The Encyclopedia Americana (1920)/Ac′etone

AC′ETONE. (1) A limpid, mobile liquid with a taste suggestive of peppermint. Formula, CH$3$COCH$3$. It occurs in crude wood-alcohol, from which it can be separated by distilling over calcium chloride. It is also obtained by the destructive distillation of acetates, notably those of barium and lead. It occurs in the urine, blood and brain of calcium diabetic patients. Lieben's test for acetone in the urine is as follows: Distilled urine is made alkaline by caustic potash and and a few drops of a solution of iodine and iodide of potassium are added. If acetone is present a yellow precipitate of iodoform is formed at once; if alcohol be present in the distillate, the same reaction takes place, but more slowly; but with acetone the reaction is immediate. Acetone is very inflammable and burns with a white smokeless flame. It boils at 133° F. at ordinary atmospheric pressure; its specific gravity at ordinary temperatures is about 0.800. Acetone is a valuable solvent for scientific and technical purposes. One of its most important uses if the solution of acetylene (q. v.). (2) Any one of a certain class of carbon compounds in which two alcoholic radicals are united by the group CO. These compounds are now called ketones to distinguish them from the particular member of the group defined in (1), above.