Problem-Based Learning Approach to Review the Principles of Green Chemistry Applied to a Polycondensation Reaction
Authors:   Laboratorio de Fisicoquímica Macromolecular, Posgrado Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, México., Salgado-Chavarría David , Palacios-Alquisira Joaquín ,   Laboratorio de Fisicoquímica Macromolecular, Posgrado Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, México.
Published: June 2021

Science Education International ¦ Volume 32 ¦ Issue 2 107 ORIGINAL ARTICLE INTRODUCTION The problem-based learning (PBL) methodology is a student-centered approach that is related to the learning process that occurs when students deal with real world problems, while working in teams to find and develop a solution, with teachers/instructors acting as facilitators (Nagarajan and Overton, 2019). Some elements seem to be common to PBL: Learning is student centered (as mentioned before), problems are structured and authentic, teachers act as advisors, and students work in small groups (Cowden and Santiago, 2016). Although, the elements are in constant interaction, students are responsible of their learning, implying that they have the main role in the cognitive process and should work actively, in group, to solve a problem. On the other hand, instructors act as coaches, they incite group discussion, and they are in charge of monitoring the process. Students are the main characters, since PBL methodology emerged from constructivist learning theories and it was developed as an alternative to conventional teaching (Loyens et al., 2006). Constructivism suggests that humans build knowledge from their experiences and, contrary to traditional education, where students receive knowledge like empty vessels to be filled, in constructivist, students are encouraged to confront what they know (Bada and Olusegun, 2015). It is evident that, long-term memorability is enhanced by PBL, because it fosters the utilization of previous knowledge to solve a new problem and demands students to put in practice what they have already been taught, therefore, facilitating the comprehension of the concepts (Schmidt et al., 2011). Other benefits that come along with PBL include the improvement of student’s creative thinking, self-regulated skills, and self-evaluation (Jansson et al., 2015; Yoon et al., 2014). Therefore, to improve chemistry student’s learning experience, the PBL approach can be used for a better comprehension of the importance of Green Chemistry. According to the U.S. Environmental Protection Agency (EPA, 1990), Green Chemistry is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances; this designing process can be assisted by the Twelve Principles of Green Chemistry (Lancaster, 2002). The principles are qualitative, and their aim is to minimize the impact of chemical activities on human health and environment without compromising the chemical process (Ribeiro and Machado, 2013). There is a commitment to green chemistry education (Armstrong et al., 2018), and efforts have been made to implement it, at the undergraduate level (Timmer et al., 2018; Kennedy, 2016; Manchanayakage, 2013), but there is an uneven development of green chemistry curricular materials, since there have been few comprehensive reforms for general chemistry lecture or laboratory curricula (Armstrong et al., 2019). For example, Green Chemistry has not been covered extensively by chemistry A problem-based learning (PBL) methodology was implemented to a project, whose main objectives were to discuss and apply the Twelve Principles of Green Chemistry to the study of poly(vinyl alcohol)’s cross-linking reaction with dicarboxylic acids. The five participating students were oriented to be responsible for their own learning and the professor participated as an advisor. The problem was proposed and students planned all their activities to accomplish the objectives and goals, reviewed recent information in scientific literature and summarized it, made experimental work, prepared written reports, and were evaluated in seminars. The results obtained by the students were assessed through the generation of a final report and also with a final oral presentation in front of faculty members. The experience lived by the collaborative workgroup during the development and execution of the project, is described. This research is an example of how the PBL methodology can motivate the active participation of students when solving problems. The next step is to introduce this tool to teachers and students of other undergraduate courses or laboratories, since it causes a difference in the way education is being perceived in our university, because it emphasizes the application and understanding of concepts over simple memorization.