Article pubs.acs.org/jchemeduc
Implementing a Student-Designed Green Chemistry Laboratory Project in Organic Chemistry Kate J. Graham,* T. Nicholas Jones, Chris P. Schaller, and Edward J. McIntee Department of Chemistry, College of Saint Benedict and Saint John’s University, Saint Joseph, Minnesota 56374, United States S Supporting Information *
ABSTRACT: A multiweek organic chemistry laboratory project is described that emphasizes sustainable practices in experimental design. An emphasis on student-driven development of the project is meant to mirror the independent nature of research. Students propose environmentally friendly modifications of several reactions. With instructor feedback, students search for a literature protocol for their most promising reaction. Students follow the procedure as described and also carry out a modified, greener reaction that they have designed on their own, incorporating a modest change in reaction conditions. The exercise concludes with a report focusing on comparative data analysis. This unique approach also focuses on teaching students the important research skills involved in locating, reproducing, and modifying a literature procedure. KEYWORDS: Second-Year Undergraduate, Organic Chemistry, Laboratory Instruction, Problem Solving/Decision Making, Green Chemistry, Reactions
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INTRODUCTION Green chemistry has become an important theme in the undergraduate organic curriculum. Teaching students to take green concerns into consideration when planning a chemistry project may increase awareness about global issues and can instill a sense of responsibility to the environment, which is particularly important for future chemists. An editorial by John Moore1 made a strong argument that green-trained graduates are better able to carry out their duties as industrial, government, or academic scientists. For these reasons, there are an increasing number of publications describing new courses, activities, and laboratory experiments.2−9 In a typical “green” organic laboratory experiment, an instructor presents students with a reaction that has been developed to incorporate one or several green principles.2−11 Students are expected to read the description of how the reaction has been improved and then perform the reaction described. An additional exercise is often added to help develop an appreciation for the impact of waste production, toxicity, and atom economy. In these types of experiments, the benefits for the environment are clearly still applicable, yet creative input and troubleshooting on the part of the students is often limited. In order to make the connection between a laboratory experiment and the research endeavor more concrete, an approach was developed that gives students more control over their experiments. Faculty-designed expository experiments often require little thought from students and induce little learning.12 In contrast, peer-developed laboratories increase student engagement.13 Project laboratories can mimic a research endeavor and thus force students to think about procedure and outcome.14 In addition, laboratories in which students are working on a variety of experiments reduce both copying and reliance on a partner. Before implementation, a © XXXX American Chemical Society and Division of Chemical Education, Inc.
department must be willing to coach students to produce a reasonable plan and then accept that student-designed projects often have lower success rates than an instructor-tested experiment.
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DISCUSSION An inquiry-based, green project was developed that can be used in an organic chemistry lab.15 Previous success with projectbased laboratories in organic chemistry16,17 laid the foundation for the implementation of a straightforward student-driven project wherein students choose their own target reactions, plan their own “green” modification, and troubleshoot when a reaction is unsuccessful. The green project was implemented in a second semester sophomore organic chemistry laboratory with 16−18 students. This green project involves two steps. Pairs of students choose their own target reaction from journal articles and run the reaction according to literature protocol; this “non-green” reaction serves as a control. Students must also carry out the same reaction with a “green” modification of their own design. Typical modifications may include a change in solvent, omission of solvent, addition of a catalyst, or safer reagents (see Supporting Information). Thus, it is not possible to provide experiment detail as each student develops a unique project based on the literature protocol retrieved. The fundamental construct for this project is that students are working toward becoming independent researchers. Any faculty considering implementation of this project lab should be prepared to coach students through a new experimental procedure that has not been optimized at their institution. As students typically run the literature procedure and the modification one time each, there is usually not sufficient data
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to determine whether the “greener” version is significantly improved. In an advanced lab or a research project, one might expect students to consider more than one green dimension or optimize reaction conditions, but there is not sufficient time allotted for extensive methodology studies. In effect, the students are merely taking the first step in the direction of greening the reaction. Since students work in pairs, they obtain two sets of data for the control reaction and two trials of the modification attempted. Duplication increases the reliability of their results and success rates. This project is similar to others that require students to perform literature searches in order to obtain experimental procedures. However, students must modify this reaction, analyze the product mixtures, and make a comparison between the two reaction conditions. Green Project Design Figure 1. Iterative planning process for student design of green chemistry project.
