Evaluation of two organic laboratory experiments according to the principles of green chemistry Molly Carpenter, Margaret Anne Gray, Helen Dauer Department of Chemistry A new trend in chemical education incorporates green chemistry practices into laboratory courses as evidenced by the Green Organic Chemistry course taught by Kenneth Doxee and James Hutchison at the University of Oregon. We sought to compare an experiment from the Doxee and Hutchison’s Green Organic Chemistry lab manual to an experiment currently done in Sewanee’s Organic Chemistry course. We performed the aldol reactions from each organic laboratory manual and evaluated these reactions based on the principles of green chemistry accepted by the US EPA and the American Chemical Society. References 1. Doxee, K., Hutchison, J., Green Organic Chemistry: Strategies, Tools, and Laboratory Experiments. Brooks/ Cole, Anastas, P., Warner, J., Green Chemistry: Theory and Practice. New York: Oxford University Press, Mayo, D., Pike, R., Trumper, P., Microscale Organic Laboratory, New York: John Wiley and Sons, 2000, Ibuprofen- A case study in green chemistry. 14, April The Twelve Principles of Green Chemistry 2 1) Prevent waste instead of treating waste 2) Design atom-efficient chemical syntheses 3) Use nontoxic compounds in synthesis 4) Create effective, nontoxic products 5) Minimize use of reagents and solvents 6) Minimize energy usage 7)Use renewable starting materials 8)Avoid unnecessary derivatization 9)Replace depleting reagents with reusable catalysts 10) Design biodegradable products 11) Analyze and monitor processes in real time 12) Design processes that minimize accidents Reagents Used Reactions Atom Economy 4 Percent of atomic mass of all starting materials that appear in the final product Green Chemistry experiment Atom economy = 96.6% Microscale Organic experiment Atom economy = 86.7% Economic Analysis Following instructions from the Green Chemistry lab manual we performed economic analysis for the major reagents used in each experiment using prices found on Sigma-Aldrich.com. Conclusions The microscale experiment done currently in Sewanee’s lab has fairly low environmental impact. The main benefits of the green chemistry aldol reaction are that it demonstrates a solventless reaction and encourages students to focus on the economic and environmental cost of the reaction in addition to its chemical mechanism. Yields Green chemistry yield = 85.6% Microscale yield = 53.0% Green Chemistry experiment 1 Microscale Organic experiment 3 Acknowledgements Dr. John Shibata, Dr. Scott Borella Green Chemistry Experiment BenefitsDrawbacks - demonstrates a solventless reaction- high cost - very high atom economy- uses higher quantities of reagent - high percent yield- extra product leads to waste - low toxicity of reagents- heating and filtration use energy Microscale Organic Experiment BenefitsDrawbacks - uses very small quantities of reagents- lower atom economy - produces small amounts of waste- lower yield - low cost- stirring, heating, filtration use energy ReactantMWUsed in productMWUnused in productMW C 9 H 10 O 3 166C 18 H 16 O 3 280H2OH2O18 C 9 H 10 O132 Total ReactantMWUsed in productMWUnused in productMW 2 C 7 H 6 O106C 17 H 14 O2342 H 2 O36 C3H6OC3H6O58 Total Green Chemistry CompoundPriceCost for 15 students 1- indanone$220 / 100 g$ ,4 dimethoxy- benzaldehyde $ / 100 g$0.68 Microscale Lab CompoundPriceCost for 15 students benzaldehyde$90.70 / 500 mL$0.22 acetone$90.40/ 4 L$0.01