View source for Propane

{{short description|Hydrocarbon compound (C3H8)}}
{{Distinguish|propene|propyne}}
{{SM|Liquefied petroleum gas|discuss=Talk:Propane#Proposed move of content from Propane article to LPG article|date=August 2024}}
{{Chembox
| Watchedfields  = changed
| verifiedrevid  = 464375285
| ImageFileL1    = Propane-2D-Skeletal.svg
| ImageClassL1 = skin-invert-image
| ImageFileL1_Ref = {{chemboximage|correct|??}}
| ImageNameL1    = Skeletal formula of propane
| ImageFileR1    = PropaneFull.png
| ImageClassR1 = skin-invert-image
| ImageFileR1_Ref = {{chemboximage|correct|??}}
| ImageNameR1    = Skeletal formula of propane with all implicit carbons shown, and all explicit hydrogens added
| ImageFileL2    = Propane-3D-balls-B.png
| ImageClassL2 = bg-transparent
| ImageFileL2_Ref = {{chemboximage|correct|??}}
| ImageNameL2    = Ball and stick model of propane
| ImageFileR2    = Propane-3D-vdW-B.png
| ImageClassR2 = bg-transparent
| ImageFileR2_Ref = {{chemboximage|correct|??}}
| ImageNameR2    = Spacefill model of propane
| PIN            = Propane<ref name=iupac2013>{{cite book | title =  Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | chapter = General Principles, Rules, and Conventions | publisher = [[Royal Society of Chemistry|The Royal Society of Chemistry]] | date = 2014 | location = Cambridge | at = P-12.1 | doi = 10.1039/9781849733069-00001 | isbn = 978-0-85404-182-4 | quote = 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'.}}</ref>
| SystematicName = Tricarbane (never recommended<ref name=iupac2013 />)
| Section1       = {{Chembox Identifiers
| CASNo = 74-98-6
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 6334
| ChemSpiderID = 6094
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| UNII = T75W9911L6
| UNII_Ref = {{fdacite|correct|FDA}}
| EINECS = 200-827-9
| UNNumber = 1978
| KEGG = D05625
| KEGG_Ref = {{keggcite|correct|kegg}}
| ChEBI = 32879
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 135416
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| RTECS = TX2275000
| Beilstein = 1730718
| Gmelin = 25044
| SMILES = CCC
| StdInChI = 1S/C3H8/c1-3-2/h3H2,1-2H3
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = ATUOYWHBWRKTHZ-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
| Section2       = {{Chembox Properties
| Properties_ref = <ref name="GESTIS">{{GESTIS|ZVG=10020|Name=Propane}}</ref>
| C=3 | H=8
| Appearance = Colorless gas
| Odor = Odorless
| Density = 2.0098&nbsp;kg/m<sup>3</sup> (at 0&nbsp;°C, 101.3&nbsp;kPa)
| MeltingPtK = 85.5
| BoilingPtK = 230.9 to 231.11
| CriticalTP = {{cvt|370|K}}, {{cvt|4.23|MPa|atm}}
| Solubility = 47&nbsp;mg⋅L<sup>−1</sup> (at 0&nbsp;°C)
| LogP = 2.236
| VaporPressure = 853.16&nbsp;kPa (at {{convert|21.1|C}})
| HenryConstant = 15&nbsp;nmol⋅Pa<sup>−1</sup>⋅kg<sup>−1</sup>
| MagSus = −40.5&nbsp;×&nbsp;10<sup>−6</sup>&nbsp;cm<sup>3</sup>/mol
| ConjugateAcid = [[Propanium]]
| Dipole = 0.083&nbsp;D<ref>{{cite journal |title= Microwave Spectrum, Structure, and Dipole Moment of Propane |journal= J. Chem. Phys. |volume= 33 |issue= 5 |pages= 1514–1518 |year= 1960 |doi= 10.1063/1.1731434 |first= David R. Jr. |last= Lide |bibcode= 1960JChPh..33.1514L }}</ref>
}}
| Section3       = {{Chembox Thermochemistry
| DeltaHf = −105.2–104.2&nbsp;kJ⋅mol<sup>−1</sup>
| DeltaHc = −2.2197–2.2187&nbsp;MJ⋅mol<sup>−1</sup>
| HeatCapacity = 73.60&nbsp;J⋅K<sup>−1</sup>⋅mol<sup>−1</sup>
}}
| Section4       = {{Chembox Hazards
| GHSPictograms = {{GHS02}}
| GHSSignalWord = '''DANGER'''
| HPhrases = {{H-phrases|220}}
| PPhrases = {{P-phrases|210}}
| NFPA-H = 2
| NFPA-F = 4
| NFPA-R = 0
| NFPA-S = 
| FlashPtC = −104
| AutoignitionPtC = 470
| ExploLimits = 2.37–9.5%
| PEL = TWA 1,000&nbsp;ppm (1,800&nbsp;mg/m<sup>3</sup>)<ref name=PGCH>{{PGCH|0524}}</ref>
| IDLH = 2,100&nbsp;ppm<ref name=PGCH />
| REL = TWA 1,000&nbsp;ppm (1,800&nbsp;mg/m<sup>3</sup>)<ref name=PGCH />
}}<ref>{{cite web|url=http://cameochemicals.noaa.gov/chemical/9018|title=PROPANE – CAMEO Chemicals – NOAA|publisher=NOAA Office of Response and Restoration, US GOV|website=cameochemicals.noaa.gov}}</ref>
| Section5       = {{Chembox Related
| OtherFunction_label = alkanes
| OtherFunction = {{unbulleted list|[[ethane]]|[[butane]]|[[isobutane]]}}
| OtherCompounds = {{unbulleted list|[[propene]]|[[allene]]|[[cyclopropane]]|}}
}}
}}
[[File:Propane tank 20lb.jpg|thumb|A 20 lb ({{nowrap|9.1 kg}}) steel propane cylinder. This cylinder is fitted with an overfill prevention device (OPD) valve, as evidenced by the trilobular handwheel.]]
'''Propane''' ({{IPAc-en|ˈ|p|r|oʊ|p|eɪ|n}}) is a three-[[carbon]] chain [[alkane]] with the molecular formula {{Chem2|C3H8}}. It is a gas at [[standard temperature and pressure]], but becomes liquid when compressed for transportation and storage. A [[by-product]] of [[natural gas]] processing and [[petroleum]] refining, it is often a constituent of [[liquefied petroleum gas]] (LPG), which is commonly used as a [[fuel]] in domestic and industrial applications and in low-emissions public transportation; other constituents of LPG may include [[propene|propylene]], [[butane]], [[butene|butylene]], [[butadiene]], and [[isobutylene]]. Discovered in 1857 by the French chemist [[Marcellin Berthelot]], it became commercially available in the US by 1911.  Propane has lower volumetric energy density than gasoline or coal, but has higher gravimetric energy density than them and burns more cleanly.<ref>{{Cite web |title=Fuels |url=https://www.globalfueleconomy.org/transport/gfei/autotool/approaches/technology/fuels.asp |access-date=2022-04-12 |website=www.globalfueleconomy.org}}</ref>

