Caracterização espectroscópica e estudo da degradação térmica do biodiesel produzido a partir dos óleos da macaúba (Acrocomia aculeata)

Abstract

The present study investigated the degradation of biodiesels produced from oils (brown and pulp) Fruit macaúba (Acrocomia aculeata) and their blends. The biodiesels were produced from a transesterification reaction. Forced degradation of biodiesel samples was done in an oven at 110 ° C. Total degradation time was 48 hours, with sampling at an interval of 2 hours during the first 24 hours. Consequently, a sample 36 and another 48 hours was collected. After degradation, UV-Vis spectra of molecular absorption and fluorescence of the samples were collected. The variation of the absorption intensities at 230 and 270 nm for both biodiesels and biodiesel 445nm in the pulp was analyzed. Regarding the fluorescence, the change in intensity was monitored at 320 and 510nm for both biodiesels. The acid value was monitored as a function of degradation time. Biodiesel blends (pulp / brown) were studied at concentrations of 25, 50 and 75% (m/m), such blends were subjected to degradation and therefore the optical characterization was performed. The results show an increase in the values of the intensities at 230 and 270nm as a result of the generation of primary and secondary compounds derived during the thermodegradation process. The emission intensity at 320 nm is decreased as a function of degradation time, while the emission intensity at 510 shows an increase in emission intensity during the initial stage of degradation, after a few hours, there is a decrease in its intensity fluorescence. Additionally, it was possible to observe an increase in the acid value as a function of time of samples thermodegradation.