Aniline is used in rubber accelerators and anti-oxidants, dyes and intermediates, photographic chemicals, as isocyanates for urethane foams, in pharmaceuticals, explosives, petroleum refining; and in production of diphenylamine, phenolics, herbicides and fungicides. Aniline is also used in the manufacture of polyurethanes, rubber processing chemicals, pesticides, fibres, dyes and pigments, photographic chemicals, and pharmaceuticals.
Substance name: Aniline (benzenamine)
CASR number: 62-53-3
Molecular formula: C6H7N
Synonyms: benzamine; aniline oil, phenylamine; aminobenzene; aniline oil; phenylamine; aminophen; kyanol; benzidam; blue oil; C.I. 76000; C.I. oxidation base 1; cyanol; krystallin; anyvim; arylamine
Aniline is a colourless to brown, oily liquid which darkens on exposure to air and light. It has a characteristic amine odour (detectable at 0.6 to 10 ppm ) and burning taste. Hygroscopic. Moderately soluble in water. Aniline is miscible with alcohol, benzene, chloroform, carbon tetrachloride, acetone, and most organic solvents.
Melting Point: -6.2°C
Boiling Point: 184°C
Specific Gravity: 1.0217
Vapour Density: 3.22
1 ppm = 3.8 mg/m3
formula weight 93.128
Combustible. Darkens on exposure to air and light. The substance decomposes on heating at temperatures above 190°C, or on burning producing toxic and corrosive fumes (ammonia, nitrogen oxides, and carbon monoxide) and flammable vapours. The substance is a weak base. Reacts vigorously with strong oxidants, acids, acetic anhydride, chloromelamine monomers, beta-propiolactone, and epichlorohydrin causing fire and explosion hazard. Reacts with metals such as sodium, potassium, and calcium, producing flammable hydrogen gas. Attacks copper and its alloys.
The National Pollutant Inventory (NPI) holds data for all sources of aniline emissions in Australia.
Short-term exposure to the substance irritates the eyes, and may cause effects on the blood: methaemoglobinaemia, resulting in cyanosis, brain damage and kidney failure. It is potentially lethal to humans.
Long-term or repeated exposure may have effects on the liver, kidneys, blood and spleen: methemoglobanaemia (see short-term exposure). Aniline (benzenamine) is a probable carcinogen.
It does not remain in the body due to its breakdown and removal. Aniline is a possible reproductive hazard.
Entering the body
The substance can be absorbed into the body by inhalation of the vapour, through the skin and by ingestion.
Aniline can be formed from the breakdown of certain pollutants found in outdoor air, from the burning of plastics, or from burning tobacco. Airborne exposure to aniline may occur from breathing contaminated air, from smoking tobacco or proximity to someone who is smoking, or from being near industrial sources that use large quantities of aniline.
Occupational exposure to aniline could occur in industries that use aniline to make other chemicals.
Small amounts of aniline may be found in some foods, such as corn, grains, rhubarb, apples, beans, and rapeseed cake (animal feed). Aniline has also been found as a volatile component of black tea. Aniline has been detected in drinking water and has also been found in surface water.
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for aniline through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 2 parts per million (7.6 mg/m3)
These standards are only appropriate for use in workplaces and are not limited to any specific industry or operation. Make sure you understand how to interpret the standards before you use them.
Drinking water guidelines
There is no guideline for aniline in the Australian Drinking Water Guidelines.
This substance may be hazardous to the environment; with special attention given to fish, crustaceans, and birds. Tests by the aniline industry show that aniline is highly toxic to aquatic life.
Aniline causes germination decrease, stunting, and size decreases (among other effects) on numerous agricultural crops.
Aniline acts to reduce the formation of photochemical smog.
Aniline is unlikely to exist in terrestrial environments in sufficient concentrations to cause serious acute or chronic effects to terrestrial organisms.
