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Acetylene
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Acetylene
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C2H2
Acetylene

Physical Properties

Under solid (grey), liquid (blue) and vapor states (white) along the equilibrium curves

  • General properties
  • Solid phase
  • Liquid Phase
  • Gas Phase
(P)
log(P)
Download
  • Molecular weight
    26.037
    g/mol
  • Content in air
    /

Critical Point

  • Temperature
    35.75
    °C
    96.35 °F 308.9 K
  • Pressure
    61.38
    bar
    6.138E6 pa 890.2413 lbf/in2 60.5774 Atm 6138 Kpa 4.6039E4 mmHg
  • Density
    232.5
    kg/m³
    14.5145 lb/ft³

Triple Point

  • Temperature
    - 80.75
    °C
    - 113.35 °F 192.4 K
  • Pressure
    1.2745
    bar
    1.2745E5 pa 18.4843 lbf/in2 1.2578 Atm 127.445 Kpa 955.9188 mmHg
Pressure 1.013 bar
  • Melting point
    - 80.75
    °C
    - 113.35 °F 192.4 K
  • Latent heat of fusion (at melting point)
    144.79
    kJ/kg
    62.2903 Btu/lb 34.6056 kcal/kg
  • Solid density
    /
Pressure 1.013 bar
  • Liquid density (at sublimation point)
    622.723
    kg/m³
    38.8752 lb/ft³
  • Boiling point (sublimation point)
    - 84.7
    °C
    - 120.46 °F 188.45 K
  • Latent heat of vaporization (at boiling point)
    /
Pressure1.013barTemperature
  • Compressibility factor Z
    /
    /
    /
  • Cp/Cv ratio γ
    /
    /
    /
  • Dynamic viscosity
    9.3603E-5
    Po
    9.3603 µPa.s 9.3603E-6 PA.S 6.2898E-6 lb/ft/s
    9.8768E-5
    Po
    9.8768 µPa.s 9.8768E-6 PA.S 6.6369E-6 lb/ft/s
    1.0217E-4
    Po
    10.2174 µPa.s 1.0217E-5 PA.S 6.8658E-6 lb/ft/s
  • Gas density at boiling point
    1.729
    kg/m³
    1.0794E-1 lb/ft³
    1.729
    kg/m³
    1.0794E-1 lb/ft³
    1.729
    kg/m³
    1.0794E-1 lb/ft³
  • Gas density
    /
    /
    /
  • Heat capacity at constant pressure Cp
    /
    /
    1.6913
    kJ/(kg.K)
    4.0422E-1 BTU/lb∙°F 1691.266 J/kg∙K 4.0422E-1 kcal/kg∙K
  • Heat capacity at constant volume Cv
    /
    /
    /
  • Liquid (at boiling point)/gas equivalent
    /
    /
    /
  • Solubility in water
    /
    /
    /
  • Specific gravity
    /
    /
    /
  • Specific volume
    /
    /
    /
  • Thermal conductivity
    19.298
    mW/m∙K
    1.1158E-2 Btu/ft/h/°F 1.6604E-1 cal/hour∙cm∙°C 4.6123E-5 cal/s∙cm∙°C 1.9298E-2 W/(m∙K)
    20.976
    mW/m∙K
    1.2128E-2 Btu/ft/h/°F 1.8048E-1 cal/hour∙cm∙°C 5.0134E-5 cal/s∙cm∙°C 2.0976E-2 W/(m∙K)
    22.094
    mW/m∙K
    1.2774E-2 Btu/ft/h/°F 1.901E-1 cal/hour∙cm∙°C 5.2806E-5 cal/s∙cm∙°C 2.2094E-2 W/(m∙K)
  • Vapor pressure
    26.4968
    bar
    2.6497E6 pa 384.3034 lbf/in2 26.1503 Atm 2649.68 Kpa 1.9874E4 mmHg
    38.5665
    bar
    3.8567E6 pa 559.3596 lbf/in2 38.0622 Atm 3856.65 Kpa 2.8927E4 mmHg
    48.7024
    bar
    4.8702E6 pa 706.3683 lbf/in2 48.0655 Atm 4870.24 Kpa 3.653E4 mmHg
C2H2
Acetylene

Liquid / Gas Volumes

Calculate a liquid or gas volume or a mass

Liquid Phase

At boiling point at 1.013 bar

m3(Volume)
kg(Mass)

Gas Phase

at 1.013 bar and boiling point

m3(Volume)
kg(Mass)
C2H2
Acetylene

Applications

Examples of uses of this molecule in Industry and Healthcare

Professionnals & Craftsmen

Acetylene is used for localized or manual operations such as welding, brazing, cutting, straightening or heating.

Professionnals & Craftsmen

Electronic components

Acetylene is used as precursor for amorphous carbon hard mask in Plasma-Enhanced Chemical Vapor Deposition (PECVD). It also is a carbon source in some silicon carbo-nitride films.

