Chemical, physical and thermal properties of ethylene, also called ethylene, acetene and olefiant gas. Phase diagram included.
You have visited, C 2 H 4 , It is a highly flammable, colorless, non-corrosive gas with a sweet odor. It is easily ignited and a flame can easily return to the source of the leak. Under prolonged exposure to fire or heat, containers may violently rupture and explode. It can cause an explosion. Vapors from the boiling liquid are lighter than air. Ethylene is not toxic, but it is a simple asphyxiant.
Ethylene is used as an anesthetic, coolant, and to make other chemicals like polymers and plastics.
Ethylene is produced in petrochemical processes such 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 the gas phase at 25 O C /77 O F/298 K and 1 bara if not other indicated phase, temperature or pressure.
| Property | Valor | Unit | Valor | Unit | Valor | Unit | Valor | Unit | |||
| auto-ignition temperature | 723 | iso-15552-srie-ke | 450 | °C | 842 | °F | |||||
| Boiling point | 169 | iso-15552-srie-ke | -104 | °C | -155 | °F | |||||
| critical density | 7,63 | mol/dm 3 | 214 | kg/ m3 | 0,415 | slug/foot 3 | 13,4 | lb/ft 3 | |||
| critical pressure | 5.06 | MPa=MN/ m2 | 50,6 | bar | 49,9 | cash machine | 734 | psi = lb f /in 2 | |||
| Critical temperature | 282,4 | iso-15552-srie-ke | 9.2 | °C | 48,6 | °F | |||||
| critical volume | 131 | cm3 / mol | 0,00467 | m3 / kg | 2,41 | foot 3 /slug | 0,0748 | foot 3 /lb | |||
| Density | 40,6 | mol / m3 | 1.138 | kg/ m3 | 0,00221 | slug/foot 3 | 0,07104 | lb/ft 3 | |||
| Density (liquid) at -104°C/-155°F | 20567 | mol / m3 | 577 | kg/ m3 | 1.12 | slug/foot 3 | 36,0 | lb/ft 3 | |||
| Flammable, gas and liquid | sim | highly | |||||||||
| Flash point | 137 | iso-15552-srie-ke | -136 | °C | -213 | °F | |||||
| Gas constant , individual, R | 296,4 | J/kg K | 0,0823 | Wh/(kg K) | 1772 | [ft lb f /slug °R] | 55,08 | [ft lb f /lb °R] | |||
| Gibbs formation free energy (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 ou 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 ou cal/g K | |||||
| Heat capacity, Cv (gas) | 34,6 | J/mol K | 1,24 | kJ/kg K | 0,295 | Btu/lb°F ou 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 ou cal/g K | |||||
| ionization potential | 10,5 | eV | |||||||||
| log K OW (Octanol/Water Partition Coefficient) | 1.13 | ||||||||||
| Fusion point | 104,15 | iso-15552-srie-ke | -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 | |||||||||
| Speed of sound | 330 | EM | 1082 | pes/s | 739 | wed/h | |||||
| Specific Gravity (gas) (relative to air) | 0,978 | ||||||||||
| Specific Heat Ratio (gas) - C P /C V | 1,24 | ||||||||||
| Specific Heat Ratio (net) - C P /C V | 1,74 | ||||||||||
| specific volume | 0,0247 | m3 / mol | 0,879 | m3 / kg | 453 | foot 3 /slug | 14.1 | foot 3 /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° (net) | 117,8 | J/mol K | 4,20 | kJ/kg K | 1,00 | Btu/lb °F | |||||
| Surface tension at -104°C/-155°F | 16h00 | dinas/cm | 0,016 | N/m | |||||||
| thermal conductivity | 0,020 | A/m°C | 0,0118 | Btu/h ft °F | |||||||
| triple point pressure | 0,000122 | MPa=MN/ m2 | 0,00122 | bar | 0,00120 | cash machine | 0,0177 | psi = lb f /in 2 | |||
| triple point temperature | 104,0 | iso-15552-srie-ke | -169,16 | °C | -272,49 | °F | |||||
| Vapor pressure (saturation) | 6,9449 | MPa=MN/ m2 | 5.21E+04 | mm Hg | 68.543 | cash machine | 1007,30 | psi = lb f /in 2 | |||
| Viscosity, dynamics (absolute) | 0,0103 | cP | 6.9 | [lb m /feet*10 -6 ] | 0,22 | [lbf s /foot 2 *10 -6 ] | |||||
| Kinematic viscosity | 9,05 | cSt | 97,4 | [foot 2 /s*10 -6 ] |
Ethylene is a gas under standard conditions. However, at low temperatures and/or high pressures, the gas becomes liquid or 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 boiling point of ethylene with changes in pressure. It also shows saturation pressure with changes in temperature.
No critical point there is no change of state when pressure is increased or heat is added.
THE triple stitch of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.
Source: https://www.engineeringtoolbox.com/ethylene-ethene-C2H4-properties-d_2104.html
