Atmospheric Chemistry and Environmental Assessment of Inhalational Fluroxene

Abstract

Smog chamber/gas chromatography techniques are used to investigate the atmospheric degradation of fluroxene, an anesthetic, through oxidation with OH and Cl radicals at 298 K and under atmospheric pressure of N2 or air. The measured rate constants (k) are: k(fluroxene+OH(.) )=(2.96±0.61)×10(-11) and k(fluroxene+Cl(.) )=(1.62±0.19)×10(-10) cm(3) molecule(-1) s(-1) . The only product detected after the oxidation of fluroxene with OH radicals is 2,2,2-trifluoroethyl formate (79 % and 83 % molar yield in the absence and presence of NOx, respectively). However, after oxidation with Cl radicals, the detected products are 2,2,2-trifluoroethyl formate (78 %), 2,2,2-trifluoroethyl-1-chloroacetate (5 %), and chloroacetaldehyde (4 %), in the absence of NOx, and 2,2,2-trifluoroethyl formate (93 %), 2,2,2-trifluoroethyl-1-chloroacetate (6 %), and chloroacetaldehyde (5 %), in the presence of NOx. The results indicate that, both in the absence and presence of NOx, the main fate of fluroxene is the addition of the oxidant to the double bond and, once the alkoxy radical is formed, the main decomposition pathway is by means of degradation. Moreover, it is expected that 2,2,2-trifluoroethyl formate is the only oxidation product able to actively contribute to climate change. To successfully assess the contribution of fluroxene to global warming, we measure the infrared spectra of fluroxene and 2,2,2-trifluoroethyl formate, and calculate the radiative efficiencies (REs) to be 0.27 and 0.28 W m(-2) ppbv(-1) , respectively. In addition, the cumulative effect owing to the formation of 2,2,2-trifluoroethyl formate is investigated, and the direct, indirect, and net global-warming potentials are calculated by using the REs and lifetimes of fluroxene and 2,2,2-trifluoroethyl formate.