The pedagogic goal of this project was to increase student engagement in the design of experiments and analysis of the outcome. Students who are encouraged to apply their knowledge in a variety of ways are more likely to retain their understanding.18 This project was designed with the following learning goals: • • • • • • •
safety risks, and which use available starting materials and reagents (see Supporting Information). Students learn the application of green principles within the iterative planning framework for this project. Early in the semester, students are introduced to the principles of green chemistry through reading assignments (see Supporting Information).4−6 Students then identify reactions that they might attempt to make more environmentally benign using guidelines, restrictions, resources, and a list of suggested types of changes (see Supporting Information). Each student must submit a set of four different proposals for a green project. Students look in their textbooks or one of the possible resources for reaction types, and use the list of possible modifications for their initial attempts. At this stage, each proposal is just an equation for a reaction, with a description of the modification to be made. For full credit on the planning process, the proposals must be substantially different reactions with different changes. Students next confer with their instructor to determine whether each reaction and the proposed modification exemplify green design, have a chance of working, do not pose undue safety risks, and are feasible given available starting materials, acceptable reaction conditions, and reagents. A typical student has at least one possible project. Students are matched with a partner and plan for the two possible projects they have generated. Working in a team gives students a sense of greater security when designing an experiment and provides an extra layer of deliberation. Planning for two projects allows an additional safeguard in case the plans do not pass inspection by the instructor in the next phase. Because each project involves a different set of reactions, the students must find two synthetic protocols from the literature and adapt these procedures for their own experiments. The use of library searching tools builds on a brief introduction in a prior semester to the use of keyword and structure searching in SciFinder.19 Some excellent examples of introducing literature skills have been published.20,21 One student is typically instructed to perform a SciFinder search, and the other is assigned a second reference, such as Organic Syntheses or Larock.22,23 With an instructor available to assist, students must find the citation and download the original research article and then show the instructor where the procedure is described in the paper. During the subsequent
Understand green chemistry parameters Know how to modify a reaction Practice independent planning Increase data analysis skills (product mixture) Improve communication skills Prepare for research and employment Apply knowledge in a new situation
In a truly independent research project, the planning stage takes on great importance. This green laboratory project places a great deal of emphasis on the design phase, and student teams must work interactively with the instructor. Projects of this type help students make the transition from being a laboratory student to being a researcher. Green Project Timeline and Execution
A brief outline of the timeline for the planning and execution of this project is shown in Table 1. The planning stages of the green project run concurrently with regular lab experiments. This planning process is done iteratively (Figure 1) until students have a reaction and a starting literature procedure as well as a greening method, neither of which pose significant Table 1. Timeline of Student Design of Green Chemistry Project Schedule Weeks 1−5 Week 6 Week 7
Week 8 Week 9 Weeks 10−11
Task Students read about principles of green chemistry Each student proposes four possible reactions to green Literature searching quiz Students are partnered Students pick two reactions to further investigate based on feedback Students find literature protocols Students submit material list to stockroom Students revise project plans based on feedback and material availability Student/faculty planning meeting Turn in final materials list (for stockroom prep) Perform projects B
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An emphasis on process and problem-solving is valued because of its obvious connection to the research experience. Some faculty instructors are less comfortable than others with the ambiguity inherent in these types of projects.
