Vol. 3 No. 1 (2019): Pesquisa e Ensino em Ciências Exatas e da Natureza

A quantum-mechanical, ab-initio-level study using the Hartree-Fock-Roothaan theory was performed on the major constituents of soybean oil. The front cover image, constructed with the free Avogadro and GIMP software, shows structures of these constituents, which are the results of the study (see article by Araújo et al. in this edition). The energy data of each of these molecules demonstrate that biodiesel obtained from soybean oil is unstable, since the percentage of unstable compounds in its constitution is higher for methyl ester molecules with 18 carbon atoms and one or two unsaturations. This finding is in agreement with data described by other authors, who they admit that biodiesel from soybean oil tends to undergo oxidation reactions easily. Thus, due to its oxidative instability, this biofuel should be well stored and not exposed.