Influence of dyes in oxidative stability of samples of biodiesel

The feasibility of using the dyequinizarin (QNZ) on the oxidative stability of soybean biodiesel samples was studiedin this work. The paper presents parameters indicative of the oxidation of biodiesel under thermal degradationthrough measurements of its acid value, peroxide and conjugated dienes and trienes. The study aimed to evaluatethe behavior/performance antioxidant of the dyequinizarin (QNZ) along with the antioxidant tert –butylhydroquinone (TBHQ) at the concentration of 5mg L-1, iea possible synergism between these two substances.The samples were characterized by physicochemical analyzes and spectrophotometric UV/Vis(200-400 nm). Theanalysis of the acid number and peroxide were consistent with the absorbance at 232and 270nm, for in bothanalyzes were detected increase in the oxidation of biodiesel samples throughout storage period and/or thermaldegradation.