In a 1500-cc. bottle are placed 100 g. (1 mole) of pinacolone (p. 462), 120 g. (1.13 moles) of freshly distilled benzaldehyde, 380 cc. of 95 per cent alcohol, 130 cc. of water, and 100 cc. of 10 per cent sodium hydroxide solution. The bottle is stoppered tightly, placed on a shaking machine, and agitated vigorously for about thirty-two hours (Note 1).

The reaction mixture is poured into a separatory funnel and diluted with an equal volume of water. The benzalpinacolone is separated by extracting three times with 300-cc. portions of benzene. The benzene extracts are combined and washed, first with water until the alkali is entirely removed, then with a saturated solution of sodium bisulfite, and finally two or three times with water. After drying over calcium chloride, the benzene is removed by distilling from a steam bath, and the residue is distilled under reduced pressure. The yield of distilled benzalpinacolone boiling at 143–146° /10 mm. is 165–175 g. (88–93 per cent of the theoretical amount). This product is slightly yellow and melts at 41–42°. It is pure enough for most purposes. It may be recrystallized from 95 per cent alcohol and is then obtained in almost pure white crystals, melting at 43°.