Photocatalysis of Sulfo and Carboxy Derivatives of Indigo in a TiO2 Slurry with the Use of Polychromatic Irradiation

0381107 - ÚCHP 2013 RIV NL eng J - Journal Article
Machalický, O. - Tichý, L. - Tomica, M. - Hrdina, R. - Šolcová, Olga
Photocatalysis of Sulfo and Carboxy Derivatives of Indigo in a TiO2 Slurry with the Use of Polychromatic Irradiation.
Reaction Kinetics Mechanism and Catalysis. Roč. 107, č. 1 (2012), s. 63-77. ISSN 1878-5190. E-ISSN 1878-5204
R&D Projects: GA ČR GA104/09/0694
Institutional support: RVO:67985858
Keywords : indigo derivatives * 2-amino-5-sulfobenzoic acid * aminoterephthalic acid * isatine derivatives * kinetic model of heterogeneous photocatalysis
Subject RIV: CC - Organic Chemistry
Impact factor: 1.104, year: 2012

The photocatalytic decomposition of indigo-5,5′-disulfonic acid (indigocarmine) and indigo-6,6′-dicarboxylic acid has been studied using TiO2 suspension and the polychromatic irradiation of a high-pressure Hg arc lamp. The dyestuffs were dissolved in aqueous medium at pH = 10 and photolyzed in a back-flow tubular photoreactor. The reaction products were determined by HPLC, NMR and MS spectroscopy. Two main photoproducts obtained from indigocarmine (2-amino-5-sulfobenzoic acid and isatine-5-sulfonic acid) were detected. The photocatalysis of indigo-6,6′-dicarboxylic acid gave aminoterephthalic acid and isatine-6-carboxylic acid as two main products. The quantitative analyses of reaction products were performed with UV/Vis and HPLC using chemical standards. A stoichiometric model and kinetic description of photocatalysis of sulfo and carboxy indigo dyes are suggested. The effect of hydroxide and carbonate anions on the rate of photocatalysis was also studied.
Permanent Link: http://hdl.handle.net/11104/0211647