The oxidative stability of biodiesel: Effects of FAME composition and antioxidant

A significant problem associated with the commercial acceptance of biodiesel is poor oxidative stability. This study investigated the effectiveness of individual and binary antioxidants to improve the oxidative stability of different types of biodiesel and distilled biodiesel. Results indicate that different types of biodiesel have different levels of oxidative stability, and that natural antioxidants and FAME composition play significant roles in determining oxidative stability. Synthetic antioxidants can enhance the oxidative stability of different types of biodiesel, and antioxidant activity increases as a function of its concentration. However, the effective activity level of antioxidant is dependent on biodiesel feedstock. Binary antioxidant formulations (TBHQ and PY) have a synergistic effect on oxidative stability of biodiesel. After long‐term storage at room temperature, the oxidative stability of untreated SBO‐based biodiesel significantly decreases as a function of time, while the addition of the antioxidant TBHQ can improve and maintain oxidative stability of biodiesel over an 18‐month period. However, the effectiveness of PY significantly decreases even after 2‐months.