A.
Acenaphthenol acetate. In a
2-l. round-bottomed flask are placed
154 g. (1 mole) of acenaphthene (Note
1) and
1.1 l. of glacial acetic acid (Note
2). The flask is fitted with a
tantalum or Nichrome wire stirrer1 and a
thermometer extending below the surface of the liquid. The solution is stirred and heated to 60°, at which point the source of heat is removed and
820 g. of red lead (Note 3) is added in portions of about 50 g., each portion being added as soon as the color due to the previous portion has been discharged. During this operation, which requires 30–40 minutes, the temperature is maintained at 60–70 (Note
4) by external cooling. The reaction is complete when a portion of the solution gives no test for
lead tetraacetate (Note
5). The dark red syrupy solution (which may contain a few suspended particles of
red lead and
lead dioxide) is poured into 2 l. of water contained in a
4-l. separatory funnel. The acetate is extracted with a
350-ml. portion of ether and then with a 250-ml. portion. The total extract is washed first with 100 ml. of water, then with
300 ml. of saturated sodium chloride solution and is finally dried over
50 g. of anhydrous sodium sulfate. The
sodium sulfate is removed by filtration and washed colorless with three
50-ml. portions of dry ether. The combined filtrate and washings are placed in a
500-ml. Claisen flask with an inset side arm, and, after distillation of the solvent, the acetate is distilled under reduced pressure. The acetate distils almost entirely at
166–168°/5 mm. (bath temperature 180–185°, raised to 220° at the end) as a mobile yellow oil. The yield is
170–175 g. (
80–82%) (Note
6).