Butanone

Butanone[1]
IUPAC name Butan-2-one
Other names Methyl ethyl ketone; MEK; 2-Butanone; Methylpropanone; Ethylmethylketone; Methylacetone
Identifiers
CAS number	78-93-3 Y
PubChem	6569
ChemSpider	6321 Y
UNII	6PT9KLV9IO Y
KEGG	C02845 Y
ChEBI	CHEBI:28398 Y
ChEMBL	CHEMBL15849 Y
RTECS number	EL6475000
Jmol-3D images	Image 1 Image 2
SMILES O=C(C)CC CCC(=O)C
InChI InChI=1S/C4H8O/c1-3-4(2)5/h3H2,1-2H3 Y Key: ZWEHNKRNPOVVGH-UHFFFAOYSA-N Y InChI=1/C4H8O/c1-3-4(2)5/h3H2,1-2H3 Key: ZWEHNKRNPOVVGH-UHFFFAOYAW
Properties
Molecular formula	C4H8O
Molar mass	72.11 g mol−1
Appearance	Colorless liquid
Density	0.8050 g/cm3
Melting point	-86 °C, 187 K, -123 °F
Boiling point	79.64 °C, 353 K, 175 °F
Solubility in water	27.5 g/100 mL
Refractive index (nD)	1.37880
Viscosity	0.43 cP
Structure
Dipole moment	2.76 D
Hazards
MSDS	External MSDS
EU classification	Flammable (F) Irritant (Xi)
R-phrases	R11 R36 R66 R67
S-phrases	(S2) S9 S16
NFPA 704	3 1 0
Flash point	−9 °C
Autoignition temperature	505 °C
LD50	6.86 mL/kg (oral, rat)
Related compounds
Related Ketones	Acetone; 3-pentanone; 3-Methylbutanone
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Butanone, also known as methyl ethyl ketone or MEK, is an organic compound with the formula CH₃C(O)CH₂CH₃. This colorless liquid ketone has a sharp, sweet odor reminiscent of butterscotch and acetone. It is produced industrially on a large scale, and also occurs in trace amounts in nature.^[2] It is soluble in water and is commonly used as an industrial solvent.^[3]

Production

Oxidation of 2-butanol is one way to produce butanone. Butanone is produced by the dehydrogenation of 2-butanol using a catalyst based on copper, zinc, or bronze:

CH₃CH(OH)CH₂CH₃ → CH₃C(O)CH₂CH₃ + H₂

In this way, approximately 700M kg are produced yearly. Other routes that have been examined but not implemented include Wacker oxidation of 2-butene and oxidation of isobutylbenzene (analogous to the industrial route to acetone).^[2]

Both liquid-phase oxidation of heavy naphtha and the Fischer-Tropsch reaction produce mixed oxygenate streams, from which 2-butanone is extracted by fractionation.^[4]

Butanone is biosynthesized by some trees and found in some fruits and vegetables in small amounts. It is released to the air from car and truck exhausts.

Applications

As a solvent

Butanone is an effective and common solvent^[3] and is used in processes involving gums, resins, cellulose acetate and nitrocellulose coatings and in vinyl films.^[5] For this reason it finds use in the manufacture of 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 has similar solvent properties to acetone but has a significantly slower evaporation rate.^[6] Butanone is also used in dry erase markers as the solvent of the erasable dye.

As a welding agent

As butanone dissolves polystyrene, it is sold as "polystyrene cement" for use in connecting together parts of scale model kits. Though often considered an adhesive, it is actually functioning as a welding agent in this context.

Other uses

Butanone is the precursor to methyl ethyl ketone peroxide, a catalyst for some polymerization reactions. It can also initiate crosslinking of unsaturated polyester resins.

Safety

Flammability

Butanone can react with most oxidizing materials, and can produce fires.^[3] It is moderately explosive; it requires only a small flame or spark to cause a vigorous reaction.^[3] Butanone fires should be extinguished with carbon dioxide, dry chemicals or alcohol foam.^[3] Concentrations in the air high enough to be flammable are also intolerable to humans due to the irritating nature of the vapour.^[6]

Health effects

Butanone is an irritant, causing irritation to the eyes and nose of humans,^[6] but serious health effects in animals have been seen only at very high levels. When inhaled, these effects included birth defects.^[7]

Butanone is listed as a Table II precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances.^[8]

On December 19, 2005, the U. S. Environmental Protection Agency removed butanone from the list of hazardous air pollutants (HAPs). After technical review and consideration of public comments, EPA concluded that potential exposures to butanone emitted from industrial processes may not reasonably be anticipated to cause human health or environmental problems. Emissions of butanone will continue to be regulated as a volatile organic compound because of its contribution to the formation of tropospheric (ground-level) ozone.

References

1. ^ Merck Index, 11th Edition, 5991.
2. ^ ^{a b} Wilhelm Neier, Guenter Strehlke "2-Butanone" in in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002.
3. ^ ^{a b c d e} Turner, Charles F.; McCreery, Joseph W. (1981). The Chemistry of Fire and Hazardous Materials. Boston, Massachusetts: Allyn and Bacon, Inc. pp. 118. ISBN 0 2050 6192 6. 
4. ^ Ashford's Dictionary of Industrial Chemicals, Third edition, 2011, ISBN 978-0-9522674-3-0, pages 6013-4
5. ^ Apps, E. A. (1958). Printing Ink Technology. London: Leonard Hill [Books] Limited. pp. 101. 
6. ^ ^{a b c} Fairhall, Lawrence T. (1957). Industrial Toxicology. Baltimore: The Williams and Wilkins Company. pp. 172–173. 
7. ^ Schwetz et al. (1991). "Developmental toxicity of inhaled methyl ethyl ketone in Swiss mice". Fund. Appl. Toxicol. 16 (4): 742–748. doi:10.1016/0272-0590(91)90160-6. 
8. ^ List of Precursors and Chemicals Frequently Used in the Illicit Manufacture of Narcotic Drugs and Psychotropic Substances Under International Control, International Narcotics Control Board

External links

• International Chemical Safety Card 0179
• National Pollutant Inventory: Methyl Ethyl Ketone Fact Sheet
• NIOSH Pocket Guide to Chemical Hazards
• US EPA Datasheet
• Record in the Household Products Database of NLM