Isobutane

  • IUPAC: 2- methyl propane
  • Methylpropane
  • I-butane
  • Trimethyl methane
  • R- 600a

Colorless, almost odorless gas

Gaseous

2.70 kg · m -3 ( gas density at 0 ° C, 1013 hPa)

-159.42 ° C

-11.7 ° C

301.9 kPa ( 20 ° C)

  • Practically insoluble in water (49 mg · l-1 at 20 ° C)
  • Soluble in ethanol and diethyl ether

0.132 D (4.40 · 10-31 C · m)

1.3518 (-25 ° C)

Risk

1000 ml · m-3

Template: Infobox chemical / molecular formula search available

Isobutane ( systematic name according to IUPAC: 2- methyl propane ) is an organic chemical compound selected from the group consisting of alkanes. It is a constitutional isomer of n-butane and the simplest branched hydrocarbon.

Occurrence

Isobutane is present in natural gas and petroleum. It is also resulting from cleaning and processing.

Properties

Isobutane is a colorless, nearly odorless, flammable gas. It is heavier than air and has a narcotic effect and asphyxiation in high concentrations. For isobutane the lower explosive limit (LEL) is 1.5 vol - % (37 g/m3) and the upper explosive limit (UEL ) at 9.4 vol - % ( 231 g/m3). These values ​​do not differ from the values ​​for the structurally isomeric n -butane.

Use

Isobutane is a raw material in the chemical industry. Large quantities are used in the production of alkylate ( alkylation, isooctane ). Some other chemicals, such as isobutene and tert. -butyl hydroperoxide are prepared from isobutane. Together with butane, it is used as a propellant in spray cans (food additive E 943b ). Because it is combustible like other alkanes, it is used as fuel. Isobutane is used as an admixture for camping gas. As isobutane (-0.5 ° C) has a lower boiling point than n-butane, camping gas is mixed from propane and isobutane. This makes the gas mixture is suitable not only for the summer, but also for use in the winter and at full speed.

Refrigerant

Isobutane has a very low greenhouse effect (GWP 3) and is therefore used in refrigerators and air conditioners as a refrigerant called R600a. The application limit is for safety reasons currently at 150 g per unit. Since 1992, Greenpeace, the project Green Freeze presented with the help of the company Foron, R600a is used in refrigerators. In Europe, the R600a R134a previously used as refrigerant in household appliances almost completely displaced because R600a is cheaper, has no ozone depletion potential, has less chemical compatibility problems and is miscible with mineral oil. Most devices come with less than 50 g of refrigerant. By 2011, already 300 million devices have come onto the market.

CAS registry number PubChem Vapor pressure Electric dipole moment Debye Dangerous Substances Directive (67/548/EEC) Flammability limit CRC Handbook of Chemistry and Physics Integrated Authority File
819
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