Acetone

ACETONE, CH₃-CO-CH₃ (dimethyl ketone), is a colorless, flammable liquid with a specific gravity of 0.79 at 18°, with a pleasant odor and a burning taste. It boils at 56.5°, and is easily soluble in water, alcohol, and ether. Acetone is obtained 1) by the dry distillation of wood, 2) by the decomposition of acetates, 3) from starch by fermentation, 4) by the catalytic decomposition of acetic acid. In the animal organism, under normal conditions, only traces of acetone are found; in various metabolic disorders—starvation, complete absence of carbohydrates in the diet, febrile diseases, and, especially, in diabetes—the content of acetone increases and sometimes reaches significant levels (acetonemia and acetonuria). Acetone is formed during the anaerobic respiration of plants and is contained in some plants and in many essential oils. Under the action of chlorine or iodine in an alkaline solution, acetone is converted into chloroform or iodoform (a sensitive reaction for acetone, provided that ethyl alcohol is absent). Acetone easily dissolves fats, resins, and gun cotton. It hardly dissolves paraffin. After fixation with formalin, it dissolves fat but does not dissolve lecithin, which can serve for their differential identification. It precipitates many proteins from aqueous solutions, therefore it is used in microtechnique as a fixative. However, in view of the fact that pure anhydrous acetone strongly shrivels tissues, mixtures of it with formalin, mercuric chloride, etc., are preferred. For fixing nervous tissue, the following acetone mixtures are recommended: 1) 1% Hg₂Cl₂ in 40% acetone; 2) 9 parts acetone + 1 part formalin. Acetone dissolves celloidin and is therefore used as an intermediate medium when embedding in celloidin. Solutions of celloidin, gun cotton, and celluloid in acetone serve for attaching sections (see Histological technique). Recently, acetone has been acquiring increasing importance as an occupational poison due to its ever-expanding use in various industries. Workers come into contact with acetone in the production of celluloid and products made from it, in the production of batteries; when using acetone as a solvent for varnishes, paints, rubber, cellulose and its compounds; when using acetone for the extraction of fats, oils, resins, tannic acids; for the preparation of napon-varnish; in the chemical industry (in the preparation of chloroform, camphor, iodoform, sulfonal, etc.); during the painting of airplane wings, etc. The effect of acetone on the organism of experimental animals was recently studied by Kagan (Kharkov). In cats, during acute poisoning, he observed a loss of balance, then light, and finally, deep narcosis. Chronic poisoning in workers manifests itself in sensations of heat, dizziness, mild fainting, irritation of the respiratory organs, conjunctivitis, and dermatitis. Prophylaxis consists of the hermetic sealing of production processes, and where this is impossible, the creation, in view of the volatility of acetone, of powerful local exhaust ventilation. The State Institute for Labor Protection (Moscow) has proposed a system of movable hoods for painting airplane wings, into which the wing must be placed during painting and drying.