week, students begin their search for potential reactions using SciFinder, Organic Syntheses, or Larock. At present, students do not search for literature precedent for their proposed modification. Since their proposed project might not have been carried out at the institution before, the students must also determine whether the starting materials are available. For this reason, the students submit a list of needed chemicals and glassware to the stockroom to check for availability. In a third round of revision, students focus on their most promising prospect, providing a final copy of synthetic protocols and materials list. Most students require a third revision before arriving at a project that has a reasonable chance of success. In our experience, additional cycles of revision do not result in increased levels of preparation and students begin to feel burned out if asked to revise four or five times. A final meeting with students before the start of the projects has proven beneficial in bolstering student preparedness. A number of issues are highlighted of which students may not have thought, such as the use of unusual equipment or the need to purify materials before proceeding. In addition, students must locate MSDS information on each of the chemicals involved and summarize the safety information in a table. This step facilitates a discussion of safety concerns. Students must also have an appropriate plan for waste management. Several bulk waste bottles are available for flammable liquids, oxidizing agents, reducing agents, and heavy metals; in some cases, students collect their own waste in a small bottle for manifesting and shipping. The two planning meetings are approximately 15 min per group. Stockroom staff ensure that all supplies are prepared and available at the start of lab. Students are given two lab periods to complete these reactions. Depending on the timing of a reaction, a student may attend another laboratory section to work up their reaction after consulting with the instructor. All students are required to run their own green and nongreen experiments, to encourage individual participation as well as to provide a duplicate set of data for reliability. Each student is graded separately on his or her own set of data, including quality of raw data and individual data analysis. For the final report, student teams select their best set of data and turn in a report in the style of an article from The Journal of Organic Chemistry.
Coaching Students
Typically, after leading multiple sections through project-based laboratory experiments, instructors learn to coach students to avoid the typical pitfalls. For example, one common mistake that students propose is running the reaction in aqueous media when an aprotic solvent should be used. Another type of mistake involves volatility, such as exchanging a long-chain ketone for an available short-chain ketone that will evaporate under the proposed reaction conditions. A third common problem is that students will propose the change of a liquid base such as pyridine with histidine (solid) and no reaction occurs in the absence of solvent. Instructors also become accustomed to the diversity of simultaneous activities in the lab; they employ several different organizational strategies to do so. During the projects, some instructors require students to draw the reaction that they are performing on the hood sash. Some instructors maintain a file of the students’ literature procedures for their own review; others institute required check-ins between lab periods. Stockroom Support
Adequate staffing of the stockroom is needed for rapid turnaround on these information requests as well as preparing materials for a range of projects. Providing students with a searchable list of stockroom inventory can also alleviate some pressure on stockroom staff. While the ideal situation would allow students to perform any reasonable transformation proposed, most departments will find that they must limit excessive purchasing of new chemicals for this project. For this reason, students are typically limited to currently available or regularly used chemicals in the chemistry department. Alternatively, students can adapt a protocol to work with available starting materials. Expectations
In an iteration of this project, students were given 3 weeks to complete the project. The reason for this extended time was to allow students to ensure that they were able to reproduce the results of the control reaction before they attempted the green variation. Thus, students had an extra week for troubleshooting and making adjustments to attempt to get reliable data. However, this added time did not substantially improve reports or learning outcomes. When considering implementation, laboratory instructors might consider the time invested in this project and the expected level of success before deciding on the allotted time to perform these reactions.
Lessons Learned
This project could be implemented in a variety of ways at different institutions. One might anticipate that different restrictions on chemicals, time allotment, planning stages, or analysis might vary depending on the facilities, stockroom staffing, available chemicals, or demands of the institution’s curriculum. For example, the key principles of green chemistry through prereading assignments and the planning process were used here, whereas another department might opt to present topics explicitly in a class, such as atom economy, pollution prevention, or renewable feedstocks.
Project Design and Implementation
In many cases, the successful reaction was the nongreen one. However, in the past two years, when a reorganization involving other experiments left only two lab periods to perform the green project, students were no longer required to obtain a successful nongreen result before proceeding with the green variation. In fact, most teams now decide to have one partner start with the green reaction while the other performs the nongreen reaction, so that they can do troubleshooting on both reactions. Other teams feel more secure working in tandem. In a small number of cases, the green variation actually turns out to be more successful than the original procedure, at least in the hands of these students.
