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Skeletal formula of butane with all implicit hydrogens shown
Skeletal formula of butane with all carbon and hydrogen atoms shown
Ball-and-stick model of the butane molecule
Space-filling model of the butane molecule
Preferred IUPAC name
Systematic IUPAC name
Tetracarbane (never recommended[3])
Other names
Butyl hydride;[1] Quartane;[2] Refrigerant 3-11-0
3D model (JSmol)
ECHA InfoCard 100.003.136 Edit this at Wikidata
EC Number
  • 203-448-7
E number E943a (glazing agents, ...)
MeSH butane
RTECS number
  • EJ4200000
UN number 1011
  • InChI=1S/C4H10/c1-3-4-2/h3-4H2,1-2H3 checkY
  • CCCC
Molar mass 58.124 g·mol−1
Appearance Colorless gas
Odor Gasoline-like or natural gas-like[1]
Density 2.48 kg/m3 (at 15 °C (59 °F))
Melting point −140 to −134 °C; −220 to −209 °F; 133 to 139 K
Boiling point −1 to 1 °C; 30 to 34 °F; 272 to 274 K
61 mg/L (at 20 °C (68 °F))
log P 2.745
Vapor pressure ~170 kPa at 283 K [4]
11 nmol Pa−1 kg−1
Conjugate acid Butanium
−57.4·10−6 cm3/mol
98.49 J/(K·mol)
−126.3–−124.9 kJ/mol
−2.8781–−2.8769 MJ/mol
GHS labelling:
GHS02: Flammable GHS04: Compressed Gas
NFPA 704 (fire diamond)
Flash point −60 °C (−76 °F; 213 K)
405 °C (761 °F; 678 K)
Explosive limits 1.8–8.4%
NIOSH (US health exposure limits):
PEL (Permissible)
REL (Recommended)
TWA 800 ppm (1900 mg/m3)[1]
IDLH (Immediate danger)
1600 ppm[1]
Related compounds
Related alkanes
Related compounds
Supplementary data page
Butane (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Butane (/ˈbjuːtn/) or n-butane is an alkane with the formula C4H10. Butane is a highly flammable, colorless, easily liquefied gas that quickly vaporizes at room temperature and pressure. The name butane comes from the root but- (from butyric acid, named after the Greek word for butter) and the suffix -ane. It was discovered in crude petroleum in 1864 by Edmund Ronalds, who was the first to describe its properties,[6][7] and commercialized by Walter O. Snelling in early 1910s.

Butane is one of a group of liquefied petroleum gases (LP gases). The others include propane, propylene, butadiene, butylene, isobutylene, and mixtures thereof. Butane burns more cleanly than gasoline and coal.


The first accidental synthesis of butane was achieved by British chemist Edward Frankland in 1849 from ethyl iodide and zinc, but he hadn't realized that the ethyl radical dimerized and misidentified the substance.[8]

The proper discoverer of the butane called it "hydride of butyl",[9] but already in the 1860s more names were used: "butyl hydride",[10] "hydride of tetryl"[11] and "tetryl hydride",[12] "diethyl" or "ethyl ethylide"[13] and others. August Wilhelm von Hofmann in his 1866 systemic nomenclature proposed the name "quartane",[14] and the modern name was introduced to English from German around 1874.[15]

Butane didn't have much practical use until the 1910s, when W. Snelling identified butane and propane as components in gasoline and found that if they were cooled, they could be stored in a volume-reduced liquified state in pressurized containers.


The density of butane is highly dependent on temperature and pressure in the reservoir.[16] For example, the density of liquid phase is 571.8±1 kg/m3 (for pressures up to 2MPa and temperature 27±0.2 °C), while the density of liquid butane is 625.5±0.7 kg/m3 (for pressures up to 2MPa and temperature -13±0.2 °C).

Density of liquid and vaporized butane
Propane & butane density data [16]


Common name normal butane
unbranched butane
IUPAC name butane methylpropane
Butan Lewis.svg Isobutane 1.svg
Butane simple.svg I-Butane-2D-Skeletal.svg

Rotation about the central C−C bond produces two different conformations (trans and gauche) for n-butane.[17]


Spectrum of the blue flame from a butane torch showing CH molecular radical band emission and C2 Swan bands

When oxygen is plentiful, butane burns to form carbon dioxide and water vapor; when oxygen is limited, carbon (soot) or carbon monoxide may also be formed. Butane is denser than air.

When there is sufficient oxygen:

2 C4H10 + 13 O2 → 8 CO2 + 10 H2O

When oxygen is limited:

2 C4H10 + 9 O2 → 8 CO + 10 H2O

By weight, butane contains about 49.5 MJ/kg (13.8 kWh/kg; 22.5 MJ/lb; 21,300 Btu/lb) or by liquid volume 29.7 megajoules per liter (8.3 kWh/L; 112 MJ/U.S. gal; 107,000 Btu/U.S. gal).

