Peroxide-Forming Compounds

Certain chemicals can form dangerous peroxides on exposure to air and light. 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 is accelerated in opened and partially emptied containers.

Peroxide Testing

  • Peroxide forming chemicals should be used or disposed of prior to the expiration date. If extenuating circumstances exist for keeping the chemical, routine testing must be performed.
  • Visually inspect all containers before opening for crystal formation or cloudiness. If either of these conditions are observed, DO NOT OPEN and ALERT ERM.
  • Test strips are available from the ERM Department.
  • Any chemical that tests greater than 100ppm should be disposed of, please contact ERM for assistance.
  • All test results should be recorded directly on the container.
  • Refer to TABLE 1 for testing or disposal frequency.
  • Refer to TABLE 2 for a listing of each peroxidizable classification.
Table 1
Peroxidizable Classification Dispose or Test After*‡
Unopened from manufacturer 18 months
Opened Containers
List A 3 months
List B, uninhibited 3 months
List B, inhibited 12 Months
List C, uninhibited 24 hours
List C, inhibited 12 months**
List D Prior to Use

* Never open or test containers of unknown origin or age, or those that have evidence of peroxide formation
**Do not store under inert atmosphere
‡ Unless otherwise specified on the bottle

Table 2
List A - form peroxides without concentration by evaporation or distillation
Butadiene Chloroprene
Divinylacetylene Isopropyl Ether
Tetrafluoroethylene  
Vinylidene Chloride  
List B - form explosive levels of peroxides upon concentration by evaporation or distillation
Acetal Acetaldehyde Benzyl Alcohol
2-Butanol Cumene Cyclohexanol
2-Cyclohexen-1-ol Cyclohexene Decahydronaphthalene
Diacetylene Dicyclopentadiene Diethyl Ether
Diglyme Dioxanes Glyme
4-Heptanol 2-Hexanol Methyl Acetylene
3-Methyl-1-Butanol Methylcyclopentane Methyl Isobutyl Ketone
4-Menthyl-2-Pentanol 2-Pentanol 4-Pentene-1-ol
1-Phenylethanol 2-Phenylethanol 2-Propanol
Tetrahydrofuran Other Secondary Alcohols Vinyl Ethers
List C - autopolymerize as a result of peroxide accumulation
Acrylic Acid Acrylonitrile Butadiene
Chloroprene Chlorotrifluoroethylene Methyl Methacrylate
Styrene Tetrafluoroethylene Vinyl Acetate
Vinylacetylene Vinyl Chloride Vinylpyridine
Vinylidene Chloride
List D - do not fall in the above categories, but require special handling nonetheless. Common chemicals are listed below contact you DCHO or ERM for a more extensive list.
Acrolein Ethyl Vinyl Ether Furan
Limonene

Recommended Work Practices

The following recommendations should be followed to control the hazards of peroxides.

  • Determine if the chemical in question poses a risk of forming peroxides.
  • Inventory all chemical storage at least twice a year.
  • Label containers with the date received, 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 within a short period of time.
  • Visually or chemically check for peroxides of any opened containers before use.
  • Clean up spills immediately.
  • More robust PPE and engineering controls may be required when working with peroxides and peroxide forming compounds. Please contact ERM for a full risk assessment.
  • Do not concentrate solutions that may contain peroxides. For example, rotary evaporation of an etheryl solvent such as tetrahydrofuran or diethyl ether could pose a significant risk.
  • Always purchase solvents that are inhibited against peroxide formation. Remove inhibitors using column purification. If inhibitor free solvent must be purchased, follow all documented instructions for use and always purge with nitrogen before storage.
  • Do not use metal spatulas or magnetic stirring bars (which may leach out iron) with peroxide forming compounds, since contamination with metals can lead to explosive decomposition. Ceramic, Teflon or wooden spatulas and stirring blades are usually safe to use.

For more information, refer to the Peroxide-Forming Chemicals informational poster. To request additional copies of the poster in various sizes, please contact ERM.