butanone

Butanone[1]
IUPAC name	butan-2-one [1]
Other names	Methyl ethyl ketone (MEK), methylpropanone, ethylmethylketone, methylacetone, meetco
Identifiers
CAS number	78-93-3 Y
PubChem	6569
RTECS number	EL6475000
SMILES	O=C(C)CC
InChI	1/C4H8O/c1-3-4(2)5/h3H2,1-2H3
InChI key	ZWEHNKRNPOVVGH-UHFFFAOYAW
ChemSpider ID	6321
Properties
Molecular formula	C4H8O
Molar mass	72.11 g/mol
Appearance	Colorless liquid
Density	0.8050 g/cm3
Melting point	-86 °C, 187 K, -123 °F
Boiling point	79.6 °C, 353 K, 175 °F
Solubility in water	27.5 g/100 ml
Viscosity	0.43 cP (20 °C)
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 (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Butanone, better 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]

Production

Oxidation of 2-Butanol is one way to produce 2-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]

MEK 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

MEK dissolves many substances and is used as a solvent in processes involving gums, resins, cellulose acetate and nitrocellulose coatings and in vinyl films. 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. MEK is also used in dry erase markers as the solvent of the erasable dye.

MEK is the precursor to methyl ethyl ketone peroxide, a catalyst for some polymerization reactions.

Health effects

Butanone is an irritant, but serious health effects in animals have been seen only at very high levels. When inhaled, these effects included birth defects.^[3]

Methyl ethyl ketone is listed as a Table II precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances.^[4]

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

References

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