Ethylene - Thermophysical Properties (original) (raw)

Ethylene, C2H4 , is a highly flammable, colorless and noncorrosive gas with a sweet odor. It is easily ignited and a flame can easily flash back to the source of the leak. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. Can cause explosion. Vapors arising from the boiling liquid are lighter than air. Ethylene is not toxic, but is a simple asphyxiant.

Ethylene is used as an anesthetic, a refrigerant, and to make other chemicals as polymers and plastics.

Ethylene is produced in petrochemical processes, as steam cracking where hydrocarbons and steam are heated to 750–950 °C. This process converts large hydrocarbons into smaller ones and introduces unsaturated products.

The phase diagram of ethylene is shown below the table.

Chemical, physical and thermal properties of ethylene:
Values are given for gas phase at 25 oC /77 oF / 298 K and 1 bara, if not other phase, temperature or pressure given.

For full table with Imperial Units - rotate the screen!

Ethylene - Thermophysical Properties

Property Value Unit Value Unit Value Unit Value Unit
Autoignition temperature 723 K 450 °C 842 °F
Boiling Point 169 K -104 °C -155 °F
Critical density 7.63 mol/dm3 214 kg/m3 0.415 slug/ft3 13.4 lb/ft3
Critical pressure 5.06 MPa=MN/m2 50.6 bar 49.9 atm 734 psi=lbf /in2
Critical temperature 282.4 K 9.2 °C 48.6 °F
Critical volume 131 cm3 /mol 0.00467 m3 /kg 2.41 ft3 /slug 0.0748 ft3 /lb
Density 40.6 mol/m3 1.138 kg/m3 0.00221 slug/ft3 0.07104 lb/ft3
Density (liquid) at -104 °C/-155°F 20567 mol/m3 577 kg/m3 1.12 slug/ft3 36.0 lb/ft3
Flammable, gas and liquid yes highly
Flash point 137 K -136 °C -213 °F
Gas constant , individual, R 296.4 J/kg K 0.0823 Wh/(kg K) 1772 [ft lbf /slug °R] 55.08 [ft lbf /lb °R]
Gibbs free energy of formation (gas) 68 kJ/mol 2424 kJ/kg 1042 Btu/lb
Heat (enthalpy) of combustion (gas) -1411 kJ/mol -50303 kJ/kg -21626 Btu/lb
Heat (enthalpy) of formation (gas) 52.4 kJ/mol 1868 kJ/kg 803 Btu/lb
Heat (enthalpy) of evaporation at -104°C/-155°F 13.6 kJ/mol 483 kJ/kg 207.7 Btu/lb
Heat capacity , Cp (gas) 42.9 J/mol K 1.53 kJ/kg K 0.365 Btu/lb°F or cal/g K
Heat capacity, Cp (liquid) at -104°C/-155°F 67.4 J/mol K 2.40 kJ/kg K 0.574 Btu/lb°F or cal/g K
Heat capacity, Cv (gas) 34.6 J/mol K 1.24 kJ/kg K 0.295 Btu/lb°F or cal/g K
Heat capacity, Cv (liquid) at -104°C/-155°F 38.7 J/mol K 1.38 kJ/kg K 0.330 Btu/lb°F or cal/g K
Ionization potential 10.5 eV
log KOW (Octanol/Water Partition Coefficient) 1.13
Melting point 104.15 K -169.0 °C -272.2 °F
Molecular Weight 28.054 g/mol 0.06185 lb/mol
Solubility in water, at 25°C 0.131 mg/ml
Sound velocity 330 m/s 1082 ft/s 739 mi/h
Specific Gravity (gas) (relativ to air) 0.978
Specific Heat Ratio (gas) - CP /CV 1.24
Specific Heat Ratio (liquid) - CP /CV 1.74
Specific Volume 0.0247 m3 /mol 0.879 m3 /kg 453 ft3 /slug 14.1 ft3 /lb
Standard molar entropy , S° (gas) 219.32 J/mol K 7.82 kJ/kg K 1.87 Btu/lb °F
Standard molar entropy, S° (liquid) 117.8 J/mol K 4.20 kJ/kg K 1.00 Btu/lb °F
Surface tension at -104°C/-155°F 16.00 dynes/cm 0.016 N/m
Thermal Conductivity 0.020 W/m°C 0.0118 Btu/hr ft °F
Triple point pressure 0.000122 MPa=MN/m2 0.00122 bar 0.00120 atm 0.0177 psi=lbf /in2
Triple point temperature 104.0 K -169.16 °C -272.49 °F
Vapor (saturation) pressure 6.9449 MPa=MN/m2 5.21E+04 mm Hg 68.543 atm 1007.30 psi=lbf /in2
Viscosity , dynamic (absolute) 0.0103 cP 6.9 [lbm /ft s*10-6 ] 0.22 [lbf s/ft2*10-6 ]
Viscosity, kinematic 9.05 cSt 97.4 [ft2/s*10-6 ]

Follow the links below to get values for the listed properties of ethylene at varying pressure and temperature :

See also more about atmospheric pressure , and STP - Standard Temperature and Pressure & NTP - Normal Temperature and Pressure ,
as well as Thermophysical properties of: Acetone , Acetylene , Air , Ammonia , Argon , Benzene , Butane , Carbon dioxide , Carbon monoxide , Ethane , Ethanol , Helium , Hydrogen , Hydrogen sulfide , Methane , Methanol , Nitrogen , Oxygen , Pentane , Propane , Toluene , Water and Heavy water, D2O .

