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1,1-Dichloro-1-fluoroethane

1,1-Dichloro-1-fluoroethane is a haloalkane with the formula C
2H
3Cl
2F. It is one of the three isomers of dichlorofluoroethane. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment.

Physiochemical properties

1,1-Dichloro-1-fluoroethane can be a non-flammable, colourless liquid under room-temperature atmospheric conditions. The compound is very volatile with a boiling point of 32°C.[1][2] Its critical temperature is near 204°C.[3] Its smell has been described as "usually ethereal" (like ether).

Production and use

1,1-Dichloro-1-fluoroethane is mainly used as a solvent and foam blowing agent under the names R-141b and HCFC-141b. It is a class 2 ozone depleting substance undergoing a global phaseout from production and use under the Montreal Protocol since the late 1990s. It is being replaced by HFCs within some applications.[4]

Environmental effects

Growth of HCFC-141b in Earth's atmosphere since year 1993.[5]
HCFC-141b measured by the Advanced Global Atmospheric Gases Experiment (AGAGE) in the lower atmosphere (troposphere) at stations around the world. Abundances are given as pollution free monthly mean mole fractions in parts-per-trillion.

The concentration of HCFC-141b in the atmosphere grew to near 25 parts per trillion by year 2016.[5] It has an ozone depletion potential (ODP) of 0.12.[6] This is low compared to the ODP=1 of trichlorofluoromethane (CFC-11, R-11), which also grew about ten times more abundant in the atmosphere prior to introduction of HFC-141b and subsequent adoption of the Montreal Protocol.

HFC-141b is also a minor but potent greenhouse gas. It has an estimated lifetime of about 10 years and a 100-year global warming potential ranging 725 to 2500.[7][8] This compares to the GWP=1 of carbon dioxide, which had a much greater atmospheric concentration near 400 parts per million in year 2020.

See also

References

  1. ^ a b c d e f g Record of 1,1-Dichloro-1-fluoroethane in the GESTIS Substance Database of the Institute for Occupational Safety and Health, accessed on 8 February 2009.
  2. ^ "Addenda d, j, l, m, and t to ANSI/ASHRAE Standard 34-2004" (PDF). ANSI/ASHRAE Standard 34-2004, Designation and Safety Classification of Refrigerants. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. 2007-03-03. ISSN 1041-2336. Archived from the original (PDF) on 2011-10-12. Retrieved 2011-12-18.
  3. ^ Schoen, J. Andrew, "Listing of Refrigerants" (PDF), Andy's HVAC/R Web Page, archived from the original (PDF) on 2009-03-19, retrieved 2011-12-17
  4. ^ "Overview of HCFC Consumption and Available Alternatives For Article 5 Countries" (PDF). ICF International. 2008. Retrieved 2021-02-12.
  5. ^ a b "HCFC-141b". NOAA Earth System Research Laboratories/Global Monitoring Division. Retrieved 2021-02-12.
  6. ^ John S. Daniel; Guus J.M. Velders; A.R. Douglass; P.M.D. Forster; D.A. Hauglustaine; I.S.A. Isaksen; L.J.M. Kuijpers; A. McCulloch; T.J. Wallington (2006). "Chapter 8. Halocarbon Scenarios, Ozone Depletion Potentials, and Global Warming Potentials" (PDF). Scientific Assessment of Ozone Depletion: 2006. Geneva, Switzerland: World Meteorological Organization. Retrieved 9 October 2016.
  7. ^ "Chapter 8". AR5 Climate Change 2013: The Physical Science Basis. p. 731.
  8. ^ "Refrigerants - Environmental Properties". The Engineering ToolBox. Retrieved 2016-09-12.