Butane () or ''n''-butane is an

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which ...

with the formula C₄H₁₀. Butane is a gas at room temperature and atmospheric pressure. Butane is a highly flammable, colorless, easily liquefied gas that quickly vaporizes at room temperature. The name butane comes from the root

but- In chemical nomenclature, the IUPAC nomenclature of organic chemistry is a method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in the ''Nomenclature of Or ...

(from

butyric acid Butyric acid (; from grc, βούτῡρον, meaning "butter"), also known under the systematic name butanoic acid, is a straight-chain alkyl carboxylic acid with the chemical formula CH3CH2CH2CO2H. It is an oily, colorless liquid with an unple ...

, named after the Greek word for butter) and the suffix

-ane The suffix -ane in organic chemistry forms the names of organic compounds where the -C-C- group has been attributed the highest priority according to the rules of organic nomenclature. Such organic compounds are called alkanes. They are saturated h ...

. It was discovered by the chemist Dr. Walter Snelling in 1912. It was found dissolved in crude petroleum in 1864 by

Edmund Ronalds Dr Edmund Ronalds FCS FRSE (18 June 1819 – 9 September 1889) was an English academic and industrial chemist. He was co-author of a seminal series of books on chemical technology that helped begin university teaching of chemical applications fo ...

, who was the first to describe its properties. Butane is one of a group of

liquefied petroleum gas Liquefied petroleum gas (LPG or LP gas) is a fuel gas which contains a flammable mixture of hydrocarbon gases, specifically propane, propylene, butylene, isobutane and n-butane. LPG is used as a fuel gas in heating appliances, cooking e ...

es (LP gases). The others include

propane Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used a ...

, propylene, butadiene, butylene, isobutylene, and mixtures thereof. Butane burns more cleanly than gasoline and coal.

Density

The density of butane is highly dependent on temperature and pressure in the reservoir. For example, the density of liquid phase is 571.8±1 kg/m³ (for pressures up to 2MPa and temperature 27±0.2 °C), while the density of liquid butane is 625.5±0.7 kg/m³ (for pressures up to 2MPa and temperature -13±0.2 °C). Propane butane liquid vapor density zivenko

History

Butane and Propane were simultaneously discovered in 1912 by an American chemist, Dr. Walter Snelling. Snelling identified these gases as components in gasoline and found that if they were cooled, they could be stored in a volume-reduced liquified state in pressurized containers.

Isomers

Rotation Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional ...

about the central C−C bond produces two different conformations (''trans'' and ''gauche'') for ''n''-butane.

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. 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 or by liquid volume . The maximum adiabatic flame temperature of butane with air is . ''n''-Butane is the feedstock for

DuPont DuPont de Nemours, Inc., commonly shortened to DuPont, is an American multinational chemical company first formed in 1802 by French-American chemist and industrialist Éleuthère Irénée du Pont de Nemours. The company played a major role in ...

'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 The bond-dissociation energy (BDE, ''D''0, or ''DH°'') is one measure of the strength of a chemical bond . It can be defined as the standard enthalpy change when is cleaved by homolysis to give fragments A and B, which are usually radical s ...

, 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

, and as a feedstock for the manufacture of

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene i ...

and butadiene, a key ingredient of

synthetic rubber A synthetic rubber is an artificial elastomer. They are polymers synthesized from petroleum byproducts. About 32-million metric tons of rubbers are produced annually in the United States, and of that amount two thirds are synthetic. Synthetic rubbe ...

Isobutane Isobutane, also known as ''i''-butane, 2-methylpropane or methylpropane, is a chemical compound with molecular formula HC(CH3)3. It is an isomer of butane. Isobutane is a colourless, odourless gas. It is the simplest alkane with a tertiary carbon a ...

is primarily used by

refineries A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value. Types of refineries Different types of refineries ar ...

to enhance (increase) the

octane Octane is a hydrocarbon and an alkane with the chemical formula , and the condensed structural formula . Octane has many structural isomers that differ by the amount and location of branching in the carbon chain. One of these isomers, 2,2,4-Tri ...

number of motor gasoline. 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. n-Butane has a relatively high

research octane number An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonating. ...