Propane gas has become a popular choice for barbecues and portable stoves because its low −42&nbsp;°C [[boiling point]] makes it vaporise inside pressurised liquid containers (it exists in two phases, vapor above liquid). It retains its ability to vaporise even in cold weather, making it better-suited for outdoor use in cold climates than alternatives with higher boiling points like butane.<ref>{{cite web |title=The difference between butane and propane |url=https://www.calor.co.uk/news-and-views/the-difference-between-butane-and-propane |website=Calor Gas News and Views |publisher=Calor Gas Ltd UK}}</ref> LPG powers buses, forklifts, automobiles, outboard boat motors, and [[Ice resurfacer|ice resurfacing machines]], and is used for heat and cooking in [[recreational vehicle]]s and [[Campervan|campers]]. Propane is also becoming popular as a replacement refrigerant (R290) for heatpumps as it offers greater efficiency than the current refrigerants: R410A / R32, higher temperature heat output and less damage to the atmosphere for escaped gases—at the expense of high gas flammability.<ref>{{Cite web |title=Propane |url=https://vasa.org.au/transition-to-latest-ghs-7-chemical-id-system-starts-in-2021/ |access-date=2024-05-11 |website=vasa.org.au}}</ref>

== History ==
Propane was first synthesized by the French chemist [[Marcellin Berthelot]] in 1857 during his researches on [[hydrogenation]].  Berthelot made propane by heating [[propylene dibromide]] (C<sub>3</sub>H<sub>6</sub>Br<sub>2</sub>) with [[potassium iodide]] and water.<ref>{{cite book|url=https://books.google.com/books?id=dzlCAQAAMAAJ&q=Berthelot+Propane+1857|language=fr|title=Comptes rendus hebdomadaires des séances de l'Académie des sciences|year=1905|volume=140|publisher=Académie des Sciences}}</ref><ref>''Acetylene and Its Polymers : 150+ Years of History'', Seth C. Rasmussen, Springer, 2018, ISBN 978-3-319-95489-9, {{doi|10.1007/978-3-319-95489-9}}.</ref>{{rp|at=p. 9, §1.1}}<ref>"Substitutions inverses", Marcellin Berthelot, pp. 48-58 in  ''[[Annales de chimie et de physique]]'', [https://gallica.bnf.fr/ark:/12148/bpt6k65708374 3rd ser., '''51''', Paris : Victor Masson, 1857.]</ref>  Propane was found dissolved in [[Pennsylvania]]n light [[crude oil]] by [[Edmund Ronalds]] in 1864.<ref>{{Cite book|title=Treatise on Chemistry|last1=Roscoe|first1=H.E.|last2=Schorlemmer|first2=C.|publisher=Macmillan|year=1881|volume=3|pages=144–145}}</ref><ref>{{Cite book|title=Dictionary of Chemistry|last=Watts|first=H.|year=1868|volume=4|pages=385}}</ref> [[Walter O. Snelling]] of the [[United States Bureau of Mines|U.S. Bureau of Mines]] highlighted it as a volatile component in [[gasoline]] in 1910, which marked the "birth of the propane industry" in the United States.<ref name="history" /> The volatility of these lighter [[hydrocarbons]] caused them to be known as "wild" because of the high vapor pressures of unrefined gasoline. On March 31, 1912, ''[[The New York Times]]'' reported on Snelling's work with liquefied gas, saying "a [[gas cylinder|steel bottle]] will carry enough [[gas]] to light an ordinary home for three weeks".<ref>{{cite news |title=Gas Plant in Steel Bottle – Dr. Snelling's Process Gives Month's Supply in Liquid Form. |url=https://query.nytimes.com/gst/abstract.html?res=9C04E3DB1F31E233A25752C0A9629C946396D6CF |work=The New York Times |date=April 1, 1912 |page=9 |access-date=2007-12-22}}</ref>

It was during this time that Snelling''—''in cooperation with Frank P. Peterson, Chester Kerr, and Arthur Kerr''—''developed ways to liquefy the LP gases during the refining of gasoline.<ref name="history" /> Together, they established American Gasol Co., the first commercial marketer of propane. Snelling had produced relatively pure propane by 1911, and on March 25, 1913, his method of processing and producing LP gases was issued patent #1,056,845.<ref name=history>{{cite web|title=The History of Propane |url=http://www.npga.org/i4a/pages/index.cfm?pageid=634 |author=National Propane Gas Association |access-date=2007-12-22 |url-status=dead |archive-url=https://web.archive.org/web/20110111065134/http://www.npga.org/i4a/pages/index.cfm?pageid=634 |archive-date=January 11, 2011 }}</ref> A separate method of producing LP gas through compression was developed by Frank Peterson and its patent was granted on July 2, 1912.<ref name="lpga">{{Cite journal | title=The First Fifty Years of LP-Gas: An Industry Chronology | journal=LPGA Times | date=January 1962 | url=http://www.npga.org/files/public/LPGA_Times_1962_History.pdf | url-status=dead | archive-url=https://web.archive.org/web/20061007140419/http://www.npga.org/files/public/LPGA_Times_1962_History.pdf | archive-date=2006-10-07 }}, Page 17.</ref>

The 1920s saw increased production of LP gases, with the first year of recorded production totaling {{convert|223,000|USgal|m3}} in 1922. In 1927, annual marketed LP gas production reached {{convert|1|e6USgal|m3}}, and by 1935, the annual sales of LP gas had reached {{convert|56|e6USgal|m3}}. Major industry developments in the 1930s included the introduction of railroad tank car transport, gas odorization, and the construction of local bottle-filling plants. The year 1945 marked the first year that annual LP gas sales reached a billion gallons. By 1947, 62% of all U.S. homes had been equipped with either natural gas or propane for cooking.<ref name=history />

In 1950, 1,000 propane-fueled buses were ordered by the [[Chicago Transit Authority]], and by 1958, sales in the U.S. had reached {{convert|7|e9USgal|m3}} annually. In 2004, it was reported to be a growing $8-billion to $10-billion industry with over {{convert|15|e9USgal|m3}} of propane being used annually in the U.S.<ref>{{cite web|title=Fact Sheet – The History of Propane |url=http://www.propanecouncil.org/newsroom/fact_sheetsDetail.cfv?id=5 |author1=Propane Education |author2=Research Council |name-list-style=amp |access-date=2007-12-22 |url-status=dead |archive-url=https://web.archive.org/web/20040216021025/http://www.propanecouncil.org/newsroom/fact_sheetsDetail.cfv?id=5 |archive-date=February 16, 2004 }}</ref>

During the [[COVID-19 pandemic]], propane [[Shortages related to the COVID-19 pandemic|shortages]] were reported in the United States due to increased demand.<ref>{{Cite web|last=Puente|first=Victor|date=7 December 2020|title=Propane shortage: An unexpected side effect of the pandemic and restaurant mandates|url=https://www.wkyt.com/2020/12/07/propane-shortage-an-unexpected-side-effect-of-the-pandemic-and-restaurant-mandates/|access-date=2021-01-30|website=WKYT|language=en}}</ref><ref>{{Cite web|last=Lott|first=Jennifer|date=14 January 2021|title=Southwest Louisiana is experiencing a propane supply shortage|url=https://www.kplctv.com/2021/01/14/southwest-louisiana-is-experiencing-propane-supply-shortage/|access-date=2021-01-30|website=KPLC|language=en-US}}</ref><ref>{{Cite web|last=Peguero|first=Joshua|date=6 December 2020|title=Pandemic is creating an increase in demand for propane, as some homeowners struggle to get some|url=https://www.wbay.com/2020/12/06/pandemic-is-creating-an-increase-in-demand-for-propane-as-some-homeowners-struggle-to-get-some/|access-date=2021-01-30|website=WBAY|language=en}}</ref>

