Butane

Butane
Identifiers
CAS number 106-97-8 Y
PubChem 7843
ChemSpider 7555 Y
UNII 6LV4FOR43R Y
EC number 203-448-7
UN number 1011
KEGG D03186 Y
MeSH butane
ChEBI CHEBI:37808 Y
ChEMBL CHEMBL134702 Y
RTECS number EJ4200000
Beilstein Reference 969129
Gmelin Reference 1148
Jmol-3D images Image 1
Properties
Molecular formula C4H10
Molar mass 58.12 g mol−1
Exact mass 58.078250320 g mol−1
Appearance Colorless gas
Odor Odorless
Density 2.48 mg mL−1 (at 15 °C)
Melting point

-140--134 °C, 133-139 K, -220--209 °F

Boiling point

-1-1 °C, 272-274 K, 30-34 °F

Solubility in water 61 mg L−1 (at 20 °C)
log P 2.745
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−126.3–−124.9 kJ mol−1
Std enthalpy of
combustion
ΔcHo298
−2.8781–−2.8769 MJ mol−1
Specific heat capacity, C 98.49 J K−1 mol−1
Hazards[2]
MSDS External MSDS
GHS pictograms
GHS signal word DANGER
GHS hazard statements H220
GHS precautionary statements P210
EU Index 601-004-00-0
EU classification F+
R-phrases R12
S-phrases (S2), S16
NFPA 704
4
1
0
Flash point −60 °C
Autoignition
temperature
500 °C
Explosive limits 1.8–8.4%
Related compounds
Related alkanes
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Butane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or isobutane.

Butanes are highly flammable, colorless, easily liquefied gases. The name butane comes from the roots but- (from butyric acid) and -ane.

Contents

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.[3]

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.

2 C4H10 + 13 O2 → 8 CO2 + 10 H2O

The maximum adiabatic flame temperature of butane with air is 2,243 K (1,970 °C; 3,578 °F).

n-Butane is the feedstock for DuPont's catalytic process for the preparation of maleic anhydride:

2 CH3CH2CH2CH3 + 7 O2 → 2 C2H2(CO)2O + 8 H2O

n-Butane, like all hydrocarbons, undergoes free radical chlorination providing both 1-chloro- and 2-chlorobutanes, as well as more highly chlorinated derivatives. The relative rates of the chlorination is partially explained by the differing bond dissociation energies, 425 and 411 kJ/mol for the two types of C-H bonds. The two central carbon atoms have the slightly weaker C-H bonds.

Uses

The most common use of butane is as lighter fuel for a common lighter or butane torch.

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 LPG, for liquified petroleum gas. It is also 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.

Very pure forms of butane, especially isobutane, can be used as refrigerants and have largely replaced the ozone layer-depleting halomethanes, for instance in household refrigerators and freezers. The system operating pressure for butane is lower than for the halomethanes, such as R-12, so R-12 systems such as in automotive air conditioning systems, when converted to butane will not function optimally.

Cordless hair irons are usually powered by butane cartridges.[4]

Effects and health issues

Inhalation of butane can cause euphoria, drowsiness, narcosis, asphyxia, cardiac arrhythmia, temporary memory loss and frostbite, which can result in death from asphyxiation and ventricular fibrillation. Butane is the most commonly misused volatile substance in the UK, and was the cause of 52% of "solvent related" deaths in 2000.[5] By spraying butane directly into the throat, the jet of fluid can cool rapidly to −20 °C by expansion, causing prolonged laryngospasm.[6] "Sudden sniffer's death" syndrome, first described by Bass in 1970,[7] is the most common single cause of "solvent related" death, resulting in 55% of known fatal cases.[6]

The paper "Emission of nitrogen dioxide from butane gas heaters and stoves indoors", from the American Journal of Applied Sciences, indicates that nitrogen dioxide, a toxic gas, results from burning butane gas, and represents a human health hazard from home heaters and stoves.

See also

References

  1. ^ "butane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=7843. Retrieved 11 December 2011. 
  2. ^ "Safety Data Sheet, Material Name: N-Butane" (PDF). USA: Matheson Tri-Gas Incorporated. 5 February 2011. http://www.chemadvisor.com/Matheson/database/msds/MAT15370000800003.PDF. Retrieved 11 December 2011. 
  3. ^ 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. doi:10.1021/jp809639s. PMID 19152252. 
  4. ^ FAA: Hazardous Materials p. 4
  5. ^ Trends in death Associated with Abuse of Volatile Substances 1971–2004 Field-Smith M, Bland JM, Taylor JC, et al., Department of Public Health Sciences. London: St George’s Medical School
  6. ^ a b Ramsey J, Anderson HR, Bloor K, et al. An introduction to the practice, prevalence and chemical toxicology of volatile substance abuse. Hum Toxicol 1989;8:261–269
  7. ^ Bass M. Sudden sniffing death. JAMA 1970;212:2075–2079

External links