Methyl isobutyl ketone

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.



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

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.