Organic Syntheses, CV 3, 452
Submitted by W. W. Prichard
Checked by Homer Adkins and Maynette Vernsten.
1. Procedure
One drop of
concentrated sulfuric acid is added to a mixture of
110 g. (1.0 mole) of hydroquinone and
206 g. (190.3 ml., 2.02 moles) of acetic anhydride (Note
1) in a
1-l. Erlenmeyer flask. The mixture is stirred gently by hand; it warms up very rapidly, and the
hydroquinone dissolves. After 5 minutes the clear solution is poured onto about 800 ml. of crushed ice. The white crystalline solid which separates is collected on a
Büchner filter and washed with 1 l. of water. The filter cake is pressed occasionally to facilitate the removal of water; the solid is dried to constant weight over
phosphorus pentoxide in a
vacuum desiccator. The nearly pure product weighs
186–190 g. (
96–98%) and melts at
121–122° (Note
2); it can be recrystallized from
dilute ethanol (Note
3).
2. Notes
1. The use of commercial
acetic anhydride in this preparation sometimes results in appreciably lower yields. The checkers used the freshly redistilled reagent.
2. The melting point is recorded in the literature
1,2 as
121° and as
123–124°.
3. Recrystallization from
50% ethanol (by weight) permits a
93–94% recovery of material melting at
121.5–122.5°; about 365 g. (400 ml.) of the solvent is required for 100 g. of the crude product.
3. Discussion
This preparation is referenced from:
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