KETONES, or ACETONES, organic substances or bodies which in general terms may be defined as composed of acid and alcohol radicals. See RADICAL. Chancel proposed the hypothesis that they are formed on a nuclear molecule of carbonic oxide, or carbonyls, CO, and Wanklyn's researches have demonstrated its correctness. Dimeth ylc ketone, or acetone, may be taken as the type. It is composed of carbonic oxide, as the acid radical, and two monatomic alcohol radicals, and in genera] it may be said that ketones•contain the group CO associated with two monatomic alcohol radicals, which may be the same or different. Thus, ethyl-methyl ketone is or The mode of , formation of the ketone may be explained by regarding it as derived from an aldehyde by the substitution of an additional alcohol radical in place of the hydrogen atom attached to the group CO. Thus, acetic aldehyde which may lie written CH,,CO311, by substitution of the radical CH, for the single atom H, becomes or as it is more commonly written, or or The only ketones which have been carefully studied are those which contain the alcohol C.11/4+; and which are analogous to the aldehydes and the fatty acids C„TI2„02. The ketones of this group, containing two equivalents of the same alcohol radical, arc produced: 1. By the action of carbonic oxide on ethyde of sodium and its homologues; 2. By the action of zinc-methyl and its homologues on the acid chlorides; 3. By the oxidation of the secondary alcohols; 4. By the dry distillation of calcium salts of the fatty acids. The ketones formed in this manner from the successive members of the fatty acid series, of which acetic acid is one, differ from one another by twice the radical thus, the salt containing Acetic acid... ...... C21140, yields Acetone ...... C.H.0
Proprionic acid... ..... " Proprione.
Butyric acid C41=1802 " Butyrone. . C711,40 Valerie acid. " Valerone There are intermediate ketones obtained from 'different alcohol radicals. Thus ethyl methyl ketone is intermediate between acetone and proprione. The ketones which contain two different alcohol radicals arc obtained by the second process enumer ated above, that is, by the action of carbonic oxide upon ethyde of sodium, or by dis tilling a mixture of calcium salts of two different fatty acids. Ketones in general are also formed by the gradual oxidation of the lactic acid series, and by the dry distillation of wood, sugar, and other carbon compounds.
Every ketone is isomeric with an aldehyde belonging to the same series; thus, acetone is isomeric with proprionic aldehyde and formic acetone is identical with formic aldehyde, COH,. These bodies are generally volatile liquids, insoluble in water. Those in which the group CO is associated with a methyl group resemble the aldehydes in forming crystalline compounds with alkaline bisulphites, from which the ketone may be obtained by distillation with an alkali, which abstracts the second equivalent of sulphur ous acid. In regard to acetone, the typical and most common of the ketones, it is best prepared by the dry distillation of acetate of calcium or acetate of lead. The crude distillate is then saturated with carbonate of potash and rectified in a water bath from. chloride of calcium. When pure, acetone is a colorless limpid liquid having a peculiar, agreeable odor and a biting taste somewhat like that of peppermint. Density, 0.792; boiling point, 131.9°F. It is inflammable, burning with a bright flame.