An alternative method by pressurized DSC to evaluate biodiesel antioxidants efficiency

• Published in: Journal of thermal analysis and calorimetry 2012-05, Vol.108 (2), p.751-759
• Main Authors: Leonardo, R. S., Murta Valle, M. L., Dweck, J.
• Format: Article
• Language: English
• Subjects: Alternative fuels. Production and utilization; Analysis; Analytical Chemistry; Antioxidants; Applied sciences; Biodiesel fuels; Biofuel production; Biological and medical sciences; Biotechnology; Calorimetry; Chemistry; Chemistry and Materials Science; Electrical conductivity; Energy; Evaluation; Exact sciences and technology; Fuels; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Inorganic Chemistry; Measurement Science and Instrumentation; Methods; Miscellaneous; Physical Chemistry; Polymer Sciences; Soybean
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-011-2175-4

The purpose of this article is to present an alternative method developed using pressurized differential scanning calorimetry (P-DSC) to evaluate the oxidative behavior of biodiesel obtained from soybean oil, produced by ethylic route (BSET), with and without the addition of synthetic antioxidants, as well as to compare the results with those obtained by Rancimat Method, which were carried out according to the European Official Standard Method EN 14112. BSET samples were analyzed using four different types of synthetic antioxidants at concentrations varying between 250, 500, and 1000 mg kg −1 . The measurements done by P-DSC were performed using static air at 80 psi and isothermal conditions at 110 °C, the same operating temperature than the Rancimat method. The experimental results of the oxidative stability measured from both methods have shown good correlations, which depend on the antioxidant, showing a gradual improvement in the oxidative stability of BSET with increasing added concentration of antioxidants. Opposite result behavior occurred for the measurements done in the presence of one of the antioxidants, which was composed by a significant content of components volatile below 110 °C, which accelerate the induction of the biodiesel oxidation in P-DSC method, but apparently do not interfere in the electrical conductivity measurement method (Rancimat). The advantages of the developed method using P - DSC technique with respect to Rancimat method is that it allows one to use a smaller sample, increases sensitivity to antioxidant action, reduces the analysis time for the evaluation of the antioxidant efficiency and detects any occurring oxidative process, independently of the volatility of the formed products, which may form oxidated products that remain in the liquid phase and that are non detectable by Rancimat method.