Abstract
This study investigates the use of the p-toluene sulphonic acid as a catalyst and a microwave heating system for synthesizing gallic acid esters from gallic acid and alcohols, including MT, EG, PG, iPG, BG, iBG and tBG. The gallic acid esters were analyzed using FTIR. The antioxidant effects in the biodiesel and the raw oils are studied with 1000ppm dosages. It was demonstrated that addition of the prepared compounds increased biodiesel oxidation stability. With the increase of the iPG and iBG antioxidant concentrations, the induction period of the biodiesel increased as well. When 250ppm of iPG and 600ppm of iBG were added, the oxidation stability of biodiesel met Chinese national standards and European standards of biodiesel stability. In comparison to commercially available antioxidants, the synthesized compounds demonstrated superior antioxidant effect.
