Mesityl Oxide

Mesityl Oxide

Mesityl oxide is a α,β-unsaturated ketone. The other name of mesityl oxide is 4-methylpent-3-en-2-one, b.p. 130^oC. This compound is a colorless,  volatile liquid with a honey-like odor.

Mesityl oxide mey be prepared by distilling diacetone alcohol (q.v.) with a trace of iodine:

(CH₃)₂C(OH)CH₂COCH₃    (-H₂O) ⟶   (CH₃)₂C=CHCOCH₃   (90%)

Stross et al. (1947) have shown that mesityl oxide prepared this way is a mixture of mesityl oxide and isomesityl oxide, CH₂=C(CH₃)CH₂COCH₃

Mesityl oxide may also be prepared as follows:

(CH₃)₂C=CH₂ + CH₃COCl   (ZnCl₂) ⟶ (CH₃)₂CClCH₂COCH₃   (-HCl) ⟶  (CH₃)₂C=CHCOCH₃

It is used as a solvent for oils, gums, etc.