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).

B. Acenaphthenol. The acetate obtained as above is dissolved in 275 ml. of methanol in a 2-l. round-bottomed flask, and a solution of 40 g. (1.2 equiv.) of sodium hydroxide in 400 ml. of water is added (Note 7). This mixture is refluxed for 2 hours (Note 7) and then cooled below 20°. The yellow crystalline acenaphthenol is collected on a filter and washed well with about 1.5 l. of water. The crude product is air-dried (138–143 g.) and then dissolved in 2 l. of boiling benzene. The solution is treated with 6–8 g. of decolorizing carbon (Note 8) and filtered through a heated funnel. The orange-red filtrate is concentrated to about 1 l., and the acenaphthenol is allowed to crystallize. After filtering with suction and washing with cold benzene (about 500 ml.) until the wash solvent is colorless, the acenaphthenol is obtained as practically colorless needles, m.p. 144.5–145.5° (cor.) (Note 9). It weighs 117–121 g. From the filtrate may be obtained an additional quantity of material which on one recrystallization gives only 3–5 g. of pure acenaphthenol. The total yield amounts to 120–126 g. (70–74% based on the acenaphthene).