Module 7 Derivatives of anthracene - anthraquinone - Preparation - Reactions

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1. Preparation of anthraquinone
1) From anthracene: It is manufactured by the vapour phase air oxidation of crude
anthracene.
2) Synthetic method: Friedel-Craft condensation of phthalic anhydride with benzene
in the presence of AlCl3 forms an intermediate which on heating with H2SO4 cyclizes
to give anthraquinone.
Reactions of anthraquinone
i) Distillation with zinc dust:
It forms anthracene on distillation with ZnCl2/NaCl/Zn dust at 200-300oC.
ii) Reduction:
With tin and HCl in acetic acid it forms anthrone; with Zn/HCl in acetic acid the
main product is dianthryl; with Zn and NH4OH it gives 9, 10-dihydroanthrol; and with
zinc and NaOH the main product is anthraquinol which is tautomeric with oxanthrol.

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iii) Nitration:
Nitration of anthraquinone gives 1-or a-nitro-anthraquinone.
iv) Sulphonation:
Anthraquinone on sulphonation with oleum in presence of catalyst mercuric
sulphate at 120oC gives mainly -anthraquinone-sulphonic acid, whereas in the
absence of catalyst at 140oC the main product is -anthraquinonesulphonic acid.

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Prepared by
Dr. A. Syed Mohamed
HoD and Senior Assistant Professor, Research Dept. of Chemistry
Sadakathullah Appa College (Autonomous)
Tirunelveli, Tamilnadu, India. asm2032@gmail.com
The author ackowledges Prof. H. Kassali Rahmathullah, Dr. T. Syed Ismail, Dr. M.
Kamalutheen, Former Professor, Dept. of Chemistry, Sadakathullah Appa College for their
valuable contribution.