Names | |||
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Preferred IUPAC name 2-Methylpropane [1] | |||
Other names
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Identifiers | |||
3D model (JSmol) | |||
1730720 | |||
ChEBI | |||
ChemSpider | |||
ECHA InfoCard | 100.000.780 | ||
EC Number |
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E number | E943b (glazing agents, ...) | ||
1301 | |||
KEGG | |||
PubChem CID | |||
RTECS number |
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UNII | |||
UN number | 1969 | ||
CompTox Dashboard (EPA) | |||
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Properties | |||
C4H10 | |||
Molar mass | 58.124 g·mol−1 | ||
Appearance | Colorless gas | ||
Odor | Odorless | ||
Density |
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Melting point | −159.42 °C (−254.96 °F; 113.73 K) [2] | ||
Boiling point | −11.7 °C (10.9 °F; 261.4 K) [2] | ||
48.9 mg⋅L−1 (at 25 °C (77 °F)) [3] | |||
Vapor pressure | 3.1 atm (310 kPa) (at 21 °C (294 K; 70 °F)) [4] | ||
Henry's law constant (kH) | 8.6 nmol⋅Pa−1⋅kg−1 | ||
Conjugate acid | Isobutanium | ||
−51.7·10−6 cm3/mol | |||
Thermochemistry | |||
Heat capacity (C) | 96.65 J⋅K−1⋅mol−1 | ||
Std enthalpy of formation (ΔfH⦵298) | −134.8 – −133.6 kJ⋅mol−1 | ||
Std enthalpy of combustion (ΔcH⦵298) | −2.86959 – −2.86841 MJ⋅mol−1 | ||
Hazards | |||
GHS labelling: | |||
Danger | |||
H220 | |||
P210 | |||
NFPA 704 (fire diamond) | |||
Flash point | −83 °C (−117 °F; 190 K) | ||
460 °C (860 °F; 733 K) | |||
Explosive limits | 1.4–8.3% | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible) | None [5] | ||
REL (Recommended) | TWA 800 ppm (1900 mg/m3) [5] | ||
IDLH (Immediate danger) | N.D. [5] | ||
Safety data sheet (SDS) | lindeus.com | ||
Related compounds | |||
Related alkane | Isopentane | ||
Supplementary data page | |||
Isobutane (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
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 colorless, odorless gas. It is the simplest alkane with a tertiary carbon atom. Isobutane is used as a precursor molecule in the petrochemical industry, for example in the synthesis of isooctane. [6]
Isobutane is obtained by isomerization of butane.
Isobutane is the principal feedstock in alkylation units of refineries. Using isobutane, gasoline-grade "blendstocks" are generated with high branching for good combustion characteristics. Typical products created with isobutane are 2,4-dimethylpentane and especially 2,2,4-trimethylpentane. [7]
In the Chevron Phillips slurry process for making high-density polyethylene, isobutane is used as a diluent. As the slurried polyethylene is removed, isobutane is "flashed" off, and condensed, and recycled back into the loop reactor for this purpose. [8]
Isobutane is oxidized to tert-butyl hydroperoxide, which is subsequently reacted with propylene to yield propylene oxide. The tert-butanol that results as a by-product is typically used to make gasoline additives such as methyl tert-butyl ether (MTBE).
Isobutane is also used as a propellant for aerosol spray cans.
Isobutane is used as part of blended fuels, especially common in fuel canisters used for camping. [9]
Isobutane is used as a refrigerant. [10] Use in refrigerators started in 1993 when Greenpeace presented the Greenfreeze project with the former East German company Foron . [11] [12] In this regard, blends of pure, dry "isobutane" (R-600a) (that is, isobutane mixtures) have negligible ozone depletion potential and very low global warming potential (having a value of 3.3 times the GWP of carbon dioxide) and can serve as a functional replacement for R-12, R-22 (both of these being commonly known by the trademark Freon), R-134a, and other chlorofluorocarbon or hydrofluorocarbon refrigerants in conventional stationary refrigeration and air conditioning systems.
As a refrigerant, isobutane poses a fire and explosion risk in addition to the hazards associated with non-flammable CFC refrigerants. Substitution of this refrigerant for motor vehicle air conditioning systems not originally designed for isobutane is widely prohibited or discouraged. [13] [14] [15] [16] [17] [18] [19]
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. [20] [21]
A leak of isobutane in the refrigerant system of a fridge initiated the 2024 Valencia residential complex fire in Spain, that claimed 10 lives. [22]
The traditional name isobutane was still retained in the 1993 IUPAC recommendations, [23] but is no longer recommended according to the 2013 recommendations. [1] Since the longest continuous chain in isobutane contains only three carbon atoms, the preferred IUPAC name is 2-methylpropane but the locant (2-) is typically omitted in general nomenclature as redundant; C2 is the only position on a propane chain where a methyl substituent can be located without altering the main chain and forming the constitutional isomer n-butane.
Ethylene is a hydrocarbon which has the formula C2H4 or H2C=CH2. It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene.
Propane is a three-carbon alkane with the molecular formula C3H8. 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 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 propylene, butane, 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.
Octane is a hydrocarbon and an alkane with the chemical formula C8H18, and the condensed structural formula CH3(CH2)6CH3. Octane has many structural isomers that differ by the location of branching in the carbon chain. One of these isomers, 2,2,4-trimethylpentane (commonly called iso-octane), is used as one of the standard values in the octane rating scale.
Liquefied petroleum gas, also referred to as liquid petroleum gas, is a fuel gas which contains a flammable mixture of hydrocarbon gases, specifically propane, n-butane and isobutane. It can sometimes contain some propylene, butylene, and isobutene.
