Butane: Difference between revisions

Butane
Names
	Preferred IUPAC name Butane
	Systematic IUPAC name Tetracarbane (never recommended)
	Other names Butyl hydride; Quartane; R600;
Identifiers
CAS Number	106-97-8 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	969129
ChEBI	CHEBI:37808 ;
ChEMBL	ChEMBL134702 ;
ChemSpider	7555 ;
ECHA InfoCard	100.003.136
EC Number	203-448-7;
E number	E943a (glazing agents, ...)
Gmelin Reference	1148
KEGG	D03186 ;
MeSH	butane
PubChem CID	7843;
RTECS number	EJ4200000;
UNII	6LV4FOR43R ;
UN number	1011
CompTox Dashboard (EPA)	DTXSID7024665 ;
	InChI InChI=1S/C4H10/c1-3-4-2/h3-4H2,1-2H3 Key: IJDNQMDRQITEOD-UHFFFAOYSA-N ;
	SMILES CCCC;
Properties
Chemical formula	C4H10
Molar mass	58.124 g·mol−1
Appearance	Colorless gas
Odor	Gasoline-like or natural gas-like
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
Solubility in water	61 mg/L (at 20 °C (68 °F))
log P	2.745
Vapor pressure	~170 kPa at 283 K
Henry's law; constant (kH)	11 nmol Pa−1 kg−1
Magnetic susceptibility (χ)	−57.4·10−6 cm3/mol
Thermochemistry
Heat capacity (C)	98.49 J/(K·mol)
Std enthalpy of; formation (ΔfH⦵298)	−126.3–−124.9 kJ/mol
Std enthalpy of; combustion (ΔcH⦵298)	−2.8781–−2.8769 MJ/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H220
Precautionary statements	P210
NFPA 704 (fire diamond)	1 4 0 SA
Flash point	−60 °C (−76 °F; 213 K)
Autoignition; temperature	405 °C (761 °F; 678 K)
Explosive limits	1.8–8.4%
	NIOSH (US health exposure limits):
PEL (Permissible)	none
REL (Recommended)	TWA 800 ppm (1900 mg/m3)
IDLH (Immediate danger)	1600 ppm
Related compounds
Related alkanes	Propane; Isobutane; Pentane;
Related compounds	Perfluorobutane
Supplementary data page
	Butane (data page)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

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Butane (/ˈbjuːteɪn/) is an alkane with the formula C₄H₁₀. Butane exists as two isomers, n-butane with connectivity CH₃CH₂CH₂CH₃ and iso-butane with the formula (CH₃)₃CH. Both isomers are highly flammable, colorless, easily liquefied gases that quickly vaporize at room temperature and pressure. Butanes are a trace components of natural gases (NG gases). The other hydrocarbons in NG include propane, ethane, and especially methane, which are more abundant. Liquefied petroleum gas is a mixture of propane and some butanes.^[6]

The name butane comes from the root but- (from butyric acid, named after the Greek word for butter) and the suffix -ane (for organic compounds).

History

The first synthesis of butane was accidentally achieved by British chemist Edward Francland in 1849 from ethyl iodide and zinc, but he had not realized that the ethyl radical dimerized and misidentified the substance.^[7]

It was discovered in crude petroleum in 1864 by Edmund Ronalds, who was the first to describe its properties,^[8]^[9] which he named "hydride of butyl",^[10] based on the naming for the then-known butyric acid, which had been named and described by the French chemist Michel Eugène Chevreul^[11] 40 years earlier. Other names arose in the 1860s: "butyl hydride",^[12] "hydride of tetryl"^[13] and "tetryl hydride",^[14] "diethyl" or "ethyl ethylide"^[15] and others. August Wilhelm von Hofmann, in his 1866 systemic nomenclature, proposed the name "quartane",^[2] and the modern name was introduced to English from German around 1874.^[16]

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.^[17] 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.^[18]

Density

The density of butane is highly dependent on temperature and pressure in the reservoir.^[19] 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).

