Educational benefits of green chemistry

1 Introduction

It may seem that green chemistry’s “ideal synthesis” is an unrealistic project, with high yields, no trace of pollution and cheap costs [1]. But, as difficult as it may sound, the demands to revert the direction of our current global environmental tendencies are great and it needs to start from the very core, the teaching of chemistry. Chemistry education is a sensitive task, especially when it comes to allowing students to have access to possibly dangerous chemicals. Therefore, we are confronted with providing highly specialized methods to handle dangerous substances and experiments or the possibility of offering an alternative that would involve a lower risk, but continue to enhance learning.

Changes to established chemistry laboratory curricula represent a challenge that many may not be willing to take. We consider that the operation of our General Chemistry Laboratories deserves close attention as we are convinced its magnitude has a significant environmental and social impact. The cost and level of handling the substances used in the experiments students perform during a semester is noteworthy, and we want to take this opportunity to demonstrate to the community that it is necessary and possible to use chemistry in a way that minimizes cost, is safer, and makes more sense.

We have decided to divide our analysis into three major areas:

1. Safety

2. Economic

3. Educational

As chemistry educators, it is our responsibility to constantly look for ways in which we can create a safer environment for our students and all the personnel involved in laboratory work to foster learning; however, it is important to quantify the impact of our efforts into making our laboratories “greener.” We need to keep in mind that the repercussions of laboratory preparations are not only associated with the laboratory itself but that one needs to plan carefully as starting materials may degrade overtime and safe storage of the reactive substances may not be practical. Aside from the preparation and storage, disposal of these materials or waste generated after a busy week of laboratory experiments may be difficult and expensive. With all these aspects, it is inevitable to provide alternatives that may allow us to more easily handle these tasks. A component that is normally ignored is the impact of these changes in the student’s perception of the chemical process they are learning about. When the experiment instructions do not warn students about the dangers associated with the handling of a certain substance, then students should have an easier time focusing on what is important, the chemistry.

We want students to be fully aware of any measures that keep them safe and represent a low-cost alternative, which means students would learn the chemical concept the experiment is designed to teach, but also the environmental impact of conducting the experiment a particular way.

In 1998, the twelve principles of green chemistry were published [2]. These are outlined in Table 1.

The conceptualization of these principles laid the framework for the development of desirable objectives for chemical reactions and processes. In the last 18 years, academic laboratories began to more seriously evaluate their laboratory curriculum with respect to these objectives. The overwhelming consensus was that while “perfectly” green laboratory courses would be difficult to achieve given the fact that many of the properties that make chemicals useful are the very same properties that make them hazardous (e.g. acid/base or redox properties), measures could be taken to become more “green.” Such measures could include: (a) choosing to use solvents and reagents that are less toxic and less flammable, (b) implementing “solvent-free” reactions and/or experiments, (c) considerable “scaling-down” of reaction volumes, and (d) minimizing the generation of hazardous waste.

2 Safety

People make safety-related decisions all the time, every day. While outside the laboratory environment these decisions might seem fairly trivial such as, “Will I wear my seatbelt to drive around the block?” “Will I floss my teeth every day?” “Will I wear a helmet when riding my bicycle?”, similar decisions associated with work in the laboratory can certainly have serious consequences.

Laboratory safety, while widely accepted as important, even critical to the laboratory environment, is not always in the forefront of people’s minds. Often, researchers and students alike become so focused on their experiments that they consciously or subconsciously choose to make safety-adverse decisions. The Lab Safety Institute has created a Memorial Wall which lists a brief historical chronology of laboratory incidents [3].

In recent years, laboratory safety incidents have become more fatal and gained increased attention in the media. Two well-known examples in academic environments are the fatal incident at UCLA in December 2008 and the explosion at Texas Tech in January 2010. In the former incident, safety training and protocols were neglected which resulted in the air ignition of tert-butyllithium. The laboratory employee, Sheri Sangji, received second- and third-degree burns across more than 40 % of her body. She died, in the hospital, two and half weeks after the incident [4]. Following a detailed investigation, this incident resulted in the first criminal case as a result of academic laboratory safety negligence. In the latter example, at Texas Tech, the graduate students involved chose to scale-up a reaction, without obtaining the approval of their research advisor. The unsafe chemical quantity in combination with the pressure and friction involved in grinding the chemical for use resulted in an explosion which left both students seriously injured [5].

The two examples mentioned are extreme cases. Serious, or even fatal, injuries do not occur every time laboratory personnel or students choose to ignore safety; however, these examples, along with countless others, allow us to begin to understand the value of laboratory safety.

The American Chemical Society has long produced important communications such as the “Safety in Chemistry Academic Laboratories,” “Guidelines for Chemical Safety in Academic Institutions,” and through its Green Chemistry Institute, “Greening the Lab” and “Less is Better.” These reports have progressively emphasized on the necessity to minimize safety risks. The Chemistry Department at the University of Illinois at Urbana-Champaign works closely with the Division of Research Safety (DRS) to guarantee state regulations are closely followed.