Expectations
The key aspect that must be considered before implementing these projects is the expectation of success. Instructors do not develop and troubleshoot these experiments, so success is not guaranteed. In fact, students may find procedures that work on related compounds, but not in their specific case. As a result, students are forced to problem-solve independently when reactions do not work or when a mixture of products results. C
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help, for any of the questions. In fact, student responses for all 8 areas are quite positive. Students reported excellent progress in two areas: their gains in planning and conducting a literature search, as well as their ability to apply knowledge to new situations. In both of these categories, the most positive ratings (much help or great help) outweighed more modest ratings (moderate help or little help) by more than four to one. Both of these learning goals represented key components of the overall pedagogic goal of being able to design their own experiments and analyze the results. Students also reported good progress in four other areas: their understanding of green chemistry, their ability to follow a literature procedure, their ability to design an experiment, and their ability to perform data analysis. In these categories, the most positive ratings outweighed the more modest ratings by more than two to one. Thus, most students felt that they had met the major goals of the experiment. In the two remaining areas, students reported only fair progress: report writing skills and confidence in conducting research. In those categories, the ratio of the more positive ratings to the more modest ratings was only a little higher than one to one. These shortfalls may have arisen for simple reasons. Report writing was incorporated into the overall course as part of a broader effort to develop writing throughout the laboratory curriculum. However, it was not given major instructional emphasis in the green project because different aspects of writing had already been introduced in earlier experiments. The modest gains in research confidence were understandable given the students’ level of experience. Although the ultimate goal of this experiment was to make students research- and workplace-ready, it should be kept in mind that the students were mostly second-year undergraduate (and some were only first-year). The students’ assessment of their research confidence likely reflected a feeling of frustration with the open-ended nature of the project and their inexperience with nonoptimized reactions. It may be that encountering difficulty on their first foray into an independent experiment caused many students to feel that the green project was only moderately helpful in preparing them for research. Faculty evaluation is the second aspect of the assessment of student success on this project. Multiple instructors compiled grade data on different components of the project using a common rubric. Student teams were given a grade based on their level of success; students were unaware of these grades when they filled out the self-assessment survey. Typically, instructors gave teams 3 of 5 if one experiment worked and 5 of 5 if both the original and green experiment were successful. Intermediate grades could reflect cases in which one student was successful but the other was not, or in which an experiment was otherwise judged to be only partially successful. Partially successful cases included those in which product mixtures contained substantial amounts of starting material or solvent or spectra that indicated significant decomposition or side reactions. Mean success score over 56 reports sampled from the past few years was 2.6 (Table 2), indicating that the average student obtained a clean set of data for one successful reaction. However, the large standard deviation in this number (1.7, Table 2) reveals a broad distribution in the data, with significant numbers of students reaching either very high or very low levels of success. Additional data from instructor-assigned grades showed narrower distributions, with standard deviations closer to 1
While some students pick challenging and exciting projects, other students propose relatively minor changes, such as a solvent change from one type of ether to another (for example, from tetrahydrofuran to methyltetrahydrofuran, which is less likely to contaminate groundwater). The lab manual has a list of potential changes (see Supporting Information) that many students use as a springboard for ideas. Since adapting literature procedures can be tricky and modifying anything from a literature procedure may require several tries to get it right, it seems appropriate that second-year undergraduate students might not tackle large changes for a 2−3 week project. The grading rubric (see Supporting Information) allots a small number of points to the difficulty level of the project. Faculty considering adopting this project might consider how much to incentivize ambitious and creative projects depending on the expected level of success and the type of students enrolled in the class. Grading Approach
With the shift in emphasis to planning and troubleshooting to mimic a research project, a student’s project grade took on a different character than a typical laboratory experiment: (1) due to the intensive design and planning aspects of this project, a significant part was given to the quality of student effort in the experimental design, including a demonstration of having investigated primary and secondary literature sources (40%); (2) whether sufficient spectral data had been obtained to analyze products (40%); (3) because these projects sometimes did not work, credit was given for providing evidence of the actual product formed and evaluating success or lack thereof (10%); (4) some credit was also given to reward effective teamwork (10%).
