PERACETIC ACID
(AND RELATED PERCARBOXYLIC ACIDS)

Peracetic acid
(Peroxyacetic acid; acetyl hydroperoxide)
CAS 79-21-0
Note: Although other percarboxylic acids have different physical properties, their reactivity and toxicology are similar to those of peracetic acid.

CH₃C(O)OOH

Colorless liquid
bp 105 °C (40% solution in acetic acid), mp 0.1 °C
Miscible with water

Acrid odor

Low

40.5 °C (open cup)

Explodes when heated to 110 °C

LD₅₀ oral (rat) 1540 mg/kg

LD₅₀ skin (rabbit) 1410 mg/kg

Severely irritating to the eyes, skin, and mucous membranes; can form explosive mixtures with easily oxidized substances.

The acute toxicity of peracetic acid is low. However, peracids are extremely irritating to the skin, eyes, and respiratory tract. Skin or eye contact with the 40% solution in acetic acid can cause serious burns. Inhalation of high concentrations of mists of peracetic acid solutions can lead to burning sensations, coughing, wheezing, and shortness of breath.

Peracetic acid has not been found to be carcinogenic or to show reproductive or developmental toxicity in humans. There is some evidence that this compound is a weak carcinogen from animal studies (mice).

Data on other peracids suggest peracetic acid may show the worst chronic and acute toxicity of this class of compounds. Other commonly available peracids, such as perbenzoic acid and m -chloroperbenzoic acid (MCPBA) are less toxic, less volatile, and more easily handled than the parent substance.

Peracetic acid explodes when heated to 110 °C, and the pure compound is extremely shock sensitive. Virtually all peracids are strong oxidizing agents and decompose explosively on heating. Moreover, most peracids are highly flammable and can accelerate the combustion of other flammable materials if present in a fire. Fires involving peracetic acid can be fought with water, dry chemical, or halon extinguishers. Containers of peracetic acid heated in a fire may explode.

Peracids such as peracetic acid are strong oxidizing agents and react exothermically with easily oxidized substrates. In some cases the heat of reaction can be sufficient to induce ignition, at which point combustion is accelerated by the presence of the peracid. Violent reactions may potentially occur, for example, with ethers, metal chloride solutions, olefins, and some alcohols and ketones. Shock-sensitive peroxides may be generated by the action of peracids on these substances as well as on carboxylic anhydrides. Some metal ions, including iron, copper, cobalt, chromium, and manganese, may cause runaway peroxide decomposition. Peracetic acid is also reportedly sensitive to light.

Peracetic acid should be handled in the laboratory using the "basic prudent practices" described in Chapter 5.C, supplemented by the additional precautions for work with reactive and explosive substances (Chapter 5.G). Reactions involving large quantities of peracids should be carried out behind a safety shield. Peracetic acid should be used only in areas free of ignition sources and should be stored in tightly sealed containers in areas separate from oxidizable compounds and flammable substances. Other commonly available peracids, such as perbenzoic acid and m -chloroperbenzoic acid (MCPBA), are less toxic, less volatile, and more easily handled than peracetic acid.

In the event of skin contact, immediately wash with soap and water and remove contaminated clothing. In case of eye contact, promptly wash with copious amounts of water for 15 min (lifting upper and lower lids occasionally) and obtain medical attention. If peracetic acid is ingested, obtain medical attention immediately. If large amounts of this compound are inhaled, move the person to fresh air and seek medical attention at once.

In the event of a spill, remove all ignition sources, soak up the peracetic acid solution with a spill pillow or a noncombustible absorbent material such as vermiculite, place in an appropriate container, and dispose of properly. Respiratory protection may be necessary in the event of a large spill or release in a confined area.

Excess peracetic acid and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines. Peracids may be incompatible with other flammable mixed chemical waste; for example, shock-sensitive peroxides can be generated by reaction with some ethers such as THF and diethyl ether.

The information in this LCSS has been compiled by a committee of the National Research Council from literature sources and Material Safety Data Sheets and is believed to be accurate as of July 1994. This summary is intended for use by trained laboratory personnel in conjunction with the NRC report Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. This LCSS presents a concise summary of safety information that should be adequate for most laboratory uses of the title substance, but in some cases it may be advisable to consult more comprehensive references. This information should not be used as a guide to the nonlaboratory use of this chemical.

Copyright 1995 National Academy of Sciences. All rights reserved.