Assessment of oxidative stability of biodiesel and biodiesel blends

This research investigates the oxidative stability of biodiesel blends produced from macauba and soybean after being stored for 45 and 90 days. The stability was evaluated through specific mass, kinematic viscosity, and water content measurements. The results showed a significant increase in water content and acidity index values during storage, particularly in the first 45 days. However, at time zero, the acidity index of all samples was below the established limit, but after 90 days of storage, only the BM100 sample remained below the limit. The fatty acid composition of macauba oil was determined by gas chromatography, and it presented 65.01% saturated fatty acids and 34.99% unsaturated fatty acids, with a higher predominance of maluric fatty acid at 36.37%. The physical-chemical characteristics of macauba oil, including acidity index, viscosity, and oxidation stability, were also determined. The acidity index of macauba oil was found to be 1.00 mg KOH/g, which is at the maximum limit for alkaline transesterification for biodiesel synthesis. The low viscosity of macauba oil (31.92 mm(2)/s) is justified by its composition rich in c12 uric acid, while the fatty acid composition may be responsible for the high oxidative stability. Spectroscopy in the infrared region was used to determine the chemical composition of soybean biodiesel, macauba biodiesel, and their blends.

Automated summary

This research examines the oxidative stability of biodiesel blends produced from macauba and soybean after a storage period of 45 and 90 days. The study evaluates stability using measurements of specific mass, kinematic viscosity, and water content. The results indicate a significant increase in water content and acidity index values during storage, particularly in the first 45 days. At time zero, the acidity index of all samples was below the established limit, but after 90 days, only the BM100 sample remained below the limit.