Cumene (1-methylethylbenzene)

Description

Cumene is used to manufacture other chemicals such as phenol, acetone, acetophenone, and methyl styrene. It is used as a thinner in paints, lacquers, and enamels. It is a component of high octane motor fuels. Cumene in used in the manufacture of rubber, iron and steel, and pulp and paper.

Substance details

Substance name: Cumene (1-methylethylbenzene)

CASR number: 98-82-8

Molecular formula: C9H12

Synonyms: Cumol; methyl ethyl benzene; isopropylbenzene; 2-phenylpropane

Physical properties

Cumene is a colourless liquid with an odour similar to gasoline.

Melting Point: -96°C

Boiling Point°C: 151

Specific Gravity: 0.862

Vapour Density: 4.1

Flashpoint: 31°C

Chemical properties

Cumene is a flammable liquid. It is insoluble in water, but soluble in most organic solvents.

Further information

The National Pollutant Inventory (NPI) holds data for all sources of cumene emissions in Australia.

Description

Short-term exposure to high levels of cumene results first in headache, irritation of the eyes, nose and throat, euphoria, followed by dizziness, sleepiness, and unconsciousness. Cumene is a central nervous system depressant and may cause narcotic effects. Long-term exposures at low levels have caused effects to the liver and kidneys.

Entering the body

Cumene will enter the body if we breathe in contaminated air, or breathe in tobacco smoke. Human exposure occurs mainly by breathing air containing cumene, from the evaporation of petroleum products. Cumene can pass through the skin.

Exposure

Workers in the industries that use or produce cumene are at risk of exposure. Consumers can be exposed to cumene by exposure to air from production and processing facilities using cumene, automotive exhaust, and tobacco smoke. Consumers may also be exposed to cumene when using consumer products containing cumene (thinners for paint lacquers and enamels, foam insulation, etc) especially if there is not good ventilation.

Workplace exposure standards

Safe Work Australia sets the workplace exposure standard for cumene through the workplace exposure standards for airborne contaminants:

  • Maximum eight hour time weighted average (TWA): 25 parts per million (125 mg/m3)
  • Maximum short term exposure limit (STEL): 75 parts per million (375 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 cumene in the Australian Drinking Water Guidelines.

Description

Cumene evaporates when exposed to air. In the air it is reacted quickly into other chemicals, in the water and soil bacteria break it down. It has moderate acute (short-term) toxicity on aquatic life, and high acute toxicity to birds. Insufficient data are available to predict the toxicity of cumene to plants and land animals. It has moderate chronic (long-term) toxicity to aquatic life. Cumene is expected to minimally bioaccumulate.

Entering the environment

Industrial emissions of cumene can produce elevated concentrations in the atmosphere around the source. Because of its short life expectancy in the atmosphere cumene is expected to be confined to the local area within which it is emitted. Cumene that makes its way into the ground, and does not evaporate, is degraded in the water with in days. Because cumene is used in many consumer products , and found in tobacco smoke, short-term indoor concentrations may be elevated above the levels considered safe for workers.

Where it ends up

Cumene evaporates to a gas if released as a liquid. It will break down in the air in a few days into other chemicals (isopropylphenols). In the water (very little will enter the water) bacteria will break it down in three to ten days. Cumene is a volatile organic chemical (VOC) and will contribute to the formation of smog.

Environmental guidelines

No national guidelines.

Industry sources

The primary sources of cumene are the industries that manufacture it or use it in production. Some of the industries that manufacture it or use it in production are oil refiners, chemical industry, rubber manufacturers, pharmaceutical industry, pulp and paper manufacturing, roofing and paving, plastics manufacturing, manufacturers of paints, varnishes and lacquers. These emissions mainly are to the air, but are also to the soil and water.

Diffuse sources, and industry sources included in diffuse emissions data

Other possible emitters of cumene are vapours and spilling of petrol, commercial and household painting and paint, varnish and lacquer removal, tobacco smoke, and consumer products containing cumene. These emissions are to the air unless there is a spill.

Natural sources

Natural sources of cumene include crude petroleum and coal tar. It is also found in the oils of plants, marsh grasses and in some foods.

Transport sources

Some cumene is found in the exhaust of motor vehicles, jet engines, and outboard motors.

Consumer products

Some of the consumer products containing cumene are foam plastic insulation, rubber floor and wall coverings, bathmats, vinyl floor tile, wood office desks and furniture (modular) and thinners for paints, lacquers and enamels.

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 Cumene (accessed, June, 1999)
  • ChemFinder WebServer Project (1995), Cumene (accessed, June, 1999)
  • Environmental Chemicals Data and Information Network (ECDIN) (date of update not given) Carbon Monoxide (accessed, March, 1999)
  • Environmental Defense Fund (1998), Cumene: The Chemical Scorecard: (accessed, June, 1999)
  • Meagher, D (1991), The Macmillan Dictionary of The Australian Environment, Macmillan Education Australia Pty Ltd.
  • National Environment Protection Council (1998), National Environment Protection Measure for the National Pollutant Inventory. (accessed, March, 1999)
  • New Jersey Department of Health, Right to Know Program (1986), TRIFacts Cumene (accessed, June, 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.
  • US Environmental Protection Agency and the Office of Air Quality Planning and Standards (May, 1998), Unified Air Toxics Website, Cumene (accessed, June, 1999)
  • Worksafe Australia (1996), Hazardous Substance Cumene (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