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Ethanol - Thermophysical properties

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

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Ethanol, C2H5-OH, is a volatile, flammable, colorless liquid with a slight characteristic odor. It is produced via petrochemical processes or naturally by the fermentation of sugars by yeasts.

Ethanol is most commonly consumed as a popular recreational drug. It is a psychoactive substance and is the principal type of alcohol found in alcoholic drinks. It also has medical applications as an antiseptic and disinfectant. The compound is widely used as a chemical solvent, either for scientific chemical testing or in synthesis of other organic compounds. Ethanol is also used as a clean-burning fuel source.

The phase diagram of ethanol is shown below the table.

Chemical, physical and thermal properties of ethanol:
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
Acidity (pKa1) 15.9
Autoignition temperature 636 K 363 °C 685 °F
Boiling Point 351.39 K 78.2 °C 172.8 °F
Critical density 5.91 mol/dm3 272 kg/m3 0.528 slug/ft3 17.0 lb/ft3
Critical Pressure 6.25 MPa=MN/m2 62.5 bara 61.7 atm 906 psia=lbf/in2
Critical temperature 513.9 K 240.8 °C 465.4 °F
Critical Volume 169 cm3/mol 0.00367 m3/kg 1.89 ft3/slug 0.0588 ft3/lb
Density (gas) at 0.08 bar 3.15 mol/m3 0.145 kg/m3 0.00028 slug/ft3 0.0091 lb/ft3
Density (liquid) 17046 mol/m3 785.3 kg/m3 1.524 slug/ft3 49.02 lb/ft3
Flammable (gas and liquid) yes
Flash point 286 K 13 °C 55 °F
Gas constant (individual) - R 180.5 J/kg K 0.05013 Wh/(kg K) 1079 [ft lbf/slug °R] 33.54 [ft lbf/lb °R]
Gibbs free energy of formation (gas) -168 kJ/mol -3647 kJ/kg -1568 Btu/lb
Heat capacity, Cp (isobaric) (gas) 74 J/mol K 1.60 kJ/kg K 0.383 Btu/lb°F or cal/g K
Heat capacity, Cp (liquid) 118 J/mol K 2.57 kJ/kg K 0.614 Btu/lb°F or cal/g K
Heat capacity, Cv (isochoric) (gas) 65 J/mol K 1.42 kJ/kg K 0.339 Btu/lb°F or cal/g K
Heat capacity, Cv (liquid) 100 J/mol K 2.18 kJ/kg K 0.520 Btu/lb°F or cal/g K
Heat (enthalpy) of combustion (gas) 1336.8 kJ/mol 29017 kJ/kg 12.5 Btu/lb
Heat (enthalpy) of formation (gas) -234 kJ/mol -5079 kJ/kg -2184 Btu/lb
Heat (enthalpy) of fusion at -173°F/-114°C 4.9 kJ/mol 106 kJ/kg 45.73 Btu/lb
Heat (enthalpy) of evaporation 42.32 kJ/mol 919 kJ/kg 394.94 Btu/lb
Ionization potential 10.47 eV
log KOW (Octanol/Water Partition Coefficient) -0.31
Melting point 159.01 K -114.1 °C -173.5 °F
Molecular Weight 46.069 g/mol 0.10156 lb/mol
Solubility in water 1000 mg/ml
Sound velocity in liquid 1139 m/s 3736 ft/s 2551 mi/h
Sound velocity in gas, at 0.08 bara 246 m/s 807 ft/s 551 mi/h
Specific Gravity (gas) (relativ to air) 1.59
Specific Gravity (liquid) (relativ to water) 0.79
Specific Heat Ratio (gas) - Cp/Cv 1.13
Specific Heat Ratio (liquid) - Cp/Cv 1.18
Specific Volume (gas), at 0.08 bar 0.318 m3/mol 6.90 m3/kg 3554 ft3/slug 110 ft3/lb
Specific Volume, (liquid) 0.0000587 m3/mol 0.00127 m3/kg 0.656 ft3/slug 0.0204 ft3/lb
Standard molar entropy, S° (gas) 283 J/mol K 6.14 kJ/kg K 1.47 Btu/lb °F
Standard molar entropy, S° (liquid) 160 J/mol K 3.47 kJ/kg K 0.83 Btu/lb °F
Surface tension 21.97 dynes/cm 0.02197 N/m
Thermal Conductivity 0.167 W/m K 0.0965 Btu/hr ft °F
Triple point pressure 4.3x10-10 MPa=MN/m2 4.3x10-9 bara 4.24x10-9 atm 6.24x10-8 psia=lbf/in2
Triple point temperature 150.00 K -123.15 °C -189.67 °F
Vapor (saturation) pressure 0.008 MPa=MN/m2 60.0 mm Hg 0.0790 atm 1.16 psi=lbf/in2
Viscosity, dynamic (absolute) 1.074 cP 721.7 [lbm /ft s*10-6] 22.43 [lbf s/ft2 *10-6]
Viscosity, kinematic 1.36 cSt 14.6 [ft2/s*10-6]

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

Ethanol is a liquid at standard conditions. However, at low temperature and/or very high pressures it becomes a solid.

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

Ethanol phase diagram C

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.

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

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