PURIFICATION OF METHYL ISOPROPENYL KETONE

PURPOSE:Methyl isopropenyl ketone containing ethyl vinyl ketone is treated with a catalytic amount of a strong base to increase the purity of the methyl isopropenyl ketone which is used as a resist material in the semiconductor industry. CONSTITUTION:Methyl isopropenyl ketone containing ethyl vinyl ketone is treated with a strong base at 0-100 deg.C, preferably 30-50 deg.C to effect selective condensation reaction of ethyl vinyl ketone whereby the ethyl vinyl ketone is removed and methyl isopropenyl ketone of increased purity is obtained. Sodium hydroxide is excellent as the strong base from operative, economical and effective points of view. The amount of sodium hydroxide used is 0.002-0.01wt%, if methyl isopropenyl ketone contains 2% of ethyl vinyl ketone. The strong base is used in the form of an aqueous solution and the concentration is preferably in the range from 4 to 10wt%.