Teaching the Undergraduate Laboratory During Pandemic Time: Using the Synthesis of a Biodiesel Model to Demonstrate Aspects of Green Chemistry

• Nicolas Keppeler ^[1] ; Luzia P. Novaki ^[1] ; Omar A. El Seoud ^[1]
  1. [1] Universidade de São Paulo

     Universidade de São Paulo

     Brasil

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 98, Nº 12, 2021, págs. 3962-3967
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • We report on a distance learning experimental project for chemistry-major students on the synthesis of ethyl dodecanoate (C11CO2Et), a model for biodiesel, considering green chemistry principles. Thus, we employed a recyclable acid catalyst (an ionic liquid) and used chemometrics and microwave heating (MW) to maximize reaction yield and reduce energy consumption. Acid-catalyzed esterification is an equilibrium that can be shifted to products by controlling reaction conditions. Of these, the students selected reaction time (t) and the molar ratio (ethanol/dodecanoic acid; χEtOH/C11CO2H); these were varied using the design of experiment (DOE) statistical method. We demonstrated that the C11CO2Et yield depends more on t than on χEtOH/C11CO2H. Relative to convection heating, the use of MW resulted in a better ester yield and less power consumption. To enhance the participation of the students, we stopped the video presentation of the experiment and asked them how to proceed to the next step (e.g., product separation; catalyst recycling). The students gave group seminars on themes related to green chemistry (nonconventional energy sources, recycling, etc.). This project introduces green chemistry principles in the undergraduate laboratory, while being safe and low-cost, and generates very little waste.