Optimization of Pistacia lentiscus Oil Transesterification Process Using Central Composite Design

In the present work, Pistacia lentiscus (PL) biodiesel was produced by converting PL oil with a single-step homogenous alkali catalyzed transesterification process. Several ethanol/vegetable oil molar ratio values (6–12:1), temperatures from 40 to 70 °C and KOH catalyst amounts in the range 0.6–1.8 wt% were considered. The response surface methodology combined with central composite design was used to optimize the process. The results showed that the optimum conditions were obtained for an ethanol/oil molar ratio of 9:1, a reaction temperature of 40 °C and catalyst amount of 1.2 wt%. Under these conditions, the predicted PL oil ethyl ester conversion was around 88%. The characterization of PL biodiesel according to the standard methods showed that the physicochemical properties were similar to those of conventional diesel fuel and in agreement with European requirements.