In a 5-l. flask (Note 1), 110 g. (0.5 mole) of iodosobenzene (p. 483) is made into a thin paste with water, and the mixture is rapidly steam-distilled (Note 2) until almost all the iodobenzene (Note 3) is removed. The distillation should not be continued any longer than necessary, and the contents of the flask should be cooled at once. The white solid is filtered with suction and dried in the air at room temperature. It is then washed with chloroform, again dried, and the resulting cake is ground lightly in a mortar to facilitate removal of moisture in a final drying. The yield is 54–56 g. (92–95%). The product has a purity of about 99%, as determined by iodimetry (Note 4). The solid may be crystallized from hot water (Note 5).

In a 2-l. round-bottomed flask equipped with an efficient mechanical stirrer (Note 1) are placed 110 g. (0.4 mole) of freshly prepared, pulverized iodobenzene dichloride (p. 482) (Note 2), 1.0 mole of sodium hypochlorite solution (Note 3), and 2 ml. of glacial acetic acid. The vigorously stirred mixture is heated on a water bath maintained at 65–75°. After 10–15 minutes the heated mixture becomes frothy and the yellow color of iodobenzene dichloride is displaced by the white color of iodoxybenzene. The stirring is stopped after 1 hour, and the flask is cooled in an ice bath. The product is filtered with suction, pressed with a glass stopper, and transferred to an 800-ml. beaker. The material is stirred thoroughly with 300 ml. of water, filtered with suction, washed on the filter with 100 ml. of water, pressed, and dried in the air. The crude product weighs 85–89 g. (90–94%) and has a purity, as determined iodimetrically, of 97–99% (Note 4). The air-dried material may be washed with 50–60 ml. of chloroform, air-dried, and finally dried in a vacuum desiccator. This product weighs 82–87g. (87–92%) and has a purity of 99.0–99.9% as determined by iodimetry (Note 5).