Two liters of water is heated to boiling in a 3-l. flask. Mean-while 50 g. (0.53 mole) of phenol, in a 250-cc. tall beaker provided with a small glass mechanical stirrer, is heated to 170° on an electric heater (Note 1). The heat is then turned off and 100 g. (0.31 mole) of powdered mercuric acetate is added gradually (five to ten minutes) to the stirred phenol. After all of the mercuric acetate has dissolved in the phenol, the mercuration mixture is poured slowly into the hot water, the burner having previously been removed (Note 2). The beaker is rinsed out with some of the hot water. The mixture is boiled for five minutes and then filtered through filter paper in a large Büchner funnel which has been previously heated by blowing steam through it. The pink residue (Note 3) consists of a small amount of dimercurated phenol and some polymerization products.

The filtrate is again brought to boiling in a clean flask and treated with a solution of 20 g. (0.34 mole) of sodium chloride in 200 cc. of boiling water. The precipitate formed is p-chloromercuriphenol together with some colored impurities (Note 4). The mixture is heated to boiling and filtered through a large preheated Büchner funnel. The filtrate on cooling deposits white feathery crystals of o-chloromercuriphenol. The mixture is allowed to stand at least twelve hours and then filtered. The crystals are air-dried. They should be colorless and should melt above 147° (m.p. of pure substance 152°). If the product is pink or melts low it should be recrystallized from hot water. The average yield of fifteen experiments was 45 g. of ortho compound melting above 147°, which corresponds to 44 per cent of the theoretical amount (Note 5).