To a solution of 25 g. of mercuric chloride in 500 cc. of water in a 5-l. flask, 800 g. of cracked ice is added. A cold solution of 190 g. of sodium hydroxide in 500 cc. of water is added, and a rapid stream of chlorine is passed into the mixture, which must be kept below 5°. The addition of chlorine is continued in this way until the yellow precipitate of mercuric oxide just disappears. Then 1600 cc. of cold nitric acid (1.5 N) is added slowly, with stirring.

The concentration of the hypochlorous acid solution is determined by adding a measured volume to an excess of potassium iodide solution acidified with hydrochloric acid, and titrating with standard thiosulfate solution. Usually the concentration is found to be between 3.5 and 4 per cent. The amount necessary to react with 123 g. (1.5 moles) of cyclohexene is calculated.

In a 5-l. round-bottomed flask equipped with a good mechanical stirrer (Note 1) is placed 123 g. (1.5 moles) of cyclohexene (p. 183), and to it is added about one-fourth the calculated amount of the hypochlorous acid solution. The mixture is kept between 15° and 20°, and stirred vigorously until a 1-cc. test portion gives no yellow color when it is treated with potassium iodide solution and dilute hydrochloric acid. When the first portion of the hypochlorous acid has reacted, a second is added and the process is repeated. When all the hypochlorous acid has been added and the reaction is complete, the oily layer should be on the bottom and a very slight excess of hypochlorous acid should be present, as indicated by the potassium iodide test. If these conditions are not fulfilled, 100-cc. portions of the hypochlorous acid solution are added until the reaction is shown to be complete.

The solution is now saturated with salt and distilled with steam (Note 2). About 2 l. of distillate is required before all of the 2-chlorocyclohexanol passes over. The distillate is saturated with salt and the oily layer separated. The aqueous layer is extracted once with about 250 cc. of ether. This is added to the main portion, which is dried with anhydrous sodium sulfate. The ether is removed by distillation and the product distilled under reduced pressure. The fraction boiling at 88–90°/20 mm. (104–106°/45 mm.) is collected. The yield is 142–148 g. (70–73 per cent of the theoretical amount).