== Etymology ==
The "[[prop-]]" root found in "propane" and names of other compounds with three-carbon chains was derived from "[[propionic acid]]",<ref>{{cite web |title=Online Etymology Dictionary entry for propane |url=http://www.etymonline.com/index.php?term=propane |access-date=2010-10-29 |publisher=Etymonline.com}}</ref> which in turn was named after the Greek words protos (meaning first) and pion (fat), as it was the "first" member of the series of [[Fatty acid|fatty acids]].<ref>{{cite book |url=http://www.websters1913.com/words/Propionic |title=Webster's Revised Unabridged Dictionary |publisher=[[Merriam-Webster|G. & C. Merriam]] |year=1913 |location=Springfield, Mass. |language=en |oclc=800618302 |accessdate=31 December 2023}}</ref>

== Properties and reactions ==
[[File:Propane flame contours-en.svg|thumb|[[Pyrometry]] of a propane flame using thin-filament velocimetry. The hottest parts of the flame are in a hollow cone-shaped area near its base and pointing upward.
{{legend|red|>{{convert|1750|K|C}}}}
{{legend|orange|{{convert|1700|K|C}}}}
{{legend|yellow|{{convert|1600|K|C}}}}
{{legend|lime|{{convert|1350|K|C}}}}
{{legend|cyan|{{convert|1100|K|C}}}}
{{legend|blue|{{convert|875|K|C}}}}
{{legend|purple|{{convert|750|K|C}}}}]]

Propane is a colorless, odorless gas. [[Ethyl mercaptan]] is added as a safety precaution as an [[odorizer]],<ref>NIOSH [2021]. Odor fade in natural gas and propane. Morgantown, WV: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention,  National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2021-106 (revised 01/2022), https://doi.org/10.26616/NIOSHPUB2021106revised012022external icon.</ref> and is commonly called a "rotten egg" smell.<ref>{{cite web | url=https://portal.ct.gov/pura/gas-pipeline-safety/what-to-do-if--you-smell-propane-gas | title=What to do if You Smell Propane Gas }}</ref> At normal pressure it liquifies below its [[boiling point]] at −42&nbsp;°C and solidifies below its [[melting point]] at −187.7&nbsp;°C. Propane crystallizes in the [[space group]] P2<sub>1</sub>/n.<ref>{{cite web| url = https://log-web.de/chemie/Start.htm?name=propaneCryst&lang=en| title = geometry of crystalline propane}}</ref><ref>{{cite journal |vauthors=Boese R, Weiss HC, Blaser D | title= The melting point alternation in the short-chain ''n''-alkanes: Single-crystal X-ray analyses of propane at 30&nbsp;K and of ''n''-butane to ''n''-nonane at 90&nbsp;K | journal= Angew Chem Int Ed | year=1999 | volume=38 | pages=988–992 |doi=10.1002/(SICI)1521-3773(19990401)38:7<988::AID-ANIE988>3.3.CO;2-S | doi-broken-date= 15 July 2025 }}</ref> The low space-filling of 58.5% (at 90 K), due to the bad stacking properties of the molecule, is the reason for the particularly low melting point.

Propane undergoes [[combustion]] reactions in a similar fashion to other [[alkane]]s. In the presence of excess oxygen, propane burns to form water and [[carbon dioxide]].
<chem display="block">C3H8 + 5 O2 -> 3 CO2 + 4 H2O + heat </chem>
When insufficient oxygen is present for complete combustion, [[carbon monoxide]], soot ([[carbon]]), or both, are formed as well:
<chem display="block">C3H8 + 9/2 O2 -> 2 CO2 + CO + 4 H2O + heat </chem>
<chem display="block">C3H8 + 2 O2 -> 3 C + 4 H2O + heat </chem>
The complete combustion of propane produces about 50 MJ/kg of heat.<ref name="nist" />

Propane combustion is much cleaner than that of coal or unleaded gasoline. Propane's per-BTU production of CO<sub>2</sub> is almost as low as that of natural gas.<ref name="eiagov">{{cite web |title=How much carbon dioxide is produced when different fuels are burned | url=https://www.eia.gov/tools/faqs/faq.php?id=73&t=11 | author=United States Energy Information Association|access-date=2019-03-25}}</ref> Propane burns hotter than home heating oil or diesel fuel because of the very high hydrogen content. The presence of [[Carbon–carbon bond|C–C bonds]], plus the multiple bonds of [[propylene]] and [[butene|butylene]], produce organic exhausts besides carbon dioxide and water vapor during typical combustion. These bonds also cause propane to burn with a visible flame.

=== Energy content ===
The [[enthalpy]] of combustion of propane gas where all products return to standard state, for example where water returns to its liquid state at standard temperature (known as [[Heat of combustion#Higher heating value|higher heating value]]), is (2,219.2 ± 0.5) kJ/mol, or (50.33 ± 0.01) MJ/kg.<ref name="nist">[http://webbook.nist.gov/cgi/cbook.cgi?ID=C74986&Units=SI&Mask=1#Thermo-Gas Propane]. NIST Standard Reference Data referring to {{Cite journal | last1 = Pittam | first1 = D. A. | last2 = Pilcher | first2 = G. | doi = 10.1039/f19726802224 | title = Measurements of heats of combustion by flame calorimetry. Part 8.—Methane, ethane, propane, n-butane and 2-methylpropane | journal = Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases | volume = 68 | pages = 2224 | year = 1972 }} and {{cite journal|author=Rossini, F.D.|title= Calorimetric determination of the heats of combustion of ethane, propane, normal butane, and normal pentane|journal=  Bureau of Standards Journal of Research|year= 1934|volume= 12|issue= 6|pages= [https://archive.org/details/calorimetricdete12673ross/page/735 735]–750|url=https://archive.org/details/calorimetricdete12673ross|doi=10.6028/jres.012.059|doi-access= free}}</ref>

The enthalpy of combustion of propane gas where products do not return to standard state, for example where the hot gases including water vapor exit a chimney, (known as [[Heat of combustion#Lower heating value|lower heating value]]) is 2,043.455 kJ/mol.<ref>{{cite book|last1=Ҫengel|first1=Yunus A.|last2=Boles|first2=Michael A.|title=Thermodynamics: An Engineering Approach|date=2006|publisher=McGraw Hill|isbn=978-0-07-288495-1|page=925|edition=Fifth}}</ref>  The lower heat value is the amount of heat available from burning the substance where the combustion products are vented to the atmosphere; for example, the heat from a fireplace when the flue is open.