Entering the environment
Aniline in solution adsorbs strongly to colloidal organic matter, which effectively increases its solubility and movement into ground water. It is also moderately adsorbed to organic material in the soil. It will slowly volatilise from soil and surface water (vapour pressure 0.67 mm Hg @ 25°C) and is subject to biodegradation. Although rapidly degraded in the atmosphere, aniline can be deposited in the soil by wet and dry deposition, and by adsorption on aerosol particles.
Where it ends up
Air: Aniline degrades in the atmosphere primarily by reaction with photochemically produced hydroxyl radicals. The estimated half-life for aniline is 2 hours. The reaction products include nitrosamines, nitrobenzene, formic acid, nitrophenols, phenol, nitrosobenzene, and benzidine.
Soil: A number of microorganisms in soil can use aniline as a sole carbon and nitrogen source. Degradation of 44.2% of the incubated aniline to CO2in 10 days and 12% in 20 days, respectively, by different isolated soil microorganisms has been demonstrated in the laboratory. Aniline bound to humic materials in the soil is subject to oxidation. Products apparently formed from oxidation include azobenzene, azoxybenzene, phenazine, formanilide, and acetanilide. Photodegradation of aniline on the soil surface is also thought to be an environmentally important removal process. The combination of these processes eventually results in the degradation of aniline to CO2. The half-life for the mineralisation of aniline to CO2 has been estimated at 4 days, utilising a model soil ecosystem. Information from studies done obtained under environmental conditions indicate that the half-life of aniline in the soil is less than one week
Water: Aniline in water is subject to biodegradation, photodegradation, and adsorption to sediment and humic materials. Low pH will increase the removal of aniline by adsorption; however, the adsorption to colloidal particles can extend the persistence of aniline in the aquatic environment. Although subject to oxidation when adsorbed to humic materials, aniline is resistant to hydrolysis. A half-life for aniline of 2.3 days has been reported in an industrial river. The presence of humic acids and various species of algae in the water can increase the photodegradation rates of aniline up to 50 fold.
Biota: The bioconcentration factor in two species of fish has been estimated at less than 1. A bioconcentration factor of 3 has also been calculated for fish. Aniline is not expected to accumulate significantly in aquatic organisms; however, it is absorbed and metabolised by fish.
No national guidelines.
Effluents from oil shale recovery and oil refiners, and from chemical and coal conversion plants.
Diffuse sources, and industry sources included in diffuse emissions data
Cigarette smoke. Agricultural uses of products containing or made from aniline.
It occurs naturally in some foods (for example, in corn, grains, beans, and tea), and in coal tars.
No mobile sources.
Aniline is predominantly used as a chemical intermediate for the dye, agricultural, polymer, and rubber industries. As such, there are few products directly containing aniline. Nevertheless, aniline is used as a solvent, and has been used as an antiknock compound for petrol.
Sources used in preparing this information
- CalEPA Air Resources Board Toxic Air Contaminant Summary (accessed, June, 1999)
- ChemFinder WebServer Project (1995) (accessed, June 1999)
- Environmental Defense Fund - Summary, Uses, Consumer Products, Rank (industrial, by quantity) (accessed, June, 1999)
- IPCS International Chemical Safety Card (accessed, June 1999)
- National Environment Protection Council (1998), National Environment Protection Measure for the National Pollutant Inventory. (accessed, March, 1999)
- New Jersey Health and Safety (accessed, June, 1999)
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- USA National Toxicology Program Health and Safety Information Sheet (accessed, June 1999)
- USEPA Health Effects Notebook for Hazardous Air Pollutants (accessed, June, 1999)
- USEPA Integrated Risk Information System Report (accessed, June 1999)
- USEPA Office of Pollution Prevention and Toxics Chemical Fact Sheet (accessed, June 1999)
- USEPA Toxic Release Inventory Fact Sheet (accessed, June 1999)
- Safe Work Australia, Workplace exposure standards for airborne contaminants, accessed June 2021.
- National Health and Medical Research Council (NHMRC), Australian Drinking Water Guidelines (2011) - Updated October 2017, accessed May 2018