Isomers

Common name	normal butane unbranched butane n-butane	isobutane i-butane
IUPAC name	butane	methylpropane
Molecular diagram
Skeletal diagram

Rotation about the central C−C bond produces two different conformations (trans and gauche) for n-butane.^[20]

Reactions

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 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 chlorinations are 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.^[21]^[22]^[23]^[24]

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.^[25] n-Butane has a relatively high research octane number (RON) and motor octane number (MON), which are 93 and 92 respectively.^[26]

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.^[27]

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.^[28]

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.^[29]

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.^[30]^[31] 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.^[32]

The butane used as a solvent for fragrance extraction does not contain these contaminants.^[33] 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.

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

Health effects

Table from the 2010 ISCD study ranking various drugs (legal and illegal) based on statements by drug-harm experts. Butane was found to be the 14th overall most dangerous drug.^[34]

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.^[35] Butane is the most commonly abused volatile substance in the UK, and was the cause of 52% of solvent related deaths in 2000.^[36] By spraying butane directly into the throat, the jet of fluid can cool rapidly to −20 °C (−4 °F) by expansion, causing prolonged laryngospasm.^[37] "Sudden sniffer's death" syndrome, first described by Bass in 1970,^[38] is the most common single cause of solvent related deaths, resulting in 55% of known fatal cases.^[37]

References

^ ^a ^b ^c ^d ^e NIOSH Pocket Guide to Chemical Hazards. "#0068". National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b August Wilhelm Von Hofmann (1867). "I. On the action of trichloride of phosphorus on the salts of the aromatic monamines". Proceedings of the Royal Society of London. 15: 54–62. doi:10.1098/rspl.1866.0018. S2CID 98496840.
^ ^a ^b "General Principles, Rules, and Conventions". Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. P-12.1. doi:10.1039/9781849733069-00001. 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'.
^ W. B. Kay (1940). "Pressure-Volume-Temperature Relations for n-Butane". Industrial & Engineering Chemistry. 32 (3): 358–360. doi:10.1021/ie50363a016.
^ ^a ^b "Safety Data Sheet, Material Name: N-Butane" (PDF). USA: Matheson Tri-Gas Incorporated. 5 February 2011. Archived from the original (PDF) on 1 October 2011. Retrieved 11 December 2011.
^ Hammer, Georg; Lübcke, Torsten; Kettner, Roland; Pillarella, Mark R.; Recknagel, Herta; Commichau, Axel; Neumann, Hans-Joachim; Paczynska-Lahme, Barbara (2006). "Natural Gas". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a17_073.pub2. ISBN 978-3-527-30385-4.
^ Seyferth, Dietmar (2001). "Zinc Alkyls, Edward Frankland, and the Beginnings of Main-Group Organometallic Chemistry". Organometallics. 20 (14): 2940–2955. doi:10.1021/om010439f.
^ Watts, H.; Muir, M. M. P.; Morley, H. F. (1894). Watts' Dictionary of Chemistry. Vol. 4. Longmans, Green. p. 385.
^ 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.
^ "Journal of the Chemical Society". 1865.
^ Chevreul (1817) "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", … )
^ Norman Tate, A. (1863). "Petroleum and Its Products: An Accoumt of the Properties, Uses, and Commercial Value Etc., of Petroleum, the Methods Employed in Refining it and the Properties, Uses, Etc., of Its Product".
^ Watts, Henry (1865). "A Dictionary of Chemistry".
^ Miller, William Allen (1867). "Elements of chemistry pt. 3 1867".
^ Miller, William Allen (1869). "Elements of Chemistry: Theoretical and Practical: Organic chemistry".
^ Schorlemmer, Carl (1874). "A Manual of the Chemistry of the Carbon Compounds: Or, Organic Chemistry".
^ Texas Propane (2022). "The History of Propane".
^ "Chemical Production Data". 2024.
^ Zivenko, Oleksiy (2019). "LPG Accounting Specificity During ITS Storage and Transportation". Measuring Equipment and Metrology. 80 (3): 21–27. doi:10.23939/istcmtm2019.03.021. ISSN 0368-6418. S2CID 211776025.
^ Roman M. Balabin (2009). "Enthalpy Difference between Conformations of Normal Alkanes: Raman Spectroscopy Study of n-Pentane and n-Butane". J. Phys. Chem. A. 113 (6): 1012–9. Bibcode:2009JPCA..113.1012B. doi:10.1021/jp809639s. PMID 19152252.
^ MarkWest Energy Partners, L.P. Form 10-K. Sec.gov.
^ Copano Energy, L.L.C. Form 10-K. Sec.gov. Retrieved on 2012-12-03.
^ Targa Resources Partners LP Form10-k. Sec.gov. Retrieved on 2012-12-03.
^ Crosstex Energy, L.P. FORM 10-K. Sec.gov.
^ Maurice Stewart, Ken Arnold. "Reid Vapour Pressure". Science Direct. Archived from the original on 13 June 2020.
^ Jechura, John. "octane rating" (PDF). Colorado School of Mines. Archived (PDF) from the original on 1 May 2015.
^ A Primer on Gasoline Blending Archived 30 June 2013 at the Wayback Machine. An EPRINC Briefing Memorandum.
^ "R600a | Product Information". www.agas.com. Retrieved 1 December 2023.
^ "Braun C 100 TS Styling Iron User Manual Type 3589". Inmar-OIQ, LLC. n.d.
^ Gresham, Chip (16 November 2019). "Hydrogen Sulfide Toxicity: Practice Essentials, Pathophysiology, Etiology". Medscape Reference. Retrieved 22 March 2021.
^ 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) – via NCBI Bookshelf.
^ "BHO Mystery Oil". Skunk Pharm Research. 26 August 2013. Retrieved 5 December 2019.
^ "Final Report of the Safety Assessment of Isobutane, Isopentane, n-Butane, and Propane". Journal of the American College of Toxicology. 1 (4). SAGE Publications: 127–142. 1982. doi:10.3109/10915818209021266. ISSN 0730-0913. S2CID 208503534.
^ Nutt DJ, King LA, Phillips LD (November 2010). "Drug harms in the UK: a multicriteria decision analysis". Lancet. 376 (9752): 1558–1565. CiteSeerX 10.1.1.690.1283. doi:10.1016/S0140-6736(10)61462-6. PMID 21036393. S2CID 5667719.
^ "Neurotoxic Effects from Butane Gas". thcfarmer.com. 19 December 2009. Retrieved 3 October 2016.
^ 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 27 March 2007.
^ ^a ^b 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. S2CID 19617950.
^ Bass M (1970). "Sudden sniffing death". JAMA. 212 (12): 2075–2079. doi:10.1001/jama.1970.03170250031004. PMID 5467774.