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ASSESSMENT An assessment plan was implemented that included both faculty evaluation of student achievement and student assessment of learning gains. Over a period of five years, faculty evaluated the green project reports in the areas of project data analysis, communication, success, troubleshooting, and creativity/difficulty. In addition, students were asked to complete a self-assessment survey. During the spring 2014 semester, all 22 students in the course completed this survey. Students rated their learning gains in eight different areas (Figure 2). In general, students reported positive gains in every area. It is important to note that no student selected the most negative possible response, no
Figure 2. Results of a survey asking students to assess their learning gains in several categories. Statistics, given no help = 0, ... great help = 4 (listed as category: mean, standard deviation), are as follows. Green chem: 2.9, 0.9. Literature search: 3.2, 0.9. Literature procedure: 3.0, 0.7. Design: 3.0, 0.9. Analysis: 3.0, 0.8. Application: 3.1, 0.7. Writing: 2.7, 0.8. Research confidence: 2.9, 1.0. D
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Table 2. Distribution of Final Instructor Scores for Components of the Green Laboratory Project Category
a
3.2 3.3 2.6 4.1 4.0
ASSOCIATED CONTENT
* Supporting Information S
Mean Score out of 5a (SD)b
Data analysis Communication Success Troubleshooting Difficulty/creativity
Article
Green project lab manual introduction, in-lab guidelines, planning assignments, a grading rubric, and examples of student projects, including literature sources for initial experimental protocols. This material is available via the Internet at http://pubs.acs.org.
(1.3) (0.8) (1.7) (1.0) (1.1)
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Scaled to 5 for comparison. bN = 56.
AUTHOR INFORMATION
Corresponding Author
(Table 2). Data analysis score (scaled to 5 of 5 for excellent analysis) was 3.2, and the mean score for communication (report writing) was 3.3; both correspond roughly to good work. On the other hand, scores for troubleshooting and difficulty/creativity were 4.1 and 4.0, respectively; both correspond roughly to very good work. These higher scores for troubleshooting and creativity might indicate some facility for research or engagement in the application of green topics, although instructors might have had more difficulty “grading down” in these “softer” categories. It is noteworthy that even those students who performed the nongreen reaction and then the green reaction in tandem might still get points for troubleshooting if they anticipated and adapted to potential problems, or responded appropriately when problems arose in the lab. The difficulty/creativity grade was instituted to discourage students from repeating projects from an earlier semester, and to encourage risk-taking beyond the substitution of one ethereal solvent for another, for example. About 50% of students do choose a solvent substitution of some kind as their green modification; the other 50% substitute a different reagent. The observed increase in learning outcomes outweighed the more intensive supervision required for this green project. This approach provides additional opportunity to learn about a realistic aspect of research but can increase the level of frustration for the student. Yet, a majority of the students stated that this was their favorite laboratory exercise; they enjoyed the independence and the environmental aspects.
