Chemistry:Butane

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Short description: Organic compound
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[3]
Systematic IUPAC name
Tetracarbane (never recommended[3])
Other names
Butyl hydride;[1] Quartane;[2] Refrigerant 3-11-0
Identifiers
3D model (JSmol)
969129
ChEBI
ChEMBL
ChemSpider
EC Number
  • 203-448-7
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[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
Thermochemistry
98.49 J/(K·mol)
−126.3–−124.9 kJ/mol
−2.8781–−2.8769 MJ/mol
Hazards[5]
GHS pictograms GHS02: Flammable GHS04: Compressed Gas
GHS Signal word DANGER
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[1]
REL (Recommended)
TWA 800 ppm (1900 mg/m3)[1]
IDLH (Immediate danger)
1600 ppm[1]
Related compounds
Related alkanes
Related compounds
Perfluorobutane
Supplementary data page
Refractive index (n),
Dielectric constantr), 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).
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Infobox references
Tracking categories (test):

Butane (/ˈbjuːtn/) or n-butane is an alkane with the formula C4H10. Butane is a gas at room temperature and atmospheric pressure. Butane is a highly flammable, colorless, easily liquefied gas that quickly vaporizes at room temperature. 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 by the chemist Dr. Walter Snelling in 1912.[6] It was found dissolved in crude petroleum in 1864 by Edmund Ronalds, who was the first to describe its properties.[7][8]

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

Density

The density of butane is highly dependent on temperature and pressure in the reservoir.[9] 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 [9]

History

Butane and Propane were simultaneously discovered in 1912 by an American chemist, Dr. Walter Snelling. Snelling identified these gases as components in gasoline and found that if they were cooled, they could be stored in a volume-reduced liquified state in pressurized containers.[10]

Isomers

Main page: Chemistry:C4H10
Common name normal butane
unbranched butane
n-butane
isobutane
i-butane
IUPAC name butane methylpropane
Molecular
diagram
Butan Lewis.svg Isobutane 1.svg
Skeletal
diagram
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.[11]

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

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.

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.[12][13][14][15]

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.[16] n-Butane has a relatively high research octane number (RON) and motor octane number (MON), which are 93 and 92 respectively.[17]

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.[18]

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 Korea n manufacturers.[19] In the 20th century the Braun of Germany made a cordless hair styling device product that used butane as its heat source to produce steam.[20]

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.[21][22] 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.[23]

The butane used as a solvent for fragrance extraction does not contain these contaminants[24] 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

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.[25] Butane is the most commonly abused volatile substance in the UK, and was the cause of 52% of solvent related deaths in 2000.[26] By spraying butane directly into the throat, the jet of fluid can cool rapidly to −20 °C (−4 °F) by expansion, causing prolonged laryngospasm.[27] "Sudden sniffer's death" syndrome, first described by Bass in 1970,[28] is the most common single cause of solvent related death, resulting in 55% of known fatal cases.[27]

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 NIOSH Pocket Guide to Chemical Hazards. "#0068". National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/npg/npgd0068.html. 
  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. 
  3. 3.0 3.1 "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'." 
  4. W. B. Kay (1940). "Pressure-Volume-Temperature Relations for n-Butane". Industrial & Engineering Chemistry 32 (3): 358–360. doi:10.1021/ie50363a016. 
  5. 5.0 5.1 "Safety Data Sheet, Material Name: N-Butane". USA: Matheson Tri-Gas Incorporated. 5 February 2011. http://www.chemadvisor.com/Matheson/database/msds/MAT15370000800003.PDF. 
  6. "Hydrocarbon Gas Liquids Explained - U.S. Energy Information Administration (EIA)". https://www.eia.gov/energyexplained/hydrocarbon-gas-liquids/. 
  7. Watts, H.; Muir, M. M. P.; Morley, H. F. (1894). Watts' Dictionary of Chemistry. Watts' Dictionary of Chemistry. 4. Longmans, Green. p. 385. https://books.google.com/books?id=J3kPAQAAIAAJ. 
  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. 
  9. 9.0 9.1 Zivenko, Oleksiy (2019). "LPG Accounting Specificity During ITS Storage and Transportation" (in en). Measuring Equipment and Metrology 80 (3): 21–27. doi:10.23939/istcmtm2019.03.021. ISSN 0368-6418. https://doi.org/10.23939/istcmtm2019.03.021. 
  10. "Hydrocarbon Gas Liquids Explained - U.S. Energy Information Administration (EIA)". https://www.eia.gov/energyexplained/hydrocarbon-gas-liquids/. 
  11. 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. Bibcode2009JPCA..113.1012B. 
  12. MarkWest Energy Partners, L.P. Form 10-K. Sec.gov.
  13. Copano Energy, L.L.C. Form 10-K. Sec.gov. Retrieved on 2012-12-03.
  14. Targa Resources Partners LP Form10-k. Sec.gov. Retrieved on 2012-12-03.
  15. Crosstex Energy, L.P. FORM 10-K. Sec.gov.
  16. Maurice Stewart, Ken Arnold. "Reid Vapour Pressure". https://www.sciencedirect.com/topics/engineering/reid-vapour-pressure. 
  17. Jechura, John. "octane rating". https://inside.mines.edu/~jjechura/Refining/11_Blending_Optimization.pdf. 
  18. A Primer on Gasoline Blending. An EPRINC Briefing Memorandum.
  19. "Entrepreneur overcame hardships of Chinese prison". 21 June 2016. http://www.houstonchronicle.com/business/article/Houston-businessman-overcame-hardships-of-Chinese-8313857.php. 
  20. "Braun C 100 TS Styling Iron User Manual Type 3589". Inmar-OIQ, LLC. n.d.. http://personalcare.manualsonline.com/manuals/mfg/braun/c_100_ts_1.html. 
  21. Gresham, Chip (16 November 2019). "Hydrogen Sulfide Toxicity: Practice Essentials, Pathophysiology, Etiology". https://emedicine.medscape.com/article/815139. 
  22. 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. National Academies Press (US). https://www.ncbi.nlm.nih.gov/books/NBK201324/. 
  23. "BHO Mystery Oil" (in en-US). 2013-08-26. https://skunkpharmresearch.com/bho-mystery-oil/. 
  24. "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. 
  25. "Neurotoxic Effects from Butane Gas". thcfarmer.com. 19 Dec 2009. https://www.thcfarmer.com/community/threads/neurotoxic-effects-from-butane-gas.15291/. 
  26. "Trends in death Associated with Abuse of Volatile Substances 1971–2004". Department of Public Health Sciences. London: St George’s Medical School. http://www.sgul.ac.uk/dms/AF54AFD9D207A9A41D353717989DC4E0.pdf. 
  27. 27.0 27.1 Ramsey J., Anderson H. R., Bloor K. (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. 
  28. Bass M. (1970). "Sudden sniffing death". JAMA 212 (12): 2075–2079. doi:10.1001/jama.1970.03170250031004. PMID 5467774. 

External links