Dichlorodifluoromethane

Source: Wikipedia, the free encyclopedia.
Dichlorodifluoromethane
Names
Preferred IUPAC name
Dichlorodi(fluoro)methane
Other names
  • Dichlorodifluoromethane
  • Carbon dichloride difluoride
  • Dichloro-difluoro-methane
  • Difluorodichloromethane
  • Freon 12
  • R-12
  • CFC-12
  • P-12
  • Propellant 12
  • Halon 122
  • Arcton 6
  • Arcton 12
  • E940
  • Fluorocarbon 12
  • Genetron 12
  • Refrigerant 12
Identifiers
3D model (
JSmol
)
ChEMBL
ChemSpider
ECHA InfoCard
 100.000.813 Edit this at Wikidata
EC Number
  • 200-893-9
E number E940 (glazing agents, ...)
KEGG
RTECS number
  • PA8200000
UNII
UN number 1028
  • InChI=1S/CCl2F2/c2-1(3,4)5 checkY
    Key: PXBRQCKWGAHEHS-UHFFFAOYSA-N checkY
  • InChI=1/CCl2F2/c2-1(3,4)5
    Key: PXBRQCKWGAHEHS-UHFFFAOYAX
  • ClC(Cl)(F)F
Properties
CCl2F2
Molar mass 120.91 g·mol−1
Appearance Colorless gas
Odor ether-like at very high concentrations
Density 1.486 g/cm3 (−29.8 °C (−21.6 °F))
Melting point −157.7 °C (−251.9 °F; 115.5 K)
Boiling point −29.8 °C (−21.6 °F; 243.3 K)
0.286 g/L at 20 °C (68 °F)
Solubility in alcohol, ether, benzene, acetic acid Soluble
log P 2.16
Vapor pressure 568 kPa (20 °C (68 °F))
0.0025 mol kg−1 bar−1
−52.2·10−6 cm3/mol
Thermal conductivity
 0.0097 W/(m·K) (300 K)[1]
Structure
Tetrahedral
0.51 D[2]
Hazards
GHS labelling:
GHS04: Compressed Gas GHS07: Exclamation mark
Warning
H280, H336, H420
P261, P271, P304+P340, P319, P403+P233, P405, P410+P403, P501, P502
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
0
0
Flash point Non-flammable[3]
Lethal dose or concentration (LD, LC):
760,000 ppm (mouse, 30 min)
800,000 ppm (rabbit, 30 min)
800,000 ppm (guinea pig, 30 min)
600,000 ppm (rat, 2 h)[4]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 1000 ppm (4950 mg/m3)[3]
REL (Recommended)
 TWA 1000 ppm (4950 mg/m3)[3]
IDLH
(Immediate danger)
 15000 ppm[3]
Supplementary data page
Dichlorodifluoromethane (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Dichlorodifluoromethane (R-12) is a colorless gas usually sold under the

solvents
. R-12 cylinders are colored white.

Preparation

It can be prepared by reacting carbon tetrachloride with hydrogen fluoride in the presence of a catalytic amount of antimony pentachloride:

CCl4 + 2HF → CCl2F2 + 2HCl

This reaction can also produce

tetrafluoromethane (CF4).[6]

History

DuPont and General Motors.[7]

Use as an aerosol

The use of chlorofluorocarbons as aerosols in medicine, such as

hydrofluoroalkane, or HFA, which was not known to harm the environment, was chosen to replace it.[8]

Retrofitting

R-12 was used in most refrigeration and vehicle air conditioning applications prior to 1994 before being replaced by

retrofitment to a refrigerant other than R-12 (most commonly R-134a which has a global warming potential 3,400 times that of carbon dioxide) is required in some jurisdictions. The United States does not require automobile owners to retrofit their systems; however, taxes on ozone-depleting chemicals coupled with the relative scarcity of the original refrigerants on the open market make retrofitting the only economical option. Retrofitment requires a system flush and a new filter/dryer or accumulator, and may also involve the installation of new seals and/or hoses made of materials compatible with the refrigerant being installed. Mineral oil used with R-12 is not compatible with R-134a. Some oils designed for conversion to R-134a are advertised as compatible with residual R-12 mineral oil. Another replacement for R-12 is the highly flammable, but truly drop-in HC-12a, whose flammability has led to injuries and deaths in a bus fire in 2006.[9][10]