=== Density ===
The density of propane gas at 25&nbsp;°C (77&nbsp;°F) is 1.808&nbsp;kg/m<sup>3</sup>, about 1.5× the density of air at the same temperature. The density of liquid propane at 25&nbsp;°C (77&nbsp;°F) is 0.493&nbsp;g/cm<sup>3</sup>, which is equivalent to 4.11 pounds per U.S. liquid gallon or 493&nbsp;g/L. Propane expands at 1.5% per 10&nbsp;°F. Thus, liquid propane has a density of approximately 4.2 pounds per gallon (504&nbsp;g/L) at 60&nbsp;°F (15.6&nbsp;°C).<ref>{{Cite journal|last=Razmi|first=Amir|date=May 2019|title=Propylene Production by Propane Dehydrogenation (PDH)|url=https://www.slideshare.net/AmirRazmi/propylene-production-by-propane-dehydrogenation-pdh|journal=Engineering|pages=3}}</ref>

As the density of propane changes with temperature, this fact must be considered every time when the application is connected with safety or custody transfer operations.<ref>{{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}}</ref> If enough headspace is not left in a tank when filling, the tank could rupture when it heats up.
[[File:Propane butane liquid vapor density zivenko.png|alt=Temperature-Density Curve for Propane|thumb|Temperature–density curve for liquid/vapor propane]]

== Uses ==
{{More citations needed section|date=April 2019}}

===Portable stoves===
Propane is a popular choice for barbecues and portable stoves because the low [[boiling point]] of {{convert|-42|C|F}} makes it vaporize as soon as it is released from its pressurized container. Therefore, no [[carburetor]] or other vaporizing device is required; a simple metering nozzle suffices.

=== Refrigerant ===
Blends of pure, dry "isopropane" [isobutane/propane mixtures of propane (R-290) and [[isobutane]] (R-600a)] can be used as the circulating refrigerant in suitably constructed compressor-based refrigeration.<ref>{{Cite journal |last=Başaran |first=Anıl |date=August 10, 2023 |title=Experimental investigation of R600a as a low GWP substitute to R134a in the closed-loop two-phase thermosyphon of the mini thermoelectric refrigerator |url=https://www.sciencedirect.com/science/article/abs/pii/S1359431122004550 |url-status=live |archive-url=https://web.archive.org/web/20230811050616/https://www.sciencedirect.com/science/article/abs/pii/S1359431122004550 |archive-date=August 11, 2023 |access-date=2023-08-11 |journal=Applied Thermal Engineering |volume=211 |article-number=118501 |doi=10.1016/j.applthermaleng.2022.118501 |s2cid=248206074 |language=en-AU |url-access=subscription }}</ref> Compared to fluorocarbons, propane has a negligible [[ozone depletion potential]] and very low [[global warming potential]] (having a GWP value of 0.072,<ref>[https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Full_Report.pdf Climate Change 2021 – The Physical Science Basis]</ref> 13.9 times lower than the GWP of carbon dioxide) and can serve as a functional replacement for [[Dichlorodifluoromethane|R-12]], [[Chlorodifluoromethane|R-22]], [[1,1,1,2-Tetrafluoroethane|R-134a]], and other [[chlorofluorocarbon]] or [[hydrofluorocarbon]] [[refrigerant]]s in conventional stationary refrigeration and air conditioning systems.<ref>{{cite web|url=http://ec.europa.eu/environment/ozone/pdf/hcfc_technical_meeting_summary.pdf |title=European Commission on retrofit refrigerants for stationary applications |access-date=2010-10-29 |archive-url=https://web.archive.org/web/20090805150605/http://ec.europa.eu/environment/ozone/pdf/hcfc_technical_meeting_summary.pdf |archive-date=August 5, 2009 }}</ref> Because its global warming effect is far less than current refrigerants, propane was chosen as one of five replacement refrigerants approved by the EPA in 2015, for use in systems specially designed to handle its flammability.<ref>{{cite web |last1=Koch |first1=Wendy |title=Why Your Fridge Pollutes and How It's Changing |url=https://www.nationalgeographic.com/science/article/150306-why-your-fridge-pollutes-and-how-its-changing |archive-url=https://web.archive.org/web/20210226092729/https://www.nationalgeographic.com/science/article/150306-why-your-fridge-pollutes-and-how-its-changing |url-status=live |archive-date=February 26, 2021 |publisher=National Geographic |access-date=22 December 2021 |date=March 6, 2015}}</ref>

Such substitution is widely prohibited or discouraged in motor vehicle air conditioning systems, on the grounds that using [[Flammability|flammable]] hydrocarbons in systems originally designed to carry non-flammable refrigerant presents a significant risk of fire or explosion.<ref>{{multiref2
|1={{cite web |url=http://www.epa.gov/ozone/snap/refrigerants/hc12alng.html |title=U.S. EPA hydrocarbon-refrigerants FAQ |publisher=Epa.gov |access-date=2010-10-29 |archive-date=2002-12-31 |archive-url=https://web.archive.org/web/20021231213807/http://www.epa.gov/ozone/snap/refrigerants/hc12alng.html |url-status=dead }}
|2=[https://web.archive.org/web/20080719055123/http://www.vasa.org.au/pdf/memberlibrary/hydrocarbons/hc_white_paper.pdf Compendium of hydrocarbon-refrigerant policy statements, October 2006]. vasa.org.au
|3={{cite web |url=http://www.autoacforum.com/MACS/HCwarning.pdf |title=MACS bulletin: hydrocarbon refrigerant usage in vehicles |access-date=2010-10-29 |url-status=dead |archive-url=https://web.archive.org/web/20110105174944/http://www.autoacforum.com/MACS/HCwarning.pdf |archive-date=2011-01-05 }}
|4={{cite web |url=http://www.sae.org/news/releases/05hydrocarbon_warning.htm |title=Society of Automotive Engineers hydrocarbon refrigerant bulletin |publisher=Sae.org |date=2005-04-27 |access-date=2010-10-29 |archive-url=https://web.archive.org/web/20050505030057/http://www.sae.org/news/releases/05hydrocarbon_warning.htm |archive-date=2005-05-05 |url-status=dead }}
|5={{cite web |url=http://www.shadetreemechanic.com/cc_hydrocarbon_refrigerants.htm |title=Shade Tree Mechanic on hydrocarbon refrigerants |publisher=Shadetreemechanic.com |date=2005-04-27 |access-date=2010-10-29 |archive-date=2010-11-27 |archive-url=https://web.archive.org/web/20101127153510/http://shadetreemechanic.com/cc_hydrocarbon_refrigerants.htm |url-status=dead }}
|6={{cite web |url=http://www.labour.gov.sk.ca/Default.aspx?DN=2fb5ac24-d90e-4408-bf40-559793bd8e96 |title=Saskatchewan Labour bulletin on hydrocarbon refrigerants in vehicles |publisher=Labour.gov.sk.ca |date=2010-06-29 |access-date=2010-10-29 |url-status=dead |archive-url=https://web.archive.org/web/20090701025850/http://www.labour.gov.sk.ca/Default.aspx?DN=2fb5ac24-d90e-4408-bf40-559793bd8e96 |archive-date=2009-07-01 }}
|7=[https://web.archive.org/web/20080719134349/http://www.vasa.org.au/content/refriggas/index.php#Bookmark%202 VASA on refrigerant legality & advisability]. vasa.org.au
|8={{cite web |url=http://www.energy.qld.gov.au/zone_files/petroleum_pdf/safety_alert025.pdf |title=Queensland (Australia) government warning on hydrocarbon refrigerants |publisher=Energy.qld.gov.au |access-date=2010-10-29 |archive-url=https://web.archive.org/web/20081217150006/http://www.energy.qld.gov.au/zone_files/petroleum_pdf/safety_alert025.pdf |archive-date=December 17, 2008 }}}}</ref>

