Powdered potassium hydroxide (29.4 g., 0.43 mole) is placed in a 500-ml. round-bottomed flask. Guaiacol (75 g., 0.60 mole) is added, and the mixture is allowed to react exothermically. After the reaction is complete, the mixture is stirred with a glass rod and then heated under reduced pressure for 3 hours at 150° in an oil bath (Note 1).

To the dry salt is added 0.3 g. of copper powder (Note 2), 81 g. (0.51 mole) of bromobenzene, and a few drops of guaiacol (Note 3). The mixture is stirred thoroughly with a glass rod; the flask is fitted with an air condenser and heated in a metal bath (Note 4). A reaction becomes evident at a bath temperature of 160–180°, liquefaction occurs, and the color of the mixture changes to red or purple. The temperature is gradually raised to 200° and maintained at 200° for 2 hours.

After cooling, the products are extracted from the reaction mixture with successive portions of water and ether. Extraction is facilitated by breaking up the solid material with a glass rod. The total amounts. of solvents required are approximately 750 ml. of water and 150 ml. of ether. The combined ether and water solutions are transferred to a 3-l. round-bottomed flask and steam-distilled with superheated steam maintained at 180–200°. After removal of the ether, 300 ml. of distillate is collected. This distillate contains the unreacted starting materials. Continued distillation gives 64–69 g. (62–67%) of crude solid 2-methoxydiphenyl ether in 14 l. of distillate. The product is filtered with suction and dried. Crystallization from a mixture of 600 ml. of low-boiling petroleum ether (b.p. 30–60°) and 435 ml. of higher-boiling petroleum ether (b.p. 60–70°) yields 54–61 g. of 2-methoxydiphenyl ether melting at 77–78°. Other 2-methoxydiphenyl ethers have been prepared by this procedure (Note 5).