Ethylene is a gas at standard conditions. However, at low temperature and/or high pressures the gas becomes a liquid or a solid.

The ethylene phase diagram shows the phase behavior with changes in temperature and pressure. The curve between the critical point and the triple point shows the ethylene boiling point with changes in pressure. It also shows the saturation pressure with changes in temperature.

Ethylene phase diagram

At the critical point there is no change of state when pressure is increased or if heat is added.

The triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.

Chemical, physical and thermal properties of acetone, also called 2-propanone, dimethyl ketone and pyroacetic acid. Phase diagram included.

Chemical, Physical and Thermal Properties of Acetylene.

Thermal properties of air at different temperatures - density, viscosity, critical temperature and pressure, triple point, enthalpi and entropi, thermal conductivity and diffusivity and more.

Chemical, Physical and Thermal Properties of Ammonia. Phase diagram included.

Chemical, Physical and Thermal Properties of Argon.

Chemical, physical and thermal properties of n-Butane.

Chemical, physical and thermal properties of carbon dioxide. Phase diagram included.

Chemical, Physical and Thermal Properties of Carbon Monoxide - CO.

Conductive heat transfer takes place in a solid if there is a temperature gradient.

Critical temperatures and pressures for some common substances like air, alcohol, ether, oxygen and more.

An introduction to density, specific weight and specific gravity.

Chemical, Physical and Thermal Properties of Ethane - C2H6.

Chemical, physical and thermal properties of ethanol (also called alcohol or ethyl alcohol). Phase diagram included.

Online calculator, figures and tables showing density and specific weight of ethylene, C2H4, at varying temperature and pressure - Imperial and SI Units.

Online calculator, figures and tables showing dynamic and kinematic viscosity of ethylene, C2H4, also called ethene or acetene, at varying temperature and pressure - Imperial and SI Units.

Online calculator, figures and table showing thermal conductivity of ethylene, also called ethene or acetene, C2H4, at varying temperature and pressure - Imperial and SI Units.

Specific heat of Ethylene Gas - C2H4 - temperatures ranging 175 - 900 K.

The amount of heat required to change the temperature of a substance by one degree.

Thermodynamic properties of heavy water (D2O) like density, melting temperature, boiling temperature, latent heat of fusion, latent heat of evaporation, critical temperature and more.

Chemical, Physical and Thermal Properties of Helium - He.

Molweight, melting and boiling point, density, flash point and autoignition temperature, as well as number of carbon and hydrogen atoms in each molecule for 200 different hydrocarbons.

Autoignition temperatures and flash points (°C and °F) of different types of hydrocarbons with varying carbon numbers up to C12.

Boiling temperatures (°C and °F) with varying carbon numbers up to C33.

Chemical, Physical and Thermal Properties of Hydrogen - H2.

Chemical, physical and thermal properties of hydrogen sulfide, H2S, also called hydrosulfuric acid, sewer gas and stink damp. Phase diagram included.

Latent heat of vaporization for fluids like alcohol, ether, nitrogen, water and more.

Vapor and saturation pressure for some common liquids.

Chemical, Physical and Thermal Properties of Methane - CH4. Phase diagram included.

Chemical, physical and thermal properties of methanol, CH3OH (also called carbinol, wood alcohol, hydroxy methyl and methyl alcohol). Phase diagram included.

Definition and molecular weight (molar mass) of some common substances.

Chemical, Physical and Thermal Properties of Nitrogen - N2.

Chemical, Physical and Thermal Properties of Oxygen - O2.

Chemical, physical and thermal properties of pentane, also called n-pentane. Phase diagram included.

Chemical, physical and thermal properties of propane gas - C3H8.

The amount of a solute that can be dissolved in a solvent.

Calculate the speed of sound (the sonic velocity) in gases, fluids or solids.

Definition and explanation of the terms standard state and standard enthalpy of formation, with listing of values for standard enthalpy and Gibbs free energy of formation, as well as standard entropy and molar heat capacity, of 370 inorganic compounds.

The definition of STP - Standard Temperature and Pressure and NTP - Normal Temperature and Pressure.

Triple points for common substances.

Surface tension of liquids like water, mercury, oils and more.

The Universal and Individual Gas Constants in fluid mechanics and thermodynamics. Individual gas constants for the most common gases.

Vicosity is a fluid's resistance to flow and can be valued as dynamic (absolute) or kinematic.

Thermal properties of water at different temperatures like density, freezing temperature, boiling temperature, latent heat of melting, latent heat of evaporation, critical temperature and more.