Estimation of the oxidation temperature of biodiesels from a limited number of chemical parameters

Biodiesel is a fuel composed by fatty acid esters, usually methyl esters (FAME), have common structural features, as allylic hydrogens, bis-allylic hydrogens and secondary hydroxyl, that determinate its oxidative stability. In this study, the oxidation temperature (OT) of biodiesels formulated from a mixture design of methyl stearate, methyl oleate, methyl linoleate and methyl ricinoleate was determined by pressurized differential scanning calorimetry (PDSC). The generic representation C a H b H c ∗ H d ∗ ∗ H e ∗ ∗ ∗ O 2 ( OH ) f for the mixtures was developed and their coefficients were used as parameters to describe the OT. A non-linear dependence of OT with the descriptors of allylic hydrogen H c ∗ , bis-allylic hydrogen H d ∗ ∗ and secondary hydroxyls ( OH ) f were observed in the empirical domain Dexp = {(a; c, d, f) ∈ R 3 ; 0 ⩽ c ⩽ 4 and 0 ⩽ d ⩽ 2 and 0 ⩽ f ⩽ 1 and a = 19}, where the Ca parameter for chain length was kept fixed.