Pentane – Thermophysical Properties
Chemical, physical and thermal properties of pentane, also called n-pentane. Phase diagram included.
Pentane, C5H12, is a clear colorless liquid with a petroleum-like odor. It belongs to the organic class alkanes, and is naturally present in crude oils and condensates. It is a component of some fuels and is employed as a specialty solvent in the laboratory.
The boling point 36°C/97°F, and the vapors are heavier than air. Both the liquid an the vapor are flammable.
The phase diagram of pentane is shown below the table.
Chemical, physical and thermal properties of pentane:
Values are given for liquid at 25oC /77oF / 298 K and 1 bara, if not other phase, temperature or pressure given.
| Property | Value | Unit | | Value | Unit | | Value | Unit | | Value | Unit |
| Autoignition temperature | 533 | K | | 260 | °C | | 500 | °F | | | |
| Boiling Point | 309.2 | K | 36.06 | °C | 96.9 | °F | | |
| Critical density | 3.22 | mol/dm3 | 232 | kg/m3 | 0.45 | slug/ft3 | 14.5 | lb/ft3 |
| Critical pressure | 3.36 | MPa=MN/m2 | 33.6 | bar | 33.2 | atm | 487 | psi=lbf/in2 |
| Critical temperature | 469.8 | K | 196.7 | °C | 386 | °F | | |
| Critical volume | 311 | cm3/mol | 0.00431 | m3/kg | 2.22 | ft3/slug | 0.069 | ft3/lb |
| Density | 8606 | mol/m3 | 620.9 | kg/m3 | 1.205 | slug/ft3 | 38.76 | lb/ft3 |
| Flammable, gas and liquid | yes | | | | | | | |
| Flash point | 224 | K | -49 | °C | -56 | °F | | |
| Gas constant, individual, R | 115.2 | J/kg K | 0.03201 | Wh/(kg K) | 689.1 | [ft lbf/slug °R] | 21.42 | [ft lbf/lb °R] |
| Gibbs free energy of formation (gas) | -8 | kJ/mol | -111 | kJ/kg | -48 | Btu/lb | | |
| Heat (enthalpy) of combustion (gas) | -3535 | kJ/mol | -48996 | kJ/kg | -21.1 | Btu/lb | | |
| Heat (enthalpy) of combustion (liquid) | -3509 | kJ/mol | -48636 | kJ/kg | -20.9 | Btu/lb | | |
| Heat (enthalpy) of formation (gas) | -147 | kJ/mol | -2037 | kJ/kg | -876 | Btu/lb | | |
| Heat (enthalpy) of formation (liquid) | -173 | kJ/mol | -2398 | kJ/kg | -1031 | Btu/lb | | |
| Heat (enthalpy) of fusion at -202 °F/-130°C | 8.4 | kJ/mol | 116 | kJ/kg | 50.05 | Btu/lb | | |
| Heat (enthalpy) of sublimation, at -202°F/-130°C | 42 | kJ/mol | 582 | kJ/kg | 250 | Btu/lb | | |
| Heat (enthalpy) of evaporation | 26.4 | kJ/mol | 366 | kJ/kg | 157 | Btu/lb | | |
| Heat capacity, Cp (gas) | 120 | J/mol K | 1.66 | kJ/kg K | 0.397 | Btu/lb°F or cal/g K | | |
| Specific heat, Cp (liquid) | 168 | J/mol K | 2.33 | kJ/kg K | 0.556 | Btu/lb°F or cal/g K | | |
| Specific heat, Cv (liquid) | 125 | J/mol K | 1.73 | kJ/kg K | 0.414 | Btu/lb°F or cal/g K | | |
| Ionization potential | 10.34 | eV | | | | | | |
| log KOW (Octanol/Water Partition Coefficient) | 3.39 | | | | | | | |
| Melting point | 143.48 | K | -129.7 | °C | -201.4 | °F | | |
| Molecular Weight | 72.149 | g/mol | | | 0.15906 | lb/mol | | |
| Solubility in water, at 25°C | 0.038 | mg/ml | | | | | | |
| Sound velocity | 1012 | m/s | | | 3319 | ft/s | 2267 | mi/h |
| Specific Gravity (gas) (relativ to air) | 2.48 | | | | | | | |
| Specific Gravity (liquid) (relativ to water) | 0.63 | | | | | | | |
| Specific Heat Ratio (gas) – CP/CV | 1.09 | | | | | | | |
| Specific Heat Ratio (liquid) – CP/CV | 1.34 | | | | | | | |
| Specific Volume | 0.0001162 | m3/mol | 0.0016106 | m3/kg | 0.8300514 | ft3/slug | 0.0257988 | ft3/lb |
| Standard molar entropy, S° (gas) | 348 | J/mol K | 4.82 | kJ/kg K | 1.15 | Btu/lb °F | | |
| Standard molar entropy, S° (liquid) | 263 | J/mol K | 3.65 | kJ/kg K | 0.87 | Btu/lb °F | | |
| Surface tension | 16 | dynes/cm | 0.016 | N/m | | | | |
| Thermal Conductivity | 0.111 | W/m°C | 0.064135 | Btu/hr ft °F | | | | |
| Triple point pressure | 7.63*10-8 | MPa=MN/m2 | 7.63*10-7 | bar | 7.53*10-7 | atm | 1.11*10-5 | psi=lbf/in2 |
| Triple point temperature | 143.5 | K | -129.7 | °C | -201.46 | °F | | |
| Vapor (saturation) pressure | 0.0685 | MPa=MN/m2 | 514 | mm Hg | 0.6762 | atm | 9.94 | psi=lbf/in2 |
| Viscosity, dynamic (absolute) | 0.2224 | cP | 149.4 | [lbm /ft s*10-6] | 4.64 | [lbf s/ft2 *10-6] | | |
| Viscosity, kinematic | 0.358 | cSt | 3.9 | [ft2/s*10-6] | | | | |