Guidance Document
Peroxide-Forming Chemicals

Some chemicals can form peroxides under normal storage conditions. Some of the peroxide chemicals
are unstable, especially when dried or concentrated, and can explode violently when subjected to heat,
light or mechanical shock. In addition, some of the inadvertently formed peroxides can initiate other
unexpected violent reactions (e.g. polymerizations) with other chemicals.

When possible and practical for your work, purchase chemicals that have inhibitors added by the
manufacturer. Label peroxide-forming chemicals with date received and date opened.

Store peroxide-formers in airtight opaque containers with screw caps. Consider oxygen exclusion
methods such as purging with inert gas or sealing containers with parafilm.

Inspect containers for signs of peroxide formation. Do not open a container which has crystals or a
visible cloudiness. Call EHS to come remove it. The friction caused by opening a lid can cause an
explosion.

Liquids can be tested for presence of peroxide. This is especially important prior to distilation. Most
explosions of peroxide forming chemicals occur when a material is distilled to dryness. Peroxide test kits
are available from chemical vendors. Contact EHS for additional guidance.

Classification Table for Peroxide-Forming Chemicals
Class I:: Unsaturated materials, especially those of low molecular weight, may polymerize violently and
hazardously due to peroxide initiation. These chemicals can spontaneously decompose, becoming

explosive after exposure to air with concentration. Discard unopened containers within 3
months. Opened containers should be tested for peroxides every 2 months.




Acrylic acid
Tetrafluoroethylene

Acrylonitrile
Vinyl acetate

1,3-Butadiene
Vinyl acetylene

Chlorobutadiene (chloroprene)
Vinyl chloride

Chlorotrifluoroethylene
Vinyl pyridine

Methyl methacrylate
Vinylidiene chloride

Styrene




Class II: The following chemicals are a peroxide hazard upon concentration (distillation/evaporation). A
test for peroxide should be performed if concentration is intended or suspected. Discard unopened
containers within 6 months. Opened containers should be tested for peroxides every 2 months.

Diethylene glycol dimethyl ether

Acetal
Isopropyl alcohol
(diglyme)

Acetaldehyde
Diethyl ether
Isopropyl propyl ether

Acrylamide
Diethyl fumatate
Isopropyl vinyl ether

Allyl ethyl ether
Diethylketene
2-Isopropylacryladehyde oxime

Allyl phenyl ether
2,3-Dihydrofuran
Isovaleraldehyde

Allyl vinyl ether
2,3-Dihydropyran
Limonene
1-Allyloxy-2,3-

1,1-Dimethoxyethane
1,5-p-Mentadiene
epoxypropane

Benzyl-1-naphthyl ether
1,2-Dimethoxyethane
Methoxy-1,3,5,7-cyclooctatetraene

Benzyl butyl ether
2,2-Dimethoxypropane
1-Methoxyethanol

Benzyl ethyl ether
3,3-Dimethoxypropane
2-Methoxyethyl vinyl ether

Bis(2-ethoxyethyl ether
2,2-Dimethyl-1,3-dioxolane
Methyl acetylene


Bis(2-ethoxymethyl)ether 2,6-Dimethyl-1,4-dioxane
Methyl cyclopentane

2-Butanol
1,3-Dioxane
4-Methyl-1,3-dioxane
2-(1-Methylheptyl)-4,6-

Buten-3-yne
1,4-Dioxane
dinitrophenyl ether

Butyl ethyl ether
1,2-Dioxep-5-ene
Methylisobutyl ketone

Butyl formate
1,3-Dioxol-4-3n-2-one
2,3-Methyl-2-methylene butanal

Butyl vinyl ether
Dipropoxymethane
4-Methyl-2-pentanone
1-Chloro-2,2-

Dipropylether
2-Methyltetrahydrofuran
diethoxyethane

2-Chloroacrynitrile
Di(2-propynyl)ether
Methyl vinyl ether

2-Chloroethyl vinyl ether 1,2-Epoxy-3-isopropoxy propane
2-Penten-4-yn-3-ol

Cinnamaldehyde
1-Ethoxy-2-propyne
α-Pentylcinnamaldehyde

Crotonaldehyde
2-Ethoxyethanol
2-Propanol

Cumene
2-Ethyl butanal
Propionaldehyde

Cyclohexene
Ethyl isopropyl ether
2-Propyne-1-thiol
Sodium 5,8,11,14-

Cyclooctene
Ethyl propenyl ether
eicosatetraenoate

Cyclopentene
Ethyl vinyl ether
Sodium ethoxyacetylide

Cyclopropyl methyl ether 2-Ethylacryladehyde oxime
1,1,2,3-Tetrachloro-1,3-butadiene
Ethylene glycol dimethyl ether

Diacetylene
Tetrahydrofuran
(glyme)

Decahydronaphthalene
2-Ethylhexanal
Tetrahydronaphthalene

Decalin
2-Ethylhexyl vinyl ether
Tetrahydropyran

Diallyl ether
2-Furaldehyde
Tetralin

Dibenzyl ether
Furan
Tridecanal

p-Dibenzyloxybenzene
4,5-Hexadien-2-yl-1-ol
1,3,3-Trimethoxypropene
3,3,5-Trimethyl-2-cyclohexen-1-

1,2-DiBenzyoxyethane
2,4-Hexadienal
one


Dibutyl ether
2,5-Hexadiyn-1-ol
4-Vinylcyclohexene

Dicyclopentadiene
2-Hexanal
Vinyl ethers

1,1-Diethoxyethane
Indole-2-carboxyaldehyde


1,2-Diethoxyethane
Isobutyl vinyl ether


Diethoxymethane
Isobutyraldehyde


3,3-Diethoxypropene
Isopropoxypropionitrile





Class III: Peroxides derived from the following compounds may explode without concentration.


Organic
Inorganic

Divinyl ether
Potassium metal

Divinyl acetylene
Potassium amide

Isopropyl ether
Sodium amide (sodamide)

Vinylidene chloride

NOTE: Lists are illustrative but not exhaustive.

From Prudent Practices in the Laboratory, National Academy Press, 1995 and other sources.