Butane

The first synthesis of butane was accidentally achieved by British chemist Edward Frankland{{cite web | url=https://www.acs.org/molecule-of-the-week/archive/b/butane.html | title=Butane }} in 1849 from ethyl iodide and zinc, but he had not realized that the ethyl radical dimerized and misidentified the substance.{{cite journal |doi=10.1021/om010439f |title=Zinc Alkyls, Edward Frankland, and the Beginnings of Main-Group Organometallic Chemistry |year=2001 |last1=Seyferth |first1=Dietmar |journal=Organometallics |volume=20 |issue=14 |pages=2940–2955 |doi-access=free}}

It was discovered in crude petroleum in 1864 by Edmund Ronalds, who was the first to describe its properties,{{cite book | last1=Watts | first1=H. | last2=Muir | first2=M. M. P. | last3=Morley | first3=H. F. | title=Watts' Dictionary of Chemistry | publisher=Longmans, Green | volume=4 | year=1894 | url=https://books.google.com/books?id=J3kPAQAAIAAJ |page=385}}{{Cite journal |last=Maybery |first=C. F. |date=1896 |title=On the Composition of the Ohio and Canadian Sulphur Petroleums |journal=Proceedings of the American Academy of Arts and Sciences |volume=31 |pages=1–66 |doi=10.2307/20020618 |jstor=20020618}} which he named "hydride of butyl",{{cite web | url=https://books.google.com/books?id=YyO3j9Yi3nEC&pg=PA54 | title=Journal of the Chemical Society | year=1865 }} based on the naming for the then-known butyric acid, which had been named and described by the French chemist Michel Eugène ChevreulChevreul (1817) [https://books.google.com/books?id=y1E3AAAAYAAJ&pg=PA79 "Extrait d'une lettre de M. Chevreul à MM. les Rédacteurs du Journal de Pharmacie"] (Extract of a letter from Mr. Chevreul to the editors of the Journal of Pharmacy), Journal de Pharmacie et des sciences accessoires, 3 : 79–81. On p. 81, he named butyric acid: "Ce principe, que j'ai appelé depuis acid butérique, … " (This principle [i.e., constituent], which I have since named "butyric acid", … ) 40 years earlier. Other names arose in the 1860s: "butyl hydride",{{cite web | url=https://books.google.com/books?id=6ss-AAAAcAAJ&pg=PA41 | title=Petroleum and Its Products: An Account of the Properties, Uses, and Commercial Value Etc., of Petroleum, the Methods Employed in Refining it and the Properties, Uses, Etc., of Its Product | last1=Norman Tate | first1=A. | year=1863 }} "hydride of tetryl"{{cite web | url=https://books.google.com/books?id=6YvPAAAAMAAJ&pg=PA181 | title=A Dictionary of Chemistry | last1=Watts | first1=Henry | year=1865 }} and "tetryl hydride",{{cite web | url=https://books.google.com/books?id=Q7YHAAAAIAAJ&pg=PA277 | title=Elements of chemistry pt. 3 1867 | last1=Miller | first1=William Allen | year=1867 }} "diethyl" or "ethyl ethylide"{{cite web | url=https://books.google.com/books?id=b7ktAAAAYAAJ&pg=PA266 | title=Elements of Chemistry: Theoretical and Practical: Organic chemistry | last1=Miller | first1=William Allen | year=1869 }} and others. August Wilhelm von Hofmann, in his 1866 systemic nomenclature, proposed the name "quartane", and the modern name was introduced to English from German around 1874.{{cite web | url=https://books.google.com/books?id=w9MJAAAAMAAJ&pg=PA154 | title=A Manual of the Chemistry of the Carbon Compounds: Or, Organic Chemistry | last1=Schorlemmer | first1=Carl | year=1874 }}

Butane did not have much practical use until the 1910s, when W. Snelling identified butane and propane as components in gasoline. He found that if they were cooled, they could be stored in a volume-reduced liquified state in pressurized containers. In 1911, Snelling's liquified petroleum gas was publicly available, and his process for producing the mixture was patented in 1913.{{Cite web |url=http://blog.texaspropane.com/history-propane/ | title=The History of Propane | author=Texas Propane | year=2022}} Butane is one of the most produced industrial chemicals in the 21st century, with around 80-90 billion lbs (40 million US tons, 36 million metric tons) produced by the United States every year.{{cite web | url=https://www.epa.gov/chemical-data-reporting/chemical-production-data | title=Chemical Production Data |year=2024 }}

The density of butane is highly dependent on temperature and pressure in the reservoir.{{Cite journal|last=Zivenko|first=Oleksiy|title=LPG Accounting Specificity During ITS Storage and Transportation |date=2019|journal=Measuring Equipment and Metrology|language=en|volume=80|issue=3|pages=21–27|doi=10.23939/istcmtm2019.03.021|s2cid=211776025 |issn=0368-6418|doi-access=free}} For example, the density of liquid butane is 571.8±1 kg/m³ (for pressures up to 2 MPa and temperature 27±0.2 °C), while the density of liquid butane is 625.5±0.7 kg/m³ (for pressures up to 2 MPa and temperature −13±0.2 °C).