Vendors and advocates of hydrocarbon refrigerants argue against such bans on the grounds that there have been very few such incidents relative to the number of vehicle air conditioning systems filled with hydrocarbons.<ref>{{cite web|url=http://www.parliament.nsw.gov.au/prod/parlment/HansArt.nsf/V3Key/LA19971016015 |title=New South Wales (Australia) Parliamentary record, 16 October 1997 |publisher=Parliament.nsw.gov.au |date=1997-10-16 |access-date=2010-10-29 |url-status=dead |archive-url=https://web.archive.org/web/20090701025536/http://www.parliament.nsw.gov.au/prod/parlment/HansArt.nsf/V3Key/LA19971016015 |archive-date=1 July 2009 }}</ref><ref>{{cite web|url=http://www.parliament.nsw.gov.au/prod/parlment/hansart.nsf/V3Key/LC20000629051 |title=New South Wales (Australia) Parliamentary record, 29 June 2000 |publisher=Parliament.nsw.gov.au |access-date=2010-10-29 |url-status=dead |archive-url=https://web.archive.org/web/20050522080708/http://www.parliament.nsw.gov.au/prod/parlment/hansart.nsf/V3Key/LC20000629051 |archive-date=22 May 2005 }}</ref>

Propane is also instrumental in providing [[off-the-grid]] refrigeration, as the energy source for a [[gas absorption refrigerator]] and is commonly used for camping and recreational vehicles.

It has also been proposed to use propane as a refrigerant in [[Heat pump|heat pumps]].<ref>{{Cite web |last=Everitt |first=Neil |date=2023-03-18 |title=Scientists back propane in heat pumps |url=https://www.coolingpost.com/world-news/scientists-back-propane-in-heat-pumps/ |access-date=2024-03-09 |website=Cooling Post |language=en-GB}}</ref>

=== Domestic and industrial fuel ===
[[File:150 gallon Propane Tank.jpg|thumb|upright|Domestic spherical steel pressure vessel for propane storage]]
Since it can be transported easily, it is a popular fuel for home heat and backup electrical generation in sparsely populated areas that do not have natural gas pipelines. In June 2023, Stanford researchers found propane combustion emitted detectable and repeatable levels of benzene that in some homes raised indoor benzene concentrations above well-established health benchmarks. The research also shows that gas and propane fuels appear to be the dominant source of benzene produced by cooking.<ref>{{Cite journal |last1=Kashtan |first1=Yannai S. |last2=Nicholson |first2=Metta |last3=Finnegan |first3=Colin |last4=Ouyang |first4=Zutao |last5=Lebel |first5=Eric D. |last6=Michanowicz |first6=Drew R. |last7=Shonkoff |first7=Seth B. C. |last8=Jackson |first8=Robert B. |date=June 15, 2023 |title=Gas and Propane Combustion from Stoves Emits Benzene and Increases Indoor Air Pollution |journal=  Environmental Science & Technology|volume=57 |issue=26 |pages=9653–9663 |doi=10.1021/acs.est.2c09289 |pmid=37319002 |pmc=10324305 |bibcode=2023EnST...57.9653K }}</ref>

In rural areas of North America, as well as northern Australia, propane is used to heat livestock facilities, in grain dryers, and other heat-producing appliances. When used for heating or [[grain drying]] it is usually stored in a large, permanently-placed cylinder which is refilled by a propane-delivery truck. {{as of|2014}}, 6.2 million American households use propane as their primary heating fuel.<ref name="Sloan-2016">{{cite web|url=https://www.afdc.energy.gov/uploads/publication/2016_propane_market_outlook.pdf|title=2016 Propane Market Outlook|author1=Sloan, Michael|publisher=Propane Education and Research Council|access-date=19 January 2018}}</ref>

In North America, local delivery trucks with an average cylinder size of {{convert|3,000|USgal|m3}}, fill up large cylinders that are permanently installed on the property, or other service trucks exchange empty cylinders of propane with filled cylinders. Large tractor-trailer trucks, with an average cylinder size of {{convert|10,000|USgal|m3}}, transport propane from the pipeline or refinery to the local bulk plant. The bobtail [[tank truck]] is not unique to the North American market, though the practice is not as common elsewhere, and the vehicles are generally called ''tankers''. In many countries, propane is delivered to end-users via small or medium-sized individual cylinders, while empty cylinders are removed for refilling at a central location.

There are also community propane systems, with a central cylinder feeding individual homes.<ref>{{Cite web|last=Council|first=Propane Education & Research|title=Community Propane Systems {{!}} Propane.com|url=https://propane.com/propane-products/community-propane-systems/|access-date=2021-12-28|website=Propane|language=en}}</ref>

=== Motor fuel ===
{{Main|Autogas}}
In the U.S., over 190,000 on-road vehicles use propane, and over 450,000 forklifts use it for power. It is the third most popular vehicle fuel in the world,<ref name="propane-as-fuel" /> behind [[gasoline]] and [[diesel fuel]]. In other parts of the world, propane used in vehicles is known as autogas. In 2007, approximately 13 million vehicles worldwide use autogas.<ref name="propane-as-fuel">{{cite web|author1=Propane Education |author2=Research Council |name-list-style=amp |title=Autogas |url=http://www.propanecouncil.org/propane-as-fuel/ |publisher=PERC |access-date=2012-05-17 |url-status=dead |archive-url=https://web.archive.org/web/20100923030304/http://www.propanecouncil.org/propane-as-fuel/ |archive-date=September 23, 2010 }}</ref>

The advantage of propane in cars is its liquid state at a moderate pressure. This allows fast refill times, affordable fuel cylinder construction, and price ranges typically just over half that of gasoline. Meanwhile, it is noticeably cleaner (both in handling, and in combustion), results in less engine wear (due to carbon deposits) without diluting engine oil (often extending oil-change intervals), and until recently{{When|date=July 2021}} was relatively low-cost in North America. The [[octane rating]] of propane is relatively high at 110. In the United States the propane fueling infrastructure is the most developed of all alternative vehicle fuels. Many converted vehicles have provisions for topping off from "barbecue bottles". Purpose-built vehicles are often in commercially owned fleets, and have private fueling facilities. A further saving for propane fuel vehicle operators, especially in fleets, is that theft is much more difficult than with gasoline or diesel fuels.

