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Abstract:
Absolute rate coefficients for the reaction between OH radicals and
perfluoro propyl vinyl ether (PPVE) were obtained using the technique of
pulsed laser photolysis with the detection of OH radicals by laser
induced fluorescence. Rate coefficients were measured over a range of
temperatures (212-298 K) and at either 50 or 200 Torr bath-gas (N-2 or
N-2/O-2). The temperature dependence of the rate coefficient is given by
k(1)(212-298 K) = (4.88 +/- 0.49) x 10(-13) exp[(564 +/- 10)/T] cm(3)
molecule(-1) s(-1) with a value at room temperature of (3.4 +/- 0.3) x
10(-12) cm(3) molecule(-1) s(-1). No pressure dependence was observed,
indicating that the reaction is at the high pressure limit under
atmospheric conditions. The accuracy of the rate coefficient obtained
was enhanced by on-line optical absorption measurements of PPVE at
184.95 nm using a value of sigma(184.95) nm = (5.64 +/- 0.28) x 10(-18)
cm(2) molecule(-1) determined in this work. An atmospheric lifetime of a
few days for PPVE was calculated. Extensive quantum chemical
calculations as a complement to the experimental work are presented in
order to determine its probable tropospheric degradation mechanism.