Pentane is an organic compound with the formula C5H12—that is, an alkane with five carbon atoms. The term may refer to any of three structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, pentane means exclusively the n-pentane isomer, in which case pentanes refers to a mixture of them; the other two are called isopentane (methylbutane) and neopentane (dimethylpropane). Cyclopentane is not an isomer of pentane because it has only 10 hydrogen atoms where pentane has 12.
Acrylic acid (IUPAC: prop-2-enoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols, ethers, and chloroform. More than a million tons are produced annually.
In organic chemistry, butyl is a four-carbon alkyl radical or substituent group with general chemical formula −C4H9, derived from either of the two isomers (n-butane and isobutane) of butane.
MAPP gas was a trademarked name, belonging to The Linde Group, a division of the former global chemical giant Union Carbide, for a fuel gas based on a stabilized mixture of methylacetylene (propyne), propadiene and propane. The name comes from the original chemical composition, methylacetylene-propadiene propane. "MAPP gas" is also widely used as a generic name for UN 1060 stabilised methylacetylene-propadiene.
Butan-2-ol, or sec-butanol, is an organic compound with formula CH3CH(OH)CH2CH3. Its structural isomers are 1-butanol, isobutanol, and tert-butanol. 2-Butanol is chiral and thus can be obtained as either of two stereoisomers designated as (R)-(−)-butan-2-ol and (S)-(+)-butan-2-ol. It is normally encountered as a 1:1 mixture of the two stereoisomers — a racemic mixture.
tert-Butyl alcohol is the simplest tertiary alcohol, with a formula of (CH3)3COH (sometimes represented as t-BuOH). Its isomers are 1-butanol, isobutanol, and butan-2-ol. tert-Butyl alcohol is a colorless solid, which melts near room temperature and has a camphor-like odor. It is miscible with water, ethanol and diethyl ether.
Pentenes are alkenes with the chemical formula C
5H
10. Each molecule contains one double bond within its molecular structure. Six different compounds are in this class, differing from each other by whether the carbon atoms are attached linearly or in a branched structure and whether the double bond has a cis or trans form.
Isobutanol (IUPAC nomenclature: 2-methylpropan-1-ol) is an organic compound with the formula (CH3)2CHCH2OH (sometimes represented as i-BuOH). This colorless, flammable liquid with a characteristic smell is mainly used as a solvent either directly or as its esters. Its isomers are 1-butanol, 2-butanol, and tert-butanol, all of which are important industrially.
Cumene (isopropylbenzene) is an organic compound that contains a benzene ring with an isopropyl substituent. It is a constituent of crude oil and refined fuels. It is a flammable colorless liquid that has a boiling point of 152 °C. Nearly all the cumene that is produced as a pure compound on an industrial scale is converted to cumene hydroperoxide, which is an intermediate in the synthesis of other industrially important chemicals, primarily phenol and acetone.
m-Xylene (meta-xylene) is an aromatic hydrocarbon. It is one of the three isomers of dimethylbenzene known collectively as xylenes. The m- stands for meta-, indicating that the two methyl groups in m-xylene occupy positions 1 and 3 on a benzene ring. It is in the positions of the two methyl groups, their arene substitution pattern, that it differs from the other isomers, o-xylene and p-xylene. All have the same chemical formula C6H4(CH3)2. All xylene isomers are colorless and highly flammable.
Butane-1-thiol, also known as butyl mercaptan, is a volatile, clear to yellowish liquid with a fetid odor, commonly described as "skunk" odor. In fact, 1-butanethiol is structurally similar to several major constituents of a skunk's defensive spray but is not actually present in the spray. The scent of 1-butanethiol is so strong that the human nose can easily detect it in the air at concentrations as low as 10 parts per billion. The threshold level for 1-butanethiol is reported as 1.4 ppb
n-Butylamine is an organic compound (specifically, an amine) with the formula CH3(CH2)3NH2. This colourless liquid is one of the four isomeric amines of butane, the others being sec-butylamine, tert-butylamine, and isobutylamine. It is a liquid having the fishy, ammonia-like odor common to amines. The liquid acquires a yellow color upon storage in air. It is soluble in all organic solvents. Its vapours are heavier than air and it produces toxic oxides of nitrogen during combustion.
Hexachlorobutadiene, (often abbreviated as "HCBD") Cl2C=C(Cl)C(Cl)=CCl2, is a colorless liquid at room temperature that has an odor similar to that of turpentine. It is a chlorinated aliphatic diene with niche applications but is most commonly used as a solvent for other chlorine-containing compounds. Structurally, it has a 1,3-butadiene core, but fully substituted with chlorine atoms.
tert-Butyl hydroperoxide (tBuOOH) is the organic compound with the formula (CH3)3COOH. It is one of the most widely used hydroperoxides in a variety of oxidation processes, like the Halcon process. It is normally supplied as a 69–70% aqueous solution. Compared to hydrogen peroxide and organic peracids, tert-butyl hydroperoxide is less reactive and more soluble in organic solvents. Overall, it is renowned for the convenient handling properties of its solutions. Its solutions in organic solvents are highly stable.
Isopropyl alcohol is a colorless, flammable organic compound with a pungent alcoholic odor.
Butane or n-butane is an alkane with the formula C4H10. Butane is a highly flammable, colorless, easily liquefied gas that quickly vaporizes at room temperature and pressure. The name butane comes from the root but- (from butyric acid, named after the Greek word for butter) and the suffix -ane. It was discovered in crude petroleum in 1864 by Edmund Ronalds, who was the first to describe its properties, and commercialized by Walter O. Snelling in the early 1910s.
The names 'isobutane', 'isopentane', and 'neopentane' are no longer recommended.