Hexane

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Hexane

General
Other names	n-Hexane
Molecular formula	C₆H₁₄
SMILES	CCCCCC
Molar mass	86.18 g/mol
Appearance	colorless liquid
CAS number	[110-54-3]
Properties
Density and phase	0.6548 g/ml, liquid
Solubility in water	immiscible
Melting point	−95 °C (178 K)
Boiling point	69 °C (342 K)
Viscosity	0.294 cP at 25 °C
Hazards
MSDS	External MSDS
EU classification	Flammable (F) Harmful (Xn) Repr. Cat. 3 Dangerous for the environment (N)
NFPA 704	3 1 0
R-phrases	R11, R38, R48/20, R62, R65, R67, R51/53
S-phrases	S2, S9, S16, S29, S33, S36/37, S61, S62
Flash point	−23.3 °C
Autoignition temperature	233.9 °C
Explosive limits	1.2–7.7%
RTECS number	MN9275000
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related alkanes	Pentane Hexanes Heptane
Related compounds	Cyclohexane
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Hexane is an alkane hydrocarbon with the chemical formula CH₃(CH₂)₄CH₃. The "hex" prefix refers to its six carbons, while the "ane" ending indicates that its carbons are connected by single bonds. Hexane isomers are largely unreactive, and are frequently used as an inert solvent in organic reactions because they are very non-polar. They are also common constituents of gasoline and glues used for shoes, leather products and roofing. Additionally, it is used in solvents to extract oils for cooking and as a cleansing agent for shoe, furniture and textile manufacturing.

1 Isomers
2 Production
3 Toxicity
4 See also
5 Reference
6 External links

[edit] Isomers

Hexane has five isomers:

Hexane, CH₃CH₂CH₂CH₂CH₂CH₃, a straight chain of six carbon atoms.
2-Methylpentane (Isohexane), CH₃CH(CH₃)CH₂CH₂CH₃, a five-carbon chain with one methyl branch on the second.
3-Methylpentane, CH₃CH₂CH(CH₃)CH₂CH₃, a five-carbon chain with one methyl branch on the third.
2,3-Dimethylbutane, CH₃CH(CH₃)CH(CH₃)CH₃, a four-carbon chain with one methyl branch on the second and third.
2,2-Dimethylbutane, CH₃C(CH₃)₂CH₂CH₃, a four-carbon chain with two methyl branches on the second.[1]

[edit] Production

Hexane is produced by the refining of crude oil. The exact composition of the fraction depends largely on the source of the oil (crude or reformed) and the constraints of the refining. The industrial product (usually around 50% by weight of the straight-chain isomer) is the fraction boiling at 65–70 °C.

[edit] Toxicity

The acute toxicity of hexane is relatively low, although it is a mild anesthetic. Inhalation of high concentrations produces first a state of mild euphoria, followed by somnolence with headaches and nausea.

Chronic intoxication from hexane has been observed in recreational solvent abusers and in workers in the shoe manufacturing, furniture restoration and automobile construction industries. The initial symptoms are tingling and cramps in the arms and legs, followed by general muscular weakness. In severe cases, atrophy of the skeletal muscles is observed, along with a loss of coordination and problems of vision.

Similar symptoms are observed in animal models. They are associated with a degeneration of the peripheral nervous system (and eventually the central nervous system), starting with the distal portions of the longer and wider nerve axons. The toxicity is not due to hexane itself but to one of its metabolites, hexane-2,5-dione. It is believed that this reacts with the amino group of the side chain of lysine residues in proteins, causing cross-linking and a loss of protein function.

The effects of hexane poisoning in humans are uncertain. In 1994, n-hexane was included in the list of chemicals on the Toxic Release Inventory (TRI).[2] In the latter part of the 20th and early part of the 21st centuries, a number of explosions have been attributed to the combustion of hexane gas. In 2001, the U.S. Environmental Protection Agency issued regulations on the control of emissions of hexane gas due to its potential carcinogenic properties and environmental concerns.[3]