Two hundred forty-two grams (1 mole) of cetyl alcohol (Note
1),
10 g. (0.32 gram atom) of red phosphorus, and 134 g. (1.06 gram atoms) of resublimed iodine are placed in a
3-l. round-bottomed flask and heated in an
oil bath until the alcohol has melted. The flask is then fitted with a
reflux condenser and a
liquid-sealed mechanical stirrer. With stirring, the mixture is heated at 145–150° (temperature of the oil bath) for five hours. When the reaction mixture has cooled, the
cetyl iodide is removed by extracting once with a
250-cc. portion and twice with 125-cc. portions of commercial ether. The combined
ether extracts are filtered free of
phosphorus and washed with 500 cc. of cold water,
250 cc. of 5 per cent sodium hydroxide solution, and again with 500 cc. of water. The
ether solution is dried over anhydrous
calcium chloride. After removal of the
ether by distilling on a
steam bath, the iodide is distilled under reduced pressure. The main fraction, distilling at
220–225°/22 mm. (
210– 215°/12 mm.), weighs
300 g. (
85 per cent of the theoretical amount) and melts at
18–20° (Note
2). Redistillation gives
275 g. (
78 per cent of the theoretical amount) boiling at
220–223°/22 mm. (
203–205°/9 mm.) and melting at
20–22° (Note
3).