Glossary / Physical hazards
Peroxide former
A peroxide former is a chemical that reacts slowly with oxygen during storage to form unstable peroxides that can detonate when shocked, heated or concentrated. Many common ethers and some other solvents fall into this group.
Explanation
The peroxides that form in these chemicals are sensitive compounds. They can build up in a bottle that has been opened and then left on a shelf for months or years. The risk rises when the liquid is evaporated, distilled or otherwise concentrated, because peroxides stay behind as the solvent leaves.
Typical peroxide formers include diethyl ether, tetrahydrofuran, dioxanes, isopropyl ether and certain alkenes and dienes. They are often grouped by how hazardous they become and how long they can be safely stored. Suppliers frequently add an inhibitor, but it is used up over time and does not protect an old container forever.
Good practice is administrative. Record the date received and the date opened on every container, buy small quantities, store in tightly sealed containers away from light and heat, and set a firm disposal or testing date. Test strips are widely used to check for peroxides before distillation.
Crystals around a cap, a cloudy liquid or an unusual viscous layer can mean serious peroxide buildup. Do not try to open or move such a container. Isolate the area and call the people responsible for hazardous waste or emergency support, because even twisting a cap can set it off.
What to do and watch for
- Date every container on receipt and again when opened.
- Test or dispose of containers by the date your safety program sets, and never distill to dryness.
- If you see crystals or a stuck cap, leave the bottle alone and report it.
Where it appears on an SDS
- Section 7: Handling and storage. Storage advice such as keeping containers sealed, dated and away from light, heat and air, and any recommended storage time.
- Section 10: Stability and reactivity. Statements that the material can form explosive peroxides and the conditions that make this more likely.
SDS content and wording vary by supplier. This page is general reference and does not replace the current SDS for your product.