Dangers

Aside from its environmental impacts, R12, like most chlorofluoroalkanes, forms phosgene gas when exposed to a naked flame.[11]

Properties

Table of thermal and physical properties of saturated liquid refrigerant 12:[12][13]

Temperature (°C) Density (kg/m^3) Specific heat (kJ/kg K) Kinematic viscosity (m^2/s) Conductivity (W/m K) Thermal diffusivity (m^2/s) Prandtl Number Bulk modulus (K^-1)
-50 1546.75 0.875 3.10E-07 0.067 5.01E-01 6.2 2.63E-03
-40 1518.71 0.8847 2.79E-07 0.069 5.14E-01 5.4 -
-30 1489.56 0.8956 2.53E-07 0.069 5.26E-01 4.8 -
-20 1460.57 0.9073 2.35E-07 0.071 5.39E-01 4.4 -
-10 1429.49 0.9203 2.21E-07 0.073 5.50E-01 4 -
0 1397.45 0.9345 2.14E-07 0.073 5.57E-01 3.8 -
10 1364.3 0.9496 2.03E-07 0.073 5.60E-01 3.6 -
20 1330.18 0.9659 1.98E-07 0.073 5.60E-01 3.5 -
30 1295.1 0.9835 1.94E-07 0.071 5.60E-01 3.5 -
40 1257.13 1.0019 1.91E-07 0.069 5.55E-01 3.5 -
50 1215.96 1.0216 1.90E-07 0.067 5.45E-01 3.5 -

Gallery

  • CFC-12 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.
    CFC-12 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.
  • Hemispheric and global mean CFC-12 concentrations (NOAA/ESRL)
    Hemispheric and global mean CFC-12 concentrations (NOAA/ESRL)
  • Time-series of atmospheric concentrations of CFC-12 (Walker et al., 2000)
    Time-series of atmospheric concentrations of CFC-12 (Walker et al., 2000)
  • 1990s sea surface CFC-12 concentration
    1990s sea surface CFC-12 concentration
  • 1990s CFC-12 oceanic vertical inventory
    1990s CFC-12 oceanic vertical inventory
  • CFC-12, CFC-11, H-1211 and SF6 vertical profiles
    CFC-12, CFC-11, H-1211 and SF6 vertical profiles

References

  1. ^ Touloukian, Y. S., Liley, P. E., and Saxena, S. C. Thermophysical properties of matter – the TPRC data series. Volume 3. Thermal conductivity – nonmetallic liquids and gases. Data book. 1970.
  2. ISBN 3642719481
    .
  3. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0192". National Institute for Occupational Safety and Health (NIOSH).
  4. ^ "Dichlorodifluoromethane". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  5. ISBN 978-1-7329317-1-8
    . Retrieved 22 November 2020.
  6. ISBN 978-0-08-037941-8
    .
  7. ISBN 978-94-011-7073-4
    .
  8. ^ "Asthma inhaler replacements coming to Pa. - Pittsburgh Tribune-Review". 16 February 2007. Archived from the original on 16 February 2007. Retrieved 26 April 2022.
  9. ^ "Se cumplen 13 años de la Tragedia de la Cresta". Ensegundos.com.pa. 23 October 2019.
  10. ^ "Victims of the La Cresta tragedy were remembered". M.metrolibra.com. Retrieved 26 April 2022.
  11. ^ "False Alarms: The Legacy of Phosgene Gas". HVAC School. 4 January 2021. Retrieved 9 May 2022.
  12. ISBN 9780072406559
    .
  13. ISBN 9780471457282.{{cite book}}: CS1 maint: numeric names: authors list (link
    )

External links
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