RCN  + R'MgI - RR'C:N•Mgl R•CO•R'+ NH3+MgLOH . 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 . 262) . They combine with hydrocyanic acid to form nitriles, which on hydrolysis furnish hydroxyacids, (CH3)2CO --> (CH3)2C•OH•CN -> (CH3)2•C•OH•CO2H; with phenylhydrazine they yield hydrazones; with hydrazine they yield in addition ketazines RR'•C:N•N:C•RR' (T . Curtius), and with hydroxylamine ketoximes . The latter readily under-go the " Beckmann " transformation on treatment with acid chlorides, yielding substituted acid amides, RR'.C:NOH --> RC(NR')•OH •-~ R.CO.NHR' (see 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. chim., 1879, 31, p . 503) . With nitrous acid (obtained from amyl nitrite and gaseous hydrochloric acid, the ketone being dissolved in acetic acid) they form isonitroso-ketones, 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, 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 . 1488, 1495, 1893, &c.) . On treatment with the Grignard reagent, in absolute ether solution, they yield addition products which are decomposed by water with production of tertiary alcohols (V . Grignard, Comptes rendus, 1900, 130, p . 1322 et seq.), RR'CO-3 RR'•C(OMgI)•R"-) RR'R"•C(OH) + MgLOH .

Ketones do not polymerize in the same way as aldehydes, but under the influence of acids and bases yield condensation products; thus acetone gives mesityl

oxide, phorone and mesitylene (see below) . _ For dimethyl ketone or acetone, see ACETONE . Diethyl ketone, (C2H6)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•C7 H15, a liquid of boiling-point 85-90° C . (7 mm.), which yields normal caprylic acid on oxidation with hypobromites . Mesatyl 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, C9Hi2-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, Gam chim . Ital., 1884, 14, P•349)• Phorone,(CH3)2C:CH•CO•CH:C(CH3)2,formsyellow crystals which melt at 28° C. and

boil at 197.2° C . When heated with phosphorus pentoxide it yields acetone, water and some pseudocumene . Dilute nitric acid oxidizes it to acetic and oxalic acids, while potassium permanganate oxidizes it to acetone, carbon dioxide and oxalic acid .