Parts-Per-Million (Salen)Fe(III) Homogeneous Catalysts for the Production of Biodiesel from Waste Cooking Oils

Abstract This work describes the application of a library iron(III)-salen catalysts in production biodiesel from vegetable oils. The conversion neutral soybean oil is complete within two hours at 160–180 °C with low catalyst loading (0.10 mol%). A comparative screening reveals that containing acetate as fifth ligand are most performing, and these have been conveniently used to convert acidic waste cooking oils (WCO). WCOs were received without further purification produce high yield (85–90%) under optimized conditions (2 h 180 °C, 0.1 mol%, alcohol molar ratio 1:20). iron content lipophilic hydrophilic phases crude mixture was investigated residual concentration found be order 10–14 ppm, comparable contained biodiesels other sources. Graphical