Online Encyclopedia


Online Encyclopedia
Originally appearing in Volume V01, Page 136 of the 1911 Encyclopedia Britannica.
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ACETONE, or DIMETHYL KETONE, 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 re-covered by fractional distillation. On the large scale it is pre-pared by the dry distillation of calcium acetate (CH3CO2)2Ca= CaCO3+CH3000H3. 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 crystal-line sodium bisulphite compound, which is separated by filtration and then distilled with sodium carbonate. 2 CHa\C< +Na2CO3=2CH3>C0+2Na2S03+CO2+H20. CH3/ S03Na CH3 It is then dehydrated and redistilled. Acetone is largely used in the manufacture of cordite (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 o• 819 (o%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 chloroform (q.v.) and sulphonal, and as a solvent. It forms a hydrazone with phenyl hydrazine, and an oxime with hydroxyl-amine. 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 triacetoneamines. It also unites directly with hydrocyanic acid to form the nitrile of a-oxyisobutyric acid. By the action of various reagents such as lime, caustic potash, hydrochloric acid, &c., acetone is converted into condensation products, mesityl oxide C6H160, phorone C9H140, &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.
ACETIC ACID (acidum aceticum)

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