Peroxide Forming Chemicals
Did you know...
- That containers of ethyl ether can become explosive over time?
- That ethyl ether is one of a group of chemicals that can form unstable peroxides?
- That peroxides can accumulate and possible detonate when you open the container?
- Ether containers have an expiration date printed on the label to indicate how long it can be safely stored.
- Dartmouth College uses a purple sticker to indicate the (1) date purchased and (2) date opened.
- Never open or move expired containers of ether or other peroxide forming compounds. Contact Environmental Health and Safety immediately.
- Additional information on peroxide forming chemicals is available from EHS.
Peroxide Forming Solvents
A significant number of laboratory solvents can undergo autoxidation under normal storage conditions to form unstable and potentially dangerous peroxide by-products.
Potential peroxide-forming solvent categories:
1. Solvents that do not need to be pre-concentrated (see Group A)
2. Solvents that need pre-concentration in order to form peroxides (see Group B)
Potential Peroxide-Forming Solvents*
Group A: Chemicals that form explosive levels of peroxides without concentration Severe peroxide hazard after prolonged storage, especially after exposure to air. Test for peroxide formation before using or discard after 3 months.
Isopropyl ether
Group B: Peroxide hazards on concentration Test for peroxide formation before distillation or evaporation. Test for peroxide formation or discard after 1 year.
Acetal Ethylene glycol ether acetates
Acetaldehyde Furan
Benzyl Alcohol 4-Heptanol
2-Butanol 2-Hexanol
Dioxanes Methyl Acetylene
Chlorofluoroethylene 3-Methyl-1-butanol
Cumene(isopropylbenzene) Methyl-isobutyl ketone
Cyclohexene 4-Methyl-2-pentanol
2-Cyclohexen-1-ol 2-Pentanol
Cyclopentene 4-Penten-1-ol
Decahydronapthalene(decal in) 1-Phenylethanol
Diacetylene(butadiyne) Tetrahydrofuran
Dicyclopentadiene Tetrahydronapthalene
Diglyme Vinyl Ethers
Diethyl ether Sec. Alcohols
* Materials other than those listed may form peroxides. Applies only to pure materials.
Use and Storage of Peroxide-Forming Solvents
The solvents most commonly used in the laboratory solvents, such as diethyl ether, tetrahydrofuran, cyclohexene, glycol ethers, decalin and 2-propanol are shown in Group B of the previous section. These compounds produce organic peroxides that are significantly less volatile than the solvent in which they are formed, as a result, evaporative concentration or distillation can produce dangerous levels of peroxides. In fact, most Group B solvents are sufficiently volatile that multiple openings of a single container can result in significant and dangerous peroxide concentration.
General Handling Considerations for Peroxidizeable Solvents:
- All peroxide-forming solvents should be checked for the presence of any peroxides prior to distillation or evaporation.
- Solvents containing low levels of free radical scavengers such as BHT should be used whenever the presence of the stabilizing species does not interfere with intended application.
- Uninhibited materials should be stored with care and frequently checked for peroxide formation.
- Peroxide-forming solvents should be purchased in limited quantities and older material in inventory should be preferentially selected for use.
- Materials should be stored away from light and heat with tightly secured caps and labeled with dates of receipt and opening.
- Periodic testing to detect peroxides should be performed and recorded on previously opened material.
