Unraveling the mechanism of thermal and thermo-oxidative degradation of tannic acid

•The thermal degradation mechanism of tannic acid has been investigated.•Py–GC–MS and TGA–FTIR are used to examine the products of degradation in gas phase.•The char study of tannic acid at various temperatures was carried with ATR–FTIR.•A mechanistic pathway for thermal degradation of tannic acid has been proposed.

The thermal and thermo-oxidative degradation of hydrolysable tannin, i.e. tannic acid is reported. The study on thermal and thermo-oxidative degradation mechanism of tannic acid was carried out by using several advanced thermal characterization techniques such as Thermogravimetric analysis (TGA) coupled with Fourier-Transform Infrared (FTIR) Spectroscopy (TGA–FTIR), pyrolysis–gas chromatography–mass spectroscopy (Py–GC–MS) and Attenuated Total Reflectance (ATR)–FTIR. The condensed phase and gaseous phase degradation studies were combined to deduce a probable degradation pathway for tannic acid molecule at high temperature under nitrogen and air atmosphere.