2,2-Dimethylbutane

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2,2-Dimethylbutane

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Template:Longitem	Template:Unbulleted list
Template:Longitem	1730736
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UN number	1208
Template:Longitem	Template:Chembox Elements/molecular formula
Molar mass	Template:Chem molar mass
Appearance	Colorless liquid
Odor	Odorless
Density	649 mg mL−1
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log P	3.51
Vapor pressure	36.88 kPa (at 20 °C)
Template:Longitem	6.5 nmol Pa−1 kg−1
Template:Longitem	−76.24·10−6 cm3/mol
Template:Longitem	1.369
Template:Longitem	189.67 J K−1 mol−1
Template:Longitem	272.00 J K−1 mol−1
Template:Longitem	−214.4 – −212.4 kJ mol−1
Template:Longitem	−4.1494 – −4.1476 MJ mol−1
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Explosive limits	1.2–7.7%
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2,2-Dimethylbutane, trivially known as neohexane at William Odling's 1876 suggestion, is an organic compound with formula C₆H₁₄ or (H₃C-)₃-C-CH₂-CH₃. It is therefore an alkane, indeed the most compact and branched of the hexane isomers — the only one with a quaternary carbon and a butane (C₄) backbone.

Synthesis

Butlerov's student V. Goryainov originally discovered neohexane in 1872 by cross-coupling of zinc ethyl with tert-butyl iodide.

2,2-Dimethylbutane can be synthesised by the hydroisomerisation of 2,3-dimethylbutane using an acid catalyst.

It can also be synthesised by isomerization of n-pentane in the presence of a catalyst containing combinations of one or more of palladium, platinum, rhodium and rhenium on a matrix of zeolite, alumina, silicon dioxide or other materials. Such reactions create a mixture of final products including isopentane, n-hexane, 3-methylpentane, 2-methylpentane, 2,3-dimethylbutane and 2,2-dimethylbutane. Since the composition of the final mixture is temperature dependant the desired final component can be obtained choice of catalyst and by combinations of temperature control and distillations.

Uses

Neohexane is used as a high-octane anti-knock additive in gasoline and in the manufacture of agricultural chemicals. It is also used in a number of commercial, automobile and home maintenance products, such as adhesives, electronic contact cleaners and upholstery polish sprays.

In laboratory settings, it is commonly used as a probe molecule in techniques which study the active sites of metal catalysts. Such catalysts are used in hydrogen-deuterium exchange, hydrogenolysis, and isomerization reactions. It is well suited to this purpose as 2,2-dimethylbutane contains both an isobutyl and an ethyl group.

See also

• Methylbutane (isopentane)
• 2-Methylpentane (isohexane)