Classification List of Peroxide Forming Chemicals

Class A - Severe Peroxide Hazard

Spontaneously decompose and become explosive with exposure to air without concentration.

Butadiene (liquid monomer) Isopropyl ether Sodium amide (sodamide)
Chloroprene (liquid monomer) Potassium amide Tetrafluoroethylene (liquid monomer)
Divinyl ether Potassium metal Vinylidene chloride

Bold chemicals constitute the UC Class 1 Settlement Agreement list.

Class B - Concentration Hazard

Require external energy for spontaneous decomposition. Form explosive peroxides when distilled, evaporated or otherwise concentrated.

Acetal Diethylene glycol dimethyl ether (diglyme) 4-Methyl-2-pentanol
Acetaldehyde Diethyl ether (ether) 2-Pentanol
Benzyl alcohol Dioxanes 4-Penten-1-ol
2-Butanol Ethylene glycol ether acetates (glyme) 1-Phenylethanol
Cumene Furan 2-Phenylethanol
Cyclohexanol 4-Heptanol Tetrahydrofuran (THF)
Cyclohexene 2-Hexanol Tetrahydronaphthalene (tetralin)
2-Cyclohexen-1-ol Methylacetylene (gas) Vinyl ethers
Decahydronaphthalene (decalin) 3-Methyl-1-butanol Other secondary alcohols
Diacetylene (butadine, gas) Methyl cyclopentane
Dicyclopentadiene Methyl isobutyl ketone

Bold chemicals constitute the UC Class 2 Settlement Agreement list.

Class C - Shock and Heat Sensitive

Highly reactive and can auto-polymerize as a result of internal peroxide accumulation. The peroxides formed in these reactions are extremely shock- and heat-sensitive.

Acrylic acid Chlorotrifluoroethylene (gas) Vinylacetylene (gas)
Acrylonitrile Methyl methacrylate Vinyladiene chloride
Butadiene (gas) Styrene Vinyl chloride (gas)
Chlorobutadiene Tetrafluoroethylene (gas) Vinyl pyridine
Chloroprene Vinyl acetate

Bold chemicals constitute the UC Class 3 Settlement Agreement list.

Class D - Potential Peroxide Forming Chemicals

May form peroxides but cannot be clearly categorized in Class A, B, or C.

Acrolein p-Chlorophenetole 4,5-Hexadien-2-yn-1-ol
Allyl ether Cyclooctene n-Hexyl ether
Allyl ethyl ether Cyclopropyl methyl ether o.p-Iodophenetole
Allyl phenyl ether Diallyl ether Isoamyl benzyl ether
p-(n-Amyloxy)benzoyl chloride p-Di-n-butoxybenzene Isoamyl ether
n-Amyl ether 1,2-Dibenzyloxyethane Isobutyl vinyl ether
Benzyl n-butyl ether p-Dibenzyloxybenzene Isophorone
Benzyl ether 1,2-Dichloroethyl ethyl ether b-Isopropoxypropionitrile
Benzyl ethyl ether 2,4-Dichlorophenetole Isopropyl-2,4,5-trichlorophenoxy acetate
Benzyl methyl ether Diethoxymethane n-Methylphenetole
Benzyl-1-naphthyl ether 2,2-Diethoxypropane 2-Methyltetrahydrofuran
1,2-Bis(2-chloroethoxyl)ethane Diethyl ethoxymethylenemalonate 3-Methoxy-1-butyl acetate
Bis(2-ethoxyethyl)ether Diethyl fumarate 2-Methoxyethanol
Bis(2-(methoxyethoxy)ethyl) ether Diethyl acetal 2-Methoxyethyl acetate
Bis(2-chloroethyl) ether Diethylketene 3-Methoxybutyl acetate
Bis(2-ethoxyethyl) adipate Diethoxybenzene (m-,o-,p-) 2-Methoxyethyl vinyl ether
Bis(2-methoxyethyl) carbonate 1,2-Diethoxyethane Methoxy-1,3,5,7-cyclooctatetraene
Bis(2-methoxyethyl) ether Dimethoxymethane b-Methoxypropionitrile
Bis(2-methoxyethyl) phthalate 1,1-Dimethoxyethane m-Nitrophenetole
Bis(2-methoxymethyl) adipate Di(1-propynl) ether 1-Octene
Bis(2-n-butoxyethyl) phthalate Di(2-propynl) ether Oxybis(2-ethyl acetate)
Bis(2-phenoxyethyl) ether Di-n-propoxymethane Oxybis(2-ethyl benzoate)
Bis(4-chlorobutyl) ether 1,2-Epoxy-3-isopropoxypropane b,b-Oxydipropionitrile
Bis(chloromethyl) ether 1,2-Epoxy-3-phenoxypropane 1-Pentene
2-Bromomethyl ethyl ether p-Ethoxyacetophenone Phenoxyacetyl chloride
beta-Bromophenetole 1-(2-Ethoxyethoxy)ethyl acetate a-Phenoxypropionyl chloride
o-Bromophenetole 2-Ethoxyethyl acetate Phenyl-o-propyl ether
p-Bromophenetole (2-Ethoxyethyl)-a-benzoyl benzoate p-Phenylphenetone
3-Bromopropyl phenyl ether 1-Ethoxynaphthalene n-Propyl ether
tert-Butyl methyl ether o,p-Ethoxyphenyl isocyanate n-Propyl isopropyl ether
n-Butyl phenyl ether 1-Ethoxy-2-propyne Sodium 8-11-14-eicosatetraenoate
n-Butyl vinyl ether 3-Ethoxypropionitrile Sodium ethoxyacetylide
Chloroacetaldehyde diethylacetal 2-Ethylacrylaldehyde oxime Tetrahydropyran
2-Chlorobutadiene 2-Ethylbutanol Triethylene glycol diacetate
1-(2-Chloroethoxy)-2-phenoxyethane Ethyl-b-ethoxypropionate Triethylene glycol dipropionate
Chloroethylene Ethylene glycol monomethyl ether 1,3,3-Trimethoxypropene
Chloromethyl methyl ether 2-Ethylhexanal 1,1,2,3-Tetrachloro-1,3-butadiene
beta-Chlorophenetole Ethyl vinyl ether 4-Vinyl cyclohexene
o-Chlorophenol 2,5-Hexadiyn-1-ol Vinylene carbonate