolyze under the sunlight.
Keywords: BrO; C2H5O2; atmospheric reaction; mechanism; photolyze.