Twenty years ago, solvents such as benzene (a carcinogen), chloroform, and carbon tetrachloride were common in the organic laboratory. Today, they are largely replaced by safer chemicals. Some examples are provided in Table 2 [6]:

The volume of chemicals used and waste generated in the academic laboratory setting is generally neglected as a significant environmental threat, and even though it tends to be smaller than that of an industrial laboratory, it still represents a major task to handle it. For our General Chemistry Labs, we generate approximately 5,000 L of waste each semester.

Ultimately, “Green chemistry is the design and use of methods that eliminate health and environmental hazards in the manufacture and use of chemicals.” [2] In considering the twelve principles of Green Chemistry, we now provide some of our current efforts aligning with some of these principles:

3 Economic reasons

(All estimates on reagent purchasing are based on the Sigma-Aldrich catalog pricing without any discounts)

Safety improvements, especially those that require changes to infrastructure, cost money. It is also expensive to comply with all the personnel training, hazard assessments, workplace surveillance, medical evaluations, record keeping, etc. Certainly, large projects are costly, although in many cases they are necessary. In our chemistry department, we recently completed the renovation of one of our main buildings, the “Chemistry Annex.” The Chemistry Annex was originally built in 1930 [14] and reached a point when its operation was not sustainable, running it represented a significant waste of money and energy. With a budget of $24.9 million [15], the renovation completely remodelled the building, removed aged laboratory benches and equipment as well as improved the energy efficiency of the building. The laboratories are state-of-the-art facilities with modern laboratory tables. As an example, ventilated oval air stations which occupy a smaller space than a hood were designed for use in the introductory chemistry laboratories for more efficient trapping of fumes. The “Chemistry Annex” is on its way to receive the certification of “green building” by the Leadership in Energy and Environmental Design organization [16], and it is projected to represent significant savings for years to come.

Cost of operation and materials is probably the strongest motivator to implement changes to chemical processes and experiments even over safety and toxicity. From an industrial standpoint, The Toxic Substances Control Act (1976) regulates the 80,000 chemicals in industrial use, but does not require that manufacturers test the toxicity of chemicals before they are used in commerce [17]. This, therefore, results in much of the design, selection and use of chemicals in the United States to be driven by history, function, price, rather than safety and toxicity. The purchasing and/or preparation of complex and reactive chemicals for laboratory experiments are an important and constant responsibility in a university chemistry department.

In the next paragraphs, we want to elaborate on the financial aspect of some of the changes mentioned in the previous section. We consider this to be a great beginning to shaping our introductory chemistry laboratories to have a more significant “green” component than they have had up to this point.

4 Educational advantages

“DON’T CHANGE THE EDUCATIONAL GOALS. THESE NEED TO BE PRIORITY #1!”

Our general chemistry laboratories are intended to provide students from different backgrounds with the fundamentals of chemistry in a curiosity-stimulating environment. The academic laboratory is the perfect platform within which to begin to incorporate green techniques and principles. It is here that the student can learn these methods, incorporate them into their laboratory practices and then be better prepared when they enter the chemical workforce [19].

It seems to be the case for many students that, when they come to a chemistry class at the undergraduate level, they are intimidated by a variety of reasons: a poor high school chemistry experience, the lack of understanding of chemical formulas, the misconception that chemistry is dangerous or even the fear to comply with the demands of the course itself [20]. This state of uncertainty is the worst scenario to promote learning. Let’s face it, students tend to be almost predisposed to hate chemistry, but anecdotally they appear to be more attracted to learn to conduct chemistry experiments. This makes the chemistry laboratory a bridge that connects us to the students, even when they may have a hard time seeing the link with the theory.

As we have seen above, safety and cost are a major push to discontinue certain experiments and adopt new ones that use less toxic and/or expensive materials. As we serve a diverse pool of students, many of whom are not going to pursue a chemistry degree, the use of complex chemicals is probably a not very effective strategy to engage students and it is bound to leave many students even more confused. We consider that the use of common substances allows students to focus on the science and removes the stress. By eliminating toxic and expensive substances and changing to more benign alternatives, we enhance the education of our students, not only with a strong chemistry foundation but also on the impact of chemistry in everyday society.

In 2012, a C&EN News article [21] noted that the implementation of the “Green Chemistry Commitment” gave “Green Chemistry” a prescriptive facet that it was not intended to have. Although we now know the “Green Chemistry Commitment” exists to provide resources and a community that works together to push for faster progress in the field, we must not get lost in semantics and get to work one experiment at a time. However, it is no surprise that the problem with sustainability and deterioration of our environment is not only a matter of discussion for chemists and physical scientists. The situation is so serious that in recent years the term “Green Chemistry” has transcended the chemistry realm and has become a topic in educational and social panels worldwide [22].

