Thermal study, identification of intermediate solid products and evolved gas analysis (EGA) during pyrolysis and oxidative decomposition of sodium complex of quercetin-5′-sulfonic acid (Na-5′-QSA)

• Published in: Journal of analytical and applied pyrolysis 2020-09, Vol.150, p.104881, Article 104881
• Main Authors: Maciołek, Urszula, Mendyk, Ewaryst, Kosińska, Małgorzata, Sternik, Dariusz, Drewniak, Marek, Kozioł, Anna E.
• Format: Article
• Language: English
• Subjects: Sodium 3,3′,4′,5,7-pentahydroxyflavon-5′-sulfonate tetrahydrate; Temperature diffractograms; TG–FTIR–MS; Thermal analysis
• ISSN: 0165-2370; 1873-250X
• DOI: 10.1016/j.jaap.2020.104881

[Display omitted] •The thermal analysis for Na-5′-QSA was performed in air and helium.•Previously unreported data on thermal behavior of flavonoid-sulfonate of Na(I) were obtained.•The crystalline anhydrous quercetin was identified as one of intermediate solid products.•Na2SO4 or a mixture of Na2C2 and soot were identified as solid degradation products.•H2O, CO2, SO2, COS and CO were mainly identified by the TG–FITR–MS analysis. The sodium 3,3′,4′,5,7-pentahydroxyflavon-5′-sulfonate tetrahydrate (sodium quercetin-5′-sulfonate; Na-5′-QSA) was fully characterized by a combined TG/DTG–DSC method in synthetic air and helium atmosphere, evolved gas analysis (EGA) by coupled TG–MS–FTIR technique as well as temperature controlled X-ray diffraction. The detailed thermal and diffraction studies provided previously unreported information on the thermal behavior of Na-5′-QSA. Intermediate solid products formed during thermal degradation in air and helium atmosphere were identified. It was proved that decomposition processes are multistage in both atmospheres and there is no significant difference in thermal behavior of Na-5′-QSA in oxidative and inert conditions up to 260 °C. The model of the crystal structure was determined for one of the components of an intermediate solid product which was crystalline anhydrous quercetin. The TG–FTIR–MS technique allowed the identification of the gaseous products evolving during oxidative decomposition and pyrolysis of the analyzed compound. Main gaseous products released during the thermal decomposition were water vapors, carbon dioxide, sulfur dioxide, carbonyl sulfide, carbon monoxide (in air and helium atmosphere) and the fragments of aromatic compounds formed additionally in helium atmosphere.