Propane is also used as fuel for [[small engine]]s, especially those used indoors or in areas with insufficient fresh air and ventilation to carry away the more toxic exhaust of an engine running on gasoline or diesel fuel. More recently,{{When|date=July 2021}} there have been lawn-care products like [[string trimmer]]s, [[lawn mowers]] and [[leaf blowers]] intended for outdoor use, but fueled by propane in order to reduce [[air pollution]].<ref>{{Cite web|url=http://www.allpropanemowers.com/wp-content/uploads/2014/06/Facts_About_Propane.pdf|title=Facts About Propane: America's Exceptional Energy|date=April 2001|publisher=National Propane Gas Association|access-date=December 15, 2016|archive-date=December 21, 2016|archive-url=https://web.archive.org/web/20161221104931/http://www.allpropanemowers.com/wp-content/uploads/2014/06/Facts_About_Propane.pdf|url-status=dead}}</ref>

Many heavy-duty highway trucks use propane as a boost, where it is added through the turbocharger, to mix with diesel fuel droplets. The very high hydrogen content of propane helps the diesel fuel to burn hotter and therefore more completely. This provides more torque, more horsepower, and a cleaner exhaust for the trucks. It is normal for a 7-liter medium-duty diesel truck engine to increase fuel economy by 20 to 33 percent when a propane boost system is used. It is cheaper because propane is much cheaper than diesel fuel. The longer distance a cross-country trucker can travel on a full load of combined diesel and propane fuel means they can maintain federal hours of work rules with two fewer fuel stops in a cross-country trip. Truckers, tractor pulling competitions, and farmers have been using a propane boost system for over forty years{{When|date=July 2021}} in North America.

=== Other uses ===
[[File:Propane cylinders type 2012 and 2000 in Tuntorp.jpg|thumb|Cylinders type 2012 containing 2 kg, and type 2000 containing 0.34 kg propane; sizes normally used for [[camping]] devices and hobby projects in workshops.]]
*Propane is the primary flammable gas in [[blowtorch]]es for [[soldering]].
*Propane is used in [[oxy-fuel welding and cutting]]. Propane does not burn as hot as acetylene in its inner cone, and so it is rarely used for welding. Propane, however, has a very high number of BTUs per cubic foot in its outer cone, and so with the right torch (injector style) it can make a faster and cleaner cut than acetylene, and is much more useful for heating and bending than acetylene.
*Propane is used as a feedstock for the production of base [[petrochemical]]s in [[steam cracking]].
*Propane is the primary fuel for [[hot-air balloon]]s.
*It is used in semiconductor manufacture to deposit [[silicon carbide]].
*Propane is commonly used in theme parks and in movie production as an inexpensive, high-energy fuel for explosions and other special effects.
*Propane is used as a propellant, relying on the expansion of the gas to fire the projectile. It does not ignite the gas. The use of a liquefied gas gives more shots per cylinder, compared to a compressed gas.
*Propane is also used as a cooking fuel.
*Propane is used as a propellant for many household aerosol sprays, including shaving creams and air fresheners.
*Propane is a promising feedstock for the production of propylene.{{citation needed|date=January 2023}}
*Liquified propane is used in the extraction of animal fats and vegetable oils.<ref>{{Ullmann|doi=10.1002/14356007.a24_437|title=Solvents|year=2000|last1=Stoye|first1=Dieter|isbn=3527306730}}</ref>

==Purity==
The North American standard grade of automotive-use propane is rated HD-5 (Heavy Duty 5%). HD-5 grade has a maximum of 5 percent butane, but propane sold in Europe has a maximum allowable amount of butane of 30 percent, meaning it is not the same fuel as HD-5. The LPG used as auto fuel and cooking gas in Asia and Australia also has very high butane content.

[[Propylene]] (also called propene) can be a contaminant of commercial propane. Propane containing too much propene is not suited for most vehicle fuels. HD-5 is a specification that establishes a maximum concentration of 5% propene in propane. Propane and other LP gas specifications are established in ASTM D-1835.<ref>{{cite web|url=http://www.astm.org/Standards/D1835.htm|title=ASTM D1835 - 16 Standard Specification for Liquefied Petroleum (LP) Gases|website=www.astm.org}}</ref> All propane fuels include an [[Aroma compound|odorant]], almost always [[ethanethiol]], so that the gas can be smelled easily in case of a leak. Propane as HD-5 was originally intended for use as vehicle fuel. HD-5 is currently being used in all propane applications.

Typically in the United States and Canada, [[Liquefied petroleum gas|LPG]] is primarily propane (at least 90%), while the rest is mostly [[ethane]], [[propylene]], [[butane]], and odorants including [[ethyl mercaptan]].<ref>{{cite web |title=Amerigas Material Safety Data Sheet for Odorized Propane |url=http://www.amerigas.com/pdfs/safe_eng.pdf |author=Amerigas |access-date=2011-10-24 |url-status=dead |archive-url=https://web.archive.org/web/20111209131917/http://amerigas.com/pdfs/safe_eng.pdf |archive-date=2011-12-09 }}</ref><ref>{{cite web |title=Suburban Propane Material Safety Data Sheet for Commercial Odorized Propane |url=http://www.suburbanpropane.com/safety/pdf/propane/SAF%205152%20MATERIAL%20SAFETY%20DATA%20SHEET.pdf |author=Suburban Propane |access-date=2011-10-24 |url-status=dead |archive-url=https://web.archive.org/web/20111025035650/http://suburbanpropane.com/safety/pdf/propane/SAF%205152%20MATERIAL%20SAFETY%20DATA%20SHEET.pdf |archive-date=2011-10-25 }}</ref> This is the HD-5 standard, (maximum allowable propylene content, and no more than 5% butanes and ethane) defined by the American Society for Testing and Materials by its Standard 1835 for internal combustion engines. Not all products labeled "LPG" conform to this standard, however. In Mexico, for example, gas labeled "LPG" may consist of 60% propane and 40% butane. "The exact proportion of this combination varies by country, depending on international prices, on the availability of components and, especially, on the climatic conditions that favor LPG with higher butane content in warmer regions and propane in cold areas".<ref>{{cite web|last=Mexican Ministry of Energy|title=Liquefied Petroleum Gas Market Outlook 2008–2017|url=http://www.energia.gob.mx/res/PE_y_DT/pub/LPG%20Outlook%202008-2017.pdf|publisher=Mexican Ministry of Energy|access-date=2012-05-17|url-status=dead|archive-url=https://web.archive.org/web/20120510162404/http://energia.gob.mx/res/PE_y_DT/pub/LPG%20Outlook%202008-2017.pdf|archive-date=2012-05-10}}</ref>

== Comparison with natural gas ==
Propane is bought and stored in a liquid form, LPG. It can easily be stored in a relatively small space.

By comparison, [[compressed natural gas]] (CNG) cannot be liquefied by compression at normal temperatures, as these are well above its [[critical temperature]]. As a gas, very high pressure is required to store useful quantities. This poses the hazard that, in an accident, just as with any compressed gas cylinder (such as a CO<sub>2</sub> cylinder used for a soda concession) a CNG cylinder may burst with great force, or leak rapidly enough to become a self-propelled missile. Therefore, CNG is much less efficient to store than propane, due to the large cylinder volume required. An alternative means of storing natural gas is as a [[Cryogenics|cryogenic]] liquid in an insulated container as [[liquefied natural gas]] (LNG). This form of storage is at low pressure and is around 3.5 times as efficient as storing it as CNG.

Unlike propane, if a spill occurs, CNG will evaporate and dissipate because it is lighter than air.

