Organic Syntheses, CV 3, 1
Submitted by C. F. H. Allen and J. A. VanAllan.
Checked by L. Matternas, H. Lloyd, and E. C. Horning.
1. Procedure
A mixture of
100 g. (0.65 mole) of a technical grade of acenaphthene,
5 g. of ceric acetate (Note
1), and
800 ml. of glacial acetic acid is placed in a
4-l. stainless-steel beaker arranged for external cooling with cold water (Note
2). A
thermometer and a powerful stirrer are inserted, and
325 g. (1.1 mole) of sodium bichromate dihydrate is added over a period of 2 hours, the temperature being kept at 40° (Note
3). Stirring is then continued at room temperature for an additional 8 hours; during this time the reaction mixture becomes quite thick, owing to the separation of the quinone and
chromium salts. The suspension is diluted with 1.5 l. of cold water, and the solid is collected on a
10-in. Büchner funnel and washed free from acid.
The solid is next digested on the
steam bath for 30 minutes with
500 ml. of a 10% sodium carbonate solution, and is filtered and washed. The solid is then extracted for 30 minutes at 80° with
1 l. of 4% sodium bisulfite solution; at the end of this period
15 g. each of Filtercel and Norit are added, and the suspension is filtered. The extraction is repeated, and the combined filtrates are acidified at 80° with constant stirring (Note
4), to Congo red paper, with concentrated
hydrochloric acid (50–60 ml.). The temperature is maintained at 80° for 1 hour with constant stirring. The
acenaphthenequinone separates as a bright yellow crystalline solid; it is collected on a
Büchner funnel and washed with water until free from acid. The yield is
45–70 g. (
38–60%); m.p.
256–260°.
The crude quinone (
50 g.) is recrystallized from
250 ml. of o-dichlorobenzene without filtering (Note
5); the crystals are rinsed with
methanol. The recovery is
45 g., m.p.
259–260° (Note
6), (Note
7).
2. Notes
1. The checkers used Eastman Kodak white label
acenaphthene. Cerium salts appear to have a beneficial effect. Probably any cerous salt will be satisfactory, it being oxidized in the reaction. The submitters have used
cerous chloride,
ceric carbonate, and
ceric acetate; the last can be obtained in the form of a 50% mixture with other rare-earth acetates from the Lindsay Light and Chemical Company, West Chicago, Illinois. The checkers used
cerous chloride.
2. The checkers found no need to cool the reaction; instead the bath was used to heat the reaction to 40°. With technical grade
acenaphthene, cooling is necessary.
3. If the oxidation temperature has been allowed to rise to 50°, tar formation makes it necessary to do five or six treatments with
sodium bisulfite. The extractions should be continued as long as the filtrate gives a precipitate on acidification.
4. The acidification should be performed in a hood; much
sulfur dioxide is evolved.
5. The quinone crystallizes so rapidly that filtration is impossible; however, there is no insoluble material if mechanical dirt has been excluded.
6. This oxidation has been run using 80 times these amounts; the yield of recrystallized material drops to
38–40%.
3. Discussion
Acenaphthenequinone has been prepared by oxidation of
acenaphthene with
chromic acid,
1,2,3,4,5,6,7,8,9,10 with
calcium permanganate,
11 with air in the presence of catalysts in various solvents,
12,13,14,15 with
30% hydrogen peroxide in
acetic acid,
16 by the formation of an oxime with an alkyl nitrite followed by hydrolysis,
17,18,19 and from
oxalyl chloride and
naphthalene.
20,21 This procedure is based on the disclosure in a P.B. report.
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