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Other names Methyl ethyl ketone (MEK); Methylpropanone; Ethylmethylketone
CAS number 78-93-3
RTECS number EL6475000
Molecular formula C4H8O
Molar mass 72.11 g/mol
Appearance Colorless liquid
Density 0.8050 g/cm³, liquid
Melting point

−86 °C (187 K)

Boiling point

80 °C (353 K)

Solubility in water 29 g/100 ml (20 °C)
Viscosity 0,43 cP at 20 °C
Dipole moment 2.76 D
MSDS External MSDS
EU classification Flammable (F)
Irritant (Xi)
NFPA 704
R-phrases R11, R36, R66, R67
S-phrases (S2), S9, S16
Flash point −9 °C
505 °C
Related Compounds
Related Ketones Acetone; 3-pentanone; 3-Methylbutanone
Supplementary data page
Structure and
n, εr, etc.
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Butanone is a manufactured organic chemical. It is a colorless liquid with a sharp, sweet odor. It is a ketone, also known as methyl ethyl ketone (MEK).

Butanone is produced in large quantities. Nearly half of it is used in paints and other coatings because it will quickly evaporate. It dissolves many substances and is used as a solvent in processes involving gums, resins, cellulose acetate and nitrocellulose coatings and in vinyl films. It is also used in the synthetic rubber industry, It is used in manufacturing plastics, textiles, in the production of paraffin wax, and in household products such as lacquer, varnishes, paint remover, a denaturing agent for denatured alcohol, glues and as a cleaning agent. It is used for synthesis of methyl ethyl ketone peroxide, a catalyst for some polymerization reactions. It is highly flammable. It is not considered a large health threat.

Butanone occurs as a natural product. It is made by some trees and found in some fruits and vegetables in small amounts. It is also released to the air from car and truck exhausts.

Health effects

The known health effects to people from exposure to butanone are irritation of the nose, throat, skin, and eyes. There are no known cases of any humans dying from breathing butanone alone. However, if butanone is breathed along with other chemicals that damage health, it can increase the amount of damage that occurs.

Serious health effects in animals have been seen only at very high levels. When breathed, these effects included birth defects (Schwetz et al. 1991. Fund. Appl. Toxicol. 16:742-748), loss of consciousness, and death. When swallowed, rats had nervous system effects including drooping eyelids and uncoordinated muscle movements. There was no damage to the ability to reproduce. Mice who breathed low levels for a short time showed temporary behavioral effects. Mild kidney damage was seen in animals that drank water with low levels of butanone for a short time.

There are no long-term studies with animals either breathing or drinking butanone.

Methyl ethyl ketone is listed as a Table II precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances[1].


    • US NIH list of products that contain butanone (MEK)
    This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Butanone". A list of authors is available in Wikipedia.
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