Propane is much more commonly used to fuel vehicles than is natural gas, because that equipment costs less. Propane requires just {{Convert|1,220|kPa|psi|0}} of pressure to keep it liquid at {{Convert|37.8|C|F|0}}.<ref name="Vapor Pressure">{{cite web|title =Propane Vapor Pressure|website =The Engineering ToolBox|year =2005|url =http://www.engineeringtoolbox.com/propane-vapor-pressure-d_1020.html|access-date =2008-07-28}}</ref><!-- The popular culture section has been deliberately removed from this article. Please do not reinsert it. -->

== Hazards ==
Propane is a simple [[asphyxia]]nt.<ref name="cdc">{{cite web  |url=https://www.cdc.gov/niosh/idlh/74986.html|publisher=The National Institute for Occupational Safety and Health (NIOSH) |title=Propane |access-date = 2016-05-12 | quote = Propane is a simple asphyxiant and does not present an IDLH hazard at concentrations below its lower explosive limit (LEL). The chosen IDLH is based on the LEL of 21,000 ppm rounded down to 20,000 ppm.}}</ref> Unlike [[natural gas]], it is denser than air. It may accumulate in low spaces and near the floor. When abused as an [[Intoxicative inhalant|inhalant]], it may cause [[hypoxia (medical)|hypoxia]] (lack of oxygen), [[pneumonia]], [[cardiac failure]] or [[cardiac arrest]].<ref name="gdcada.org">{{cite web |archive-url=https://web.archive.org/web/20090408021738/http://www.gdcada.org/statistics/inhalants.htm |url=http://www.gdcada.org/statistics/inhalants.htm |archive-date=2009-04-08 |publisher=Greater Dallas Council on Alcohol & Drug Abuse |date=March 4, 2006 |title=Inhalants – Facts and Statistics}}</ref><ref>{{cite web|url=http://www.inhalants.org/final_medical.htm | title = Inhalants | date = 30 May 2020 | publisher = National Inhalant Prevention Coalition}}</ref> Propane has low [[toxicity]] since it is not readily absorbed and is not [[Biological activity|biologically active]]. Commonly stored under pressure at room temperature, propane and its mixtures will [[Flash evaporation|flash evaporate]] at atmospheric pressure and cool well below the freezing point of water. The cold gas, which appears white due to moisture condensing from the air, may cause frostbite.

Propane is denser than air. If a leak in a propane fuel system occurs, the vaporized gas will have a tendency to sink into any enclosed area and thus poses a risk of explosion and fire. The typical scenario is a leaking cylinder stored in a basement; the propane leak drifts across the floor to the pilot light on the furnace or water heater, and results in an explosion or fire. This property makes propane generally unsuitable as a fuel for boats. In 2007, a heavily investigated vapor-related [[Ghent, West Virginia#2007 Propane Disaster|explosion]] occurred in Ghent, West Virginia, U.S., killing four people and completely destroying the Little General [[convenience store]] on [[US Route 19|Flat Top Road]], causing several injuries.<ref>{{cite web|title=Little General Store Propane Explosion|url=https://www.csb.gov/little-general-store-propane-explosion/|publisher=US Chemical Safety and Hazard Investigation Board|date=September 25, 2008|access-date=June 16, 2021}}</ref><ref>{{cite web|title=Investigation Report:Little General Store-Propane Explosion (four killed, six injured)|url=https://www.csb.gov/assets/1/20/csbfinalreportlittlegeneral.pdf?13741|author=US Chemical Safety and Hazard Investigation Board|date=September 25, 2008|access-date=June 16, 2021}}</ref>

And Another hazard associated with propane storage and transport is known as a BLEVE or [[boiling liquid expanding vapor explosion]]. The [[Kingman Explosion]] involved a railroad tank car in Kingman, Arizona, U.S., in 1973 during a propane transfer. The fire and subsequent explosions resulted in twelve fatalities and numerous injuries.<ref name="Kingman">{{cite web|title=The Disaster Story|url=http://kingmanhistoricdistrict.com/points-of-interest/firefighters-memorial-park/the-disaster-story.htm|publisher=Kingman Historic District|access-date=1 July 2013}}</ref>

== Production ==
Propane is produced as a [[by-product]] of two other processes, [[natural gas processing]] and [[Oil refinery|petroleum refining]]. The processing of natural gas involves removal of [[butane]], propane, and large amounts of [[ethane]] from the raw gas, to prevent condensation of these volatiles in natural gas pipelines. Additionally, oil refineries produce some propane as a by-product of [[cracking (chemistry)|cracking]] petroleum into gasoline or heating oil.

The supply of propane cannot easily be adjusted to meet increased demand, because of the by-product nature of propane production. About 90% of U.S. propane is domestically produced.<ref name="Sloan-2016" /> The United States imports about 10% of the propane consumed each year, with about 70% of that coming from Canada via pipeline and rail. The remaining 30% of imported propane comes to the United States from other sources via ocean transport.

After it is separated from the crude oil, North American propane is stored in huge [[Natural gas storage#Salt formation|salt caverns]]. Examples of these are [[Fort Saskatchewan]], [[Alberta]]; [[Mont Belvieu, Texas]]; and [[Conway, Kansas]]. These salt caverns<ref>{{cite web |author=Argonne National Laboratory |year=1999 |title=Salt Cavern Information Center |url=http://web.ead.anl.gov/saltcaverns/uses/hcstorage/index.htm |url-status=dead |archive-url=https://web.archive.org/web/20071223143256/http://web.ead.anl.gov/saltcaverns/uses/hcstorage/index.htm |archive-date=2007-12-23 |access-date=2007-12-22}}</ref> can store {{convert|80000000|oilbbl|m3}} of propane.

=== Retail cost ===
{{Globalize|section|USA|2name=the [[United States]]|date=August 2017}}

==== United States ====
{{As of|2013|10}}, the retail cost of propane was approximately $2.37 per gallon, or roughly $25.95 per 1 million BTUs.<ref>{{cite web|url =http://www.eia.gov/dnav/pet/pet_pri_wfr_dcus_nus_m.htm|title = Heating Oil and Propane Prices|author = US Energy Information Administration|date = November 12, 2013}}</ref> This means that filling a 500-gallon propane tank, which is what households that use propane as their main source of energy usually require, cost $948 (80% of 500 gallons or 400 gallons), a 7.5% increase on the 2012–2013 winter season average US price.<ref>{{cite web|url =http://propanedeal.com/prices/current-propane-prices|title = Current Propane Prices|author = Propane Deal|date = November 12, 2013}}</ref> However, propane costs per gallon change significantly from one state to another: the Energy Information Administration (EIA) quotes a $2.995 per gallon average on the East Coast for October 2013,<ref>{{cite web|url =http://www.eia.gov/dnav/pet/pet_pri_wfr_dcus_R10_m.htm|title = East Coast Heating Oil and Propane Prices|author = US Energy Information Administration|date = November 12, 2013}}</ref> while the figure for the Midwest was $1.860 for the same period.<ref>{{cite web|url =http://www.eia.gov/dnav/pet/pet_pri_wfr_dcus_R20_m.htm|title = Midwest Heating Oil and Propane Prices|author = US Energy Information Administration|date = November 12, 2013}}</ref>

