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Hydroxyanthraquinones Carminic Acid and Chrysazin Anodic Oxidation
Author(s) -
de Souza Gil Eric,
de Oliveira Severino Carlos B.,
de OliveiraBrett Ana Maria
Publication year - 2012
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201200433
Subject(s) - hydroquinone , catechol , chemistry , moiety , anodic oxidation , anthraquinone , quinone , tautomer , inorganic chemistry , redox , photochemistry , medicinal chemistry , anode , organic chemistry , electrode
The anodic oxidation of the hydroxyanthraquinones carminic acid (CA) and chrysazin (CR) was investigated. The oxidation of CA proceeds in a pH‐dependent cascade mechanism, concerning the hydroquinone, the catechol and the 3‐OH groups in the anthraquinone moiety. The oxidation of the hydroquinone following the catechol electron‐donating groups occurs first at low positive potentials, the 3‐OH group is oxidized irreversibly at a higher potential. The oxidation of CR is pH‐dependent and occurs in successive steps. Oxidation of the hydroquinone tautomer in the CR‐ring occurs first, and the symmetrical 1‐OH and 8‐OH groups are irreversibly oxidized at the same higher potential.