Solvent Peroxides : Formation and disposal
Related links :
Laboratory waste disposal
Peroxide Forming Compounds
Chemicals that are sensitive to peroxide formation can be broken into three categories
shown in the following table. (Jackson, J. Chem. Ed., 1970)
Peroxides from Storage
Peroxides from Concentration
* Indicates a peroxide
former when stored
as a liquid monomer.
chemicals should be tested for peroxide formation before using, or discarded after 3
Diethylene glycol dimethyl ether (diglyme)
Other secondary alcohols
chemicals should be tested for peroxides before distillation or evaporation and
tested for peroxide formation, or discarded after 1 year.
** Can form explosive
levels of peroxides
if stored as a liquid.
When stored as gas,
may cause autopoly-
chemicals should be tested for peroxide formation, or discard liquids aftter 6 months; and
gases after 1 year.
The materials in group A are particularly hazardous and are capable of forming peroxides that may explode even without
undergoing distillation or evaporation. One of the more dangerous is isopropyl ether, which decomposes rapidly on storage so
that crystals of peroxides accumulate in the threads under the cap. This condition is extremely dangerous and the container
should not be opened - friction may initiate detonation.
The chemicals in groups B and C should be discarded or tested for peroxide formation after 12 months.
If the age of any of these compounds is unknown, or is suspected to be greater than these recommended time frames, the
container should not be opened.
Test for Peroxides
Test for peroxide using freshly prepared KI solution based on the oxidation of iodide ion to iodine. Dissolve 1 gram of KI or
sodium iodide in 10 mls glacial acetic acid, and add 1 ml test substance to 1 ml reagent :
Yellow color = low concentration of peroxide
Brown color = high cncentration of peroxide
This test is sensitive to the formation of hydroperoxides (ROOH), which is the principal hazard associated with
peroxide-forming solvents, but does not detect difficult to reduce peroxides such as dialkyl peroxides (ROOR).
of peroxide can be detected by a reagent consisting of 3 g of sodium iodide dissolved in 50 mL of glacial acetic acid and
adding 2 mL of 37% hydrochloric acid.
More recently, test strips have been developed that will test for the presence of peroxides.
Disposal of Peroxides
Liquids : Dilution and Inceneration.
For small quantities of both refrigerated and ambient storage organic peroxides. Dilute peroxide to 1 % active oxygen or less
than 10 % by weight (whichever is lower) in common hydrocarbons which are readily soluble with organic peroxides. The
hydrocarbon solvent should be the same temperature as the peroxide being diluted, so that the heat contribution from the
peroxide will be negligible. The mixture is then incinerated in a chemical incinerator.
Note : This procedure is NOT
reccommended for solid peroxides.
Solids : Solids are disposed of 'as is' or as water wet mixtures by the process of inceneration.
Inceneration not only gives rapid and complete decomposition, but also eliminates the decomposition products. Direct inceneration has become the accepted means of disposal of all types of peroxides.
MEKP : Disposal of Methyl Ethyl Ketone Peroxide (MEKP) :
1.Harden with polyester resin, and dispose in landfill.
Incremental addition of MEKP to a rapidly stirred, cold 5 - 10 % sodium hydroxide solution. Reaction requires adequate
agitation and temperature control between 30 to 40 °C. Note : NEVER add the caustic to the MEKP.
converts the MEKP to water soluble salts which can be disposed of as non hazardous waste.
1. Safety Guidelines for Peroxidizable Organic Chemicals, Jackson, J. Chem. Ed., 1970
Signature: Dhanlal De Lloyd, Chem. Dept, The University of The West Indies, St. Augustine campus
The Republic of Trinidad and Tobago.
Copyright: delloyd2000© All rights reserved.