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| Names | |
|---|---|
| Preferred IUPAC name 2-Methylhexane[1] | |
| Identifiers | |
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3D model (JSmol) | |
| 1696856 | |
| ChemSpider |
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| ECHA InfoCard | 100.008.847 |
| EC Number |
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| RTECS number |
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| UNII | |
| UN number | 3295 |
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| Properties | |
| C7H16 | |
| Molar mass | 100.205 g·mol−1 |
| Appearance | Colorless liquid |
| Odor | Odorless |
| Density | 0.679 g cm−3 |
| Melting point | −119.0 to −117.8 °C; −182.3 to −180.1 °F; 154.1 to 155.3 K |
| Boiling point | 89.6 to 90.6 °C; 193.2 to 195.0 °F; 362.7 to 363.7 K |
| Vapor pressure | 15.7 kPa (at 37.7 °C) |
Henry's law constant (kH) | 19 nmol Pa−1 kg−1 |
| −86.24·10−6 cm3/mol | |
Refractive index (nD) | 1.384 |
| Thermochemistry | |
| 222.92 J K−1 mol−1 | |
Std molar entropy(S⦵298) | 323.34 J K−1 mol−1 |
Std enthalpy of formation(ΔfH⦵298) | −231.1 – −228.5 kJ mol−1 |
Std enthalpy of combustion(ΔcH⦵298) | −4.8127 – −4.8103 MJ mol−1 |
| Hazards | |
| GHS labelling: | |
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| Danger | |
| H225,H304,H315,H336,H410 | |
| P210,P261,P273,P301+P310,P331 | |
| NFPA 704 (fire diamond) | |
| Flash point | −1 °C (30 °F; 272 K) |
| 280 °C (536 °F; 553 K) | |
| Explosive limits | 1–7% |
| Related compounds | |
Related alkanes | |
Related compounds | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
2-Methylhexane (C7H16, also known asisoheptane,ethylisobutylmethane) is anisomer ofheptane. It is structurally ahexane molecule with amethyl group attached to its second carbon atom. It exists in most commercially available heptane merchandises as animpurity but is usually not considered as impurity in terms of reactions since it has very similarphysical andchemical properties when compared to n-heptane (straight-chained heptane).
Being an alkane, 2-methylhexane is insoluble inwater, but is soluble in many organic solvents, such asalcohols andether. However, 2-methylhexane is more commonly considered as asolvent itself. Therefore, even though it is present in many commercially available heptane products, it is not considered as a destructive impurity, as heptane is usually used as a solvent. Nevertheless, by concise processes ofdistillation andrefining, it is possible to separate 2-methylhexane from n-heptane.
Within a group of isomers, those with morebranches tend to ignite more easily andcombust more completely. Therefore, 2-methylhexane has a lowerAutoignition temperature andflash point when compared to heptane. Theoretically 2-methylhexane also burns with a less sooty flame, emitting higher-frequency radiation; however, as heptane and 2-methylhexane differ by only one carbonatom, in terms of branching, both burn with a bright yellow flame when ignited.
Compared to n-heptane, 2-methylhexane has lowermelting andboiling points. 2-methylhexane is also less dense than heptane.
On theNFPA 704 scale, 2-methylhexane is listed as a reactivity level-0 chemical, along with various otheralkanes. In fact, most alkanes are unreactive except in extreme conditions, such as combustion or strongsunlight. At the presence ofoxygen and flame, 2-methylhexane, like heptane, combusts mostly completely intowater andcarbon dioxide. WithUV-light and mixed withhalogens in solvents, usuallybromine in1,1,1-trichloroethane, asubstitution reaction occurs.