Electronic components

Glass

Acetylene is used to lubricate the molds used in glass bottle manufacturing processes. A layer of fine soot is applied onto the glass mold, so that the glass article can be easily separated from the mold after cooling down.

Glass

Hospital care

Acetylene is a component of a gaseous mixture used for pulmonary function diagnosis test.

Hospital care

Laboratories & Research Centers

Acetylene is used as fuel gas in atomic absorption spectrophotometry.

Laboratories & Research Centers
C2H2
Acetylene

Safety

Information to safely use this molecule

  • Major hazards
  • Material compatibility
  • GHS02
    Flammable
  • GHS04
    Gas under pressure

Autoignition Temperature in Air at Patm and Flammability Limits in Air at Patm and 293.15 K (except if the temperature is indicated)

  • Europe (according to EN1839 for Limits and EN 14522 for autoignition temperature)

    • Auto-ignition temperature
      305
      °C
      581 °F 578.15 K
    • Flash point
      /
    • Lower flammability limit
      2.3
      vol/%
      2.3E4 ppm 2.3E4 ppm 2.3E-2 vol/vol
    • Upper flammability limit (due to the decomposition)
      100
      vol/%
      10.E5 ppm 10.E5 ppm 1 vol/vol
  • US (according to NFPA for Limits and ASTM E659 for autoignition temperature)

    • Auto-ignition temperature
      305
      °C
      581 °F 578.15 K
    • Flash point
      /
    • Lower flammability limit
      2.5
      vol/%
      2.5E4 ppm 2.5E4 ppm 2.5E-2 vol/vol
    • Upper flammability limit (due to the decomposition)
      100
      vol/%
      10.E5 ppm 10.E5 ppm 1 vol/vol

Odor

Garlic like

Metals

  • Aluminium
    Satisfactory
  • Brass
    Satisfactory
    non recommended if >70% cooper
  • Monel
    Satisfactory
  • Copper
    Not recommended
  • Ferritic Steel
    Satisfactory
  • Stainless steel
    Satisfactory
  • Zinc
    Satisfactory
  • Titanium
    no data

Plastics

  • Polytetrafluoroethylene
    Satisfactory
  • Polychlorotrifluoroethylene
    Satisfactory
  • Polyvinylidene fluoride
    Satisfactory
  • Polyvinyl chloride
    no data
  • Ethylene tetrafluoroethylene
    Satisfactory
  • Polycarbonate
    Acceptable
    be careful with the solvent used to packaged
  • Polyamide
    Acceptable
    significant loss of mass and be careful with impurities
  • Polypropylene
    Satisfactory

Elastomers

  • Buthyl (isobutene- isoprene) rubber
    Satisfactory
  • Nitrile rubber
    Not recommended
    significant loss of mass and be careful with impurities
  • Chloroprene
    Satisfactory
  • Chlorofluorocarbons
    Not recommended
    significant loss of mass and be careful with impurities
  • Silicon
    Not recommended
    significant loss of mass and be careful with impurities
  • Perfluoroelastomers
    Satisfactory
  • Fluoroelastomers
    Acceptable
    be careful with the solvent used to packaged
  • Nitrile rubber
    Acceptable
    be careful with the solvent used to packaged
  • Neoprene
    Satisfactory
    be careful with the solvent used to packaged
  • Polyurethane
    Satisfactory
    be careful with the solvent used to packaged
  • Ethylene-Propylene
    Satisfactory

Lubricants

  • Hydrocarbon based lubricant
    Not recommended
    significant loss of mass and be careful with impurities
  • Fluorocarbon based lubricant
    Not recommended
    significant loss of mass and be careful with impurities

Materials compatibility

Recommendations : Air Liquide has gathered data on the compatibility of gases with materials to assist you in evaluating which materials to use for a gas system. Although the information has been compiled from what Air Liquide believes are reliable sources (International Standards: Compatibility of cylinder and valve materials with gas content; Part 1- Metallic materials: ISO11114-1 (March 2012), Part 2 - Non-metallic materials: ISO11114-2 (April 2013), it must be used with extreme caution and engineering judgement. No raw data such as these can cover all conditions of concentration, temperature, humidity, impurities and aeration. It is therefore recommended that this table is only used to identify possible materials for applications at high pressure and ambient temperature. Extensive investigation and testing under the specific conditions of use need to be carried out to validate a material selection for a given application. Contact the regional Air Liquide team for expertise service.

C2H2
Acetylene

Learn More

General information

More information

Acetylene was discovered in 1836 by Sir Edmund Davy. Acetylene is a synthesis gas generally produced from the reaction of calcium carbide with water. It used to be burnt in "acetylene lamps" to light homes and mining tunnels in the 19th century. It is colorless, unstable, highly combustible and has a strong garlic odor. It produces a very hot flame (over 3000 °C or 5400 °F) when combined with oxygen. It has been widely used for oxy-cutting and welding metal materials until it was remplaced by arc-based welding processes using argon.