Biodiesel Promotes Iron-Catalyzed Oxidation of Engine Lubricating Oil

The growing trend of increasing biodiesel concentrationsin dieselfuel blends has led to concerns about its effect on the oxidationof formulated oils within internal combustion engines. We observethat biodiesel is not only susceptible to rapid oxidation at elevatedtemperatures but is also responsible for acceleration of the oxidationprocess of the lubricant base oil when in the presence of solubleiron; this is supported by a range of control and model experiments.A mixture of oxidized biodiesel and Fe(III) leads to the formationof catalytic iron carboxylate networks that remain solubilized, asobserved by UV-Vis and infrared absorption studies. These observationsare important for the fundamental understanding of the chemistry withinindustry standard laboratory bench tests for lubricant oil formulationsand can aid the design of new lubricants with improved biodiesel compatibility.Such lubricants have the potential for a reduced carbon footprintvia waste reduction.

Automated summary

The increasing biodiesel concentrations in diesel fuel blends have raised concerns about their impact on formulated oil oxidation within internal combustion engines. It has been observed that biodiesel not only undergoes rapid oxidation at elevated temperatures but also accelerates the oxidation process of lubricant base oil in the presence of soluble iron. This observation is important for understanding the chemistry in laboratory tests for lubricant oil formulations and can contribute to the design of new lubricants with improved biodiesel compatibility, potentially reducing carbon footprint through waste reduction.