What are peroxides and why are they perilous?
Organic peroxides are carbon-based chemicals that include a double oxygen
(-O-O-) bond in their molecular structure. This double-oxygen bond contributes to the chemical instability of organic peroxides because it can readily decompose, yielding heat, flammable vapors, fire, or explosion. This potentially hazardous decomposition can be triggered by heat, shock, friction, and contamination with incompatible substances.
How hazardous is this decomposition? Russian authorities have acknowledged that the fire and explosion that sank the submarine
Kursk was caused by the violent decomposition of highly concentrated hydrogen peroxide leaking from one of the ship's torpedoes. The initial explosion and fire in turn caused the remaining torpedoes to simultaneously explode about 2 minutes later, sealing the ship's fate.
Some chemicals can form peroxides through contamination, presenting a lurking danger to laboratory workers, as the following account from Dr. Jim Kauffman of the
Laboratory Safety Institute illustrates:
When I was a graduate student, I was rotary evaporating column chromatography eluent. The solvent was ether. When I went to do the GC
[gas chromatograph] analysis of the concentrate, I drew a 1 µL sample into the $25 Hamilton syringe. When I inserted the syringe into the GC's septum, the syringe exploded, leaving the needle in the septum and the plunger and stump in my hand. I said "Wow!" I went and got another $25 syringe and proceeded to have another explosion. At this point I realized it was the peroxides.
How do chemicals become contaminated with organic peroxides?
Many common laboratory chemicals can form peroxides when exposed to air over a period of time. Even opening a container once to remove some of its contents may introduce enough air for peroxide formation to occur. Peroxide-forming liquids can become violently explosive in concentrated solutions or solids, so they should not be distilled or evaporated. A brief list of some common peroxide-forming chemicals and reagents is given below. If you are uncertain as to whether or not a chemical or reagent is peroxide forming, consult its Material Safety Data Sheet
(MSDS).
Common peroxide-forming chemicals and reagents
| Acetal |
Diethyl ether |
Methyl acetylene |
| Cumene |
Diethylene glycol |
Sodium amide |
| Cyclohexene |
Diisopropyl ether |
Tetrahydrofuran (THF) |
| Cyclooctene |
Dimethyl ether |
Tetrahydronaphthalene |
| Decahydronaphthalene |
Dioxane |
Tetralin |
| Decalin |
Divinyl acetylene |
Vinyl acetate |
| Diacetylene |
Ethylene glycol dimethyl ether (Glyme) |
Vinylidene chloride |
| Dicyclopentadiene |
Isopropyl ether |
|
How should I handle and store organic peroxides?
Warning: Do not handle organic peroxides or peroxide-forming chemicals and reagents that have been stored longer than 6 months, have no test history, or show obvious signs of contamination such as crystallization and discoloration. Call your chemical emergency responders for safe disposal of these materials. When handling organic peroxides and peroxide-forming chemicals and reagents, always wear proper protective equipment to include eye and face protection, impermeable gloves, and a rubber lab apron.
Review our guidelines for safe chemical storage
and observe the following recommendations for storing organic peroxides and peroxide-forming chemicals and reagents:
|
| • |
Store material in the original container, or in sealed, airtight containers. In most cases, dark amber glass with a tight-fitting cap is acceptable. Do not store in containers with loose-fitting caps or ground glass stoppers. |
| • |
Plastic containers are not recommended; however, plastic storage containers (e.g., squeeze bottles) are permissible for short-term use of isopropyl alcohol. |
| • |
Diethyl ether should be stored in steel containers. |
| • |
Label storage containers with the following information: chemical name, date received, date opened, test date, test results. |
| • |
Store within a ventilated area. |
| • |
Store away from incompatible material. |
| • |
Protect from flame, static electricity, sparks, and sources of heat. |
| • |
Protect from shock or friction. |
| • |
Peroxide-forming chemicals and reagents should be tested at least every 6 months for the presence of peroxides. If you are going to distill or evaporate one of these chemicals, you should test it for the presence of peroxides before each use. |
| • |
Reagents with low peroxide levels may be safely used; however, it depends on the application of the reagent. Do not distill or evaporate these reagents. |
| • |
See the Organic Peroxide Producers Safety Division's recommendations for
proper disposal of liquid organic
peroxides. |
| • |
See the Organic Peroxide Producers Safety Division's recommendations for
proper disposal of used organic peroxide
containers. |
| • |
See the Organic Peroxide Producers Safety Division's recommendations for
proper technique for cleaning up an organic peroxide
spill.
|
How do I test a peroxide-forming chemical or reagent for peroxides?
Warning: Do not test peroxide-forming chemicals and reagents that have been stored longer than 6 months, have no test history, or show obvious signs of contamination such as crystallization and discoloration. Call your chemical emergency responders for safe disposal of these materials.
When used as part of a regular testing and labeling program, Quantofix® Peroxide 25 test strips are a reliable and easy way to test for the presence of peroxides in peroxide-forming chemicals and reagents. Be sure to follow the package directions to get an accurate reading. Record the test date and results on the label of the chemical or reagent's container.
Chemicals and reagents that test positive for a low concentration of peroxides normally do not present thermal or shock hazards. They may be safely disposed of or treated to remove the peroxides.
Where can I learn more?
If you are interested in learning more about peroxides, visit the following Web sites: |
| • |
Canadian Centre for Occupational Health and Safety |
| • |
Hazards of Organic Peroxides, Stanford University |
| • |
Lab Safety Plan, University of California, San Diego |
| • |
Safety and Handling of Organic Peroxides: A Guide
|
.jpg){kind=small}
