One hundred and forty-six grams (0.96 mole) of mandelic acid is dissolved in 440 ml. (6.2 moles) of acetone, and the resulting solution is placed in a 2-l. three-necked flask fitted with an efficient stirrer, a dropping funnel, and a thermometer. The reaction flask is placed in an ice-salt bath, and 98 g. of concentrated sulfuric acid (sp. gr. 1.84) is added through the dropping funnel at such a rate that the temperature does not exceed −10°. The reaction mixture is then poured into an ice-cold solution of sodium carbonate containing 200 g. of the anhydrous salt in 1800 ml. of water. The mandelic acid-acetone condensation product precipitates from the solution. The curdy product is washed by grinding with ice water (200 ml.) and is then filtered and dried over calcium chloride under reduced pressure. The crude product weighs 181 g. (Note 1).

The mandelic acid-acetone condensation product is added in small portions to about 1.8 l. of liquid ammonia (Note 2) contained in two silvered 1-l. Dewar flasks. Each flask is fitted with a stopper containing a capillary tube to serve as an ammonia outlet. The ammonolysis is allowed to proceed overnight, after which the contents of the flasks are poured into open beakers to facilitate rapid evaporation of the liquid ammonia.

After the ammonia has been removed to a point where a pulverulent mass remains, the product is treated with 475 ml. of hot absolute ethanol and the resulting solution is filtered through a hot funnel to remove insoluble impurities. The filtrate is cooled in an ice bath to give about 90 g. of glistening white crystals of mandelamide melting at 132° (62% based upon the mandelic acid) (Note 3) and (Note 4).