Diethyl ether peroxides are a class of peroxides that slowly form in diethyl ether upon storage under air, light, or in the presence of metal by autoxidation .
Diethyl ether hydroperoxide
Diethyl ether hydroperoxide (CH3-CH2-O-CH(OOH)-CH3) is a colorless liquid of low viscosity with a pleasant smell. Upon heating it weakly deflagrates, resulting in a fog of acetic acid and water. Diethyl ether hydroperoxide decomposes in the presence of sodium hydroxide and Fe2+ containing salts.
Diethyl ether peroxide
Diethyl ether peroxide, also known as ethylidene peroxide, (-CH(CH3)OO-)n is a polymerization product of diethyl ether hydroperoxide. It is a colorless oily liquid that is an extremely brisant and friction sensitive explosive material. Amounts of less than 5 milligrams can damage chemical apparatuses. The dangerous properties of ether peroxides are the reason that diethyl ether and other peroxide forming ethers like tetrahydrofuran (THF) or ethylenglycoldimethylether (1,2-dimethoxyethane) are avoided in industrial processes.
Tests
Diethyl ether peroxides can be detected with potassium iodide (KI) solution or potassium iodide / starch paper. A positive test results in the formation of iodine (I2) that causes a pink color of the ether phase or a dark bluish spot on the paper strip.
Degradation
Ether peroxides can be destroyed by disproportionation to acetaldehyde with Fe2+ or Mn2+ ions or with triphenylphosphine (PPh3). The resulting aldehyde has to be removed to prevent a rapid back-formation of peroxides.
References
- A. Rieche, R. Meister, Modellversuche zur Autoxidation der Äther, Angewandte Chemie 49(5):106 (1936) (German)