Org. Synth. 1938, 18, 15
Submitted by W. J. Scott and C. F. H. Allen.
Checked by Louis F. Fieser and E. B. Hershberg.
A 2-l. three-necked flask
fitted with a stirrer (Note 1)
and (Note 2)
, and dropping funnel (Note 3)
is mounted in the hood
, and in it are placed 20 g. (0.061 mole) of potassium anthraquinone-α-sulfonate (p. 539)
, 500 cc. of water, and 85 cc. (1 mole) of concentrated hydrochloric acid
. The solution is heated to boiling and stirred, while a solution of 20 g. (0.19 mole) of sodium chlorate (Note 4)
in 100 cc. of water is added dropwise over a period of three hours (Note 5)
. The mixture is refluxed very slowly for an additional hour before the precipitated α-chloroanthraquinone
is collected by suction filtration and washed free from acid with hot water (about 350 cc.). After drying in vacuo
at 100°, the bright yellow product melts at 158–160°
(corr.) and weighs 14.6–14.7 g.
per cent of the theoretical amount) (Note 6)
and (Note 7)
Since the mixture tends to foam toward the end of the reaction, it is advisable to use an effective stirrer. A Hershberg stirrer (p. 117)
of tantalum wire gave good service in the hands of the checkers; the metal was not appreciably attacked after repeated use.
Since the usual dropping funnel has the disadvantage of requiring considerable attention from the operator, the checkers found it much more convenient to employ the device (of E. B. H.) shown in Fig. 5
is less satisfactory because of its lower solubility.
If the addition is too rapid or the boiling too vigorous, chlorinating gases are lost through the condenser.
Crystallization of the product from 200 cc. of n-butyl alcohol
gives 13.4 g.
of material in the form of yellow needles, m.p. 161–162°
(corr.). Larger amounts are conveniently crystallized from toluene, using 2 cc.
The melting point given for highly purified α-chloroanthraquinone
(corr.). The possible contaminants include the β-isomer, 1,5-, and 1,8-dichloroanthraquinone
, all of which melt at higher temperatures but depress the melting point of the α-monochloro compound.
has been prepared from α-aminoanthraquinone
by the diazo reaction,1
by the action of thionyl chloride
on potassium anthraquinone-α-sulfonate
and by the above process.3
This preparation is referenced from:
Chemical Abstracts Nomenclature (Collective Index Number);
1,5-, and 1,8-dichloroanthraquinone
hydrochloric acid (7647-01-0)
thionyl chloride (7719-09-7)
n-butyl alcohol (71-36-3)
sodium chlorate (7775-09-9)
potassium chlorate (3811-04-9)
Anthraquinone, 1-chloro- (82-44-0)
Potassium anthraquinone-α-sulfonate (30845-78-4)
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