A mixture of
22 g. (0.1 mole) of iodosobenzene (p. 483),
24 g. (0.1 mole) of iodoxybenzene (p. 485), and
200 ml. of 1 N sodium hydroxide (Note
1) is gently stirred for 24 hours. The resulting brown slurry is thoroughly stirred with 1 l. of cold water, and, after the mixture settles, the supernatant solution of
diphenyliodonium iodate is decanted through a filter. The solid residue is extracted twice with 500-ml. portions of water, and the extracts are separated, by decantation through a filter, from the small amount of tarry residue. An aqueous solution of
20 g. (0.12 mole) of potassium iodide is added to the combined filtrates. After the bulky white precipitate of
diphenyliodonium iodide has stood for an hour or two, with occasional shaking, it is filtered with suction, washed with water, and dried on
porous tile at room temperature. The product weighs
29–30 g. (
70–72%) and melts at
172–175° with vigorous decomposition.