External links

[PGCH-1] NIOSH Pocket Guide to Chemical Hazards. "#0068". National Institute for Occupational Safety and Health (NIOSH).

[quartane-2] August Wilhelm Von Hofmann (1867). "I. On the action of trichloride of phosphorus on the salts of the aromatic monamines". Proceedings of the Royal Society of London. 15: 54–62. doi:10.1098/rspl.1866.0018. S2CID 98496840.

[iupac2013-3] "General Principles, Rules, and Conventions". Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. P-12.1. doi:10.1039/9781849733069-00001. 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.

[chemadvisor-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] Hammer, Georg; Lübcke, Torsten; Kettner, Roland; Pillarella, Mark R.; Recknagel, Herta; Commichau, Axel; Neumann, Hans-Joachim; Paczynska-Lahme, Barbara (2006). "Natural Gas". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a17_073.pub2. ISBN 978-3-527-30385-4.

[7] Seyferth, Dietmar (2001). "Zinc Alkyls, Edward Frankland, and the Beginnings of Main-Group Organometallic Chemistry". Organometallics. 20 (14): 2940–2955. doi:10.1021/om010439f.

[Watts-8] Watts, H.; Muir, M. M. P.; Morley, H. F. (1894). Watts' Dictionary of Chemistry. Vol. 4. Longmans, Green. p. 385.

[9] 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.

[10] "Journal of the Chemical Society". 1865.

[11] Chevreul (1817) "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", … )

[12] Norman Tate, A. (1863). "Petroleum and Its Products: An Accoumt of the Properties, Uses, and Commercial Value Etc., of Petroleum, the Methods Employed in Refining it and the Properties, Uses, Etc., of Its Product".

