Reactions of aromatic ethers with atomic oxygen O(3P) in the gas phase

Decomposition of gas-phase diphenylether at 473 K by electron beam generated plasma

“…Additional formation of O radical from the dissociation of CO 2 may account for the enhancement. From the relations between the decrease in DPE decomposition efficiencies and the amount of NO addition, the rate coefficient of O( 3 P)-DPE reaction was roughly estimated to be in the order of 5.6 × 10 −10 -1 × 10 −9 cm 3 molecule −1 s −1 at 473 K. Koch et al [23] reported that the rate coefficient of DPE-O( 3 P) reaction is 1.8 × 10 −8 cm 3 molecule −1 s −1 at 473 K using a flow type microwave system, which is around 10 times larger than our estimation. The discrepancy is due at least partly to pressure because their work was performed at low pressure (at several mbar) but contains no data on pressure-dependent behaviour of the DPE-O( 3 P) reaction.…”

“…that the reaction channel of the O( 3 P)-DPE reaction is likely to be addition to the aromatic ring rather than the H-atom abstraction. From the consideration of reaction enthalpies Koch et al [23] also indicated that the formation of HQ is favourable from the O( 3 P)-DPE reaction. Considering the electrophilic nature of O( 3 P) radical, two important interpretations may be inferred regarding the reaction with DPE.…”

“…First, attack point of O( 3 P) may be the phenyl group rather than the C-O bond because electron density in the DPE is higher in phenyl group than in C-O bond. The compounds with lower ionization potential (IP) are susceptible to the attack of O( 3 P), O 3 and OH radicals [23,31]. The IP of DPE is relatively small at 8.82 eV compared to those of O 2 (12.1 eV), H 2 O (12.6 eV), and N 2 (15.6 eV).…”