Isobutane

C₄H₁₀
CAS Number 75-28-5
UN1969 (gas)

Molecule
Properties
Applications
Safety & Compatibility

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Liquid / Gas Volumes

Calculate the volume or mass of a quantity of gas or liquid

Liquid Phase

At boiling point at 1.013 bar

m³ (Volume)

kg (Mass)

Gas Phase

In standard conditions (1.013 bar, 15°C)

m³ (Volume)

kg (Mass)

Physical Properties

Download the set of data (XLS - 78.26 KB)

General Properties
Solid Phase
Liquid Phase
Gas Phase

Molecule phase diagram showing the transition phases between solid, liquid and gas as a function of temperature and pressure

Pressure (bar)

- Molar mass 58.122 g/mol
- Content in dry air /
Critical Point
- Temperature 134.65 °C
- Pressure 36.4 bar
- Density 224.41 kg/m³
Triple Point
- Temperature -159.42 °C
- Pressure 1.206E-7 bar

Pressure 1.013 bar

Latent heat of fusion (at melting point)	78.112 kJ/kg
Melting point	- 159.61 °C

Pressure 1.013 bar

Boiling point	- 11.75 °C
Latent heat of vaporization (at boiling point)	365.101 kJ/kg
Liquid density (at boiling point)	593.821 kg/m³

Pressure 1.013 bar

0 °C
15 °C
25 °C

Compressibility factor Z	9.6446E-1
Cp/Cv ratio γ	1.1185
Gas density (at boiling point)	2.826 kg/m³
Gas density	2.688 kg/m³
Gas/(liquid at boiling point) equivalent	220.92 vol/vol
Heat capacity Cp	1.5902 kJ/(kg.K)
Heat capacity Cv	1.4218 kJ/(kg.K)
Specific volume	3.72E-1 m³/kg
Thermal conductivity	14.343 mW/(m.K)
Vapor pressure	1.577 bar
Viscosity	6.8759E-5 Po

Compressibility factor Z	9.7035E-1
Cp/Cv ratio γ	1.11
Gas density	2.5326 kg/m³
Gas/(liquid at boiling point) equivalent	234.47 vol/vol
Heat capacity Cp	1.6503 kJ/(kg.K)
Heat capacity Cv	1.4867 kJ/(kg.K)
Solubility in water	2.333E-5 mol/mol
Specific volume	3.949E-1 m³/kg
Thermal conductivity	15.85 mW/(m.K)
Vapor pressure	2.598 bar
Viscosity	7.2505E-5 Po

Compressibility factor Z	9.7354E-1
Cp/Cv ratio γ	1.1052
Gas density	2.4397 kg/m³
Gas/(liquid at boiling point) equivalent	243.4 vol/vol
Heat capacity Cp	1.6923 kJ/(kg.K)
Heat capacity Cv	1.5312 kJ/(kg.K)
Solubility in water	4.659E-5 mol/mol
Specific volume	4.099E-1 m³/kg
Thermal conductivity	16.887 mW/(m.K)
Vapor pressure	3.512 bar
Viscosity	7.4978E-5 Po

Applications

Examples of uses of this molecule in Industry and Healthcare

Laboratories & Research Centers

In mixture with argon, isobutane is used in Geiger counter and for the detector in X ray fluorescence as quentching gas. Isobutane is also used as reagent gas in chemical ionization mass spectrometry. In mixture with other hydrocarbons, isobutane is used as reference point in calorimetric measurements for the measurement of LHV of hydrocarbons. Isobutane is used in calibration gas mixtures for petrochemical industry, environmental emission monitoring, industrial hygiene monitors and trace impurity analyzers.

Other

Isobutane is used as a propellant, a solvent or a refrigerant.

Safety & Compatibility

Major Hazards
Material Compatibility

Autoignition Temperature, Flammability Limits & Flash Point

Europe (according to EN1839 for Limits and EN 14522 for autoignition temperature)

Autoignition temperature (Chemsafe)	460 °C
Lower flammability limit (IEC 80079-20-1)	1.5 vol%
Upper flammability limit (IEC 80079-20-1)	9.4 vol%

US (according to ASTM E681 for Limits and ASTM E659 for autoignition temperature)

Autoignition temperature (NFPA 325)	460 °C
Lower flammability limit (NFPA 325)	1.8 vol%
Upper flammability limit (NFPA 325)	8.4 vol%

Metals

Aluminium	Satisfactory
Brass	Satisfactory
Monel	No data
Copper	No data
Ferritic Steel	Satisfactory
Stainless steel	Satisfactory
Zinc	No data
Titanium	No data

Plastics

Polytetrafluoroethylene	Satisfactory
Polychlorotrifluoroethylene	Satisfactory
Polyvinylidene fluoride	Satisfactory
Polyvinyl chloride	Satisfactory
Ethylene tetrafluoroethylene	No data
Polycarbonate	No data
Polyamide	Satisfactory
Polypropylene	Satisfactory

Elastomers

Butyl (isobutene- isoprene) rubber	significant swelling Not recommended
Nitrile rubber	Satisfactory
Chloroprene	Satisfactory
Chlorofluorocarbons	No data
Silicone	significant swelling and modification of the properties of the material Not recommended
Perfluoroelastomers	Satisfactory
Fluoroelastomers	Satisfactory
Neoprene	No data
Polyurethane	Satisfactory
Ethylene-Propylene	significant swelling and modification of the properties of the material Not recommended

Lubricants

Hydrocarbon based lubricant	significant loss of mass Not recommended
Fluorocarbon based lubricant	Satisfactory

Materials compatibility

Recommendations : Air Liquide has gathered data on the compatibility of gases with materials to assist you in evaluating which materials to use for a gas system. Although the information has been compiled from what Air Liquide believes are reliable sources (International Standards: Compatibility of cylinder and valve materials with gas content; Part 1- Metallic materials: ISO11114-1 (March 2012), Part 2 - Non-metallic materials: ISO11114-2 (April 2013), it must be used with extreme caution and engineering judgement. No raw data such as these can cover all conditions of concentration, temperature, humidity, impurities and aeration. It is therefore recommended that this table is only used to identify possible materials for applications at high pressure and ambient temperature. Extensive investigation and testing under the specific conditions of use need to be carried out to validate a material selection for a given application. Contact the regional Air Liquide team for expertise service.