Iron oxide and pyrocatechol: a spectroscopy study of the reaction products

• Main Authors: Wagner José Barreto, Sônia Regina Giancoli Barreto, Ivanira Moreira, Yoshio Kawano
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química 2006-12-01
• Series: Química Nova
• Subjects: pyrocatechol; iron oxide; sodium thiosulfate
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422006000600021&lng=en&tlng=en

The reaction of 1,2-dihydroxy-benzene (pyrocatechol) (C6H6O2) with iron oxide (Fe2O3) and sodium thiosulfate (Na2S2O3) in aqueous medium (pH 7) was investigated. Pyrocatechol suffers autoxidation and coordinates with Fe3+ in solution. The presence of S2O3(2-) in solution was fundamental to generate and stabilize the pyrocatechol oxidation products as o-semiquinones. This compound was isolated and its structure characterized using FT-IR, EPR and UV-Vis Spectroscopy as [CTA][Fe(SQ)2(Cat)]. A thermal mass loss mechanism was proposed based on Thermogravimetric Analysis (TG) to support the structural characterization.