Volume 4, Issue 2 - Green Chemistry

Green chemistry became an eminent trend in chemical research and industry since the 1990s, and thus green chemistry is also increasingly suggested to become an issue in chemistry education. One of the principles of green chemistry is to use effective catalysis in general, and enzymatic catalysis under mild conditions in particular. This article presents a set of experiments under catalysis by immobilized lipase that were developed and tested in an action research project for developing a green organic chemistry curriculum for the senior secondary schooling level in Germany.

We have highlighted an example of a natural process like photosynthesis to introduce the subject of Green Chemistry. Photosynthesis can be an ideal example to illustrate a green process explaining all the features such as selection of raw materials, solvent, catalyst, energy, etc. for an environment-friendly reaction. From the same reaction, all the principles of Green Chemistry can be derived in a simpler way without the need of memorizing these in a set language. In this article, a few examples of green procedures for the synthesis of useful molecules have been illustrated in light of the knowledge of photosynthesis. The visible-light mediated reactions, organic reactions in water, and solvent-free organic reactions are discussed here for a practical illustration of Green synthesis.

Currently, the world is facing climate change, environmental burden, and health aspects caused, among others, by chemical substances spread by humans. In order to preserve or even improve the Earth’s habitat for future generations, the development and use of sustainable technologies are necessary. Additionally, every individual must have knowledge and skills to be able to act in an informed sustainable and responsible way. Neither of these can be achieved without science education that provides appropriate learning opportunities. This paper gives insight into the project SpottingScience whose digital learning environments focus on green chemistry. The learning environments are accessible via QR-Codes in public space at the Campus of the University of Vienna. One can follow the content presented via texts and graphics in a linear way or use provided links to get further information. SpottingScience offers the opportunity for passers-by and secondary school students to get a general idea of green chemistry and its significance for everyday life. We use menthol, a well-known ingredient in several everyday products, as an example to unfold chemical backgrounds, to highlight the necessity to create new and environment-friendly production processes, and to provide an impetus to reflect on one’s own actions while using everyday products.

Teaching experiments involving edible, biodegradable calcium alginate beads serve as an attractive model system to introduce upper secondary age students to core chemistry topics through innovations in sustainable consumer products. A teaching experiment is described that engages students with the synthesis of calcium alginate hydrogel beads from sodium alginate and calcium lactate, two food-safe and renewable materials. The beads’ outer membranes are a result of ionic interactions between carboxylate groups from alginate strands and the divalent calcium cations between them, thus forming cross-linked polymers. Protonation of the carboxylate groups on the alginate strands decreases crosslinking density affecting bead formation. First, various concentrations of citric acid are used to lower the pH of the sodium alginate solution and the effect on the calcium alginate bead formation is observed. A correlation between pH and bead shape and firmness is derived. This information is then used to explore juices with varying natural acidities. The experiment is amenable to implementation in the classroom or as an at-home activity. Learning outcomes include acid-base reactions, chemical bonding, polymer structures, and green chemistry concepts. Students consider the environmental challenges of traditional plastics used in packaging and how innovative new commercial products are attempting to provide solutions.

Microwave systems have been used in organic chemistry since the late 1990s for applications including Microwave-Assisted Organic Synthesis (MAOS). The main advantages of microwave-assisted procedures compared to traditional synthesis methods are the 100- to 1000-fold increase in reaction speeds, higher yields, purer products, and less energy consumption. So far, only a few examples for integrating microwave-induced chemistry into high school chemistry classes have been proposed. This paper presents a set of experiments intended to provide insights into using microwave technology in the context of green, organic chemistry lessons in high school.

Recently, the importance of sustainable environment has been engaged in many science practices and learning. This article intends to provide teachers in secondary school and research beginners with knowledge background on conducting polymers (CPs) for its application in environmental protection studies. A concise and straightforward discussion on the basic concept of CPs and its role as i) sensors for gas pollutants ii) photocatalyst are explained. A general workflow to guide readers in identifying and validating suitable sensors is included. In addition, the article provides a step-by-step guideline to assist readers in performing photocatalytic degradation experiments associated with CPs.

As a result of social distancing measures in response to the Covid-Sars 2 pandemic, our school sent chemistry kits to the students’ homes for remote experimentation. This allowed the performance of ∼25 experiments per person in each of the Fall 2020 and Spring 2021 semesters in an elective chemistry course. Students were requested to design some experiments of their own and then have the entire group reproduce them. One such experiment consisted of the anodic indirect electrogeneration of colloidal sulfur by solution acidification to produce thiosulfate disproportionation. This was evidenced by the well-known Rayleigh scattering phenomenon. Here, the trajectory and polarization state of light are modified by its interaction with a medium containing particles of smaller diameter than the wavelengths of incident light. If white light interacts with this medium, the smaller wavelengths (e.g., blue, violet) are radially scattered while the longer wavelengths (e.g., orange, red) pass through the suspension. Such scattering is responsible for beautiful sunsets and blue skies and is produced here by an indirect electrochemical process that generates colloidal sulfur. Students evidence the scattering of light shone from simple cell phone flashlights. The entire procedure is performed in a 2-h class session. Key student outcomes are presented.

This study first developed content for a series of textbooks on green and sustainable chemistry (hereinafter referred to as GSC) targeted for university use. The textbooks focus on technology and products that have been awarded prizes in recognition of their contribution and performance toward GSC promotion. We also supplemented the textbooks with a video teaching material on dyeing systems that do not use water. We then surveyed aspiring secondary school teachers about the developed teaching materials using the questionnaire method. The results from university students’ questionnaires showed that 82% understood the importance of GSC and were interested in the subject. Second, we developed a series of leaflets on GSC targeted for use in upper secondary schools. Specifically, the content emphasizes the relationship between high school chemistry textbooks and daily life, other subjects, society, and the global environment. The results showed that approximately 60% of the senior high school students’ first impression of the leaflet was “interesting.” Twenty years after GSC has been defined, it has still not become completely pervasive in Japan. In the future, it will be necessary to foster instructors capable of teaching GSC in secondary education.