ACETIC ACID

Substance

Acetic acid
(Ethanoic acid)
CAS 64-19-7

CH₃COOH

Colorless liquid
bp 118 °C, mp 17 °C
Miscible in water (100 g/100 mL)

Strong, pungent, vinegar-like odor detectable at 0.2 to 1.0 ppm

2.1 (air = 1.0)

11 mmHg at 20 °C

39 °C

426 °C

LD₅₀ oral (rat) 3310 mg/kg

LD₅₀ skin (rabbit) 1060 mg/kg

LC₅₀ inhal (mice) 5620 ppm (1 h)

PEL (OSHA) 10 ppm (25 mg/m³)

TLV-TWA (ACGIH) 10 ppm (25 mg/m³)

STEL (ACGIH) 15 ppm (37 mg/m³)

Corrosive to the skin and eyes; vapor or mist is very irritating and can be destructive to the eyes, mucous membranes, and respiratory system; ingestion causes internal irritation and severe injury.

The acute toxicity of acetic acid is low. The immediate toxic effects of acetic acid are due to its corrosive action and dehydration of tissues with which it comes in contact. A 10% aqueous solution of acetic acid produced mild or no irritation on guinea pig skin. At 25 to 50%, generally severe irritation results. In the eye, a 4 to 10% solution will produce immediate pain and sometimes injury to the cornea. Acetic acid solutions of 80% or greater concentration can cause serious burns of the skin and e yes. Acetic acid is slightly toxic by inhalation; exposure to 50 ppm is extremely irritating to the eyes, nose, and throat.

Acetic acid has not been found to be carcinogenic or to show reproductive or developmental toxicity in humans.

Acetic acid is a combustible substance (NFPA rating = 2). Heating can release vapors that can be ignited. Vapors or gases may travel considerable distances to ignition source and "flash back." Acetic acid vapor forms explosive mixtures with air at concentrations of 4 to 16% (by volume). Carbon dioxide or dry chemical extinguishers should be used for acetic acid fires.

Contact with strong oxidizers may cause fire.

Acetic acid should be handled in the laboratory using the "basic prudent practices" described in Chapter 5.C. In particular, acetic acid should be used only in areas free of ignition sources, and quantities greater than 1 liter should be stored in tightly sealed metal containers in areas separate from oxidizers.

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 acetic 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 acetic acid with a spill pillow or absorbent material, place in an appropriate container, and dispose of properly. Cleaned-up material is a RCRA Hazardous Waste. Respiratory protection may be necessary in the event of a large spill or release in a confined area.

Excess acetic acid and waste material containing this substance should be placed in a covered metal container, clearly labeled, and handled according to your institution's waste disposal guidelines.

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.