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Moore, J. W. Faculty Responsibilities. J. Chem. Educ. 2006, 83 (8), 1111. (2) Green Chemistry at the University of Oregon. http://greenchem. uoregon.edu/ (accessed Jan 2014). (3) Hjeresen, D. L.; Schutt, D. L.; Boese, J. M. Green Chemistry and Education. J. Chem. Educ. 2000, 77 (12), 1543−1547. (4) Doxsee, K. M.; Hutchinson, J. E. Green Organic Chemistry: Strategies, Tools and Laboratory Experiments, 1st ed.; Brooks/Cole: Pacific Grove, CA, 2004. (5) Goodwin, T. E. An Asymptotic Approach to the Development of a Green Chemistry Laboratory. J. Chem. Educ. 2004, 81 (8), 1187− 1190. (6) Collins, T. J. Introducing Green Chemistry in Teaching and Research. J. Chem. Educ. 1995, 72 (11), 965−966. (7) Manchanayakage, R. Designing and Incorporating Green Chemistry Courses at a Liberal Arts College To Increase Students’ Awareness and Interdisciplinary Collaborative Work. J. Chem. Educ. 2013, 90 (9), 1167−1171. (8) Marteel-Parrish, A. E. Toward the Greening of Our Minds: A New Special Topics Course. J. Chem. Educ. 2007, 84 (2), 245−247. (9) Prescott, S. Green Goggles: Designing and Teaching a General Chemistry Course to Non-majors Using a Green Chemistry Approach. J. Chem. Educ. 2013, 90 (4), 423−428. (10) Mercer, S. M.; Andraos, J.; Jessop, P. G. Choosing the Greenest Synthesis: A Multivariate Metric Green Chemistry Exercise. J. Chem. Educ. 2012, 89 (2), 215−220. (11) Van Arnum, S. D. An Approach Towards Teaching Green Chemistry Fundamentals. J. Chem. Educ. 2005, 82 (11), 1689−1692. (12) Schoffstall, A. M.; Gaddis, B. A. Incorporating Guided-Inquiry Learning into the Organic Chemistry Laboratory. J. Chem. Educ. 2007, 84 (5), 848−851. (13) Kostka, K.; Tribe, L. Peer-Developed and Peer-Led Labs in General Chemistry. J. Chem. Educ. 2007, 84 (6), 1031−1034. (14) Horowitz, G. The State of Organic Teaching Laboratories. J. Chem. Educ. 2007, 84 (2), 346−353. (15) Graham, K. J.; Jones, T. N. Green chemistry: Student Designed Laboratory Projects. 241st American Chemical Society National Meeting, Anaheim, CA, 2011; CHED 1474. (16) Graham, K. J.; Schaller, C. P.; Johnson, B. J.; Klassen, J. B. Student-designed Multi-step Synthesis Projects in Organic Chemistry. Chem. Educ. 2002, 7 (6), 376−378. (17) Graham, K. J.; Johnson, B. J.; Jones, T. N.; McIntee, E. J.; Schaller, C. P. Open-Ended Purification Schemes for an Organic Chemistry Laboratory Practical Experiment. J. Chem. Educ. 2008, 85 (12), 1644−1645. (18) Mervis, J. And Then There Was One. Science 2008, 321 (5896), 1622−1628. (19) SciFinder American Chemical Society. https://scifinder.cas.org (accessed May 2014).
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CONCLUSIONS The key feature of this green chemistry project was allowing students to design and troubleshoot their own projects. The background work necessary to design a synthesis mirrored the type of planning that is integral to research, including the use of primary and secondary literature to work out experimental procedures. Independent projects, when practiced in this form, provided students with an experience that was a closer approximation to a research experience than a structured synthetic project.14 In addition, the demonstrated goals of increasing communication skills, data analysis, teamwork, and application of knowledge align closely with the needs of the workforce.24 In a recent student survey, a majority of the students stated that this was their favorite laboratory exercise; they enjoyed the independence and the environmental aspects. In addition, students reported more confidence in their ability to do research. This approach provided additional opportunity to learn about a realistic aspect of research but can increase the level of frustration for the student. The added value of student independence and engagement provided the impetus to maintain the more intensive supervision required for this green project. E
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(20) Gawalt, E. S.; Adams, B. A Chemical Information Literacy Program for First-Year Students. J. Chem. Educ. 2011, 88 (4), 402− 407. (21) Rosenstein, I. J. A Literature Exercise Using SciFinder Scholar for the Sophomore-Level Organic Chemistry Course. J. Chem. Educ. 2005, 82 (4), 652−654. (22) Organic Syntheses; Danheiser, R. L., Ed.; Organic Syntheses, Inc. http://www.orgsyn.org (accessed May 2014). (23) Larock, R. C. Comprehensive Organic Transformations: A Guide to Functional Group Preparations, 2nd ed.; Wiley-VCH: New York, 1999. (24) Kerr, S.; Runquist, O. Are We Serious about Preparing Chemists for the 21st Century Workplace or Are We Just Teaching Chemistry? J. Chem. Educ. 2005, 82 (2), 231−233.
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