HEPTANE

Heptane
General
Molecular formula	C7H16
SMILES	CCCCCCC
Molar mass	100.21 g/mol
Appearance	colorless liquid
CAS number	[142-82-5]
Properties
Density and phase	0.684 g/ml, liquid
Solubility in water	Immiscible
Melting point	−90.61 °C (182.55 K)
Boiling point	98.42 °C (371.58 K)
Viscosity	0.386 cP at 25 °C
Hazards
MSDS	External MSDS
EU classification	Flammable ('F') Harmful ('Xn') Dangerous for the environment ('N')
NFPA 704
R-phrases	, , , ,
S-phrases	, , , , , , ,
Flash point	−4 °C
Autoignition temperature	285 °C
Explosive limits	1.1–6.7%
RTECS number	MI7700000
Supplementary data page
Structure and properties	''n'', εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related alkanes	Hexane Octane
Related compounds	Methylcyclohexane Cycloheptane
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

'Heptane' (also known as 'dipropyl methane', 'gettysolve-C' or 'heptyl hydride') is an alkane with the chemical formula H₃C(CH₂)₅CH₃. Heptane has nine isomers:

★ Heptane (''n''-heptane), CH₃CH₂CH₂CH₂CH₂CH₂CH₃, straight chain of seven carbon atoms.

★ 2-Methylhexane, CH₃CH(CH₃)CH₂CH₂CH₂CH₃, chain of six carbon atoms, and a methyl group attached to the second.

★ 3-Methylhexane, CH₃CH₂CH(CH₃)CH₂CH₂CH₃ (chiral), chain of six carbon atoms, and a methyl group attached to the third.

★ 2,2-Dimethylpentane, CH₃C(CH₃)₂CH₂CH₂CH₃, chain of five carbon atoms, and two methyl groups attached to the second.

★ 2,3-Dimethylpentane, CH₃CH(CH₃)CH(CH₃)CH₂CH₃ (chiral), chain of five carbon atoms, and methyl groups attached to the second and third.

★ 2,4-Dimethylpentane, CH₃CH(CH₃)CH₂CH(CH₃)CH₃, chain of five carbon atoms, and methyl groups attached to the second and fourth.

★ 3,3-Dimethylpentane, CH₃CH₂C(CH₃)₂CH₂CH₃, chain of five carbon atoms, and two methyl groups attached to the third.

★ 3-Ethylpentane, CH₃CH₂CH(CH₂CH₃)CH₂CH₃, chain of five carbons, and an ethyl group attached to the third.

★ 2,2,3-Trimethylbutane, CH₃C(CH₃)₂CH(CH₃)CH₃, chain of four carbon atoms, with two methyl groups attached to the second, and one to the third.[1]
The straight-chain isomer ''n''-heptane is the zero point of the octane rating scale. It is undesirable in petrol, as it burns explosively, causing engine knocking, as opposed to branched-chain octane isomers, which burn more slowly and give better performance. Its choice for the zero point of the scale was due to the availability of very high purity ''n''-heptane, unmixed with other isomers of heptane or other alkanes, distilled from the resin of Jeffrey Pine. Other sources of heptane and octane, produced from crude oil, contain a mixture of different isomers with greatly differing ratings, so do not give a precise zero point.

Contents

Uses

External links

Uses

Heptane, as well as its many isomers, are widely applied in laboratories as a totally non-polar solvent. Being a liquid, it is ideal for transport and storage. In the grease spot test, heptane is used to dissolve the oil spot to show the previous presence of organic compounds on a stained paper. This is done by shaking the stained paper in a heptane solution for about half a minute.
Heptane is also used as a medium to distinguish bromine from iodine from aqueous mixtures. While both bromine and iodine appear brown in aqueous media, bromine remains brown when dissolved in heptane, while iodine turns purple when mixed with heptane.
Heptane is commercially available as the rubber cement solvent Bestine.

External links

★ International Chemical Safety Card 0657 (''n''-heptane)

★ International Chemical Safety Card 0658 (2-methylhexane)

★ NIOSH Pocket Guide to Chemical Hazards

★

★ Material Safety Data Sheet for Heptane

★ Phytochemical database entry