This compound is used as a solvent to dissolve cellulose ethers, lacquers, resins, fats, waxes, oils, bitumen and crude rubber. It is also used in perfume manufacturing, during surface coating operations (lacquers), in synthesis of adipic acid for production of nylon 66 and engineering plastics, during synthesis of caprolactam in nylon 6, paint and varnish remover, in the extraction of essential oils, in analytical chemistry for molecular weight determinations, in the manufacturing of adipic acid, benzene, cyclohexyl chloride, nitrocyclohexane, cyclohexanol and cyclohexanone, in the manufacturing of solid fuel for camp stoves, in fungicidal formulations (possesses slight fungicidal action) in the industrial recrystallising of steroids, organic synthesis, recrystallising medium glass substitutes, solid fuels, in analytical chemistry and in manufacturing of adhesives.
Substance name: Cyclohexane
CASR number: 110-82-7
Molecular formula: C6H12
Synonyms: hexamethylene; hexanaphthene; hexahydrobenzene, benzenehexahydride
Cyclohexane is a colourless, mobile liquid with a mild, sweet odour. It is slightly soluble in water and soluble in alcohol, acetone, benzene, ethanol, ethyl ether, olive oil, and carbon tetrachloride.
Melting Point: 6.47°C
Boiling Point: 80.7°C
Specific Gravity: 0.779
Vapour Density: 2.98
1 ppm = 3.44 mg/m3
Formula weight 84.161
Cyclohexane is a flammable, non-corrosive liquid.
The National Pollutant Inventory (NPI) holds data for all sources of cyclohexane emissions in Australia.
Effects of cyclohexane on human health and the environment depend on how much cyclohexane is present and the length and frequency of exposure. Effects also depend on the health of a person or the condition of the environment when exposure occurs. Breathing large amounts of cyclohexane for short periods of time adversely affects the human nervous system. Effects range from headaches to anaesthesia, tremors, and convulsions. Contact with cyclohexane liquid or vapour can damage the eyes. These effects are not likely to occur at levels of cyclohexane that are normally found in the environment. Human health effects associated with breathing or otherwise consuming smaller amounts of cyclohexane over long periods of time are not known. Studies show that repeat exposure to large amounts of cyclohexane in air causes nervous system effects, eye damage, and respiratory effects in animals. The cyclohexane industry is now studying how its chemical affects the reproductive system and the development of the foetus of animals.
Entering the body
Cyclohexane enters the body when breathed in with contaminated air or when consumed with contaminated food or water. It can also be absorbed through skin contact. Cyclohexane is not likely to remain in the body due to its breakdown and removal in exhaled air and in urine.
Exposure to cyclohexane can occur in the workplace or in the environment following releases to air, water, land, or groundwater. Exposure can also occur when people use products that contain cyclohexane or when they smoke cigarettes.
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for cyclohexane through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 100 parts per million (350 mg/m3)
- Maximum short term exposure limit (STEL): 300 parts per million (1050 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 cyclohexane in the Australian Drinking Water Guidelines.
Cyclohexane is non-persistent in water, with a half-life of less than 2 days. The half-life of a pollutant is the amount of time it takes for one-half of the chemical to be degraded. Virtually 100% of cyclohexane will end up in the air.
The concentration of cyclohexane found in fish tissues is expected to be somewhat higher than the average concentration of cyclohexane in the water from which the fish was taken.
Cyclohexane has moderate acute toxicity to aquatic life. It has caused membrane damage in an ornamental crop species. Insufficient data are available to evaluate or predict the short-term effects of cyclohexane to birds or land animals.
Cyclohexane has moderate chronic toxicity to aquatic life. Insufficient data are available to evaluate or predict the long-term effects of cyclohexane to plants, birds, or land animals.
Entering the environment
Cyclohexane enters the environment mainly in industrial and municipal discharges. Cyclohexane evaporates when exposed to air. It dissolves slightly when mixed with water. Most direct releases of cyclohexane to the environment are to air. Cyclohexane also evaporates from water and soil exposed to air. Once in air, it is expected to break down to other chemicals. Because it is a liquid that does not bind well to soil, cyclohexane that makes its way into the ground can move through the ground and enter groundwater. Plants and animals living in environments contaminated with cyclohexane can store small amounts of the chemical.
Where it ends up
Cyclohexane by itself is not likely to cause environmental harm at levels normally found in the environment. Cyclohexane can contribute to the formation of photochemical smog when it reacts with nitrogen dioxide, ozone, and other volatile organic carbon substances in air.
No national guidelines.
The primary point sources are petroleum refining, automotive repair shops, and commercial printing and publishing.
Diffuse sources, and industry sources included in diffuse emissions data
Cyclohexane is a natural constituent of crude petroleum. It also occurs naturally as a plant volatile and can be released from volcanoes.
Cyclohexane has been detected in motor vehicle exhaust.
Cyclohexane is used as a solvent, oil extractant, paint and varnish remover, and in solid fuels.
Sources used in preparing this information
- Australian and New Zealand Environment and Conservation Council (ANZECC) (1992), Australian Water Quality Guidelines for Fresh and Marine Waters.
- CalEPA Air Resources Board Toxic Air Contaminant Summary (accessed, May, 1999)
- ChemFinder WebServer Project (1995) (accessed, May, 1999)
- Environmental Defense Fund - Summary, Uses, Consumer Products, Rank (industrial, by quantity) (accessed, May, 1999)
- EPA Office of Pollution Prevention and Toxics Chemical Fact Sheet (accessed, May, 1999)
- EPA Office of Pollution Prevention and Toxics Chemical Fact Summary (accessed, May, 1999)
- EPA Toxic Release Inventory Fact Sheet (accessed, May, 1999)
- IPCS International Chemical Safety Card (accessed, May, 1999)
- Meagher, D (1991), The Macmillan Dictionary of The Australian Environment, Macmillan Education Australia Pty Ltd.
- National Toxicology Program Health and Safety Information Sheet (accessed, May, 1999)
- Richardson, M (1992), Dictionary of Substances and their Effects, Royal Society of Chemistry, Clays Ltd, England.
- Sittig, M (1991), Handbook of Toxic and Hazardous Chemicals and Carcinogens, 3rd edition, Noyes Publications, USA.
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- US Department of Health and Human Services (1990), NIOSH Pocket Guide to Chemical Hazards, Publication No. 90-117.
- USEPA Health Effects (accessed, May, 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