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1-Chloro-1,1-difluoroethane
Names
Preferred IUPAC name
1-Chloro-1,1-difluoroethane
Other names
Freon 142b; R-142b; HCFC-142b; Chlorodifluoroethane
Identifiers
3D model ( JSmol)
ChemSpider
ECHA InfoCard 100.000.811 Edit this at Wikidata
PubChem CID
UNII
  • InChI=1S/C2H3ClF2/c1-2(3,4)5/h1H3 checkY
    Key: BHNZEZWIUMJCGF-UHFFFAOYSA-N checkY
  • CC(F)(F)Cl
Properties
C2H3ClF2
Molar mass 100.49 g·mol−1
Appearance Colorless gas [1]
Melting point −130.8 °C (−203.4 °F; 142.3 K) [1]
Boiling point −9.6 °C (14.7 °F; 263.5 K) [1]
Slight [1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Asphyxiant
632 °C (1,170 °F; 905 K) [1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY  verify ( what is checkY☒N ?)

1-Chloro-1,1-difluoroethane (HCFC-142b) is a haloalkane with the chemical formula C H3 C Cl F2. 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. It is primarily used as a refrigerant where it is also known as R-142b and by trade names including Freon-142b. [2]

Physiochemical properties

1-Chloro-1,1-difluoroethane is a highly flammable, colorless gas under most atmospheric conditions. It has a boiling point of -10 °C. [1] [3] Its critical temperature is near 137 °C. [4]

Applications

HCFC-142b is used as a refrigerant, as a blowing agent for foam plastics production, and as feedstock to make polyvinylidene fluoride (PVDF). [5] It was introduced to replace the chlorofluorocarbons (CFCs) that were initially undergoing a phase-out per the Montreal Protocol, but HCFCs still have a significant ozone-depletion ability. As of year 2020, HCFC's are replaced by non ozone depleting HFCs within many applications. [6]

In the United States, the EPA stated that HCFCs could be used in "processes that result in the transformation or destruction of the HCFCs", such as using HCFC-142b as a feedstock to make PVDF. HCFCs could also be used in equipment that was manufactured before January 1, 2010. [7] The point of these new regulations was to phase-out HCFCs in much the same way that CFCs were phased out. HCFC-142b production in non article 5 countries like the United States was banned on January 1, 2020, under the Montreal Protocol. [6]

Production history

According to the Alternative Fluorocarbons Environmental Acceptability Study (AFEAS), in 2006 global production (excluding India and China who did not report production data) of HCFC-142b was 33,779 metric tons and an increase in production from 2006 to 2007 of 34%. [8]

For the most part, concentrations of HCFCs in the atmosphere match the emission rates that were reported by industries. The exception to this is HCFC-142b which had a higher concentration than the emission rates suggest it should. [9]

Environmental effects

Growth of HCFC-142b in Earth's atmosphere since year 1992. [10]
HCFC-142b 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-142b in the atmosphere grew to over 20 parts per trillion by year 2010. [10] It has an ozone depletion potential (ODP) of 0.07. [11] 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 by year 1985 (prior to introduction of HFC-142b and the Montreal Protocol).

HFC-142b is also a minor but potent greenhouse gas. It has an estimated lifetime of about 17 years and a 100-year global warming potential ranging 2300 to 5000. [12] [13] 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 Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  2. ^ "Safety Data Sheet for 1-Chloro-1,1-difluoroethane" (PDF). Archived from the original (PDF) on 24 October 2018. Retrieved 24 February 2018.
  3. ^ "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.
  4. ^ 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
  5. ^ "Phaseout of Class II Ozone-Depleting Substances". Environmental Protection Agency. 22 July 2015.
  6. ^ a b "Overview of HCFC Consumption and Available Alternatives For Article 5 Countries" (PDF). ICF International. 2008. Retrieved 2021-02-12.
  7. ^ U.S. Government Publishing Office Federal Register 2005 November 4, Protection of Stratospheric Ozone: Notice of Data Availability; Information Concerning the Current and Predicted Use of HCFC-22 and HCFC-142b Pages 67172 - 67174 [FR DOC # 05-22036].
  8. ^ "Production and Sales of Fluorocarbons - AFEAS". Archived from the original on 2015-09-28. Retrieved 2018-02-13.
  9. ^ "Good news from the stratosphere, sort of: Accumulating HCFCs won't stop ozone-hole mending". Archived from the original on 2016-03-03. Retrieved 2018-02-13.
  10. ^ a b "HCFC-142b". NOAA Earth System Research Laboratories/Global Monitoring Division. Retrieved 2021-02-12.
  11. ^ 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.
  12. ^ "Chapter 8". AR5 Climate Change 2013: The Physical Science Basis. p. 731.
  13. ^ "Refrigerants - Environmental Properties". The Engineering ToolBox. Retrieved 2016-09-12.
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