Student Lab Series: Synthesis of Biodiesel from Coffee Beans
Mentor:Michael Page, Assistant Professor of Chemistry, California State Polytechnic University, Pomona
During the last two decades scientists and policy makers alike have been working together to define complex issues of sustainability including, but not limited to: water purity, climate change, renewable energy, and material synthesis just to name a few. The transesterification of triglycerides has been widely reported starting from commercial and waste vegetable oils. However the extraction of triglycerides from coffee grounds (10% w/w) that are traditionally disposed of could provide an economic upside from the alternative fuel industry. Biodiesel serves as a broad teaching platform to link the skills and concepts learned in the organic, physical, and analytical chemistry courses to a real industrial application. In addition to the synthesis, this series of labs will also reinforce important thermodynamic concepts such as heat value, vapor pressure, enthalpy, entropy, and Gibbs free energy while also providing relevant experience in the quality control testing aspect of the fuel industry. This is a unique opportunity to provide educationally relevant experience to undergraduate students enrolled in organic laboratory courses. Starting from used coffee grounds collected from an on-campus vendor, a novel lab series will be presented that challenges students to extract, collect, and neutralize triglycerides. The oil can then be transesterified, purified, and characterized by FT-IR, combustion analysis, and NMR spectroscopy to indicate the presence of a Fatty Acid Methyl Ester (FAME). The methyl ester is readily identified by a sharp resonance peak at 1738.9 cm-1 and 1170.8 cm-1 (FT-IR), 3.640 ppm (1H NMR), and 51.401 ppm (13C NMR). This lab series is currently being implemented to elicit if the use of biodiesel as a teaching platform will provide a greater understanding of spectroscopy and the overall learning goals of organic chemistry lab courses. By incorporating green methodologies in university curriculum students will be better prepared to integrate sustainability into future innovations.