$3{\mathrm{CH}}_3{\mathrm{COCH}}_3\underset{-3{\mathrm{H}}_2\mathrm{O}}{\overset{\mathrm{HCI}}{\to }}{\left({\mathrm{CH}}_3\right)}_2\mathrm{C}=\mathrm{CH}-\underset{\left(\mathrm{B}\right)}{\mathrm{CO}}-\mathrm{CH}=\mathrm{C}{\left({\mathrm{CH}}_3\right)}_2$

\This polymer (B) is obtained when acetone is saturated with hydrogen chloride gas, B can be

.typically obtained by the acid-catalysed two fold aldol condensation of three molecules of acetone. Mesityl oxide is obtained as an intermediate and can be isolated. Crude phorone can be purified by repeated recrystallization from ethanol or ether, in which it is soluble.