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Methyl isobutyl ketone

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Methyl isobutyl ketone
Skeletal formula of methyl isobutyl ketone
Ball-and-stick model of the methyl isobutyl ketone molecule
Names
Preferred IUPAC name

4-Methylpentan-2-one

Other names
  • 4-Methyl-2-pentanone
  • Isopropylacetone
  • Hexone
  • Isobutyl methyl ketone
  • 2-Methylpropyl methyl ketone
  • 4-Methyl-2-oxopentane
  • Isobutylmethyl ketone
  • Isohexanone
Identifiers

3D model (JSmol)
Abbreviations MIBK
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.228 Edit this at Wikidata
EC Number
  • 203-550-1
KEGG
RTECS number
  • SA9275000
UNII
UN number 1245

  • InChI=1S/C6H12O/c1-5(2)4-6(3)7/h5H,4H2,1-3H3 X mark

    Key: NTIZESTWPVYFNL-UHFFFAOYSA-N X mark

  • InChI=1/C6H12O/c1-5(2)4-6(3)7/h5H,4H2,1-3H3

    Key: NTIZESTWPVYFNL-UHFFFAOYAQ

  • CC(C)CC(=O)C

Properties[1]
C6H12O
Molar mass 100.161 g·mol−1
Appearance colorless liquid
Density 0.7965 g/mL
Melting point −85 °C (−121 °F; 188 K)
Boiling point 115.7 °C (240.3 °F; 388.8 K)
Critical point (T, P) 575.4 K, 3.4 MPa
1.91 g/100 mL (20.0 °C (68.0 °F; 293.1 K))
Solubility
log P 1.31
Vapor pressure 2.64 kPa
−69.7×10−6 cm3/mol
1.3962
Viscosity 0.545 cP
Thermochemistry[1]
213.3 J⋅mol−1·K-1
40.61 kJ⋅mol−1
Hazards
GHS labelling:[2]
GHS02: FlammableGHS07: Exclamation markGHS08: Health hazard
Danger
H225, H319, H332, H336, H351
P201, P202, P210, P233, P240, P241, P242, P243, P261, P264, P271, P280, P303+P361+P353, P304+P340+P312, P305+P351+P338, P308+P313, P337+P313, P370+P378, P403+P233, P403+P235, P405, P501
NFPA 704 (fire diamond)
Flash point 18 °C (64 °F; 291 K)[1]
448 °C (838 °F; 721 K)[1]
Explosive limits 1.2%–8.0%[1]
20 ppm (TWA), 75 ppm[1] (STEL)
Lethal dose or concentration (LD, LC):
2080 mg/kg (oral, rat)[2]
11.6 mg/L (4h, rat, vapor)[2]
NIOSH (US health exposure limits):[4]

PEL (Permissible)

 TWA 100 ppm (410 mg/m3)

REL (Recommended)
  • TWA 50 ppm (205 mg/m3)
  • ST 75 ppm ppm (300 mg/m3)

IDLH (Immediate danger)

 500 ppm
Related compounds

Related ketones

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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Methyl isobutyl ketone (MIBK, 4-methylpentan-2-one) is an organic compound with the condensed chemical formula (CH3)2CHCH2C(O)CH3. This ketone is a colourless liquid that is used as a solvent for gums, resins, paints, varnishes, lacquers, and nitrocellulose.[5]

At laboratory scale, MIBK can be produced via a three-step process using acetone as the starting material. Self-condensation, a type of aldol reaction, produces diacetone alcohol, which readily dehydrates to give 4-methylpent-3-en-2-one (commonly, mesityl oxide).[6][7] Mesityl oxide is then hydrogenated to give MIBK.[citation needed]

Synthesis of MIBK from acetone

Industrially, these three steps are combined. Acetone is treated with a strongly acidic, palladium catalyst-doped cation exchange resin under medium pressure of hydrogen.[8] Several million kilograms are produced annually.[citation needed]

MIBK tank car in Europe.

MIBK is used as a solvent for nitrocellulose, lacquers, and certain polymers and resins.[citation needed]

Another major use is as a precursor to N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylene diamine (6PPD), an antiozonant used in tires. 6PPD is prepared by reductive coupling of MIBK with 4-aminodiphenylamine.[9]

Solvent and niche applications

[edit]

Unlike the other common ketone solvents, acetone and MEK, MIBK has quite low solubility in water, making it useful for liquid-liquid extraction. For example, the purification of tantalum from its ores often relies on MIBK extractions.[10] It has a similar polarity to ethyl acetate, but greater stability towards aqueous acids and bases.[citation needed]

It can be used to extract gold, silver and other precious metals from cyanide solutions, such as those used in gold mines, to determine the levels of those dissolved metals.[citation needed]

When mixed with water or isopropyl alcohol MIBK serves as a developer for PMMA electron beam lithography resist. MIBK is used as a solvent for CS in the preparation of the CS spray used currently by American and British police forces.[11][12]

  1. 1 2 3 4 5 6 Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). Boca Raton, Florida: CRC Press. pp. 3–386, 5–28, 5–158, 5–175, 6–77, 6–148, 6–246, 15–18. ISBN 9781498754293.
  2. 1 2 3 Sigma-Aldrich Co., Methyl isobutyl ketone.
  3. ↑ "Methyl isobutyl ketone". www.fishersci.com. ThermoFisher Scientific. Retrieved 13 May 2026.
  4. ↑ "NIOSH Pocket Guide to Chemical Hazards".
  5. ↑ United States Environmental Protection Agency (January 2000). "Methyl Isobutyl Ketone (Hexone)" (PDF). Retrieved 13 May 2026.
  6. ↑ Conant, J. B.; Tuttle, N. (1921). "Diacetone Alcohol". Organic Syntheses. 1: 45. doi:10.15227/orgsyn.001.0045.
  7. ↑ Conant, J. B.; Tuttle, N. (1921). "Mesityl Oxide". Organic Syntheses. 1: 53. doi:10.15227/orgsyn.001.0053.
  8. ↑ Uhde GmbH (2005). "Uhde Technology Profile: MIBK" (PDF). Archived from the original (PDF) on 2013-12-03. Retrieved 18 October 2021.
  9. ↑ Engels, H.-W.; Weidenhaupt, H.-J.; Pieroth, M.; Hofmann, W.; Menting, K.-H.; Mergenhagen, T.; Schmoll, R.; Uhrlandt, S. (2007). "Rubber, 4. Chemicals and Additives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a23_365.pub2. ISBN 978-3-527-30673-2.
  10. ↑ Shikika, A.; Sethurajan, M.; Muvundja, F.; Mugumaoderha, M.C.; Gaydardzhiev, St. (2020). "A review on extractive metallurgy of tantalum and niobium". Hydrometallurgy. 198 105496. doi:10.1016/j.hydromet.2020.105496.
  11. ↑ Peter J Gray; Stark, MM; Gray, P. J; Jones, G R. N (2000). "Is CS spray dangerous? : CS is a particulate spray, not a gas" (Response to editorial). BMJ. 321 (7252): 26. doi:10.1136/bmj.321.7252.46. PMC 1127688. PMID 10939811.
  12. ↑ Roger Eardley-Pryor (2017). "A Tear Gas Tale". Science History Institute. Retrieved 2021-02-22.