Employment of thermal analysis applied to the oxidative stability evaluation of biodiesel using chalcone analogues

Biodiesel is a prominent green combustible constituted of alkyl esters of fatty acids that can be prone to oxidation leading to undesirable effects in the fuel that can difficult its use. In this sense, there is a need for the development of antioxidants decelerating the oxidation of biodiesel. In this way, the aim of this work was to evaluate synthetic chalcones, which have the potential to act as oxidative stabilizers, from an initial screening of a series of chalcone analogues at different concentrations as antioxidant agents in biodiesel obtained from frying soybean oil. It should be noted that this is the first work to report the analysis of stabilization of biodiesel from soybean frying oil with synthetic chalcones. Results indicated that all of the quality parameters required for biodiesel were attended, except for the oxidative stability, as determined by standards of the European Union, USA and Brazil. Chalcone analogues were synthesized in moderate to good yields, while DPPH assay showed that these molecules had an antioxidant activity. Differential scanning calorimetry revealed that hydroxychalcones had an antioxidant activity in biodiesel at concentration equal to or above 1250 ppm. Therefore, this study indicates that chalcones have a structural template worth exploring to be applied as stabilizer agents in biodiesel. [GRAPHICS] .