Fluoroform (CHF3) Production from CF3CHO Photolysis and Implications for the Decomposition of Hydrofluoroolefins and Hydrochlorofluoroolefins in the Atmosphere
Journal Publication ResearchOnline@JCUAbstract
Hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs) are the leading synthetic replacements for compounds successively banned by the Montreal Protocol and amendments. HFOs and HCFOs readily decompose in the atmosphere to form fluorinated carbonyls, including CF<inf>3</inf>CHO in yields of up to 100%, which are then photolyzed. A long-standing issue, critical for the transition to safe industrial gases, is whether atmospheric decomposition of CF<inf>3</inf>CHO yields any quantity of CHF<inf>3</inf> (HFC-23), which is one of the most environmentally hazardous greenhouse gases. This comprehensive experimental investigation employs purpose-built photoionization mass spectrometry, Fourier-transform infrared, and microwave spectroscopy techniques and confirms production of CHF<inf>3</inf> following excitation at a tropospherically relevant wavelength (λ = 308 nm) and under atmospheric pressure conditions. Pressure-dependent CHF<inf>3</inf> quantum (Φ) and molar (Y) yields are reported from Φ = Y = 0.16 ± 0.03 under collision-free conditions to Φ = (2.3 ± 0.3) × 10<sup>-4</sup>, Y = (1.17 ± 0.27) × 10<sup>-3</sup> at 1 bar N<inf>2</inf>
Journal
Journal of the American Chemical Society
Publication Name
Journal of the American Chemical Society
Volume
147
ISBN/ISSN
1520-5126
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Pages Count
6
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Publisher
American Chemical Society
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DOI
10.1021/jacs.4c11776