The Inexhaustible Teaching Potential of the Transesterification Reaction: The Kinetics of the Production of Biodiesel for Undergraduate Students

The replacement of conventional fuels with sustainable and renewable green fuels such as biodiesel to protect the environment is an important focus of today’s research and a strong area of interest among students. Here, we develop a research-oriented experiment in the context of renewable fuels aimed at introducing fundamental concepts in physical chemistry, organic chemistry, and analytical chemistry to undergraduate chemistry students. Specifically, the students first carry out the organic chemistry task of base-catalyzed transesterification of rapeseed oil to biodiesel. Second, they execute the analytical chemistry task of observing the time dependent, temperature-controlled increase of fatty acid methyl ester concentration using gas chromatography based on flame ionization detection (GC-FID). Finally, the students carry out the physical chemistry task of extracting kinetic properties from the data, including the concepts of rate constants, reaction order, activation energies, catalysts, and mathematical modeling. These data reveal the transesterification is either a pseudo first or second order reaction, where the kinetics change a few minutes after the start of the reaction. The activation energies of 51 kJ mol–1 (pseudo first order reaction) and 52 kJ mol–1 (second order reaction) determined here are similar to literature values for similar oils and similar catalysts. Here, we have developed an inquiry-based, research-oriented experiment emphasizing deductive reasoning, which arises in the context of renewable fuels aimed at undergraduate students.