A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1953, 33, 50
DOI: 10.15227/orgsyn.033.0050
Submitted by E. A. Braude and J. S. Fawcett1.
Checked by Charles C. Price, R. S. Schreiber, R. D. Birkenmeyer, Paul F. Kirk, and William Bradley Reid, Jr..
1. Procedure
In a 2-l. three-necked flask, fitted with a mechanical stirrer, a 1-l. dropping funnel, and a thermometer, is placed a solution of 120 g. (1.2 moles) of pure chromium trioxide (Note 1) in 150 ml. of 80% aqueous acetic acid. The flask is surrounded by a freezing mixture of ice and salt, and, when the temperature of the contents of the flask has fallen to 0°, a solution of 64 g. (0.5 mole) of naphthalene in 600 ml. of glacial acetic acid is gradually added, with constant stirring, over a period of 2–3 hours. The internal temperature is maintained at about 10–15°. Stirring is continued overnight, during which time the reaction mixture and cooling bath gradually attain room temperature (Note 2). The dark green solution is then set aside for 3 days and occasionally stirred.
The crude naphthoquinone is precipitated by pouring the reaction mixture into 6 l. of water. The yellow precipitate is filtered, washed with 200 ml. of water, and dried in a desiccator. The product can be crystallized from 500 ml. of petroleum ether (b.p. 80–100°) (Note 3) and separates in the form of long yellow needles, m.p. 124–125°. The yield is 14–17 g. (18–22%) (Note 4).
2. Notes
1. An equivalent quantity of technical grade chromium trioxide, ground to a fine powder, may be employed.
2. It is necessary to continue vigorous stirring at this stage in order to prevent local overheating and to keep the mixture from setting to a solid mass.
3. Crystallization from petroleum ether (b.p. 80–100°) is far more convenient than steam distillation as a method of purification, and a product of high purity is obtained after a single crystallization. The checkers used Skellysolve C (b.p. 88–115°) with consistent results. Crystallization from ether has also been employed.2
4. The yield is substantially unchanged on increasing the proportion of chromium trioxide used in the oxidation. The submitters report consistent yields of 25–28 g. (32–35%).
3. Discussion
The present method of preparation is adapted from Miller.3 Although the yield is relatively low, the method is less costly and time-consuming than those starting from α-naphthol2 or 1,4-benzoquinone.4 Other methods that have been employed include the oxidation of naphthalene with hydrogen peroxide,5 the oxidation of 1,4-naphthalenediamine6 and naphthylaminesulfonic acid7 and the oxidation of 4-amino-1-naphthol prepared by electrolytic reduction of 1-nitronaphthalene.8

References and Notes
  1. Imperial College of Science and Technology, London, England.
  2. Conant and Fieser, J. Am. Chem. Soc., 46, 1862 (1924); Fieser and Fieser, J. Am. Chem. Soc., 57, 491 (1935); Org. Syntheses Coll. Vol. 1, 383 (1946).
  3. Miller, J. Russ. Phys. Chem. Soc., 16, 414 (1884); Japp and Miller, J. Chem. Soc., 39, 220 (1881).
  4. Fieser, J. Am. Chem. Soc., 70, 3165 (1948); Grinev and Terentév, Vestnik Moskov. Univ., Ser. Mat. Mekh. Astron. Fiz., Khim., 12, No. 6, 147 (1957) [C. A., 53, 3187 (1959)].
  5. Arnold and Larson, J.Org. Chem., 5, 250 (1940); Ibuki, J. Chem. Soc. Japan, Pure Chem. Sect., 70, 286 (1949) [C. A., 45, 4702 (1951)].
  6. Liebermann, Ann., 183, 242 (1876); Russig, J. prakt. Chem., 62, 31 (1900).
  7. Monnet, Reverdin, and Nolting, Ber., 12, 2306 (1879).
  8. Harman and Cason, J. Org. Chem., 17, 1058 (1952).

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

petroleum ether

Skellysolve C

acetic acid (64-19-7)

ether (60-29-7)

α-naphthol (90-15-3)

Naphthalene (91-20-3)

hydrogen peroxide (7722-84-1)

1,4-benzoquinone (106-51-4)

naphthoquinone (130-15-4)

1,4-naphthalenediamine (2243-61-0)

1-nitronaphthalene (86-57-7)

chromium trioxide (1333-82-0)

naphthylaminesulfonic acid