Organic Syntheses, CV 5, 1011
Submitted by A. J. Fatiadi and W. F. Sager
1.
Checked by B. C. McKusick and J. K. Williams.
1. Procedure
A
5-l., three-necked round-bottomed flask is fitted with a
thermometer, an
air-inlet tube of 10-mm. diameter extending to within approximately 1 cm. of the bottom, and an
outlet tube connected to an
aspirator (Note
1). A solution of
400 g. (3.17 moles) of anhydrous sodium sulfite and
150 g. (1.79 moles) of anhydrous sodium bicarbonate (Note
2) in 3 l. of water is heated to 40–45° in the flask.
Six hundred grams (480 ml., 3.11 moles) of 30% glyoxal solution (Note
3) is added, and a brisk stream of air is drawn through the solution for 1 hour without application of heat. Within a few minutes, greenish black crystals of the
sodium salt of tetrahydroxyquinone begin to separate. The flask is warmed to between 80° and 90° over a period of an hour. The air current is then stopped, and the mixture is heated to incipient boiling and set aside for 30 minutes. It is then cooled to 50° (Note
4), and the
sodium salt of tetrahydroxyquinone is separated by filtration and washed successively with
50 ml. of cold 15% sodium chloride solution,
50 ml. of cold 1:1 methanol-water, and
50 ml. of methanol. The air-dried salt weighs
20–21 g.
The salt is added to
250 ml. of 2N hydrochloric acid, and the mixture is heated to incipient boiling. The resultant solution is cooled in an
ice bath, and the glistening black crystals of
tetrahydroxyquinone that precipitate are collected on a
Büchner funnel and washed with ice water to give
11–15 g. (
6.2–8.4%) of product. The
quinone fails to melt on a hot plate at 320° (Note
5).
2. Notes
1. A tube of 10-mm. diameter is necessary to prevent the clogging of the outlet that occurs if tubing of smaller diameter is used.
2. Equivalent amounts of hydrated salt may be used.
3.
Dow commercial grade 30% glyoxal solution is satisfactory.
4. It is not necessary to cool below this temperature since crystallization is essentially complete at 50°.
5. This material is pure enough for reduction to
hexahydroxybenzene2 and most other purposes. A purer product can be obtained by dissolving the crude
tetrahydroxyquinone in
acetone and adding
petroleum ether of b.p.
60–80° to precipitate it.
3. Discussion
4. Merits of the Preparation
Tetrahydroxyquinone is of interest because of its application in analytical chemistry to the determination of
barium and as a complexing agent for many ions.
6 Moreover, it serves as a convenient source not only of the reduction product
hexahydroxybenzene2 but also of the oxidation products
rhodizonic acid and triquinoyl and of the product of catalytic reduction,
meso-inositol.
This procedure serves as a particularly simple method for preparing
tetrahydroxyquinone. The low yield is more than offset by the simplicity of the set-up, the ease of manipulation, and the low cost and ready availability of the starting materials.
This preparation is referenced from:
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