A small volume reaction chamber couple
d to a mass spectrometer was use
d to stu
dy the gas-phase kineticsan
d mechanism of the reaction of OH ra
dicals with
diphenyl ether an
d seven polybrominate
d diphenyl ethers(PBDEs) with 1-2 bromines. Relative rate constants for these reactions were
determine
d using isopropylnitrite photolysis in He-air mixtures at ~740 Torr between the temperatures of 326-388 K. The Arrheniusexpression for each compoun
d was use
d to extrapolate the following OH rate constants at 298 K (in units of10
-12 cm
3 molecule
-1 s
-1, with 95% confi
dence intervals):
diphenyl ether, 7.45 ± 0.13; 2-bromo
diphenylether, 4.7
![](/isubscribe/journals/jpcafh/110/i37/eqn/jp0630222e10001.gif)
; 3-bromo
diphenyl ether, 4.6
![](/isubscribe/journals/jpcafh/110/i37/eqn/jp0630222e10002.gif)
; 4-bromo
diphenyl ether, 5.7
![](/isubscribe/journals/jpcafh/110/i37/eqn/jp0630222e10003.gif)
; 2,2'-
dibromo
diphenylether, 1.3
![](/isubscribe/journals/jpcafh/110/i37/eqn/jp0630222e10004.gif)
; 2,4-
dibromo
diphenyl ether, 3.8
![](/isubscribe/journals/jpcafh/110/i37/eqn/jp0630222e10005.gif)
; 3,3-
dibromo
diphenyl ether, 3.2
![](/isubscribe/journals/jpcafh/110/i37/eqn/jp0630222e10006.gif)
; an
d 4,4'-bromo
diphenyl ether, 5.1
![](/isubscribe/journals/jpcafh/110/i37/eqn/jp0630222e10007.gif)
. The measure
d OH rate constants are in reasonable agreement with thosepre
dicte
d by structure activity relationships. Positive temperature
depen
dences of these OH rate constants areobserve
d for all compoun
ds measure
d except for
diphenyl ether an
d 4,4'-
dibromo
diphenyl ether. Bromophenols(in yiel
ds up to 20% relative to the amount of PBDE consume
d) an
d Br
2 were characterize
d as pro
ducts ofthese reactions, suggesting that OH a
ddition to ipso positions of these brominate
d aryls may be an importantreaction pathway.