Improving oxidation stability of sunflower biodiesel by partial hydrogenation using a special catalyst

Abstract

AbstractThe aim of this study was to increase the oxidation stability of biodiesel from sunflower‐oil by partial‐hydrogenation. Activated carbon, which was obtained from viscum album L., was used as a new and effective original phase transfer catalyst during partial hydrogenation. Temperature, pressure, and catalyst/biodiesel ratios were selected as the experimental parameters and their effects on the oxidation stability were investigated by using the 23 factorial design. A first‐order model was obtained using analysis of variance. The physical properties such as density, viscosity, pour point, and cloud point of sunflower biodiesel samples were determined using the standard methods. The oxidative stability (induction period, IP) values were found experimentally by the Rancimat method and cis and trans‐configurations of the biodiesel samples were characterized by Fourier transform infrared (FTIR) spectra before and after hydrogenation. Partially hydrogenated biodiesels were found to have better oxidative stability, and lower pour point and cloud point properties compared to non‐hydrogenated sunflower biodiesel. It can be stated that kinematic viscosities and the densities of the partial hydrogenated biodiesels did not change significantly.