Rotation about the central C−C bond produces two different conformations (trans and gauche) for n-butane.{{cite journal |journal=J. Phys. Chem. A |volume = 113 |issue = 6 |pages = 1012–9 |doi=10.1021/jp809639s |title=Enthalpy Difference between Conformations of Normal Alkanes: Raman Spectroscopy Study of n-Pentane and n-Butane |year=2009 |author=Roman M. Balabin|pmid=19152252|bibcode = 2009JPCA..113.1012B |author-link = Roman Balabin }}

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File:Spectrum of blue flame - intensity corrected.png showing CH molecular radical band emission and C₂ Swan bands]]

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When oxygen is plentiful, butane undergoes complete combustion to form carbon dioxide and water vapor; when oxygen is limited, due to incomplete combustion, carbon (soot) or carbon monoxide may be formed instead of carbon dioxide. 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 {{convert|49.5|MJ/kg|kWh/kg MJ/lb Btu/lb|lk=on|abbr=on|sp=us}} or by liquid volume {{convert|29.7|MJ/L|kWh/L MJ/usgal Btu/usgal|abbr=out|lk=in|sp=us}}.

The maximum adiabatic flame temperature of butane with air is {{convert|2243|K}}.

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 chlorinations are 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.[https://www.sec.gov/Archives/edgar/data/1166036/000104746912001759/a2207469z10-k.htm MarkWest Energy Partners, L.P. Form 10-K]. Sec.gov.[https://www.sec.gov/Archives/edgar/data/1297067/000119312512089552/d270993d10k.htm Copano Energy, L.L.C. Form 10-K]. Sec.gov. Retrieved on 2012-12-03.[https://www.sec.gov/Archives/edgar/data/1379661/000138917012000005/form10-k.htm Targa Resources Partners LP Form10-k]. Sec.gov. Retrieved on 2012-12-03.[https://www.sec.gov/Archives/edgar/data/1179060/000104746912001738/a2207540z10-k.htm Crosstex Energy, L.P. FORM 10-K]. Sec.gov.

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.{{Cite web|last=Maurice Stewart, Ken Arnold|title=Reid Vapour Pressure|url=https://www.sciencedirect.com/topics/engineering/reid-vapour-pressure|url-status=live|website=Science Direct|archive-url=https://web.archive.org/web/20200613130216/https://www.sciencedirect.com/topics/engineering/reid-vapour-pressure |archive-date=13 June 2020 }} n-Butane has a relatively high research octane number (RON) and motor octane number (MON), which are 93 and 92 respectively.{{Cite web|last=Jechura|first=John|title=octane rating|url=https://inside.mines.edu/~jjechura/Refining/11_Blending_Optimization.pdf|url-status=live|website=Colorado School of Mines|archive-url=https://web.archive.org/web/20150501041749/http://inside.mines.edu:80/~jjechura/Refining/11_Blending_Optimization.pdf |archive-date=1 May 2015 }}

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.[http://eprinc.org/?p=300 A Primer on Gasoline Blending] {{Webarchive|url=https://web.archive.org/web/20130630221725/http://eprinc.org/?p=300 |date=30 June 2013 }}. An EPRINC Briefing Memorandum.

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 operating pressures for halomethanes such as Freon-12 (R-12). Hence, R-12 systems, such as those in automotive air conditioning systems, when converted to pure butane, will function poorly. Instead, a mixture of isobutane and propane is used to give cooling system performance comparable to R-12.{{Cite web |title=R600a {{!}} Product Information |url=https://www.agas.com/au/products-services/refrigerants/r600a/ |access-date=2023-12-01 |website=www.agas.com |language=en-AU}}

Butane is also used as lighter fuel for common lighters or butane torches, and is sold bottled as a fuel for cooking, barbecues and camping stoves. 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.{{cite news |title=Braun C 100 TS Styling Iron User Manual Type 3589 |url=http://personalcare.manualsonline.com/manuals/mfg/braun/c_100_ts_1.html |publisher=Inmar-OIQ, LLC |date=n.d.}}

