SECTION 2D: Peroxide Forming Compounds and Reactives
Many chemicals form dangerous peroxides on exposure to air
and light. Since they are sometimes packaged in an air atmosphere, peroxides
can form even though
the containers have not been opened. Peroxides may detonate with extreme
violence when concentrated by evaporation or distillation, when combined
with other compounds, or when disturbed by unusual heat, shock or friction.
Formation of peroxides in ethers is accelerated in opened and partially
emptied containers. Refrigeration will not prevent peroxide formation
and stabilizers will only retard formation.
Peroxide formation may be detected by visual inspection for crystalline
solids or viscous liquids, or by using chemical methods or specialized
kits for quantitative or qualitative analysis.
Near the end of this section is a list of examples of peroxidizable compounds
that should be extended to include primary and secondary alcohols, allylic-benzylic
alcohols, ketones, and, possibly, aralkanes with benzylic hydrogens.
Recommended Work Practices (top)
The following recommendations should be followed to control the hazards
- Know the properties and hazards of all chemicals you are using through
adequate research and study, including reading the label and MSDS.
- Inventory all chemical storage at least twice a year to detect forgotten
items, leaking containers, and those that need to be discarded.
- Identify chemicals that form peroxides or otherwise deteriorate or
become more hazardous with age or exposure to air. Label containers
with the date first opened and the date for disposal as recommended
by the supplier.
- Minimize peroxide formation in ethers by storing in tightly sealed
containers placed in a cool place in the absence of light. Do not store
ethers at or below the temperature at which the peroxide freezes or
the solution precipitates.
- Choose the size container that will ensure use of the entire contents
with in a short period of time.
- Require testing for peroxides of any opened containers before use.
- Clean up spills immediately (Section 8). The
safest method is to absorb the material onto vermiculite or a similar
- When working with peroxidizable compounds, wear impact-resistant
safety eyewear and face shields. Visitor specs are intended only for
slight and brief exposure, and should not be used when working with
- Do not use solutions of peroxides in volatile solvents under conditions
in which the solvent might be vaporized. This could increase the concentration
of peroxide in the solution.
- Do not use metal spatulas or magnetic stirring bars (which may leach
out iron), since contamination with metals can lead to explosive decomposition.
Ceramic, Teflon or wooden spatulas and stirring blades are usually safe
- Do not use glass containers with screw-top lids or glass stoppers.
Polyethylene bottles with screw-top lids may be used.
TABLE 2: Examples of Peroxidizable Compounds
|Peroxide Hazard on Storage: Discard After
|Peroxide Hazard on Concentration: Discard
After One Year
Diethylene glycol dimethyl ether (diglyme)
Ethylene glcyol dimethyl ether (glyme)
Methyl isobutyl ketone
|Hazardous Due to Peroxide Initiation of Polymerization*: Discard
After One Year
* Under storage conditions in the liquid state the peroxide-forming
potential increases and certain of these monomers(especially butadiene,
chloroprene, and tetrafluoroethylene) should be discarded after three
Detection of Peroxides (top)
Peroxide test strips, which change color to indicate the presence of peroxides, may be purchased through most laboratory reagent distributors. For proper testing, reference the manufacturer’s instruction. Do not perform a peroxide test on outdated materials that potentially have dangerous levels of peroxide formation
Removal of Peroxides (top)
If peroxides are anticipated, the safest route is to alert EHS and dispose
of the material as hazardous waste. Attempting to remove peroxides may
be very dangerous under some conditions.