Peroxide Forming Chemicals

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.