[13] Watts, Henry (1865). "A Dictionary of Chemistry".

[14] Miller, William Allen (1867). "Elements of chemistry pt. 3 1867".

[15] Miller, William Allen (1869). "Elements of Chemistry: Theoretical and Practical: Organic chemistry".

[16] Schorlemmer, Carl (1874). "A Manual of the Chemistry of the Carbon Compounds: Or, Organic Chemistry".

[17] Texas Propane (2022). "The History of Propane".

[18] "Chemical Production Data". 2024.

[Zivenko-2019-19] Zivenko, Oleksiy (2019). "LPG Accounting Specificity During ITS Storage and Transportation". Measuring Equipment and Metrology. 80 (3): 21–27. doi:10.23939/istcmtm2019.03.021. ISSN 0368-6418. S2CID 211776025.

[Balabin_2009-20] Roman M. Balabin (2009). "Enthalpy Difference between Conformations of Normal Alkanes: Raman Spectroscopy Study of n-Pentane and n-Butane". J. Phys. Chem. A. 113 (6): 1012–9. Bibcode:2009JPCA..113.1012B. doi:10.1021/jp809639s. PMID 19152252.

[21] MarkWest Energy Partners, L.P. Form 10-K. Sec.gov.

[22] Copano Energy, L.L.C. Form 10-K. Sec.gov. Retrieved on 2012-12-03.

[23] Targa Resources Partners LP Form10-k. Sec.gov. Retrieved on 2012-12-03.

[24] Crosstex Energy, L.P. FORM 10-K. Sec.gov.

[25] Maurice Stewart, Ken Arnold. "Reid Vapour Pressure". Science Direct. Archived from the original on 13 June 2020.

[26] Jechura, John. "octane rating" (PDF). Colorado School of Mines. Archived (PDF) from the original on 1 May 2015.

[27] A Primer on Gasoline Blending Archived 30 June 2013 at the Wayback Machine. An EPRINC Briefing Memorandum.

[28] "R600a | Product Information". www.agas.com. Retrieved 1 December 2023.

[braun-29] "Braun C 100 TS Styling Iron User Manual Type 3589". Inmar-OIQ, LLC. n.d.

[Gresham_2019-30] Gresham, Chip (16 November 2019). "Hydrogen Sulfide Toxicity: Practice Essentials, Pathophysiology, Etiology". Medscape Reference. Retrieved 22 March 2021.

[Toxicology2013-31] 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) – via NCBI Bookshelf.

[32] "BHO Mystery Oil". Skunk Pharm Research. 26 August 2013. Retrieved 5 December 2019.

[SAGE-33] "Final Report of the Safety Assessment of Isobutane, Isopentane, n-Butane, and Propane". Journal of the American College of Toxicology. 1 (4). SAGE Publications: 127–142. 1982. doi:10.3109/10915818209021266. ISSN 0730-0913. S2CID 208503534.

[Nutt_2010-34] Nutt DJ, King LA, Phillips LD (November 2010). "Drug harms in the UK: a multicriteria decision analysis". Lancet. 376 (9752): 1558–1565. CiteSeerX 10.1.1.690.1283. doi:10.1016/S0140-6736(10)61462-6. PMID 21036393. S2CID 5667719.

[35] "Neurotoxic Effects from Butane Gas". thcfarmer.com. 19 December 2009. Retrieved 3 October 2016.

[36] 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 27 March 2007.

[multiple-37] 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. S2CID 19617950.

[38] Bass M (1970). "Sudden sniffing death". JAMA. 212 (12): 2075–2079. doi:10.1001/jama.1970.03170250031004. PMID 5467774.

