Follow in Rudolf Diesel Footsteps: Introducing High School Students to Microwave-assisted Preparation of Biodiesel from Peanut Oil

Abstract

The term biodiesel, BD, denotes the fuel composed of mixture of fatty acid monoesters (usually methyl or ethyl) obtained by transesterification of oils and fats<i>.</i>We developed a three-stage project for twelfth grade high school students on microwave (MW)-assisted preparation of BD and its analysis. We used this project to introduce new concepts (catalysis; quantitative analysis) and techniques (use of MW in chemistry; product separation from mixtures), and promote contact of high school students with the university. The first stage, carried out in the school, involved literature survey on BD, and laboratory purification of BD samples that we prepared at the Institute of Chemistry of the University of São Paulo, Chem-USP. In the second-stage, the students visited Chem-USP, where we demonstrated MW-assisted transesterification of peanut oil, PNO. Then they participated in the following experimental activities: (i) analysis of PNO-based BD by gas chromatography; (ii) determination of the refractive indices and densities of the reactants (ethanol and PNO) and products (glycerol and BD) of the transesterification reaction; (iii) investigating the dependence of MW-heating of ethanol-isooctane mixtures on their ethanol content. The third stage was carried out at the school where the students presented/discussed their results, and evaluated the project. The experimental part of the project is simple, safe, low-cost, generates little waste, and can be carried out in a typical high school laboratory.