Measurements of Radical Reactivity with an Imine, (CF3)2CNH: Rate Constants for Chlorine Atoms and Hydroxyl Radicals and the Global Warming Potential

The rate constant kOH for the reaction of 1,1,1,3,3,3-hexafluoroprop-2-imine with OH radicals was measured relative to two reference compounds, CH3F and CH3CHF2, to be kOH = (4.2 ± 1.1) × 10−14 cm3 molecule−1 s−1 at 295 K. This implies an atmospheric lifetime with respect to consumption by OH of 0.75 years. Reaction with Cl atoms yielded kCl = (7.9 ± 1.7) × 10−16 cm3 molecule−1 s−1 at 295 K, and reaction with O3 has an upper limit of kO3 < 4 × 10−23 cm3 molecule−1 s−1, so that the atmospheric consumption by Cl and O3 is negligibly slow. Absolute infrared cross sections of the imine yield a radiative efficiency of 0.34 W m−2 ppb−1, which is corrected to 0.23 W m−2 ppb−1 for the effects of atmospheric lifetime. The imine’s corresponding 100-year global warming potential is 64 ± 19. This value is an upper limit, given that heterogenous atmospheric removal paths, such as hydrolysis in water droplets, are not included.