As fuel, butane 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.{{cite web | last=Gresham | first=Chip | title=Hydrogen Sulfide Toxicity: Practice Essentials, Pathophysiology, Etiology | website=Medscape Reference | date=16 November 2019 | url=https://emedicine.medscape.com/article/815139 | access-date=22 March 2021 |url-access=registration}}{{cite book |author1=Committee on Acute Exposure Guideline Levels |author2=Committee on Toxicology |author3=Board on Environmental Studies and Toxicology |author4=Division on Earth and Life Studies |author5=National Research Council |title=2. Methyl Mercaptan Acute Exposure Guideline Levels |via=NCBI Bookshelf |date=26 September 2013 |publisher=National Academies Press (US) |url=https://www.ncbi.nlm.nih.gov/books/NBK201324/ }} Most commercially available butane also contains some contaminant oil, which can be removed by filtration. If not removed, it will otherwise leave a deposit at the point of ignition and may eventually block the uniform flow of gas.{{Cite web |title=BHO Mystery Oil |date=2013-08-26 |website=Skunk Pharm Research |url=https://skunkpharmresearch.com/bho-mystery-oil/ |access-date=2019-12-05}}

The butane used as a solvent for fragrance extraction does not contain these contaminants.{{cite journal |title=Final Report of the Safety Assessment of Isobutane, Isopentane, n-Butane, and Propane |journal=Journal of the American College of Toxicology |publisher=SAGE Publications |volume=1 |issue=4 |year=1982 |issn=0730-0913 |doi=10.3109/10915818209021266 |pages=127–142| s2cid=208503534}} Butane gas can cause gas explosions in poorly ventilated areas if leaks go unnoticed and are ignited by spark or flame. Purified butane is used as a solvent in the industrial extraction of cannabis oils.

File:Photo D2.jpg | Butane fuel canisters for use in camping stoves

File:The Green Lighter 1 cropped.jpg | Butane lighter, showing liquid butane reservoir

File:Aerosol.png | An aerosol spray can, which may be using butane as a propellant

File:ButaneGasCylinder WhiteBack.jpg | Butane gas cylinder used for cooking

File:HarmCausedByDrugsTable.svg

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. Butane enters the blood supply, and within seconds, leads to intoxication.{{cite web |title=Neurotoxic Effects from Butane Gas |date=19 Dec 2009 |website=thcfarmer.com |url=https://www.thcfarmer.com/community/threads/neurotoxic-effects-from-butane-gas.15291/ |access-date=3 October 2016}} Butane is the most commonly abused volatile substance in the UK, and was the cause of 52% of solvent related deaths in 2000.{{cite web |title=Trends in death Associated with Abuse of Volatile Substances 1971–2004 |vauthors=Field-Smith M, Bland JM, Taylor JC |publisher=Department of Public Health Sciences. London: St George’s Medical School |url=http://www.sgul.ac.uk/dms/AF54AFD9D207A9A41D353717989DC4E0.pdf |display-authors=etal |url-status=dead |archive-url=https://web.archive.org/web/20070327161634/http://www.sgul.ac.uk/dms/AF54AFD9D207A9A41D353717989DC4E0.pdf |archive-date=March 27, 2007}} By spraying butane directly into the throat, the jet of fluid can cool rapidly to {{convert|−20|C}} by expansion, causing prolonged laryngospasm.{{cite journal |vauthors=Ramsey J, Anderson HR, Bloor K |display-authors=etal |title=An introduction to the practice, prevalence and chemical toxicology of volatile substance abuse |journal=Hum Toxicol |year=1989 |volume=8 |pages=261–269 |doi=10.1177/096032718900800403 |pmid=2777265 |issue=4| s2cid=19617950}} "Sudden sniffer's death" syndrome, first described by Bass in 1970,{{cite journal |vauthors=Bass M |title=Sudden sniffing death |journal=JAMA |year=1970 |volume=212 |issue=12 |pages=2075–2079 |doi=10.1001/jama.1970.03170250031004 |pmid=5467774}} is the most common single cause of solvent related deaths, resulting in 55% of known fatal cases.

• Cyclobutane
• Volatile substance abuse
• Butane (data page)
• Industrial gas

{{Reflist}}

{{commons}}

• [http://www.inchem.org/documents/icsc/icsc/eics0232.htm International Chemical Safety Card 0232]
• [https://www.cdc.gov/niosh/npg/npgd0068.html NIOSH Pocket Guide to Chemical Hazards]

{{Alkanes}}

{{Hydrides by group}}

{{E number infobox 930-949}}

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Category:Alkanes

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