2-Methylhexane

{{#if:OdorlessOdorlessColorless liquid679 mg ml^–115.7 kPa (at 37.7 °C)1.384154.1155.3167|! style="background: #F8EABA; text-align: center;" colspan="2" | Properties

2-Methylhexane
Skeletal formula of 2-methylhexane
Skeletal formula of 2-methylhexane with all implicit carbons shown, and all explicit hydrogens added
Ball and stick model of 2-methylhexane
IUPAC name 2-Methylhexane
Identifiers
CAS number	591-76-4 7pxY
PubChem	11582
ChemSpider	11094 7pxY
EC number	209-730-6
UN number	3295
RTECS number	MO3871500
Beilstein Reference	1696856
Jmol-3D images	Image 1
SMILES CCCCC(C)C <p><p style="word-wrap: break-word;">
InChI InChI=1S/C7H16/c1-4-5-6-7(2)3/h7H,4-6H2,1-3H3 7pxY Key: GXDHCNNESPLIKD-UHFFFAOYSA-N 7pxY
Molecular formula	C7H16
Molar mass	100.2 g mol−1
Thermochemistry
Std enthalpy of formation ΔfHo298	−231.1–−228.5 kJ mol−1
Std enthalpy of combustion ΔcHo298	−4.8127–−4.8103 MJ mol−1
Standard molar entropy So298	323.34 J K−1 mol−1
Specific heat capacity, C	222.92 J K−1 mol−1
Hazards
GHS pictograms	The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word	DANGER
GHS hazard statements	H225, H304, H315, H336, H410
GHS precautionary statements	P210, P261, P273, P301+310, P331
EU Index	601-008-00-2
EU classification	Flammable F Harmful Xn Dangerous for the Environment (Nature) N
R-phrases	R11, R38, R50/53, R65, R67
S-phrases	(S2), S16, S29, S33
NFPA 704	75px 3 2 0
Flash point	−1 °C
Autoignition temperature	280 °C
Explosive limits	1–7%
Related compounds
Related alkanes	2-Methylpentane 3-Methylpentane 3-Ethylpentane 3-Methylhexane 2-Methylheptane 3-Methylheptane
Related compounds	2-Ethyl-1-butanol Valnoctamide 2-Ethylhexanol Valpromide 2-Ethylhexanoic acid
14pxY (verify) (what is: 10pxY/10pxN?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

2-Methylhexane (C₇H₁₆, also known as isoheptane, ethylisobutylmethane) is an isomer of heptane. It is structurally a hexane molecule with a methyl group attached to its second carbon atom. It exists in most commercially available heptane merchandises as an impurity but is usually not considered as impurity in terms of reactions since it has very similar physical and chemical properties when compared to n-heptane (straight-chained heptane).

Being an alkane, 2-methylhexane is insoluble in water, but is soluble in many organic solvents, such as alcohols and ether. However, 2-methylhexane is more commonly considered as a solvent 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 of distillation and refining, it is possible to separate 2-methylhexane from n-heptane.

Within a group of isomers, those with more branches tend to ignite more easily and combust more completely. Therefore, 2-methylhexane has a lower autoignition temperature and flash 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 carbon atom, in terms of branching, both burn with a bright yellow flame when ignited.

Compared to n-heptane, 2-methylhexane also has lower melting and boiling points. A lower density of liquid is found in 2-Methylhexane than heptane.

On the NFPA 704 scale, 2-methylhexane is listed as a reactivity level-0 chemical, along with various other alkanes. In fact, most alkanes are unreactive except in extreme conditions, such as combustion or strong sunlight. At the presence of oxygen and flame, 2-methylhexane, like heptane, combusts mostly completely into water and carbon dioxide. With UV-light and mixed with halogens in solvents, usually bromine in 1,1,1-trichloroethane, a substitution reaction occurs.

See also

• 3-Methylhexane

References

• "2-Methylhexane". chemexper.com. http://www.chemexper.com/search/cas/591764.html. Retrieved 22 November 2011.
• "Material Safety Data Sheet". ChemADVISOR. https://www.mathesongas.com/pdfs/msds/MAT27910.pdf. Retrieved 22 November 2011.
• "Isoheptane". INCHEM: Chemical Safety Information from Intergovernmental Organizations. International Programme on Chemical Safety. October 2002. http://www.inchem.org/documents/icsc/icsc/eics0658.htm. Retrieved 22 November 2011.

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