Organic Syntheses, Coll. Vol. 1, p.517 (1941); Vol. 4, p.73
(1925). A 2-l. round-bottomed flask is clamped to a ring stand
and equipped with a rubber stopper carrying a glass stirrer with
mercury seal , and a reflux condenser connected with a trap
(Fig. 7 on p. 97) for removing the evolved hydrogen chloride One
hundred grams (0.68 mole) of phthalic anhydride and 400 g. (462
cc., 4.35 moles) of toluene are placed in the flask, which is
cooled in an ice bath while 200 g. (1.5 moles) of anhydrous
aluminum chloride (Note 1) is being ground to a fine powder. The
chloride is now added all at once (Note 2) . Stirring is
commenced at once, and the ice bath is removed. The mixture
warms up considerably and becomes olive-green in color. When the
evolution of hydrogen chloride begins to slacken (ten minutes) a
water bath is put into place and heated to 90° in the course of
forty-five minutes. The temperature of the bath is kept at 90°
and vigorous stirring continued for two and one-half hours. At
this point, the evoluti