Benzene - Thermophysical properties
Chemical, physical and thermal properties of benzene, also called benzol. Phase diagram included.
Benzene, C6H6, is a clear colorless to light-yellow liquid, flammable with a petroleum-like, aromatic odor.
Benzene is less dense than water and is slightly soluble in water . Hence it floats on water . Benzene vapor is heavier than air. Benzene causes central nervous system damage acutely and bone marrow damage chronically and is carcinogenic. It was formerly used as parasiticide.
Benzene is present in crude oils and is a product of oil-refining processes. There are limitations on the content of benzene in gasoline. In industry benzene is used as a solvent, as a chemical intermediate, and is used in the synthesis of numerous chemicals.
The phase diagram of benzene is shown below the table.
Chemical, physical and thermal properties of benzene :
Values are given for liquid 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!
| Property | Value | Unit | Value | Unit | Value | Unit | Value | Unit | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Autoignition temperature | 771 | K | 498 | °C | 928 | °F | |||||
| Boiling Point | 353.2 | K | 80.08 | °C | 176.1 | °F | |||||
| Critical density | 4.00 | mol/dm3 | 312 | kg/m3 | 0.606 | slug/ft3 | 19.5 | lb/ft3 | |||
| Critical pressure | 4.89 | MPa=MN/m2 | 48.9 | bar | 48.3 | atm | 709 | psi=lbf/in2 | |||
| Critical temperature | 562.0 | K | 288.9 | °C | 551.9 | °F | |||||
| Critical volume | 250 | cm3/mol | 0.00320 | m3/kg | 1.65 | ft3/slug | 0.0513 | ft3/lb | |||
| Density | 11185 | mol/m3 | 873.7 | kg/m3 | 1.695 | slug/ft3 | 54.54 | lb/ft3 | |||
| Flammable, gas and liquid | yes | ||||||||||
| Flash point | 262 | K | -11 | °C | 12 | °F | |||||
| Gas constant, individual, R | 106.4 | J/kg K | 0.02957 | Wh/(kg K) | 636.5 | (ft lbf/slug °R) | 19.78 | (ft lbf/lb °R) | |||
| Gibbs free energy of formation (gas) | 130 | kJ/mol | 1664 | kJ/kg | 716 | Btu/lb | |||||
| Heat (enthalpy) of combustion (liquid) | -3267.6 | kJ/mol | -41832 | kJ/kg | -18.0 | Btu/lb | |||||
| Heat (enthalpy) of formation (gas) | 82.9 | kJ/mol | 1061 | kJ/kg | 456 | Btu/lb | |||||
| Heat (enthalpy) of formation (liquid) | 49 | kJ/mol | 627 | kJ/kg | 270 | Btu/lb | |||||
| Heat (enthalpy) of fusion at 42°F/5.85°C | 9.9 | kJ/mol | 127 | kJ/kg | 54.49 | Btu/lb | |||||
| Heat (enthalpy) of sublimation, at 42°F/5.85°C | 45 | kJ/mol | 576 | kJ/kg | 248 | Btu/lb | |||||
| Heat (enthalpy) of evaporation | 33.8 | kJ/mol | 433 | kJ/kg | 186 | Btu/lb | |||||
| Specific heat capacity, Cp (gas) | 82.4 | J/mol K | 1.05 | kJ/kg K | 0.252 | Btu/lb°F or cal/g K | |||||
| Specific heat capacity, Cp (liquid) | 133 | J/mol K | 1.70 | kJ/kg K | 0.407 | Btu/lb°F or cal/g K | |||||
| Specific heat capacity, Cp (solid) at 32°F/0°C | 118 | J/mol K | 1.51 | kJ/kg K | 0.361 | Btu/lb°F or cal/g K | |||||
| Specific heat capacity, Cv (liquid) | 92.8 | J/mol K | 1.19 | kJ/kg K | 0.284 | Btu/lb°F or cal/g K | |||||
| Ionization potential | 9.24 | eV | |||||||||
| log KOW (Octanol/Water Partition Coefficient) | 2.13 | ||||||||||
| Melting point | 278.708 | K | 5.6 | °C | 42.0 | °F | |||||
| Molecular Weight | 78.112 | g/mol | 0.17221 | lb/mol | |||||||
| Solubility in water, at 25°C | 1.79 | mg/ml | |||||||||
| Sound velocity | 1330 | m/s | 4362 | ft/s | 2979 | mi/h | |||||
| Specific Gravity (gas) (relativ to air) | 2.77 | ||||||||||
| Specific Gravity (liquid) (relativ to water) | 0.88 | ||||||||||
| Specific Heat Ratio (liquid) - CP/CV | 1.43 | ||||||||||
| Specific Volume | 0.0000894 | m3/mol | 0.00114 | m3/kg | 0.590 | ft3/slug | 0.0183 | ft3/lb | |||
| Standard molar entropy, S° (gas) | 269 | J/mol K | 3.44 | kJ/kg K | 0.82 | Btu/lb °F | |||||
| Standard molar entropy, S° (liquid) | 173 | J/mol K | 2.21 | kJ/kg K | 0.53 | Btu/lb °F | |||||
| Standard molar entropy, S° (solid), at 1 bara | 45.56 | J/mol K | 0.58 | kJ/kg K | 0.14 | Btu/lb °F | |||||
| Surface tension | 28.2 | dynes/cm | 0.02822 | N/m | |||||||
| Thermal Conductivity | 0.143 | W/m°C | 0.0826 | Btu/hr ft °F | |||||||
| Triple point pressure | 4.80E-03 | MPa=MN/m2 | 4.80E-02 | bar | 4.74E-02 | atm | 6.96E-01 | psi=lbf/in2 | |||
| Triple point temperature | 278.7 | K | 5.6 | °C | 41.99 | °F | |||||
| Vapor (saturation) pressure | 0.0128 | MPa=MN/m2 | 96 | mm Hg | 0.126 | atm | 1.86 | psi=lbf/in2 | |||
| Viscosity, dynamic (absolute) | 0.6040 | cP | 405.9 | (lbm/ft s ×10-6) | 12.61 | (lbf s/ft2 ×10-6) | |||||
| Viscosity, kinematic | 0.691 | cSt | 7.4 | (ft2/s ×10-6) |
See also the following documents for changes in benzene properties with changes in 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, Butane, Carbon dioxide, Carbon monoxide, Ethane, Ethanol, Ethylene, Helium, Hydrogen, Hydrogen sulfide, Methane, Methanol, Nitrogen, Oxygen, Pentane, Propane, Toluene, Water and Heavy water, D2O.
Benzene is a liquid at standard conditions. However, if heated it becomes a gas, and when cooled it becomes a solid. The phase diagram for benzene shows the phase behavior with changes in temperature and pressure. The curve between the critical point and the triple point shows the benzene boiling point with changes in pressure. It also shows the saturation pressure with changes in temperature.
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.
