Atmospheric HFEs degradation in the gas phase: reactions of HFE-7100 and HFE-7200 with Cl atoms at low temperatures.
Kinetic rate coefficients for the reactions of HFE-7100 (1) (C4F9OCH3) and HFE-7200 (2) (C4F9OC2H5) with Cl atoms have been measured using a discharge flow mass spectrometric technique (DFMS) at 1 Torr total pressure. The reactions have been studied under pseudo-first-order kinetic conditions in excess of HFEs over Cl atoms and the study has been extended from 333 down to 234 K to approach the tropospheric temperature profile. At room temperature the measured rate constants are k (1) = (1.43 +/- 0.28) x 10(-13) cm3molecule(-1)s(-1) and k (2) = (2.1 +/- 0.1) x 10(-12) cm3molecule(-1)s(-1). The Arrhenius expressions from our results are (units in cm3molecule(-1)s(-1)): k (1) = (2.3 +/- 1.4) x 10(-10) exp - (2254 +/- 177)/T(234-315 K) and k (2) = (3.7 +/- 0.5) x 10(-11) exp - (852 +/- 38)/T(234-333 K) (errors are sigma). The reactions proceed through the abstraction of an H atom to form HCl and the corresponding halo-alkyl radical. At 298 K and 1 Torr, yields on HCl of 0.88 +/- 0.09 and 0.95 +/- 0.10 (errors are 2sigma) were obtained for HFE-7100 and HFE-7200 reactions, respectively.
Aranda
Alfonso
A
Facultad de Química, Universidad Castilla-La Mancha, Ciudad Real, Spain. alfonso.aranda@uclm.es
Díaz-De-Mera
Yolanda
Y
Bravo
Iván
I
Rodríguez
Diana
D
Rodríguez
Ana
A
Martínez
Ernesto
E
D000393:Air Pollutants / Q000737:chemistry; D001966:Bromine / Q000737:chemistry; D002713:Chlorine / Q000737:chemistry*; D004987:Ethers / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry; D013696:Temperature
D000393:Air Pollutants; D004987:Ethers; D002713:Chlorine; D006851:Hydrochloric Acid; D001966:Bromine