Methyl isobutyl ketone


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

Methyl isobutyl ketone
Skeletal formula of methyl isobutyl ketone
Ball-and-stick model of the methyl isobutyl ketone molecule
Preferred IUPAC name
Other names
4-Methyl-2-pentanone, Isopropylacetone, Hexone, Isobutyl methyl ketone, 2-Methylpropyl methyl ketone, 4-Methyl-2-oxopentane, MIK, Isobutylmethyl ketone, MIBK, Isohexanone
  • 108-10-1 checkY
3D model (JSmol)
  • Interactive image
Abbreviations MIBK
  • CHEBI:82344
  • ChEMBL285323
  • 7621 checkY
ECHA InfoCard 100.003.228 Edit this at Wikidata
EC Number
  • 203-550-1
  • C19263 checkY
  • 7909
RTECS number
  • SA9275000
  • U5T7B88CNP checkY
UN number 1245
  • DTXSID5021889 Edit this at Wikidata
  • InChI=1S/C6H12O/c1-5(2)4-6(3)7/h5H,4H2,1-3H3 ☒N
  • InChI=1/C6H12O/c1-5(2)4-6(3)7/h5H,4H2,1-3H3
  • CC(C)CC(=O)C
Molar mass 100.16 g/mol
Appearance colorless liquid
Odor pleasant[1]
Density 0.802 g/mL, liquid
Melting point −84.7 °C (−120.5 °F; 188.5 K)
Boiling point 117 to 118 °C (243 to 244 °F; 390 to 391 K)
1.91 g/100 mL (20 °C)
Vapor pressure 16 mmHg (20 °C)[1]
-70.05·10−6 cm3/mol
Viscosity 0.58 cP at 20.0 °C
2.8 D
GHS labelling:
GHS02: FlammableGHS07: Exclamation mark
H225, H319, H332, H335
P210, P233, P240, P241, P242, P243, P261, P264, P271, P280, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P312, P337+P313, P370+P378, P403+P233, P403+P235, P405, P501
NFPA 704 (fire diamond)
Flash point 14 °C (57 °F; 287 K)
449 °C (840 °F; 722 K)
Explosive limits 1.2–8.0% (93 °C)[1]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 100 ppm (410 mg/m3)[1]
REL (Recommended)
TWA 50 ppm (205 mg/m3) ST 75 ppm (300 mg/m3)[1]
IDLH (Immediate danger)
500 ppm[1]
Related compounds
Related ketones
Methyl isopropyl ketone
Diisobutyl ketone
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references


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,[3] which readily dehydrates to give 4-methylpent-3-en-2-one (commonly, mesityl oxide).[4] Mesityl oxide is then hydrogenated to give MIBK.[5]


Industrially, these three steps are combined. Acetone is treated with a strongly acidic, palladium catalyst-doped cation exchange resin under medium pressure of hydrogen.[6] Several million kilograms are produced annually.[5]


MIBK tank car in Europe.

MIBK is used as a solvent for nitrocellulose, lacquers, and certain polymers and resins.[5]

Precursor to 6PPDEdit

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.[7]

Solvent and niche applicationsEdit

Unlike the other common ketone solvents, acetone and MEK, MIBK has quite low solubility in water, making it useful for liquid-liquid extraction. It has a similar polarity to ethyl acetate, but greater stability towards aqueous acid and base. It can be used to extract gold, silver and other precious metals from cyanide solutions, such as those found at gold mines, to determine the levels of those dissolved metals. Diisobutyl ketone (DIBK), a related lipophilic ketone, is also used for this purpose. Methyl isobutyl ketone is also used as a denaturing agent for denatured alcohol. 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.[8][9]


  1. ^ a b c d e f NIOSH Pocket Guide to Chemical Hazards. "#0326". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ United States Environmental Protection Agency (September 2016). "Methyl Isobutyl Ketone (Hexone)". Retrieved 2015-12-13.
  3. ^ Conant, J. B.; Tuttle, N. (1921). "Diacetone Alcohol". Organic Syntheses. 1: 45. doi:10.15227/orgsyn.001.0045.
  4. ^ Conant, J. B.; Tuttle, N. (1921). "Mesityl Oxide". Organic Syntheses. 1: 53. doi:10.15227/orgsyn.001.0053.
  5. ^ a b c Stylianos Sifniades, Alan B. Levy, "Acetone" in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.
  6. ^ Uhde GmbH (2005). "Uhde Technology Profile: MIBK" (PDF). Archived from the original (PDF) on 2013-12-03. Retrieved 18 October 2021.
  7. ^ Hans-Wilhelm Engels et al., "Rubber, 4. Chemicals and Additives" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a23_365.pub2
  8. ^ 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.
  9. ^ Roger Eardley-Pryor (2017). "A Tear Gas Tale". Science History Institute. Retrieved 2021-02-22.

External linksEdit

  • International Chemical Safety Card 0511
  • National Pollutant Inventory - Methyl isobutyl ketone fact sheet
  • NIOSH Pocket Guide to Chemical Hazards