Petroleum ether

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Benzine redirects here. For other uses, see benzene.

Petroleum ether
Other names	Benzine Ligroine Naphtha petroleum
Identifiers
CAS number	[8032-32-4.]
RTECS number	OI6180000
Properties
Molecular formula	Mixture of hydrocarbons
Molar mass	87 to 90 g/mol
Appearance	Colorless liquid
Density	0.625 to 0.660g/cm³, liquid
Melting point	< -73 °C
Boiling point	20 to 75 °C
Solubility in water	Insoluble
Hazards
Main hazards	Highly flammable irritant
NFPA 704	4 2 0
R-phrases	R12, R38, R51/53, R62, R65, R67
S-phrases	S9, S16, S23, S24, S33, S62
Flash point	-18 °C
Related compounds
Related compounds	naphtha, kerosene
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Petroleum ether, also known as benzine, X4 or Ligroin, is a group of various volatile, highly flammable, liquid hydrocarbon mixtures used chiefly as nonpolar solvents.

Petroleum ether is obtained from petroleum refineries as the portion of the distillate which is intermediate between the lighter naphtha and the heavier kerosene. It has a specific gravity of between 0.6 and 0.8 depending on its composition.

Benzine should not be confused with benzene. Benzine is a mixture of alkanes, e.g., pentane, hexane, and heptane, whereas benzene is a cyclic, aromatic hydrocarbon, C₆H₆. Likewise, petroleum ether should not be confused with the class of organic compounds called ethers, which contain the -O- functional group.

During the Second World War some extermination camps experimented by killing people with benzine injections.^[1]

[edit] Ligroin

Ligroin is a refined saturated hydrocarbon petroleum fraction similar to petroleum ether used mainly as a laboratory solvent. It predominantly consists of C₇ through C₁₁ in the form of about 55% paraffins, 30% monocycloparaffins, 2% dicycloparaffins and 12% alkylbenzenes. It is nonpolar. Generally laboratory grade ligroin boils at 60 to 90 °C, but the following fractions of petroleum ether are commonly available: 30 to 40 °C, 40 to 60 °C, 60 to 80 °C, 80 to 100 °C and sometimes 100 to 120 °C. The 60 to 80 °C fraction is often used as a replacement for hexane.