solution of sodium ethylate, the mixture being kept cool. The liquid changes to a faint amber colour. The calculated quantity (125 grms.) of ethyl monochloracetate is now slowly introduced, the flask being cooled in water if much heat is developed. The reaction is completed by heating for two hours on the water-bath. The liquid becomes gradually muddy from the separation of sodium chloride and assumes a brown tint. If the reaction is finished a sample of the product diluted with water should no longer have an alkaline reaction. After distilling off the alcohol the residual dark-coloured product is diluted with water and the oily liquid which settles down (ethyl acetosuccinate) is separated, dried over previously heated potassium carbonate and then distilled, whereby the chief portion passes over at 250-260° and is nearly pure ethyl acetosuccinate. It usually has a faint yellow colour. Chloracetic Ether. CH.CO.CHNa. CO2C2H5 + CH2CI.CO2C2H5 = CH.CO,C,HS + NaCl Ethyl Acetosuccinate. = Properties.-Colourless liquid; b. p. 254-256°; sp. gr. 1079 at 21°; insoluble in water; soluble in alcohol. PREPARATION LXIII. MONOCHLORACETIC ACID, C,H,O,C1 = CH2CI CO2H. LITERATURE.-R. Hofmann (1857), Ann. Ch. Pharm. 102, 1; H. Müller (1865), Chem. Soc. J. 17, 398. 250 grms, glacial acetic acid, Two hundred and fifty grms. commercial glacial acetic acid are gently boiled (in a retort of about litre capacity provided with a reflux condenser) over wire gauze and chlorine, dried through sulphuric acid, is passed into the hot liquid. The operation must be conducted in such a way that the chlorine comes in contact as much as possible with the vapours of the boiling acid. This is effected by fixing the chlorine inlet tube just below the surface of the liquid, At the upper end of the condenser quantities of unabsorbed chlorine and hydrochloric acid gas escape. The retort is placed in direct sunlight, the action proceeding more or less quickly according to the strength of the sun's rays. In direct sunlight the greater part of the acetic acid is converted into the monochlorinated compound in 6-8 hours. The action slackens as the formation of the chloacetic acid proceeds, The yellow product is distilled with the thermometer in the liquid; the portion distilling below 130° consists chiefly of unchanged acetic acid and may be used for a fresh operation, that boiling at 130-190° contains nearly the whole of the monochloracetic acid, the portion which boils above 190° consists of higher chlorinated products (di- and trichloracetic acid). The fraction boiling at 130-190° quickly solidifies on cooling. The colourless crystalline plates are separated from the mother liquor by pressing them well at the filter pump and are dried in vacuo over sulphuric acid and caustic potash. On redistilling the monochloracetic acid, thus purified, it passes over at 184-188°. Properties.-Rhombic plates or prisms; m. p. 63°; b. p. 185-187°; easily soluble in water, PREPARATION LXIV. /NH2 GLYCOCOLI, CH,NO2=CH2CO.OH. (Amidoacetic Acid.) LITERATURE.-Braconnot (1820), Ann. Ch. Phys. (2) 13, 114; Dessaignes (1846), Ann. Ch. Phys. (3) 17, 50; Strecker (1848), Ann. Ch. Pharm. 65, 130; Perkin, Duppa (1859), Chem. Soc. J. 11, 22; Nencki (1883), Ber. 16, 2827. 50 grms, monochloracetic acid. 150 ammonium carbonate (commercial). Fifty grms. monochloracetic acid are well mixed with 150 grms. dry powdered commercial ammonium carbonate, and the mixture slowly heated in an open flask (1 litre capacity) on the oil-bath. At 60-70° the action begins, the mass melts and froths up with strong evolution of carbon dioxide. As the temperature slowly rises to 130° the evolution of gas slackens, and the contents of the flask, which have a faint brown tint, become semi-solid, from the separation of ammonium chloride. The lamp is now removed, the cooled mass dissolved in water and the aqueous solution boiled with lead oxide until the smell of ammonia is no longer perceptible. From the warm filtered solution lead is precipitated with sulphuretted hydrogen and the filtrate is now heated with copper carbonate. The deep blue liquid filtered from excess of carbonate is concentrated. On cooling, the characteristic blue crystals of the copper salt of glycocoll separate out. These are filtered, drained, redissolved in water, and the copper precipitated with sulphuretted hydrogen. The clear solution, evaporated on the water-bath, yields colourless crystals of free glycocoll. CH,C!.COOH+(NH,),CO,=CH,COH+CO,+H,O + Properties. Large monoclinic crystals, are discoloured at 228° and melt at 232-236°; scarcely soluble in alcohol and ether, readily soluble in water (1 part glycocoll in 4 parts water). The aqueous solution gives a deep red colour with ferric chloride. PREPARATION LXV. ETHYL MONOCHLORACETATE, C1H-O2Cl= LITERATURE.-Willm (1857), Ann. Ch. Phys. (3) 49, 97; Conrad (1877), Ann. Ch Pharm. 188, 218. A mixture of 200 grms. monochloracetic acid, 120 grms. absolute alcohol, and 25 grms. conc. sulphuric acid, is heated for about six hours on the water-bath in a round-bottomed flask, of about litre capacity, connected with a reflux condenser. On the addition of water to the product of the reaction, previously allowed to cool, the ether separates out. The ethereal layer is removed, dehyrated over calcium chloride, and distilled. The portion passing over at 138-145°, is collected, and after fractionation boils constantly at 143–144°. CH,CICO2H + C2H5(OH) = CH2C1.CO2C2H5 + H2O Chloracetic Acid Ethylchloracetic Ether. Properties. Colourless liquid, possessing an ethereal odour; b. p. 143 ̊5°; sp. gr. 1'1585 at 20°. |