In a
loosely stoppered 1-l. round-bottomed flask are placed
37.5 g. (48 ml.) of t-butyl alcohol,
150 ml. of dimethyl sulfoxide (Note
1), and a
Teflon®-coated magnetic stirring bar. The solution is heated in an
oil bath which is placed on a combination
magnetic stirrer-hotplate. When the temperature of the mixture reaches 125–130°,
75 g. (0.67 mole) of alcohol-free potassium t-butoxide (Note
2) and (Note
3) is added, the stopper is replaced loosely, and the mixture is stirred. When all the
potassium t-butoxide is in solution, the stopper is removed,
25 g. (0.159 mole, 17 ml.) of bromobenzene is added in one portion to the hot solution, and an
air condenser fitted with a drying tube is
rapidly placed on the flask. The solution immediately turns dark brown, and an extremely vigorous, exothermic reaction occurs. After 1 minute the reaction mixture is poured into 500 ml. of water. The aqueous solution is saturated with
sodium chloride and extracted with four
200-ml. portions of ether (Note
4). The
ether extract is washed with three 100-ml. portions of water and dried over anhydrous
potassium carbonate. The
ether is distilled at atmospheric pressure on a
steam bath to leave
17–18 g. of crude
phenyl t-butyl ether (Note
5). The brown oil is distilled to yield
10–11 g. (
42–46%) of pure
phenyl t-butyl ether, b.p.
45–46° (2 mm.), m.p.
−17 to −16°,
n25D 1.4860–1.4890 (Note
6). The
ether may be hydrolyzed readily to phenol (Note
7).