P142: Quantifying waste in undergraduate organic laboratories via the aza-Morita-Baylis-Hillman reaction

Author: Andrew P. Dicks, University of Toronto, Canada

Co-Author: Rodolfo Gomez, University of Toronto, Canada

Date: 8/4/14

Time: 11:50 AM12:10 PM

Room: LMH 114

Related Symposium: S7

This talk describes use of a multi-component aza-Morita-Baylis-Hillman (aza-MBH) reaction at the third-year undergraduate level to teach principles of green chemistry. The aza-MBH reaction between benzaldehyde, methyl acrylate and p-toluenesulfonamide is subject to dual catalysis by a Lewis acid (La (III)) and a Lewis base (DABCO), and proceeds with exceptionally high atom economy (95%) under benign reaction conditions. Students undertake such a transformation from the primary research literature, and calculate additional metrics for it (E-factor and process mass intensity: the latter being the preferred green chemistry metric of pharmaceutical industries (Org. Process Res. Dev. 2011, 15, 912)). The amount of aqueous and halogenated waste produced is easily quantified, and factored into undergraduate formal reports that compare and contrast different metrics and suggest improvements from a sustainability perspective. Over 70 students have performed this reaction and analysis at the University of Toronto in a course that focuses on the principles and practice of sustainable organic synthesis (J. Chem. Educ. 2013, 90, 519).

P45: Examining student understanding of green chemistry metrics using the EcoScale

Author: Andrew P. Dicks, University of Toronto, Canada

Co-Author: Andrei Hent, University of Toronto, Canada

Date: 8/3/14

Time: 4:00 PM4:20 PM

Room: LMH 114

Related Symposium: S7

This presentation outlines an organic practical and written examination implemented at the third-year undergraduate level to assess student comprehension of green chemistry metrics. Students undertake the straightforward preparation of a benzodiazepine under catalytic conditions from 1,2-diaminobenzene and acetone, and evaluate the “greenness” of their synthesis by calculating its EcoScale score (Beilstein J. Org. Chem. 2006, 2, no. 3). This semi-quantitative approach accounts for factors including reaction yield, reactant/solvent toxicity, experimental techniques employed and work-up/purification methods. Comparisons are made with a research literature synthesis of the same compound, along with a critique of the strengths and weaknesses of the EcoScale and potential improvements. The examination additionally introduces the concept of process mass intensity (PMI) as the preferred green chemistry metric of pharmaceutical industries (Org. Process Res. Dev. 2011, 15, 912) and its relationship to Sheldon’s E-factor. Over 70 students have undertaken this examination at the University of Toronto in a course that focuses on the principles and practice of sustainable organic synthesis (J. Chem. Educ. 2013, 90, 519).