A
1-l., three-necked, round-bottomed flask is fitted with a mechanical stirrer and a thermometer; the third neck of the flask is fitted with a 50-ml., pressure-equalizing addition funnel, carrying a drying tube attached to a gas trap. The flask is charged with
200 ml. of dry nitrobenzene (Note
1), followed by
43 g. (0.32 mole) of anhydrous aluminum chloride. After the
aluminum chloride has dissolved,
39.5 g. (0.250 mole) of finely ground 2-methoxynaphthalene (nerolin, (Note 2)) is added. An
ice bath is used to cool the stirred solution to about 5° before
25 g. (23 ml., 0.32 mole) of redistilled acetyl chloride (Note
3) is added dropwise over a 15–20 minute period, with stirring and at a rate which holds the temperature between 10.5 and 13° (Note
4). After addition of the
acetyl chloride is complete, the flask is kept immersed in the ice water while stirring is continued for 2 hours. The mixture is then allowed to stand at room temperature for at least 12 hours.
The reaction mixture is cooled in an ice bath, poured with stirring into a
600-ml. beaker containing 200 g. of crushed ice, and treated with
100 ml. of concentrated hydrochloric acid. The resulting two-phase mixture and
50 ml. of chloroform are transferred to a
1-l. separatory funnel (Note
5); the
chloroform-nitrobenzene layer is separated and washed with three 100-ml. portions of water. The organic layer is transferred to a
2-l., round-bottomed flask, and steam-distilled. A fairly rapid flow of steam is used, and the distillation flask is heated in an
oil bath at about 120°. After about 3 hours (3–4 l. of water) the distillation is stopped, and the residue in the flask is allowed to cool. Residual water in the flask is decanted from the solid organic material and extracted with
chloroform. The solid residue in the flask is dissolved in
100 ml. of chloroform and separated from any water left in the flask, and the
chloroform layers are combined and dried over
anhydrous magnesium sulfate. The
chloroform is removed on a
rotary evaporator, and the solid residue, weighing 50–65 g. (still slightly wet with
chloroform), is distilled under vacuum (Note
6). The receiving flask should be immersed in ice water, and the fraction boiling about
150–165° (0.02 mm.) is collected (Note
7).