69310-14-1Relevant academic research and scientific papers
PHOTOCHEMICAL HYDROXYLATION OF ANTHRAQUINONE IN SULFURIC ACID
Studzinskii, O.P.,El'tsov, A.V.
, p. 1666 - 1673 (2007/10/02)
The photolysis of anthraquinone in sulfuric acid leads to hydroxylation of its ring with the preferential formation of 2-hydroxyanthraquinone in concentrated and 1-hydroxyanthraquinone in dilute sulfuric acid.The second hydroxy group only enters photochemically at position 4 of 1-hydroxyanthraquinone if the latter is activated by complex formation with boric acid.During photolysis in deaerated sulfuric acid the nitroanthraquinones are reduced photochemically to (hydroxyamino)anthraquinones; here 1-(hydroxyamino)anthraquinones with an unoccupied para position in the same condensed benzene ring undergo rearrangement under the reaction conditions to 1-amino-4-hydroxyanthraquinones.The main photochemical stage of hydroxylation in concentrated sulfuric acid is nucleophilic substitution of hydrogen in the monoprotonated anthraquinone by the HSO4(-) ion, while in dilute sulfuric acid it is electron transfer from water to anthraquinone.
