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| Names | |||
|---|---|---|---|
| Preferred IUPAC name Butan-2-one[2] | |||
Other names
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| Identifiers | |||
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3D model (JSmol) | |||
| 741880 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider |
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| ECHA InfoCard | 100.001.054 | ||
| 25656 | |||
| KEGG |
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| RTECS number |
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| UNII | |||
| UN number | 1193 | ||
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| Properties | |||
| C4H8O | |||
| Molar mass | 72.107 g·mol−1 | ||
| Appearance | Colorless liquid | ||
| Odor | Mint or acetone-like[3] | ||
| Density | 0.8050 g/mL | ||
| Melting point | −86 °C (−123 °F; 187 K) | ||
| Boiling point | 79.64 °C (175.35 °F; 352.79 K) | ||
| 27.5 g/100 mL | |||
| logP | 0.37[4] | ||
| Vapor pressure | 78 mmHg (20 °C)[3] | ||
| Acidity (pKa) | 14.7 | ||
| −45.58·10−6 cm3/mol | |||
Refractive index (nD) | 1.37880 | ||
| Viscosity | 0.43 cP | ||
| Structure | |||
| 2.76 D | |||
| Hazards | |||
| GHS labelling: | |||
  [5] | |||
| Danger[5] | |||
| H225,H319,H336[5] | |||
| P210,P233,P240,P241,P242,P243,P261,P264,P271,P280,P303+P361+P353,P304+P340,P305+P351+P338,P312,P337+P313,P370+P378,P403+P233,P403+P235,P405,P501[5] | |||
| NFPA 704 (fire diamond) | |||
| Flash point | −9 °C (16 °F; 264 K) | ||
| 505 °C (941 °F; 778 K) | |||
| Explosive limits | 1.4–11.4%[3] | ||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) |
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LC50 (median concentration) |
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| NIOSH (US health exposure limits): | |||
PEL (Permissible) | TWA 200 ppm (590 mg/m3)[3] | ||
REL (Recommended) | TWA 200 ppm (590 mg/m3) ST 300 ppm (885 mg/m3)[3] | ||
IDLH (Immediate danger) | 3000 ppm[3] | ||
| Safety data sheet (SDS) | Safety Data Sheet | ||
| Related compounds | |||
Relatedketones | Acetone;3-pentanone;3-methylbutanone | ||
| Supplementary data page | |||
| Butanone (data page) | |||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Butanone, also known asmethyl ethyl ketone (MEK) orethyl methyl ketone,[a] is anorganic compound with theformula CH3C(O)CH2CH3. This colorless liquidketone has a sharp, sweet odor reminiscent ofacetone. It is produced industrially on a large scale, but occurs in nature only in trace amounts.[7] It is partially soluble in water, and is commonly used as an industrial solvent.[8] It is anisomer of another solvent,tetrahydrofuran.
Butanone may be produced by oxidation of2-butanol. Thedehydrogenation of 2-butanol iscatalysed bycopper,zinc, orbronze:
This is used to produce approximately 700 million kilograms yearly. Other syntheses that have been examined but not implemented includeWacker oxidation of2-butene and oxidation ofisobutylbenzene, which is analogous to the industrial production ofacetone.[7] Thecumene process can be modified to produce phenol and a mixture of acetone and butanone instead of only phenol and acetone in the original.[9]
Both liquid-phase oxidation of heavynaphtha and theFischer–Tropsch reaction produce mixed oxygenate streams, from which 2-butanone is extracted by fractionation.[10]
Butanone is an effective and common solvent[8] and is used in processes involvinggums,resins,cellulose acetate andnitrocellulose coatings and in vinyl films.[11] For this reason it finds use in the manufacture of plastics, textiles, in the production ofparaffin wax, and in household products such aslacquer,varnishes, paint remover, a denaturing agent fordenatured alcohol,glues, and as a cleaning agent. It is a prime component of plumbers' priming fluid, used to clean PVC materials. It has similar solvent properties toacetone but boils at a higher temperature and has a significantly slower evaporation rate.[12] Unlike acetone, it forms anazeotrope with water,[13][14] making it useful for azeotropic distillation of moisture in certain applications. Butanone is also used indry erase markers as the solvent of the erasable dye.
The hydroxylamine derivative of butanone ismethylethyl ketone oxime (MEKO), which also find use in paints and varnishes as an anti-skinning agent.
As butanone dissolvespolystyrene and many other plastics, it is sold as "model cement" for use in connecting parts ofscale model kits. Though often considered anadhesive, it is functioning as awelding agent in this context.
Butanone is theprecursor tomethyl ethyl ketone peroxide, which is a catalyst for somepolymerization reactions such as crosslinking of unsaturated polyester resins.Dimethylglyoxime can be prepared from butanone first by reaction withethyl nitrite to givediacetyl monoxime followed by conversion to the dioxime:[15]
In theperoxide process on producinghydrazine, the starting chemical ammonia is bonded to butanone, oxidized by hydrogen peroxide, bonded to another ammonia molecule.
In the final step of the process, hydrolysis produces the desired product, hydrazine, and regenerates the butanone.
Butanone can react with most oxidizing materials and can produce fires.[8] It is moderately explosive, requiring only a small flame or spark to cause a vigorous reaction.[8] The vapor is heavier than air, so it can accumulate at low points. It is explosive at concentrations between 1.4 and 11.4%.[16] Concentrations in the air high enough to be flammable are intolerable to humans due to the irritating nature of the vapor.[12] Butanone fires should be extinguished withcarbon dioxide, dry agents, oralcohol-resistant foam.[8]
The ignition of butanone vapor was theproximate cause of the 2007Xcel Energy Cabin Creek fire, resulting in the deaths of five workers in a hydroelectricpenstock. After the incident, theU.S. Chemical Safety and Hazard Investigation Board specifically noted the danger posed by butanone in confined spaces, and suggested1,1,1-trichloroethane orlimonene as safer alternatives.[17]
Butanone is a constituent oftobacco smoke.[18] It is anirritant, causing irritation to the eyes and nose of humans.[12] Serious animal health effects have been seen only at very high levels. There are no long-term studies with animals breathing or drinking it,[19] and no studies for carcinogenicity in animals breathing or drinking it.[20]: 96 There is some evidence that butanone canpotentiate the toxicity of other solvents, in contrast to the calculation of mixed solvent exposures by simply adding exposures.[21]
As of 2010[update], the United States Environmental Protection Agency (EPA) listed butanone as a toxic chemical. There are reports of neuropsychological effects. It is rapidly absorbed through undamaged skin and lungs. It contributes to the formation ofground-level ozone, which istoxic in low concentrations.[16]
Butanone is listed as a Table II precursor under theUnited Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances.[22]
Emission of butanone was regulated in the US as ahazardous air pollutant, because it is avolatile organic compound contributing to the formation oftropospheric (ground-level)ozone. In 2005, theUS Environmental Protection Agency removed butanone from the list ofhazardous air pollutants (HAPs).[23][24][25]
