Rate constants for the reactions of OH radicals with CH3OCF2CHF2, CHF2OCH2CF2CHF2, CHF2OCH2CF2CP3, and CF3CH2OCF2CHF2 over the temperature range 250-430 K
K. Tokuhashi et al., Rate constants for the reactions of OH radicals with CH3OCF2CHF2, CHF2OCH2CF2CHF2, CHF2OCH2CF2CP3, and CF3CH2OCF2CHF2 over the temperature range 250-430 K, J PHYS CH A, 104(6), 2000, pp. 1165-1170
The OH reaction rate constants have been measured for CH3OCF2CHF2, CHF2OCH2
CF2CHF2, CHF2OCH2CF2CF3 and CF3CH2OCF2CHF2 over the temperature range 250-4
30 K, Kinetic measurements have been carried out using the flash photolysis
, laser photolysis, and discharge flow methods, combined respectively with
the laser-induced fluorescence technique to monitor the OH radical concentr
ations. The influence of impurities contained in the samples of fluorinated
ethers has been investigated by means of sample purification using gas chr
omatography. No sizable effect of impurities was found on the measured rate
constants of these fluorinated ethers, if the purified samples were used i
n the kinetic measurements. The Arrhenius rate constants have been determin
ed from the respective kinetic data as k(CH3OCF2CHF2), = 2.60 x 10(-12) exp
[-(1420 +/- 170)/T], k(CHF2OCH2CF2CHF2)= 2.49 x 10(-12) exp[-(1500 +/- 170)
/T], k(CHF2OCH2CF2CF3)= 2.14 x 10(-12) exp[-(1580 +/- 170)/T], and k(CF3CH2
OCF2CHF2) = 1.49 x 10(-12) exp[-(1520 +/- 170)/T] cm(3) molecule(-1) s(-1),
where the quoted errors represent the 95% confidence level and included sy
stematic errors. Uncertainty factors at 298 K (with the formulation of the
NASA panel for data evaluation(14)) for these fluorinated ethers were 1.1.