Evaluating the oxidation stability of biodiesel. An experimental contribution

In this paper procedures and results obtained during the oxidation stability evaluation of biodiesel samples prepared from different vegetable oils, having a wide range of fatty acid composition and Iodine Value are reported. The accelerated oxidation test has been carried out both heating and bubbling air inside the samples. For each sample viscosity increase, polymerization of methylesters and the degradation rate of single unsaturated fatty acid have been evaluated. The obtained results indicated no relationship between Iodine Value and oxidation stability, while very important seem to be, according to the test used, the nature and the storage history of biodiesel samples.