We want to take a very pragmatic position about what the changes to our curricula and laboratory experiments involve and how they can make a significant difference for our students’ learning process. For example, in teaching acid–base chemistry, the notion that acids are dangerous may distract students from focusing on the important aspects of acid–base chemistry. We believe that by using Kool-Aid we allow students to think more easily about the chemistry. Using Kool-Aid instead of other acid solutions provides multiple advantages. Probably, all students have consumed Kool-Aid. They are not afraid of it, they know it won’t hurt them, but curiously there are many aspects of it that they have no idea about. In fact, the discovery of the “secrets” of Kool-Aid sparks an amazing desire to discover more about the substance and maybe other household substances.

These changes put the students in control to start making important decisions to create judgements about chemistry, which is what we ultimately would want them to do. This may even inspire students to pursue a degree in chemistry. Once they are confident about the fundamentals, they will be able to tackle more complex systems.

As mentioned in the previous section, we use LON-CAPA to manage our laboratory courses. We would like to take this approach to the next level and rely more heavily on assessment through this online tool. How do we assess the laboraotry? Depending on the educational goal of the laboratory, we need to evaluate our assessment. For some laboratories, learning how to write a laboratory report or learning how to write journal-style papers is important. However, grading these assessments is very time consuming and the rigor in grading depends on the TA. The chemistry major’s series of introductory laboratories are the only ones in which students need to write one part of a report for each laboratory; they learn how to make a full report at the end, but save time/writing along the way.

Students who are not in a chemistry track may or may not benefit from a rigorous report-writing curriculum. If we are to only use LON-CAPA to provide assignments and expect students to obtain the foundation that will tell us they are prepared and our academic goals have been met, then the material that they receive must be of the highest quality, which becomes challenging at times if we have to circumvent a technological problem.

A valid question centers around the validity of the online assignment method using LON-CAPA and how bulletproof is it with respect to academic dishonesty. To reduce or even eliminate the potential for academic dishonesty with the online data submission during the course of a laboraotry, we have been able to create a dedicated online network that prevents students from signing into the laboratory assignment while the laboratory experiment is taking place from areas physically remote from the laboratory room. This virtually eliminates the need for any paper evidence of the student’s work. We realize that, however, this is still contingent upon the particular instructor’s preferences, although we plan to evaluate the possibility of making it a general policy as it aligns us with a less wasteful laboraotry culture.

Last, we have, over the last few years, identified some weak points in the conduction of general chemistry laboratory courses. Some of the most critical points are:

1. Students not complying with safety rules

2. Not completing data submission during laboraotry resulting in inability to do the postlab

3. Reliability on TAs to help to apply safety rules and be knowledgeable about the upcoming experiment.

During 2016, a series of measures implemented by the Laboratory Coordination team with the use of our online tools has seen a great improvement in all respects. Regular communication via LON-CAPA, providing audio-visuals that describe clearly what the students need to do to comply with the regulations has made a big difference and has substantially reduced the number of students that do not want to adhere to the protocol. This makes it much easier to identify the students that may need to be asked to leave the laboraotry to correct their fault. Also, a rigorous TA training programme, similar to others found in the literature [23], responds to the necessity to have reliable TAs. As of 2016, we have had TA training sessions and TA meetings for each experiment which helps tremendously with the problem of students getting the wrong advice. When TAs know the details of the experiment, they are motivated and their interaction with the students is much more fruitful. Additionally, TAs encourage and evaluate if students have left their stations clean, to prevent any safety problem with the next group and in return students could collect a minimum amount of points which they receive gladly. This system has also been extremely successful and has made a great difference in the condition in which the laboratory is found at all times. The problem of not completing data submission has been basically eliminated as our students are now required to stay the complete laboratory period regardless of them finishing data submission. They are then required to continue on with the postlab assignment, which is due a week later. This way students do not lose points unnecessarily rushing out of the laboratory. All these changes have been facilitated by the use of LON-CAPA, and we plan to create more tools that allow us to maintain a consistent pace to offer students a rich variety of chemistry experiments with an emphasis on safety and sustainability.

We are sure that as these changes are yielding excellent results internally for our purpose of conducting the laboratory, they will also be shaping the way students carry themselves in their future challenges.

5 Conclusions and future work

In conclusion, we present here a group of basic but steady changes that we deem necessary to be able to teach students the chemistry fundamentals that will prepare them for their chosen disciplines. Also we are beginning to make a clear note of the environmental benefits of conducting various laboratories with environmentally benign alternatives and saving materials that will also teach students the importance of sustainability. We plan to offer more experiments with Green Chemistry alternatives by scaling down where appropriate and trying to implement solvent-less experiments, e. g. caffeine extraction with supercritical CO₂. We are currently creating assessment tools that will allows us to compile the data necessary to measure the impact of all these implementations and create a more informed and scientific description of our success.