Diisopropyl ether

Diisopropyl ether is a secondary ether that is used as a solvent. It is a colorless liquid that is slightly soluble in water, but miscible with organic solvents. It is also used as an oxygenate gasoline additive. It is obtained industrially as a byproduct in the production of isopropanol by hydration of propylene. Diisopropyl ether is sometimes represented by the abbreviation DIPE.

Use as a solvent

Whereas at 20 °C, diethyl ether will dissolve 1% by weight water, diisopropyl ether dissolves 0.88%. Diisopropyl ether is used as a specialized solvent to remove or extract polar organic compounds from aqueous solutions, e.g. phenols, ethanol, acetic acid.
In the laboratory, diisopropyl ether is useful for recrystallizations because it has a wide liquid range. Diisopropyl ether is used for converting bromoboranes, which are thermally labile, into isopropoxy derivatives.

Diisopropyl ether forms explosive organic peroxides similar to TATP upon standing in air. This reaction proceeds more easily than for diethyl ether due to the increased lability of the C-H bond adjacent to oxygen. Many explosions have been known to occur during handling of old diisopropyl ether bottles. Some laboratory procedures recommend use of freshly opened bottles. Antioxidants such as butylated hydroxytoluene can be used to prevent this process. The stored solvent is generally tested for the presence of peroxides. It is recommended to test once every 3 months for diisopropyl ether compared to once every 12 months for diethyl ether. Peroxides may be removed by stirring the ether with an aqueous solution of iron(II) sulfate or sodium metabisulfite. For safety reasons, methyl tert-butyl ether is often used as an alternative solvent.