Petroleum ether

''Benzine redirects here. For the Rammstein single, see Benzin. For the aromatic compound, see benzene. For the automobile fuel (called benzine in many countries) see gasoline.''

Petroleum ether, also known as benzine or X4, 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.

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.