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Methyl isobutyl ketone

Methyl isobutyl ketone
IUPAC name 4-Methyl-2-pentanone
Other names Isopropylacetone
Isobutyl methyl ketone
CAS number 108-10-1
RTECS number SA9275000
Molecular formula C6H12O
Molar mass 100.2 g/mol
Appearance colorless liquid
Density 0.80 g/ml, liquid
Melting point

−84.7 °C

Boiling point

117-118 °C

Solubility in water 1.91 g/100 ml (20 °C)
Viscosity 0.58 cP at 20.0 °C
Dipole moment 4.2 D
EU classification Flammable (F)
Harmful (Xn)
NFPA 704
R-phrases R11, R20, R36/37, R66
S-phrases (S2), S9, S16, S29
Flash point 14 °C
Related Compounds
Related ketones Methyl isopropyl ketone
Related compounds 2-Methylpentan-4-ol
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Methyl isobutyl ketone (MIBK) is a ketone that is widely used as a solvent. Unlike the other common ketone solvents, acetone and MEK, MIBK has quite low solubility in water, allowing it to be used for liquid-liquid extraction. It has a similar polarity to the ester solvent ethyl acetate, but higher stability towards aqueous acid or base than ethyl acetate.

Methyl isobutyl ketone is manufactured from acetone, via a three-step process. Firstly acetone is dimerised via the aldol condensation to give diacetone alcohol, which readily dehydrates to give mesityl oxide. Mesityl oxide can then be hydrogenated to give MIBK.


It is used as a solvent for CS in the preparation of the CS spray used currently by British police forces. [1]

When mixed with water or isopropyl alcohol it is also used as a developer for PMMA electron-beam lithography resist.

Another major use is as raw material in the preparation of 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.[citation needed]

Methyl isobutyl ketone is also used as a denaturing agent for denatured alcohol.


  1. ^ Peter J Gray (2000). "CS gas is not CS spray - formulation is important" (Response to editorial). BMJ 321: 26. doi:10.1136/bmj.321.7252.46.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Methyl_isobutyl_ketone". A list of authors is available in Wikipedia.
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