(RON) and motor octane number (MON), which are 93 and 92 respectively. When blended with

and other hydrocarbons, the mixture may be referred to commercially as

(LPG). It is used as a petrol component, as a feedstock for the production of base

petrochemicals Petrochemicals (sometimes abbreviated as petchems) are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sou ...

steam cracking Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons. It is the principal industrial method for producing the lighter alkenes (or commonly olefins), including ethe ...

, as fuel for cigarette lighters and as a

propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the e ...

in aerosol sprays such as deodorants. Pure forms of butane, especially isobutane, are used as

refrigerant A refrigerant is a working fluid used in the heat pump and refrigeration cycle, refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Ref ...

s and have largely replaced the ozone-layer-depleting

halomethane Halomethane compounds are derivatives of methane () with one or more of the hydrogen atoms replaced with halogen atoms ( F, Cl, Br, or I). Halomethanes are both naturally occurring, especially in marine environments, and human-made, most notably ...

s in refrigerators, freezers, and air conditioning systems. The operating pressure for butane is lower than for the halomethanes such as

Freon-12 Dichlorodifluoromethane (R-12) is a colorless gas usually sold under the brand name Freon-12, and a chlorofluorocarbon halomethane (CFC) used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture w ...

(R-12), so R-12 systems such as those in automotive air conditioning systems, when converted to pure butane, will function poorly. A mixture of isobutane and propane is used instead to give cooling system performance comparable to use of R-12. Butane is also used as lighter fuel for a common lighter or butane torch and is sold bottled as a fuel for cooking, barbecues and camping stoves. The global market for butane canisters is dominated by South Korean manufacturers. 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 Steam is a substance containing water in the gas phase, and sometimes also an aerosol of liquid water droplets, or air. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization ...

. As fuel, it is often mixed with small amounts of

mercaptan In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

s 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. Most commercially available butane also contains some contaminant oil, which can be removed by filtration and will otherwise leave a deposit at the point of ignition and may eventually block the uniform flow of gas. The butane used as a solvent for fragrance extraction does not contain these contaminants and butane gas can cause

gas explosions A gas explosion is an explosion resulting from mixing a gas, typically from a gas leak, with air in the presence of an ignition source. In household accidents, the principal explosive gases are those used for heating or cooking purposes such as na ...

in poorly ventilated areas if leaks go unnoticed and are ignited by spark or flame. Purified butane is used as a solvent in the industrial extraction of cannabis oils. File:Photo D2.jpg , Butane fuel canisters for use in camping stoves File:The Green Lighter 1 ies.jpg , Butane lighter, showing liquid butane reservoir File:Aerosol.png , An aerosol spray can, which may be using butane as a propellant File:ButaneGasCylinder WhiteBack.jpg , Butane gas cylinder used for cooking

Effects and health issues

Inhalation of butane can cause

euphoria Euphoria ( ) is the experience (or affect) of pleasure or excitement and intense feelings of well-being and happiness. Certain natural rewards and social activities, such as aerobic exercise, laughter, listening to or making music and da ...

, 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. It enters the blood supply and within seconds produces intoxication. Butane is the most commonly abused volatile substance in the UK, and was the cause of 52% of solvent related deaths in 2000. By spraying butane directly into the throat, the jet of fluid can cool rapidly to by expansion, causing prolonged laryngospasm. " Sudden sniffer's death" syndrome, first described by Bass in 1970, is the most common single cause of solvent related death, resulting in 55% of known fatal cases.

References

External links

International Chemical Safety Card 0232

{{Authority control Alkanes Fuel gas Refrigerants GABAA receptor positive allosteric modulators E-number additives