The Determination of Acetone

In the determination of P-oxybutyric acid through oxidation to acetone by the Shaffer bichromate method’ with subsequent estimation of the acetone by Messinger’s iodimetric titration,” difficulty was experienced in obtaining the t,heoretical amount of acetone from known amounts of pure P-oxybutyric acid. It was suspected that either the Messinger titration was inaccurate or that the acetone was incompletely recovered in the distillates. Messinger in his original paper,3 found that in dilute aqueous solutions of acetone, slightly low results were obtained. Collischonn4 found that the Messinger method gave low results in verl dilute acetone solutions. Geelmuyden5 using the Messinger method obtained satisfactory results on purified acetone in aqueous solutions, but found that, on distillation of such solutions, loss of acetone of from 5 to 10 per cent was unavoidable, even when icecooled receivers were used and the solutions were distilled almost t,o dryness. Denig&@ claims that the first quarter of the distillate from aqueous acetone solutions contains only about 90 per cent. of the acetone present. In view of the results cited above, it seemed desirable to investigate the accuracy of the Messinger titration and also to determine whether a dilute aqueous acetone solution could be distilled without loss. In addition I have tested the accuracy of the recently described acetone estimation of Scott-Wilson.7