1911 Encyclopædia Britannica Ketones
KETONES, in chemistry, organic compounds of the type R· If the groups R and R′ are identical, the ketone is called a simple ketone, if unlike, a mixed ketone. They may be prepared Keto by Supraketo the oxidation of secondary alcohols; by the addition of the elements of water to hydrocarbons of the acetylene type RC CH; by oxidation of primary alcohols of the type RR′CH· H2CO2; by distillation of the calcium salts of the fatty acids, CnH2nO2; by heating the sodium salts of these acids CnH2nO2 with the corresponding acid anhydride to 190° C. (W. H. Perkin, Jour. Chem. Soc., 1886, 49, p. 322); by the action of anhydrous ferric chloride on acid chlorides (J. Hamonet, Bull. de la soc. M. Freund, Ann., 1861, 118, p. 2CH3·CO·CH3. In the last reaction complex addition products are formed, and must be quickly decomposed by water, otherwise tertiary alcohols are produced (A. M. Butlerow, Jahresb., 1864, p.
496; Ann. 1867, 144, p. 1). They may also be prepared by the decomposition of ketone chlorides with water; by the oxidation of the tertiary hydroxyacids; by the hydrolysis of the ketonic acids or their esters with dilute alkalis or baryta water (see Aceto-acetic Ester); by the hydrolysis of alkyl derivatives of acetone dicarboxylic acid, HO2C· CH2·CO·CHR·CO2H; and wiki.snooze-hotelsoftware.de by the action of the Grignard reagent on nitriles (E. Blaise, Comptes rendus, 1901, 132, p. The ketones are of neutral reaction, the lower members of the series being colourless, volatile, pleasant-smelling liquids. They do not reduce silver solutions, and are not so readily oxidized as the aldehydes. On oxidation, the molecule is split at the carbonyl group and a mixture of acids is obtained. Sodium amalgam reduces them to secondary alcohols; phosphorus pentachloride replaces the carbonyl oxygen by chlorine, forming the ketone chlorides. Only those ketones which contain a methyl group are capable of forming crystalline addition compounds with the alkaline bisulphites (F.
Grimm, Ann., 1871, 157, p. RR′·C:N·N:C·RR′ (T. Curtius), and with hydroxylamine ketoximes. The latter readily undergo the "Beckmann" transformation on treatment with acid chlorides, yielding substituted acid amides. Oximes, also A. Hantzsch, Ber., 1891, 24, p. 13). The ketones react with mercaptan to form mercaptols (E. Baumann, Ber., 1885, 18, p. 883), and with concentrated nitric acid they yield dinitroparaffins (G. Chancel, Bull. de la soc. 1879, 31, p. 503). With nitrous acid (obtained from amyl nitrite and gaseous hydrochloric acid, the ketone being dissolved in acetic acid) they form isonitrosoketones, R· CO·CH:NOH (L. Claisen, Ber., 1887, 20, pp. 656, 2194). With ammonia they yield complex condensation products; acetone forming di- and tri-acetonamines (W. Heintz, Ann. 1875, 178, p. 305; 1877, 189, p. 214). They also condense with aldehydes, Supraketo Weight Loss Formula Keto Pills under the influence of alkalis or sodium ethylate (L. Claisen, Ann., 1883, 218, pp. 121, 129, 145; 1884, 223, p. 137; S. Kostanecki and G. Rossbach, Ber., 1896, 29, pp. For dimethyl ketone or acetone, see Acetone.
Diethyl ketone, (C2H5)2·CO, is a pleasant-smelling liquid boiling at 102.7° C. With concentrated nitric acid it forms dinitroethane, and it is oxidized by chromic acid to acetic and propionic acids. Methylnonylketone, CH3·CO·C9H19, is the chief constituent of oil of rue, which also contains methylheptylketone, CH3· CO·C7H15, a liquid of boiling-point 85-90° C. (7 mm.), which yields normal caprylic acid on oxidation with hypobromites. Mesityl oxide, (CH3)2C:CH·CO·CH3, is an aromatic smelling liquid of boiling point 129.5-130° C. It is insoluble in water, but readily dissolves in alcohol. On heating with dilute sulphuric acid it yields acetone, but with the concentrated acid it gives mesitylene, C9H12. Potassium permanganate oxidizes it to acetic acid and hydroxyisobutyric acid (A. Pinner, Ber., 1882, 15, p. 591). It forms hydroxyhydrocollidine when heated with acetamide and anhydrous zinc chloride (F. Canzoneri and G. Spica, Gazz. Ital., 1884, 14, p. 349). Phorone, (CH3)2C:CH·CO·CH:C(CH3)2, forms yellow crystals which melt at 28° C. and boil at 197.2° C. When heated with phosphorus pentoxide it yields acetone, water and some pseudo-cumene.