Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compound 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 CFCs, HCFCs, and HFCs. Many refrigerants in the HFO class is 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 also show promise as blowing agents, i.e. in production of insulation foams, food industry, construction materials, and others.
HFOs currently in use include:
- 2,3,3,3-tetrafluoropropene (HFO-1234yf) and 1,3,3,3-tetrafluoropropene (HFO-1234ze).
- cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z; DR-2) shows also a promise in high temperature applications like cogeneration, heat recovery and medium temperature heat pumps.
- trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-E) also do have good properties, and is being investigated. (developements lead by Dr Kostas Kontomaris, from DuPont Flurochemicals; multiple publications in 2012-2019 and dozens of related patents).
- "HETEROGENEOUS CATALYSIS UNDER MICROWAVE HEATING" (PDF). La Chimica & L'Industria (in Italian). Società Chimica Italiana (4): 22. May 2012.
- HFO, i nuovi gas refirgerant
- Hydrofluoroolefins (HFOs) Archived 2012-02-04 at the Wayback Machine, European Fluorocarbons Technical Committee
- Honeywell Sells Novel Low-Global-Warming Blowing Agent To European Customers, Honeywell press release, Oct. 7, 2008