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v t e GABA_A receptor positive modulators
Alcohols	Brometone Butanol Chloralodol Chlorobutanol (cloretone) Ethanol (alcohol) (alcoholic drink) Ethchlorvynol Isobutanol Isopropanol Menthol Methanol Methylpentynol Pentanol Petrichloral Propanol tert-Butanol (2M2P) tert-Pentanol (2M2B) Tribromoethanol Trichloroethanol Triclofos Trifluoroethanol
Barbiturates	(-)-DMBB Allobarbital Alphenal Amobarbital Aprobarbital Barbexaclone Barbital Benzobarbital Benzylbutylbarbiturate Brallobarbital Brophebarbital Butabarbital/Secbutabarbital Butalbital Buthalital Butobarbital Butallylonal Carbubarb Crotylbarbital Cyclobarbital Cyclopentobarbital Difebarbamate Enallylpropymal Ethallobarbital Eterobarb Febarbamate Heptabarb Heptobarbital Hexethal Hexobarbital Metharbital Methitural Methohexital Methylphenobarbital Narcobarbital Nealbarbital Pentobarbital Phenallymal Phenobarbital Phetharbital Primidone Probarbital Propallylonal Propylbarbital Proxibarbital Reposal Secobarbital Sigmodal Spirobarbital Talbutal Tetrabamate Tetrabarbital Thialbarbital Thiamylal Thiobarbital Thiobutabarbital Thiopental Thiotetrabarbital Valofane Vinbarbital Vinylbital
Benzodiazepines	2-Oxoquazepam 3-Hydroxyphenazepam Adinazolam Alprazolam Arfendazam Avizafone Bentazepam Bretazenil Bromazepam Bromazolam Brotizolam Camazepam Carburazepam Chlordiazepoxide Ciclotizolam Cinazepam Cinolazepam Clazolam Climazolam Clobazam Clonazepam Clonazolam Cloniprazepam Clorazepate Clotiazepam Cloxazolam CP-1414S Cyprazepam Delorazepam Demoxepam Diazepam Diclazepam Dimdazenil Doxefazepam Elfazepam Estazolam Ethyl carfluzepate Ethyl dirazepate Ethyl loflazepate Etizolam FG-8205 Fletazepam Flubromazepam Flubromazolam Fludiazepam Flunitrazepam Flunitrazolam Flurazepam Flutazolam Flutemazepam Flutoprazepam Fosazepam Gidazepam Halazepam Haloxazolam Iclazepam Imidazenil Irazepine Ketazolam Lofendazam Lopirazepam Loprazolam Lorazepam Lormetazepam Meclonazepam Medazepam Menitrazepam Metaclazepam Mexazolam Midazolam Motrazepam N-Desalkylflurazepam Nifoxipam Nimetazepam Nitrazepam Nitrazepate Nitrazolam Nordazepam Nortetrazepam Oxazepam Oxazolam Phenazepam Pinazepam Pivoxazepam Prazepam Premazepam Proflazepam Pyrazolam QH-II-66 Quazepam Reclazepam Remimazolam Rilmazafone Ripazepam Ro48-6791 Ro48-8684 SH-053-R-CH3-2′F Sulazepam Temazepam Tetrazepam Tolufazepam Triazolam Triflubazam Triflunordazepam (Ro5-2904) Tuclazepam Uldazepam Zapizolam Zolazepam Zomebazam
Carbamates	Carisbamate Carisoprodol Clocental Cyclarbamate Difebarbamate Emylcamate Ethinamate Febarbamate Felbamate Hexapropymate Hydroxyphenamate Lorbamate Mebutamate Meprobamate Nisobamate Pentabamate Phenprobamate Procymate Styramate Tetrabamate Tybamate
Flavonoids	6-Methylapigenin Ampelopsin (dihydromyricetin) Apigenin Baicalein Baicalin Catechin EGC EGCG Hispidulin Linarin Luteolin Rc-OMe Skullcap constituents (e.g., baicalin) Wogonin
Imidazoles	Etomidate Metomidate Propoxate
Kava constituents	10-Methoxyyangonin 11-Methoxyyangonin 11-Hydroxyyangonin Desmethoxyyangonin 11-Methoxy-12-hydroxydehydrokavain 7,8-Dihydroyangonin Kavain 5-Hydroxykavain 5,6-Dihydroyangonin 7,8-Dihydrokavain 5,6,7,8-Tetrahydroyangonin 5,6-Dehydromethysticin Methysticin 7,8-Dihydromethysticin Yangonin
