Difference between revisions of "Butane" - New World Encyclopedia
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== Uses == | == Uses == | ||
− | [[Image:ButaneGasCylinder.jpg|thumb|right| | + | [[Image:ButaneGasCylinder.jpg|thumb|right|A butane gas cylinder that may be used for cooking.]] |
Butane gas is sold bottled as a fuel for cooking and camping. When blended with [[propane]] and other hydrocarbons, it is referred to commercially as [[Liquified petroleum gas]] (LPG). It is also used as a component of [[gasoline]] (petrol), as a feedstock for the production of base petrochemicals in steam cracking, and as a fuel for [[cigarette lighter]]s. | Butane gas is sold bottled as a fuel for cooking and camping. When blended with [[propane]] and other hydrocarbons, it is referred to commercially as [[Liquified petroleum gas]] (LPG). It is also used as a component of [[gasoline]] (petrol), as a feedstock for the production of base petrochemicals in steam cracking, and as a fuel for [[cigarette lighter]]s. | ||
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When used as a refrigerant, the flammability of isobutane is not a major issue because the amount of this substance in an appliance is not enough to cause a combustible mix, given the amount of air in a room. The system operating pressure for butane is lower than that for the halomethanes, such as [[Dichlorodifluoromethane]] (R-12). Thus, the direct conversion of R-12 systems to butane, such as in automotive air conditioning systems, will not function optimally. | When used as a refrigerant, the flammability of isobutane is not a major issue because the amount of this substance in an appliance is not enough to cause a combustible mix, given the amount of air in a room. The system operating pressure for butane is lower than that for the halomethanes, such as [[Dichlorodifluoromethane]] (R-12). Thus, the direct conversion of R-12 systems to butane, such as in automotive air conditioning systems, will not function optimally. | ||
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==Effects and health issues== | ==Effects and health issues== |
Revision as of 20:02, 20 May 2008
n-Butane | |
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Identifiers | |
CAS number | [ | ]
SMILES | CCCC |
Properties | |
Molecular formula | C4H10 |
Molar mass | 58.124 g/mol |
Appearance | Colorless gas |
Density | 2.48 g/l, gas (15 °C, 1 atm) |
Melting point |
−138.4 °C (135.4 K) |
Boiling point |
−0.5 °C (272.6 K) |
Solubility in water | 6.1 mg/100 ml (20 °C) |
Hazards | |
EU classification | Highly flammable (F+) |
NFPA 704 |
|
Flash point | −60 °C |
Related Compounds | |
Related alkanes | Propane; Pentane |
Related compounds | Isobutane; Cyclobutane |
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
Isobutane | |
---|---|
IUPAC name | Isobutane Methylpropane |
Other names | 2-Methylpropane |
Identifiers | |
CAS number | [ | ]
SMILES | C(C)CC |
Properties | |
Molecular formula | C4H10 |
Molar mass | 58.12 g mol-1 |
Appearance | colorless gas |
Density | 2.51 g/l, gas (15 °C, 1 atm);593.4 kg · m-3, liquid |
Melting point |
-159.6 °C, 114 K, -255 °F |
Boiling point |
-11.7 °C, 261 K, 11 °F |
Solubility in water | Insoluble |
Hazards | |
MSDS | External MSDS |
EU classification | Highly flammable (F+) |
NFPA 704 |
|
R-phrases | R12 |
S-phrases | S2, S9, S16 |
Flash point | flammable gas |
Autoignition temperature |
460 °C |
Explosive limits | 1.8–8.4% |
Related Compounds | |
Related alkane | Butane |
Related compounds | Isopentane Neopentane |
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
Butane, also called n-butane, is an unbranched alkane with four carbon atoms in each molecule, and its molecular formula may be written as CH3CH2CH2CH3. Butane is also used as a collective term for both n-butane and its only other isomer, isobutane (also called i-butane or methylpropane), CH(CH3)3. Both isomers of butane are highly flammable, colorless gases that can be readily liquefied.
