Hydrofluoroolefin

Chemical structure of 1,3,3,3-tetrafluoropropene (HFO-1234ze)

Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compounds are of interest as refrigerants. Unlike traditional hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), which are saturated, HFOs are olefins, otherwise known as alkenes.

HFO refrigerants are categorized as having zero ozone depletion potential (ODP) and low global warming potential (GWP) and so offer a more environmentally friendly alternative to CFC, HCFC, and HFC refrigerants. Compared to HCFCs and HFCs, HFOs have shorter tropospheric lifetimes due to the reactivity of the C=C bond with hydroxyl radicals and chlorine radicals.^[1] This quick reactivity prevents them from reaching the stratosphere and participating in the depletion of good ozone, leading to strong interest in the development and characterization of new HFO blends for use as refrigerants.^[2] Many refrigerants in the HFO class are inherently stable chemically and inert, non toxic, and non-flammable or mildly flammable. Many HFOs have the proper freezing and boiling points to be useful for refrigeration at common temperatures. They have also been adopted as blowing agents, i.e. in production of insulation foams, food industry, construction materials, and others. However, HFOs degrade to produce trifluoroacetic acid, a persistent toxic chemical which can lead to acidification of water bodies, and which can accumulate in wetlands, a sensitive ecosystem.^[3]

HFOs are being developed as "fourth generation" refrigerants with 0.1% of the GWP of HFCs.^[4]^[5]^[6]

^ Cynthia B. Rivela; Carmen M. Tovar; Mariano A. Teruel; Ian Barnes; Peter Wiesen; María B. Blanco (2019). "CFCs replacements: Reactivity and atmospheric lifetimes of a series of Hydrofluoroolefins towards OH radicals and Cl atoms". Chemical Physics Letters. 714: 190–196. Bibcode:2019CPL...714..190R. doi:10.1016/j.cplett.2018.10.078. S2CID 106382701.
^ Wael A. Fouad; Lourdes F. Vega (2018). "Next generation of low global warming potential refrigerants: Thermodynamic properties molecular modeling". AIChE J. 64: 250–262. doi:10.1002/aic.15859.
^ Toit, Louise du (2023-12-01), "Strengthening the Global Regulation of Hydrofluorocarbons under the Montreal Protocol", Reducing Emissions of Short-Lived Climate Pollutants, Brill Nijhoff, pp. 90–124, ISBN 978-90-04-68408-9, retrieved 2024-04-25
^ Pizzetti, Marianna; Petricci, Elena (May 2012). "Heterogeneous Catalysis Under Microwave Heating" (PDF). La Chimica & l'Industria. 4. Società Chimica Italiana: 78–81.
^ HFO, i nuovi gas refirgerant
^ Hydrofluoroolefins (HFOs) Archived 2012-02-04 at the Wayback Machine, European Fluorocarbons Technical Committee

[1] Cynthia B. Rivela; Carmen M. Tovar; Mariano A. Teruel; Ian Barnes; Peter Wiesen; María B. Blanco (2019). "CFCs replacements: Reactivity and atmospheric lifetimes of a series of Hydrofluoroolefins towards OH radicals and Cl atoms". Chemical Physics Letters. 714: 190–196. Bibcode:2019CPL...714..190R. doi:10.1016/j.cplett.2018.10.078. S2CID 106382701.

[2] Wael A. Fouad; Lourdes F. Vega (2018). "Next generation of low global warming potential refrigerants: Thermodynamic properties molecular modeling". AIChE J. 64: 250–262. doi:10.1002/aic.15859.

[3] Toit, Louise du (2023-12-01), "Strengthening the Global Regulation of Hydrofluorocarbons under the Montreal Protocol", Reducing Emissions of Short-Lived Climate Pollutants, Brill Nijhoff, pp. 90–124, ISBN 978-90-04-68408-9, retrieved 2024-04-25

[C&I2012-4] Pizzetti, Marianna; Petricci, Elena (May 2012). "Heterogeneous Catalysis Under Microwave Heating" (PDF). La Chimica & l'Industria. 4. Società Chimica Italiana: 78–81.

[5] HFO, i nuovi gas refirgerant

[6] Hydrofluoroolefins (HFOs) Archived 2012-02-04 at the Wayback Machine, European Fluorocarbons Technical Committee

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