Monoureides	Acecarbromal Apronal (apronalide) Bromisoval Carbromal Capuride Ectylurea
Neuroactive steroids	Acebrochol Allopregnanolone (brexanolone) Alfadolone Alfaxalone 3α-Androstanediol Androstenol Androsterone Certain anabolic-androgenic steroids Cholesterol DHDOC 3α-DHP 5α-DHP 5β-DHP DHT Etiocholanolone Ganaxolone Hydroxydione Minaxolone ORG-20599 ORG-21465 P1-185 Posovolone Pregnanolone (eltanolone) Progesterone Renanolone SAGE-105 SAGE-324 SAGE-516 SAGE-689 SAGE-872 Testosterone THDOC Zuranolone
Nonbenzodiazepines	Cyclopyrrolones: Eszopiclone Pagoclone Pazinaclone Suproclone Suriclone Zopiclone Imidazopyridines: Alpidem DS-1 Necopidem Saripidem Zolpidem Pyrazolopyrimidines: Divaplon Fasiplon Indiplon Lorediplon Ocinaplon Panadiplon Taniplon Zaleplon Others: Adipiplon CGS-8216 CGS-9896 CGS-13767 CGS-20625 CL-218,872 CP-615,003 CTP-354 ELB-139 GBLD-345 Imepitoin JM-1232 L-838,417 Lirequinil (Ro41-3696) NS-2664 NS-2710 NS-11394 Pipequaline ROD-188 RWJ-51204 SB-205,384 SX-3228 TGSC01AA TP-003 TPA-023 TP-13 U-89843A U-90042 Viqualine Y-23684
Phenols	Fospropofol Propofol Thymol
Piperidinediones	Glutethimide Methyprylon Piperidione Pyrithyldione
Pyrazolopyridines	Cartazolate Etazolate ICI-190,622 Tracazolate
Quinazolinones	Afloqualone Cloroqualone Diproqualone Etaqualone Mebroqualone Mecloqualone Methaqualone Methylmethaqualone Nitromethaqualone SL-164
Volatiles/gases	Acetone Acetophenone Acetylglycinamide chloral hydrate Aliflurane Benzene Butane Butylene Centalun Chloral Chloral betaine Chloral hydrate Chloroform Cryofluorane Desflurane Dichloralphenazone Dichloromethane Diethyl ether Enflurane Ethyl chloride Ethylene Fluroxene Gasoline Halopropane Halothane Isoflurane Kerosine Methoxyflurane Methoxypropane Nitric oxide Nitrogen Nitrous oxide Norflurane Paraldehyde Propane Propylene Roflurane Sevoflurane Synthane Teflurane Toluene Trichloroethane (methyl chloroform) Trichloroethylene Vinyl ether
Others/unsorted	3-Hydroxybutanal α-EMTBL AA-29504 Alogabat Avermectins (e.g., ivermectin) Bromide compounds (e.g., lithium bromide, potassium bromide, sodium bromide) Carbamazepine Chloralose Chlormezanone Clomethiazole Darigabat DEABL Deuterated etifoxine Dihydroergolines (e.g., dihydroergocryptine, dihydroergosine, dihydroergotamine, ergoloid (dihydroergotoxine)) DS2 Efavirenz Etazepine Etifoxine Fenamates (e.g., flufenamic acid, mefenamic acid, niflumic acid, tolfenamic acid) Fluoxetine Flupirtine Hopantenic acid KRM-II-81 Lanthanum Lavender oil Lignans (e.g., 4-O-methylhonokiol, honokiol, magnolol, obovatol) Loreclezole Menthyl isovalerate (validolum) Monastrol Nicotinic acid Nicotinamide Org 25,435 Phenytoin Propanidid Retigabine (ezogabine) Safranal Seproxetine Stiripentol Sulfonylalkanes (e.g., sulfonmethane (sulfonal), tetronal, trional) Terpenoids (e.g., borneol) Topiramate Valerian constituents (e.g., isovaleric acid, isovaleramide, valerenic acid, valerenol) Unsorted benzodiazepine site positive modulators: α-Pinene MRK-409 (MK-0343) TCS-1105 TCS-1205
See also: Receptor/signaling modulators • GABA receptor modulators • GABA metabolism/transport modulators