Butane

Butane (/ˈbjuːteɪn/) or n-butane is an alkane with the formula C4H10. Butane is a gas at room temperature and atmospheric pressure. Butane is highly flammable, colorless, easily liquefied gas that quickly vaporize at room temperature. The name butane comes from the roots but- (from butyric acid, named after the Greek word for butter) and -ane. It was discovered by the chemist Edward Frankland in 1849.[6] It was found dissolved in crude petroleum in 1864 by Edmund Ronalds, who was the first to describe its properties.[7][8]

Not to be confused with butene, butyne, or Bhutan.
Butane
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
Names
Preferred IUPAC name
Butane[1]
Systematic IUPAC name
Tetracarbane (never recommended[1])
Other names
Butyl hydride;[2] Quartane;[3] Refrigerant 3-11-0
Identifiers
3D model (JSmol)
969129
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.136
EC Number
  • 203-448-7
E number E943a (glazing agents, ...)
1148
KEGG
MeSH butane
RTECS number
  • EJ4200000
UNII
UN number 1011
Properties
C4H10
Molar mass 58.124 g·mol−1
Appearance Colorless gas
Odor Gasoline-like or natural gas-like[2]
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−1 (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
Thermochemistry
98.49 J K−1 mol−1
Std enthalpy of
formation (ΔfH⦵298)
 −126.3–−124.9 kJ mol−1
Std enthalpy of
combustion (ΔcH⦵298)
 −2.8781–−2.8769 MJ mol−1
Hazards[5]
Safety data sheet See: data page
GHS pictograms
GHS Signal word Danger
GHS hazard statements
 H220
P210
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)
 none[2]
REL (Recommended)
 TWA 800 ppm (1900 mg/m3)[2]
IDLH (Immediate danger)
 1,600 ppm[2]
Related compounds
Related alkanes
Related compounds
 Perfluorobutane
Supplementary data page
Refractive index (n),
Dielectric constant (εr), etc.
Thermodynamic
data
 Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Isomers
Main article: C4H10
Common name normal butane
unbranched butane
n-butane		 isobutane
i-butane
IUPAC name butane 2-methylpropane
Molecular
diagram
Skeletal
diagram

Rotation about the central C−C bond produces two different conformations (trans and gauche) for n-butane.[9]

Reactions
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

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.

Uses

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.[10][11][12][13]

When blended with propane and other hydrocarbons, it may be referred to commercially as LPG, for liquefied petroleum gas. 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.[14]

Very pure forms of butane, especially isobutane, can be used as refrigerants and have largely replaced the ozone-layer-depleting halomethanes, for instance in household refrigerators and freezers. The system operating pressure for butane is lower than for the halomethanes, such as R-12, so R-12 systems such as in automotive air conditioning systems, when converted to pure butane will not function optimally and therefore a mix of isobutane and propane is used to give cooling system performance comparable to 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. Butane canisters global market is dominated by South Korean manufacturers.[15]

As fuel, it is often mixed with small amounts of hydrogen sulfide and mercaptans which will 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. Most commercially available butane also contains a certain amount of contaminant oil which can be removed through filtration but which will otherwise leave a deposit at the point of ignition and may eventually block the uniform flow of gas.[16] Contaminants are not used in fragrance extraction and butane gases can cause gas explosions in poorly ventilated areas if leaks go unnoticed and are ignited by spark or flame.

Butane fuel canisters for use in camping stoves.Butane lighter, showing liquid butane reservoirAn aerosol spray can, which may be using butane as a propellantButane gas cylinder used for cooking

Effects and health issues

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.[17] Butane is the most commonly abused volatile substance in the UK, and was the cause of 52% of solvent related deaths in 2000.[18] By spraying butane directly into the throat, the jet of fluid can cool rapidly to −20 °C (−4 °F) by expansion, causing prolonged laryngospasm.[19] "Sudden sniffer's death" syndrome, first described by Bass in 1970,[20] is the most common single cause of solvent related death, resulting in 55% of known fatal cases.[19]

A small amount of nitrogen dioxide, a toxic gas, results from burning butane gas, along with any combustion in the earth's atmosphere, and represents a human health hazard from home heaters and stoves.[21]

See also

References
  1. "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’.
  2. NIOSH Pocket Guide to Chemical Hazards. "#0068". National Institute for Occupational Safety and Health (NIOSH).
  3. 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.
  4. W. B. Kay (1940). "Pressure-Volume-Temperature Relations for n-Butane". Industrial & Engineering Chemistry. 32 (3): 358–360. doi:10.1021/ie50363a016.
  5. "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. "Occ paper" (PDF). www.chem.qmul.ac.uk.
  7. Watts, H. (1868). Dictionary of Chemistry. 4. p. 385.
  8. 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.
  9. 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. doi:10.1021/jp809639s. PMID 19152252.
  10. MarkWest Energy Partners, L.P. Form 10-K. Sec.gov
  11. Copano Energy, L.L.C. Form 10-K. Sec.gov. Retrieved on 2012-12-03.
  12. Targa Resources Partners LP Form10-k. Sec.gov. Retrieved on 2012-12-03.
  13. Crosstex Energy, L.P. FORM 10-K. Sec.gov
  14. A Primer on Gasoline Blending. An EPRINC Briefing Memorandum
  15. "Entrepreneur overcame hardships of Chinese prison". houstonchronicle.com. 21 June 2016. Retrieved 20 September 2018.
  16. "BHO Mystery Oil". Skunk Pharm Research. 2013-08-26. Retrieved 2019-12-05.
  17. "Neurotoxic Effects from Butane Gas". thcfarmer.com. 19 Dec 2009. Retrieved 3 October 2016.
  18. Field-Smith M, Bland JM, Taylor JC, 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 March 27, 2007.
  19. Ramsey J, Anderson HR, 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.
  20. Bass M. (1970). "Sudden sniffing death". JAMA. 212 (12): 2075–2079. doi:10.1001/jama.1970.03170250031004. PMID 5467774.
  21. Ghosn, Marwan; Flouty, Roula; Saliba, Najat A. (2005). "Emission of Nitrogen Dioxide from Butane Gas Heaters and Stoves Indoors". American Journal of Applied Sciences. 2 (3): 707. doi:10.3844/ajassp.2005.707.710.
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