202 REDUCTION WITH ALUMINUM ALKOXIDES alcohol), and 450 cc. of dry isopropyl alcohol. A Hahn partial condenser (or a reflux condenser or Vigreux column may be used), with a 1-cm. layer of ethanol in the inner condensing tube (p. 197), is attached, and the solution is heated on the steam bath. After six hours of slow distillation (2 to 6 drops per minute) the distillate may no longer give a direct test for acetone, but after five minutes of total reflux, followed by resumption of distillation, the first portion of the distillate usually contains acetone. (If the volume of the mixture should fall below 200 cc. during the reduc-tion, it is advisable to add more isopropyl alcohol.) Heating is con-tinued until the acetone test is completely negative, which requires about ten hours, the time depending to some extent upon the rate of distilla-tion. A bent glass tube, attached to a water condenser set for distilla-tion, is substituted for the Hahn condenser, and most of the remaining isopropyl alcohol is removed at atmospheric pressure. The cooled
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