Page:EB1911 - Volume 01.djvu/167

 with salt solution, separated from the salt solution, washed, dried and fractionated. The portion boiling between 175° and 185°C. is redistilled. The yield amounts to about 30% of that required by theory.

A. Ladenburg and J. A. Wanklyn have shown that pure ethyl acetate free from alcohol will not react with sodium to produce aceto-acetic ester. L. Claisen, whose views are now accepted, studied the reactions of sodium ethylate and showed that if sodium ethylate be used in place of sodium in the above reaction the same result is obtained. He explains the reactions thus:



this reaction being followed by



and on acidification this last substance gives aceto-acetic ester. Aceto-acetic ester is a colourless liquid boiling at 181°C.; it is slightly soluble in water, and when distilled undergoes some decomposition forming dehydracetic acid C8H8O4. It undoubtedly contains a keto-group, for it reacts with hydrocyanic acid, hydroxylamine, phenylhydrazine and ammonia; sodium bisulphite also combines with it to form a crystalline compound, hence it contains the grouping CH3·CO–. J. Wislicenus found that only one hydrogen atom in the –CH2– group is directly replaceable by sodium, and that if the sodium be then replaced by an alkyl group, the second hydrogen atom in the group can be replaced in the same manner. These alkyl substitution products are important, for they lead to the synthesis of many organic compounds, on account of the fact that they can be hydrolysed in two different ways, barium hydroxide or dilute sodium hydroxide solution giving the so-called ketone hydrolysis, whilst concentrated sodium hydroxide gives the acid hydrolysis. Ketone hydrolysis:— CH3·CO·C(XY)·CO2C2H5→CH3·CO·CH(XY) + C2H5OH + CO2; Acid hydrolysis:— CH3·CO·C(XY)·CO2C2H5→CH3·CO2H + C2H5OH + CH(XY)·COOH; (where X and Y = alkyl groups).

Both reactions occur to some extent simultaneously. Acetoacetic ester is a most important synthetic reagent, having been used in the production of s (q.v.), s (q.v.), pyrazolones, (q.v.), s (q.v.),  (q.v.), and many complex acids and ketones.

ACETONE, or, CH3·CO·CH3, in chemistry, the simplest representative of the aliphatic ketones. It is present in very small quantity in normal urine, in the blood, and in larger quantities in diabetic patients. It is found among the products formed in the destructive distillation of wood, sugar, cellulose, &c., and for this reason it is always present in crude wood spirit, from which the greater portion of it may be recovered by fractional distillation. On the large scale it is prepared by the dry distillation of calcium acetate (CH3CO2)2Ca = CaCO3 + CH3COCH3. E. R. Squibb (Journ. Amer. Chem. Soc., 1895, 17, p. 187) manufactures it by passing the vapour of acetic acid through a rotating iron cylinder containing a mixture of pumice and precipitated barium carbonate, and kept at a temperature of from 500° C. to 600° C. The mixed vapours of acetone, acetic acid and water are then led through a condensing apparatus so that the acetic acid and water are first condensed, and then the acetone is condensed in a second vessel. The barium carbonate used in the process acts as a contact substance, since the temperature at which the operation is carried out is always above the decomposition point of barium acetate. Crude acetone may be purified by converting it into the crystalline sodium bisulphite compound, which is separated by filtration and then distilled with sodium carbonate.



It is then dehydrated and redistilled.

Acetone is largely used in the manufacture of (q.v.) For this purpose the crude distillate is redistilled over sulphuric acid and then fractionated.

Acetone is a colourless mobile liquid of pleasant smell, boiling at 56·53°C., and has a specific gravity 0·819 (0°/4°C.). It is readily soluble in water, alcohol, ether, &c. In addition to its application in the cordite industry, it is used in the manufacture of (q.v.) and sulphonal, and as a solvent. It forms a hydrazone with phenyl hydrazine, and an oxime with hydroxylamine. Reduction by sodium amalgam converts it into isopropyl alcohol; oxidation by chromic acid gives carbon dioxide and acetic acid. With ammonia it reacts to form di- and tri-acetoneamines. It also unites directly with hydrocyanic acid to form the nitrile of -oxyisobutyric acid.

By the action of various reagents such as lime, caustic potash, hydrochloric acid, &c., acetone is converted into condensation products, mesityl oxide C6H10O, phorone C9H14O, &c., being formed. On distillation with sulphuric acid, it is converted into mesitylene C9H12 (symmetrical trimethyl benzene). Acetone has also been used in the artificial production of indigo. In the presence of iodine and an alkali it gives iodoform. Acetone has been employed medicinally in cases of dyspnoea. With potassium iodide, glycerin and water, it forms the preparation spirone, which has been used as a spray inhalation in paroxysmal sneezing and asthma.

 ACETOPHENONE, or, C8H8O or C6H5CO·CH3, in chemistry, the simplest representative of the class of mixed aliphatic-aromatic ketones. It can be prepared by distilling a mixture of dry calcium benzoate and acetate, Ca(O2CC6H5)2+(CH3CO2)2Ca=2CaCO3+2C6H5CO·CH3, or by condensing benzene with acetyl chloride in the presence of anhydrous aluminium chloride (C. Friedel and J. M. Crafts), C6H6+CH3COCl=HCl+C6H5COCH3. It crystallizes in colourless plates melting at 20°C. and boiling at 202°C.; it is insoluble in water, but readily dissolves in the ordinary organic solvents. It is reduced by nascent hydrogen to the secondary alcohol C6H5·CH·OH·CH3 phenyl-methyl-carbinol, and on oxidation forms benzoic acid. On the addition of phenylhydrazine it gives a phenylhydrazone, and with hydroxylamine furnishes an oxime C=N·OH melting at 59°C. This oxime undergoes a peculiar rearrangement when it is dissolved in ether and phosphorus pentachloride is added to the ethereal solution, the excess of ether distilled off and water added to the residue being converted into the isomeric substance acetanilide, C6H5NHCOCH3, a behaviour shown by many ketoximes and known as the Beckmann change (see Berichte, 1886, 19, p. 988). With sodium ethylate in ethyl acetate solution it forms the sodium derivative of benzoyl acetone, from which benzoyl acetone, C6H5·CO·CH2·CO·CH3, can be obtained by acidification with acetic acid. When heated with the halogens, acetophenone is substituted in the aliphatic portion of the nucleus; thus bromine gives phenacyl bromide, C6H5CO·CH2Br. Numerous derivatives of acetophenone have been prepared, one of the most important being ortheaminoacetophenone, NH2·C6H4·CO·CH3, which is obtained by boiling orthoaminophenylpropiolic acid with water. It is a thick yellowish oil boiling between 242° C. and 250° C. It condenses with acetone in the presence of caustic soda to a quinoline. Acetanyl-acetophenone, C6H5·CO·CH2·CH2·CO·CH3, is produced by condensing phenacyl bromide with sodium acetoacetate with subsequent elimination of carbon dioxide, and on dehydration gives -phenyl-methyl-furfurane. (q.v.) are produced on condensing phenacyl bromide with acid-amides (M. Lewy, Berichte, 1887, 2, p. 2578). K. L. Paal has also obtained pyrrol derivatives by condensing acetophenone-aceto-acetic-ester with substances of the type NH2R.