Synthesis of alkyl esters from three unconventional Sudanese oils for their use as biodiesel

Abstract

Biodiesel is a renewable, biodegradable, and nontoxic fuel that can be derived from vegetable oils by transesterification. In this study, Sclerocarya birrea oil (SCO), melon bug oil (MBO), and sorghum bug oil (SBO), three long-term stable oils from Sudan, were transesterified using methanol or ethanol in the presence of sulfuric acid; the obtained biodiesel characteristics were studied in accordance with the DIN EN 14214 specifications for biodiesel. Most of the biodiesel characteristics met the DIN specifications (water content, iodine number, phosphorus content). The kinematic viscosity values of all samples were higher than those of biodiesel standard limits. Concerning the oxidative stability, only SCO has an induction period higher than the required limit. It was possible to prepare the methyl and ethyl esters catalyzed by H2SO4 from the three unconventional Sudanese oils. Under the described transesterification conditions, SCO seems more suitable for biodiesel than MBO and SBO. © 2006 American Chemical Society.