The maximum adiabatic flame temperature of butane with air is 2,243 K (1,970 °C; 3,578 °F).

n-Butane is the feedstock for DuPont's catalytic process for the preparation of maleic anhydride:

2 CH3CH2CH2CH3 + 7 O2 → 2 C2H2(CO)2O + 8 H2O

n-Butane, like all hydrocarbons, undergoes free radical chlorination providing both 1-chloro- and 2-chlorobutanes, as well as more highly chlorinated derivatives. The relative rates of the chlorination is partially explained by the differing bond dissociation energies, 425 and 411 kJ/mol for the two types of C-H bonds.


Normal butane can be used for gasoline blending, as a fuel gas, fragrance extraction solvent, either alone or in a mixture with propane, and as a feedstock for the manufacture of ethylene and butadiene, a key ingredient of synthetic rubber. Isobutane is primarily used by refineries to enhance (increase) the octane number of motor gasoline.[18][19][20][21]

For gasoline blending, n-butane is the main component used to manipulate the Reid vapor pressure (RVP). Since winter fuels require much higher vapor pressure for engines to start, refineries raise the RVP by blending more butane into the fuel.[22] n-Butane has a relatively high research octane number (RON) and motor octane number (MON), which are 93 and 92 respectively.[23]

When blended with propane and other hydrocarbons, the mixture may be referred to commercially as liquefied petroleum gas (LPG). It is used as a petrol component, as a feedstock for the production of base petrochemicals in steam cracking, as fuel for cigarette lighters and as a propellant in aerosol sprays such as deodorants.[24]

Pure forms of butane, especially isobutane, are used as refrigerants and have largely replaced the ozone-layer-depleting halomethanes in refrigerators, freezers, and air conditioning systems. The operating pressure for butane is lower than for the halomethanes such as Freon-12 (R-12), so R-12 systems such as those in automotive air conditioning systems, when converted to pure butane, will function poorly. A mixture of isobutane and propane is used instead to give cooling system performance comparable to use of R-12.

Butane is also used as lighter fuel for a common lighter or butane torch and is sold bottled as a fuel for cooking, barbecues and camping stoves. The global market for butane canisters is dominated by South Korean manufacturers.[25] In the 20th century the Braun (company) of Germany made a cordless hair styling device product that used butane as its heat source to produce steam.[26]

As fuel, it is often mixed with small amounts of mercaptans to give the unburned gas an offensive smell easily detected by the human nose. In this way, butane leaks can easily be identified. While hydrogen sulfide and mercaptans are toxic, they are present in levels so low that suffocation and fire hazard by the butane becomes a concern far before toxicity.[27][28] Most commercially available butane also contains some contaminant oil, which can be removed by filtration and will otherwise leave a deposit at the point of ignition and may eventually block the uniform flow of gas.[29]

The butane used as a solvent for fragrance extraction does not contain these contaminants[30] and butane gas can cause gas explosions in poorly ventilated areas if leaks go unnoticed and are ignited by spark or flame.[5] Purified butane is used as a solvent in the industrial extraction of cannabis oils.

Effects and health issues[edit]

Inhalation of butane can cause euphoria, drowsiness, unconsciousness, asphyxia, cardiac arrhythmia, fluctuations in blood pressure and temporary memory loss, when abused directly from a highly pressurized container, and can result in death from asphyxiation and ventricular fibrillation. It enters the blood supply and within seconds produces intoxication.[31] Butane is the most commonly abused volatile substance in the UK, and was the cause of 52% of solvent related deaths in 2000.[32] By spraying butane directly into the throat, the jet of fluid can cool rapidly to −20 °C (−4 °F) by expansion, causing prolonged laryngospasm.[33] "Sudden sniffer's death" syndrome, first described by Bass in 1970,[34] is the most common single cause of solvent related death, resulting in 55% of known fatal cases.[33]

See also[edit]


