If alcohol is separated from phenol by distilling a

1 Chem. Zeit., 1910, 34, 1193. 2 J. Amer. Chem. Soc, 1914, 36, 115, strongly alkaline solution of the two substances, the distillate will contain some phenol, due to dissociation of the alkali phenate. According to J. Ehrlich,1 a complete separation is obtained if the phenol is converted into tribromophenol before distilling. A preliminary separation by distillation from alkali is, however, desirable unless the quantity of phenol is small.

Fifty c.c. of the sample are measured into a 300 c.c. flask containing 30 c.c. of water, and made strongly alkaline with about 20 c.c. of sodium hydroxide solution. The liquid is then distilled into a 50 c.c. flask containing 1 or 2 c.c. of water, the end of the condenser being extended so that it almost touches the level of the liquid in the receiver. When nearly 50 c.c. of distillate have been collected, the contents of the receiver are made up to the mark, shaken, and 25 c.c. measured out into another 300 c.c. flask containing 30 c.c. of water. The phenol is precipitated by adding bromine water drop by drop in slight excess, and the liquid at once decolorised with a few drops of normal solution of sodium thiosulphate. Sufficient strong sodium hydroxide solution is then added to dissolve the tribromophenol and leave a decided excess of alkali, but the total volume should be less than 100 c.c. The liquid is distilled as before, the contents of the receiver are made up to 50 c.c, and the specific gravity taken. The percentage of alcohol corresponding with this specific gravity, multiplied by 2, gives the percentage in the original sample. The action of the small excess of bromine on the ethyl alcohol is inappreciable in a short time at the ordinary temperature, and introduces no error.