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| Names | |||
|---|---|---|---|
| Preferred IUPAC name 2,2-Dimethylbutane[2] | |||
| Other names Neohexane,[1] 22DMB | |||
| Identifiers | |||
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3D model (JSmol) | |||
| 1730736 | |||
| ChEMBL | |||
| ChemSpider |
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| ECHA InfoCard | 100.000.825 | ||
| EC Number |
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| RTECS number |
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| UNII | |||
| UN number | 1208 | ||
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| Properties | |||
| C6H14 | |||
| Molar mass | 86.178 g·mol−1 | ||
| Appearance | Colorless liquid | ||
| Odor | Odorless | ||
| Density | 649 mg mL−1 | ||
| Melting point | −102 to −98 °C; −152 to −145 °F; 171 to 175 K | ||
| Boiling point | 49.7 to 49.9 °C; 121.4 to 121.7 °F; 322.8 to 323.0 K | ||
| logP | 3.51 | ||
| Vapor pressure | 36.88 kPa (at 20 °C) | ||
Henry's law constant (kH) | 6.5 nmol Pa−1 kg−1 | ||
| −76.24·10−6 cm3/mol | |||
Refractive index (nD) | 1.369 | ||
| Thermochemistry | |||
| 189.67 J K−1 mol−1 | |||
Std molar entropy(S⦵298) | 272.00 J K−1 mol−1 | ||
Std enthalpy of formation(ΔfH⦵298) | −214.4 – −212.4 kJ mol−1 | ||
Std enthalpy of combustion(ΔcH⦵298) | −4.1494 – −4.1476 MJ mol−1 | ||
| Hazards | |||
| GHS labelling: | |||
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| Danger | |||
| H225,H304,H315,H336,H411 | |||
| P210,P261,P273,P301+P310,P331 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | −29 °C (−20 °F; 244 K) | ||
| 425 °C (797 °F; 698 K) | |||
| Explosive limits | 1.2–7.7% | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible) | none[3] | ||
| Related compounds | |||
Related alkanes | |||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
2,2-Dimethylbutane, trivially known asneohexane atWilliam Odling's 1876 suggestion,[4] is anorganic compound with formula C6H14 or (H3C-)3-C-CH2-CH3. It is therefore analkane, indeed the most compact and branched of thehexane isomers — the only one with aquaternary carbon and abutane (C4) backbone.
Butlerov's student V. Goryainov originally discovered neohexane in 1872 bycross-coupling ofzinc ethyl with tert-butyl iodide.[5]
2,2-Dimethylbutane can be synthesised by the hydroisomerisation of2,3-dimethylbutane using an acid catalyst.[6]
It can also be synthesised by isomerization ofn-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.[7][8][9]
Neohexane is used as ahigh-octaneanti-knock additive ingasoline and in the manufacture of agricultural chemicals.[10] It is also used in a number of commercial, automobile and home maintenance products, such as adhesives, electronic contact cleaners and upholstery polish sprays.[11]
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.[12]
