Thermal degradation and evolved gas analysis of some vegetable oils using TG/FT-IR/MS technique

Abstract

Thermal behavior and evolved gases analysis at thermal degradation of some vegetable oils in nitrogen atmosphere were evaluated using thermogravimetric analysis coupled with FT-IR and MS spectroscopy. The thermal analysis revealed that the degradation process of these oils occurred in many steps, due to the different chemical structures of fatty acids. The kinetic parameters of thermal degradation were evaluated by the data processing at three heating rates (5, 7.5, and 10 °C min−1). According to activation energy values and the onset of the first thermal process, it was found that corn oil is more thermally stable than castor oil. Based on the obtained data from the FT-IR and MS spectra, the main gaseous products resulting at thermal degradation are water, carbon dioxide, saturated and unsaturated aliphatic hydrocarbons, and also some the hydroxylic, carbonylic, and carboxylic compounds.