Estimation of the storage time of biodiesel at room temperature in mixture with natural antioxidants and metallic ions: A semi-empirical study

Abstract

Biodiesel is derived from renewable sources and can be considered as an energy alternative to partially replace diesel. However, it contains unsaturated organic molecules in its composition, which increases its tendency towards oxidative degradation when exposed to oxygen in the air and metallic ions. Consequently, this leads to alterations in the physicochemical properties of biodiesel. To inhibit or delay the oxidative process and increase the induction period, natural extracts with antioxidant properties from gabiroba leaves (Campomanesia Xanthocarpa), jabuticaba peels (Myrciaria Cauliflora), and hibiscus flowers (Malvaviscus arboreus) were added. The samples’ oxidative stability was evaluated in the presence or absence of extracts, as well as Fe2+, Fe3+, and Cu2+ ions at temperatures of 110, 115, 120, and 125 °C, obtaining the induction period values. By extrapolating the experimental data of the logarithm of the IP values at different temperatures, the storage time at room temperature was estimated without altering the values determined during the experimental assays. The use of inedible products such as peels, leaves, and flowers, with antioxidant properties, not only aligns with the recommendations and legislation of several countries but also proves to be a viable alternative to synthetic substances for delaying the oxidation reaction of biodiesel.