{{As of|2015|12}}, the propane retail cost was approximately $1.97 per gallon,<ref name=EIAdecember2015>{{cite web|url=http://www.eia.gov/dnav/pet/pet_pri_wfr_a_epllpa_prs_dpgal_w.htm|title=Residential Propane: Weekly Heating Oil and Propane Prices (October – March)|author=US Energy Information Administration|date=December 12, 2015}}</ref> which meant filling a 500-gallon propane tank to 80% capacity costed $788, a 16.9% decrease or $160 less from November 2013. Similar regional differences in prices are present with the December 2015 EIA figure for the East Coast at $2.67 per gallon and the Midwest at $1.43 per gallon.<ref name=EIAdecember2015 />

{{As of|2018|8}}, the average US propane retail cost was approximately $2.48 per gallon. The wholesale price of propane in the U.S. always drops in the summer as most homes do not require it for home heating. The wholesale price of propane in the summer of 2018 was between 86 cents to 96 cents per U.S. gallon, based on a truckload or railway car load. The price for home heating was exactly double that price; at 95 cents per gallon wholesale, a home-delivered price was $1.90 per gallon if ordered 500 gallons at a time. Prices in the Midwest are always less than in California. Prices for home delivery always go up near the end of August or the first few days of September when people start ordering their home tanks to be filled.<ref name=EIAaugust2018>{{cite web|url=http://www.eia.gov/dnav/pet/pet_pri_wfr_a_epllpa_prs_dpgal_w.htm|title=Residential Propane: Weekly Heating Oil and Propane Prices (October – March)|author=US Energy Information Administration|date=August 11, 2018}}</ref>

== On other planets ==

Propane was first discovered in space in 1981 in the atmosphere of [[Saturn|Saturn's]] [[Moons of Saturn|moon]] [[Titan (moon)|Titan]] based on spectroscopic observations from the [[Voyager 1]] [[Infrared interferometer spectrometer and radiometer|IRIS]] instrument.<ref>{{Cite journal |last1=Maguire |first1=W. C. |last2=Hanel |first2=R. A. |last3=Jennings |first3=D. E. |last4=Kunde |first4=V. G. |last5=Samuelson |first5=R. E. |date=August 1981 |title=C3H8 and C3H4 in Titan's atmosphere |url=https://www.nature.com/articles/292683a0 |journal=Nature |language=en |volume=292 |issue=5825 |pages=683–686 |doi=10.1038/292683a0 |issn=0028-0836}}</ref> This was subsequently confirmed by ground-based observations using the TEXES instrument on the [[NASA Infrared Telescope Facility|IRTF]] telescope <ref>{{Cite journal |last1=Roe |first1=H. G. |last2=Greathouse |first2=T. K. |last3=Richter |first3=M. J. |last4=Lacy |first4=J. H. |date=2003-11-01 |title=Propane on Titan |url=https://iopscience.iop.org/article/10.1086/379816 |journal=The Astrophysical Journal |language=en |volume=597 |issue=1 |pages=L65–L68 |doi=10.1086/379816 |arxiv=astro-ph/0309653 |bibcode=2003ApJ...597L..65R |issn=0004-637X}}</ref> and mapped by the CIRS instrument on [[Cassini–Huygens|Cassini]].<ref>{{Cite journal |last1=Coustenis |first1=A. |last2=Jennings |first2=D.E. |last3=Nixon |first3=C.A. |last4=Achterberg |first4=R.K. |last5=Lavvas |first5=P. |last6=Vinatier |first6=S. |last7=Teanby |first7=N.A. |last8=Bjoraker |first8=G.L. |last9=Carlson |first9=R.C. |last10=Piani |first10=L. |last11=Bampasidis |first11=G. |last12=Flasar |first12=F.M. |last13=Romani |first13=P.N. |date=May 2010 |title=Titan trace gaseous composition from CIRS at the end of the Cassini–Huygens prime mission |url=https://linkinghub.elsevier.com/retrieve/pii/S0019103509004734 |journal=Icarus |language=en |volume=207 |issue=1 |pages=461–476 |doi=10.1016/j.icarus.2009.11.027|bibcode=2010Icar..207..461C }}</ref> 

Propane was subsequently been detected in the atmosphere of Saturn using TEXES,<ref>{{Cite journal |last1=Greathouse |first1=T |last2=Lacy |first2=J |last3=Bezard |first3=B |last4=Moses |first4=J |last5=Richter |first5=M |last6=Knez |first6=C |date=March 2006 |title=The first detection of propane on Saturn |url=https://linkinghub.elsevier.com/retrieve/pii/S0019103505003647 |journal=Icarus |language=en |volume=181 |issue=1 |pages=266–271 |doi=10.1016/j.icarus.2005.09.016|bibcode=2006Icar..181..266G }}</ref> and predicted but unconfirmed on Jupiter, Neptune and Uranus. 

== See also ==
*[[Blau gas]]
*[[National Propane Gas Association]]

== References ==
{{Reflist|30em}}

== External links ==
{{Commons}}
* [http://www.propane.ca/ Canadian Propane Association]
* {{cite book |author=Kaoru Fujimoto |author2=Hiroshi Kaneko |author3=Qianwen Zhang |author4=Qingjie Ge |author5=Xiaohong Li |chapter=Direct synthesis of propane/butane from synthesis gas |chapter-url=https://www.sciencedirect.com/science/article/pii/S016729910780156X |editor-first=F.B. |editor-last=Noronha |editor2-first=M. |editor2-last=Schmal |editor3-first=E.F. |editor3-last=Sousa-Aguiar |title=Natural Gas Conversion VIII, Proceedings of the 8th Natural Gas Conversion Symposium |series=Studies in Surface Science and Catalysis |publisher=Elsevier |date=2007 |isbn=9780444530783 |pages=349–354 |volume=167 |doi=10.1016/S0167-2991(07)80156-X}}  ([[syngas]])
* [http://www.inchem.org/documents/icsc/icsc/eics0319.htm International Chemical Safety Card 0319]
* [https://web.archive.org/web/20160901034345/http://www.npga.org/i4a/pages/index.cfm?pageid=1 National Propane Gas Association (U.S.)]
* [https://www.cdc.gov/niosh/npg/npgd0524.html NIOSH Pocket Guide to Chemical Hazards]
* [http://www.propanecouncil.org/ Propane Education & Research Council (U.S.)]
* [http://www.propane101.com/aboutpropane.htm Propane Properties Explained] Descriptive Breakdown of Propane Characteristics
* [http://www.uklpg.org/ UKLPG: Propane and Butane in the UK]
* [http://www.eia.gov/ US Energy Information Administration]
* [https://web.archive.org/web/20061110134237/http://www.worldlpgas.com/ World LP Gas Association (WLPGA)]

{{Alkanes}}
{{Hydrides by group}}
{{Fuel gas}}
{{E number infobox 930-949}}
{{Alternative propulsion}}
{{GABAAR PAMs}}
{{Authority control}}

[[Category:Propane| ]]
[[Category:Aerosol propellants]]
[[Category:Alkanes]]
[[Category:Camping equipment]]
[[Category:E-number additives]]
[[Category:Fossil fuels]]
[[Category:Fuel gas]]
[[Category:GABAA receptor positive allosteric modulators]]
[[Category:Industrial gases]]
[[Category:Natural gas]]
[[Category:Refrigerants]]