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Org. Synth. 1950, 30, 1
DOI: 10.15227/orgsyn.030.0001
9-ACETYLANTHRACENE
[Ketone, 9-anthryl methyl]
Submitted by Charles Merritt, Jr. and Charles E. Braun1.
Checked by William S. Johnson and Ralph F. Hirschmann.
1. Procedure
Fifty grams (0.28 mole) of purified anthracene (Note 1) is suspended in 320 ml. of anhydrous benzene and 120 ml. (1.68 moles) of reagent grade acetyl chloride contained in a 1-l. three-necked flask. The flask is fitted with a thermometer which is immersed in the suspension, a calcium chloride drying tube, an efficient motor-driven sealed stirrer, and a rubber addition tube to which a 125-ml. Erlenmeyer flask containing 75 g. (0.56 mole) of anhydrous aluminum chloride is attached.2
The flask is surrounded by an ice-calcium chloride cooling mixture, and the aluminum chloride is added in small portions from the Erlenmeyer flask at such a rate that the temperature is maintained between −5° and 0°. After the addition is complete, the mixture is stirred for an additional 30 minutes, and the temperature is then allowed to rise slowly to 10°. The red complex which forms is collected with suction on a sintered-glass funnel and washed thoroughly with dry benzene (Note 2). The complex is added in small portions by means of a spatula with stirring to a 600-ml. beaker nearly filled with a mixture of ice and concentrated hydrochloric acid. The mixture is then allowed to come to room temperature, and the crude ketone is collected on a suction filter.
The product is digested under reflux for about 20 minutes with 100–150 ml. of boiling 95% ethanol. The suspension (Note 3) is cooled quickly almost to room temperature and filtered rapidly with suction to remove any anthracene. The 9-acetylanthracene, which separates in the filtrate, is redissolved by heating and allowed to crystallize by slowly cooling the solution (finally to 0–5° in an icebox) (Note 4). A second recrystallization from 95% ethanol yields 35–37 g. (57–60%) of light-tan granules of 9-acetylanthracene melting at 75–76° (Note 5).
2. Notes
1. The Eastman Kodak Company grade melting at 214–215° is satisfactory. Technical grade anthracene can be purified by codistillation with ethylene glycol. (See Fieser, Experiments in Organic Chemistry, 2nd ed., p. 345, footnote 13, D. C. Heath and Company, 1941.)
2. A regular Büchner funnel fitted with a mat of glass wool can be employed successfully. The filtration should be carried out as rapidly as possible, and the hydrolysis should be performed immediately thereafter if the humidity is high to minimize reaction on the funnel.
3. Most of the unreacted anthracene remains undissolved as a brown fluffy residue.
4. If the product has a tendency to separate as an oil, the addition of more solvent followed by heating to redissolve the material and subsequent cooling will usually yield a crystalline product.
5. Lüttringhaus and Kacer3 reported the melting point as ca. 80°, but May and Mosettig4 have found it to be 74–76°.
3. Discussion
The procedure described is essentially that of Lüttringhaus and Kacer3 except for the method of isolation of the product, which is due to May.5

References and Notes
  1. University of Vermont, Burlington, Vermont.
  2. Fieser, Experiments in Organic Chemistry, 3rd ed., p. 265, Fig. 46.4, D. C. Heath and Company, 1955.
  3. Lüttringhaus and Kacer, Ger. pat. 493,688 [C. A., 24, 2757 (1930)].
  4. May and Mosettig, J. Am. Chem. Soc., 70, 686 (1948).
  5. May, Private communication.

Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

ethanol (64-17-5)

hydrochloric acid (7647-01-0)

Benzene (71-43-2)

acetyl chloride (75-36-5)

aluminum chloride (3495-54-3)

ethylene glycol (107-21-1)

anthracene (120-12-7)

9-Acetylanthracene,
Ketone, 9-anthryl methyl (784-04-3)