Mechanistic and kinetic study on the reaction of 2;4-dibrominated diphenyl ether (BDE-7) with OH radicals

The mechanism and kinetic properties of OH-initiated gas-phase reaction of 2;4-dibrominated diphenyl ether (BDE-7) were studied at the MPWB1K/6-311+G(3df;2p)//MPWB1K/6-31+G(d;p) level of theory. Two types of reactions;hydroxyl addition and hydrogen abstraction;were investigated. The calculation results indicate that addition reactions;except for the bromo-substituted one;have lower barriers than hydrogen abstraction reactions. Moreover;hydroxyl radicals are likely to react with phenyl ring without bromine atoms. Rate constants were deduced over 200–1000 K using canonical variational transition state theory with small curvature tunneling contribution. At 298 K the calculated rate constant for the title reaction is 3.76 × 10−12 cm−3 molecule−1 s−1.