Butane is useful for many applications. Bottled butane gas is a fuel for cooking and camping. It is also used as a component of gasoline (petrol), as a feedstock component for the production of base petrochemicals in steam cracking, and as a fuel for cigarette lighters. When butane is blended with propane and other hydrocarbons, the mixture is referred to commercially as liquefied petroleum gas (LPG), which is a fuel for heating appliances and vehicles.
Recent concerns regarding depletion of the ozone layer by freon gases (chlorofluorocarbons or halomethanes) have led to increased use of isobutane and LPG as refrigerants, especially in domestic refrigerators and freezers, and as propellants in aerosol sprays.
Etymology
The name butane was derived by back-formation from the name butyric acid. The latter is a carboxylic acid with four carbon atoms, including the carbon atom in the carboxyl group.
Properties
At ordinary temperatures and pressures, n-butane is a colorless gas. Its boiling point is −0.5 °C (272.6 K), and its melting point is −138.4 °C (135.4 K).
As noted above, the term butane is also used for i-butane, the structural isomer of n-butane. i-butane is also a colorless gas, with a boiling point of -11.7 °C (261 K) and a melting point of -159.6 °C (114 K).
Structural isomers
A molecule of either isomer, n-butane or i-butane, is made up of four carbon atoms and ten hydrogen atoms, so their common molecular formula is C4H10. However, the molecular structures of these isomers differ. In particular, a molecule of n-butane consists of a linear arrangement of the four carbon atoms, so that it can also be represented as CH3-CH2-CH2-CH3. By contrast, a molecule of i-butane has three carbon atoms attached directly to a central carbon atom. The structures of these two isomers are shown in the diagrams below.
Reactions
When oxygen is plentiful, butane burns to form carbon dioxide and water vapor; when oxygen is limited, carbon (soot) or carbon monoxide may also be formed. The reaction may be written as follows:
- 2C4H10 + 13O2 → 8CO2 + 10H2O
n-Butane is the feedstock for DuPont's catalytic process for the preparation of maleic anhydride (C2H2(CO)2O), as shown by the following reaction:
- CH3CH2CH2CH3 + 3.5O2 → C2H2(CO)2O + 4H2O
n-Butane, like all hydrocarbons, undergoes free radical chlorination producing both 1-chlorobutane and 2-chlorobutane, as well as more highly chlorinated derivatives.
Uses
Butane gas is sold bottled as a fuel for cooking and camping. When blended with propane and other hydrocarbons, it is referred to commercially as Liquified petroleum gas (LPG). It is also used as a component of gasoline (petrol), as a feedstock for the production of base petrochemicals in steam cracking, and as a fuel for cigarette lighters.
The highly purified form of isobutane is useful as a refrigerant and as a propellant in aerosol sprays. It is used, for instance, in household refrigerators and freezers, largely replacing the halomethanes that are believed to deplete the ozone layer. When used as a refrigerant or propellant, isobutane may be referred to as R-600a. It is also used as a feedstock in the petrochemical industry, such as for the synthesis of isooctane.[1]
When used as a refrigerant, the flammability of isobutane is not a major issue because the amount of this substance in an appliance is not enough to cause a combustible mix, given the amount of air in a room. The system operating pressure for butane is lower than that for the halomethanes, such as Dichlorodifluoromethane (R-12). Thus, the direct conversion of R-12 systems to butane, such as in automotive air conditioning systems, will not function optimally.
Effects and health issues
Inhaling butane can cause drowsiness, narcosis, asphyxia; cardiac arrhythmia and frostbite, which can result in instant death from Asphyxiation, Acute toxicity and ventricular fibrillation. Butane is the most commonly misused volatile solvent in the UK, and was the cause of 52 percent of solvent-related deaths in 2000.[2] If butane is sprayed directly into the throat, the jet of fluid may cool rapidly to –20 °C by expansion, causing prolonged laryngospasm.[3] "Sudden Sniffer's Death syndrome," first described by Bass in 1970,[4] is the most common single cause of solvent-related death, resulting in 55 percent of known fatal cases.[3]
See also
Notes
- ↑ Patent Watch, July 31, 2006.