  1. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0068". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ Hofmann, August Wilhelm Von (1 January 1867). "I. On the action of trichloride of phosphorus on the salts of the aromatic monamines". Proceedings of the Royal Society of London. 15: 54–62. doi:10.1098/rspl.1866.0018. S2CID 98496840.
  3. ^ a b "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 4. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. Similarly, the retained names 'ethane', 'propane', and 'butane' were never replaced by systematic names 'dicarbane', 'tricarbane', and 'tetracarbane' as recommended for analogues of silane, 'disilane'; phosphane, 'triphosphane'; and sulfane, 'tetrasulfane'.
  4. ^ W. B. Kay (1940). "Pressure-Volume-Temperature Relations for n-Butane". Industrial & Engineering Chemistry. 32 (3): 358–360. doi:10.1021/ie50363a016.
  5. ^ a b "Safety Data Sheet, Material Name: N-Butane" (PDF). USA: Matheson Tri-Gas Incorporated. 5 February 2011. Archived from the original (PDF) on 1 October 2011. Retrieved 11 December 2011.
  6. ^ Watts, H.; Muir, M. M. P.; Morley, H. F. (1894). Watts' Dictionary of Chemistry. Watts' Dictionary of Chemistry. Vol. 4. Longmans, Green. p. 385.
  7. ^ Maybery, C. F. (1896). "On the Composition of the Ohio and Canadian Sulphur Petroleums". Proceedings of the American Academy of Arts and Sciences. 31: 1–66. doi:10.2307/20020618. JSTOR 20020618.
  8. ^ Seyferth, Dietmar (2001). "Zinc Alkyls, Edward Frankland, and the Beginnings of Main-Group Organometallic Chemistry". Organometallics. 20 (14): 2940–2955. doi:10.1021/om010439f.
  9. ^ "Journal of the Chemical Society". 1865.
  10. ^ Norman Tate, A. (1863). "Petroleum and Its Products: An Accoumt of the Properties, Uses, and Commercial Value Etc., of Petroleum, the Methods Employed in Refining it and the Properties, Uses, Etc., of Its Product".
  11. ^ Watts, Henry (1865). "A Dictionary of Chemistry".
  12. ^ Miller, William Allen (1867). "Elements of chemistry pt. 3 1867".
  13. ^ Miller, William Allen (1869). "Elements of Chemistry: Theoretical and Practical: Organic chemistry".
  14. ^ "Proceedings of the Royal Society". 1867.
  15. ^ Schorlemmer, Carl (1874). "A Manual of the Chemistry of the Carbon Compounds: Or, Organic Chemistry".
  16. ^ a b Zivenko, Oleksiy (2019). "LPG Accounting Specificity During ITS Storage and Transportation". Measuring Equipment and Metrology. 80 (3): 21–27. doi:10.23939/istcmtm2019.03.021. ISSN 0368-6418. S2CID 211776025.
  17. ^ Roman M. Balabin (2009). "Enthalpy Difference between Conformations of Normal Alkanes: Raman Spectroscopy Study of n-Pentane and n-Butane". J. Phys. Chem. A. 113 (6): 1012–9. Bibcode:2009JPCA..113.1012B. doi:10.1021/jp809639s. PMID 19152252.
  18. ^ MarkWest Energy Partners, L.P. Form 10-K. Sec.gov.
  19. ^ Copano Energy, L.L.C. Form 10-K. Sec.gov. Retrieved on 2012-12-03.
  20. ^ Targa Resources Partners LP Form10-k. Sec.gov. Retrieved on 2012-12-03.
  21. ^ Crosstex Energy, L.P. FORM 10-K. Sec.gov.
  22. ^ Maurice Stewart, Ken Arnold. "Reid Vapour Pressure". Science Direct. Archived from the original on 13 June 2020.
  23. ^ Jechura, John. "octane rating" (PDF). Colorado School of Mines. Archived (PDF) from the original on 1 May 2015.
  24. ^ A Primer on Gasoline Blending. An EPRINC Briefing Memorandum.
  25. ^ "Entrepreneur overcame hardships of Chinese prison". houstonchronicle.com. 21 June 2016. Retrieved 20 September 2018.
  26. ^ "Braun C 100 TS Styling Iron User Manual Type 3589". Inmar-OIQ, LLC. n.d.
  27. ^ Gresham, Chip (16 November 2019). "Hydrogen Sulfide Toxicity: Practice Essentials, Pathophysiology, Etiology". Medscape Reference. Retrieved 22 March 2021.
  28. ^ Committee on Acute Exposure Guideline Levels; Committee on Toxicology; Board on Environmental Studies and Toxicology; Division on Earth and Life Studies; National Research Council (26 September 2013). 2. Methyl Mercaptan Acute Exposure Guideline Levels. NCBI Bookshelf. National Academies Press (US).{{cite book}}: CS1 maint: multiple names: authors list (link)
  29. ^ "BHO Mystery Oil". Skunk Pharm Research. 26 August 2013. Retrieved 5 December 2019.
  30. ^ "Final Report of the Safety Assessment of Isobutane, Isopentane, n-Butane, and Propane". Journal of the American College of Toxicology. SAGE Publications. 1 (4): 127–142. 1982. doi:10.3109/10915818209021266. ISSN 0730-0913. S2CID 208503534.
  31. ^ "Neurotoxic Effects from Butane Gas". thcfarmer.com. 19 December 2009. Retrieved 3 October 2016.
  32. ^ Field-Smith M., Bland J. M., Taylor J. C. et al. "Trends in death Associated with Abuse of Volatile Substances 1971–2004" (PDF). Department of Public Health Sciences. London: St George’s Medical School. Archived from the original (PDF) on 27 March 2007.{{cite web}}: CS1 maint: uses authors parameter (link)
  33. ^ a b Ramsey J., Anderson H. R., Bloor K. et al. (1989). "An introduction to the practice, prevalence and chemical toxicology of volatile substance abuse". Hum Toxicol. 8 (4): 261–269. doi:10.1177/096032718900800403. PMID 2777265. S2CID 19617950.{{cite journal}}: CS1 maint: uses authors parameter (link)
  34. ^ Bass M. (1970). "Sudden sniffing death". JAMA. 212 (12): 2075–2079. doi:10.1001/jama.1970.03170250031004. PMID 5467774.

External links[edit]