Put anhydrous ether in boiling flask. Note: The
anhydrous ether is prepared by washing commercial
ethyl ether with two or three portions
of H2O, adding NaOH or KOH, and letting
stand until most of H2O is absorbed from the
ether. Add small pieces of metallic Na and
let hydrogen evolution cease (AOAC Method
920.39B). Petroleum ether may be used instead
of anhydrous ether (AOAC Method 960.39).