- ↑ Field-Smith, M.E., B.K. Butland, J.D. Ramsey, and H.R. Anderson. July 2006. Trends in Death Associated with Abuse of Volatile Substances 1971-2004. Report 19, Division of Community Health Sciences. London: St George’s, University of London. Retrieved May 20, 2008.
- ↑ 3.0 3.1 Ramsey, J., H.R. Anderson, K. Bloor, et al. 1989. An introduction to the practice, prevalence and chemical toxicology of volatile substance abuse. Hum. Toxicol. 8:261–269.
- ↑ Bass, M. 1970. Sudden sniffing death. JAMA 212:2075–79.
ReferencesISBN links support NWE through referral fees
- McMurry, John. 2004. Organic Chemistry, 6th ed. Belmont, CA: Brooks/Cole. ISBN 0534420052.
- Morrison, Robert T., and Robert N. Boyd. 1992. Organic Chemistry, 6th ed. Englewood Cliffs, NJ: Prentice Hall. ISBN 0136436692.
- Olah, George A., and Árpád Molnár. 2003. Hydrocarbon Chemistry. Hoboken, NJ: Wiley-Interscience. ISBN 978-0471417828.
- Solomons, T.W. Graham, and Craig B. Fryhle 2004. Organic Chemistry, 8th ed. Hoboken, NJ: John Wiley. ISBN 0471417998.
- Yaws, Carl L. 2005. The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals: Physical Properties for More Than 41,000 Organic and Inorganic Chemical Compounds : Coverage for C1 to C100 Organics and Ac to Zr Inorganics. Houston, TX: Gulf Pub. Co. ISBN 978-0976511373.
External links
- International Chemical Safety Card 0232: Butane. Retrieved May 20, 2008.
- NIOSH Pocket Guide to Chemical Hazards: n-Butane. Retrieved May 20, 2008.
- Toxicology and Chemical Substances, European Chemicals Bureau.] Retrieved May 20, 2008.
- The Molecule of the Month, October 2004, n-Butane. Retrieved May 20, 2008.
- Butane. Molview. (See Butane in 3D.) Retrieved May 20, 2008.
- World LP Gas Association (WLPGA). Retrieved May 20, 2008.
- LP Gas Association. Retrieved May 20, 2008.
- Global BioSciences, Inc. (In-Situ Bioremediation utilizing Butane.) Retrieved May 20, 2008.
- Butane Viscosity. (Viscosity as a function of temperature and pressure.) Retrieved May 20, 2008.
Alkanes | |||||||||||||||||||||||||||||||
methane |
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ethane |
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propane |
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butane |
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pentane |
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hexane |
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heptane |
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octane |
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nonane |
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decane |
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undecane |
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dodecane |
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E numbers
| ||
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Colours (E100-199) • Preservatives (E200-299) • Antioxidants & Acidity regulators (E300-399) • Thickeners, stabilisers & emulsifiers (E400-499) • pH regulators & anti-caking agents (E500-599) • Flavour enhancers (E600-699) • Miscellaneous (E900-999) • Additional chemicals (E1100-1599) | ||
Waxes (E900-909) • Synthetic glazes (E910-919) • Improving agents (E920-929) • Packaging gases (E930-949) • Sweeteners (E950-969) • Foaming agents (E990-999) | ||
Argon (E938) • Helium (E939) • Dichlorodifluoromethane (E940) • Nitrogen (E941) • Nitrous oxide (E942) • Butane (E943a) • Isobutane (E943b) • Propane (E944) • Oxygen (E948) • Hydrogen (E949) |
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