Acetic acid (ethanoic acid)
Acetic acid is used in a number of topical medical preparations, including the destruction of warts, in eardrops, as an expectorant, liniment and astringent. It is used in the manufacture of a number of chemical compounds, plastics, pharmaceuticals, dyes, insecticides, photographic chemicals, vitamins, antibiotics, cosmetics and hormones. It is used as an antimicrobial agent, latex coagulant and oil-well acidifier. It is used in textile printing, as a preservative in foods and as a solvent for gums, resins and volatile oils.
Substance name: Acetic acid
CASR number: 64-19-7
Molecular formula: C2H4O2
Synonyms: Ethanoic acid, vinegar, ethylic acid, vinegar acid, methanecarboxylic acid, TCLP extraction fluid 2, shotgun, glacial acetic acid, glacial ethanoic acid.
Acetic acid is a colourless liquid; with a strong vinegar-like odour. It is flammable, and at temperatures warmer than 39°C, explosive vapour/air mixtures may be formed. Acetic acid is considered a volatile organic compound by the National Pollutant Inventory.
Specific Gravity: 1.049 @ 25°C
Melting Point: 16.7°C
Boiling Point: 118°C
Vapour pressure: 1.5 kPa @ 20°C
Acetic acid is hygroscopic, meaning that it tends to absorb moisture. It mixes with ethyl alcohol, glycerol, ether, carbon tetrachloride and water and reacts with oxidants and bases. Concentrated acetic acid is corrosive and attacks many metals forming flammable or explosive gases. It can also attack some forms of plastic, rubber and coatings.
The National Pollutant Inventory (NPI) holds data for all sources of acetic acid emissions in Australia.
Inhalation of acetic acid causes irritation to the nose, throat and lungs. It is a corrosive substance, where inhalation of concentrated vapour may cause serious damage to the linings of these organs and later, breathing difficulties may result. Sensitisation may result from repeated exposures.
Ingestion of this substance may cause severe corrosion of the mouth and gastrointestinal tract, leading to vomiting, diarrhoea, circulatory collapse, kidney failure and death.
Skin contact with concentrated solutions causes skin damage, indicated by pain, redness and blisters. Second degree burns may form after a few minutes of contact. Skin sensitisation is a rare consequence of exposure.
Direct eye contact with concentrated acetic acid results in redness and pain, and severe deep burns. Opacification (the process of becoming milky or opaque) of the eye, leading to blindness may result in the cornea of humans, with the severity of the injury not being apparent for a day or two after exposure. Long term exposure may cause erosion of dental enamel, bronchitis and eye irritation.
Entering the body
Acetic acid can enter the body by inhaling vapours or exposure of the vapours to the eyes. Exposure may also result from eating or drinking foods containing acetic acid or by skin contact.
Exposure to acetic acid can result from breathing vapours, drinking solutions containing acetic acid or by contact with the skin and eyes.
Currently, the eight-hour time weighted average (TWA) exposure limit is 25 milligrams acetic acid per cubic metre of air. The 15-minute short term exposure limit (STEL) is 37 milligrams acetic acid per cubic metre of air.
Drinking water guidelines:
No drinking water guidelines have been established for acetic acid.
Environmental effects depend on the concentration and duration of exposure to acetic acid. In high concentrations it can be harmful to plants, animals and aquatic life.
Entering the environment
Acetic acid can be transferred as a vapour and is soluble in water.
Where it ends up
Acetic acid degrades rapidly to harmless substances in the environment.
Currently there are no environmental guidelines for acetic acid.
Industries reporting acetic acid emissions include those that manufacture paper and paper products, meat and meat products, textile products and chemicals. Metal ore mining can also produce acetic acid.
Diffuse sources, and industry sources included in diffuse emissions data
Solid fuels burning for heating in the home and for barbeques are thought to be the highest sources of emissions. Acetic acid is also present in domestic or commercial solvents or aerosols. A range of products and foodstuffs may contain acetic acid.
Acetic acid is a natural product resulting from fermentation of some foods.
There are no sources of acetic acid that arise from transport.
Acetic acid is present in vinegar, pickled foods, some preserved foods, agricultural chemicals (including herbicides), car body polish and cleaners, glass window cleaning preparations, household detergents and cleaners, laundry aids including ironing aids and dry cleaning spot preparation, specialty cleaning and sanitation products, paint and varnish removers, pharmaceutical preparations and paints.
Sources used in preparing this information
- Merck and Co. 2001, Merck Index, 13th Edition, USA.
- National Health and Medical Research Council (NHMRC) and the National Resource
- Management Ministerial Council (NRMMC) (2004), Australian Drinking Water Guidelines 6, accessed February 2007.
- National Pollutant Inventory (1999), Contextual Information.
- Office of the Australian Safety and Compensation Council, Exposure Standards: Acetic Acid, accessed February 2007.
- Technical Advisory Panel 1999, Final Report to the National Environment Protection Council.
- United Nations, International Chemical Safety Cards: Acetic Acid, accessed February 2007.