A
2-l. round-bottomed, short-necked flask is equipped with a
glass mechanical stirrer. A suspension of
165 g. (0.5 mole) of o-chloromercuriphenol (p. 161) (m.p.
147° or higher) in
500 cc. of chloroform is placed in the flask and treated with
127 g. (0.5 mole) of iodine, the stirring being continued until a small sample on filtration shows no unreacted
iodine. This requires from one to two hours. The solid inorganic
mercury compounds are removed by suction filtration. The filtrate is distilled from a
1-l. distilling flask on the
water bath to remove most of the
chloroform, which is saved for later runs (Note
1). The residual liquid is shaken vigorously with a solution of
5 g. of potassium iodide in 10 cc. of water, to remove dissolved
mercuric iodide. The heavier layer, which still possesses a reddish color, is transferred without drying to a
200-cc. Claisen flask and distilled under reduced pressure. At first a small amount of
chloroform and water distils over, after which the higher-boiling material is collected in a separate
receiver. Small amounts of inorganic
mercury compounds remain in the flask (Note
2).
The
o-iodophenol solidifies upon cooling. The yield of material melting at
32–34° is
70 g. (
63 per cent of the theoretical amount). The product obtained in this way is slightly yellow. If a purer product is desired, it may be redistilled under reduced pressure. Most of the crude material will distil over a 5° range (b.p.
130°/18 mm. and
186°/160 mm., m.p.
43°).