Designing a Green, Inquiry-Based Organic Chemistry Laboratory to Educate the Next Generation of Scientists

Loyd Bastin & Kaitlyn GerhartWidener University

Teaching Green Chemistry“The era of procrastination, of half-measures, of soothing and baffling expedients, of delays is coming to its close. In its place we re entering a period of consequences.” – Winston Churchill

• We need to change the culture/mindset• We must educate students about GC in a way that encourages

application of their knowledge• Green Organic Chemistry Experience VS Green Organic Chemistry

Labs

• Involve Students in the Process• Interviewed faculty about desired techniques for students

to learn

• Searched for experiments in the Journal of Chemical Education and GEMS database

http://greenchem.uoregon.edu/gems.html• Developed a 3-step synthesis as capstone experience• Designed course to introduce Green Principles and

techniques• Students APPLY this knowledge in the final experiment

How We Designed Our Lab

Extractions Chemical/Waste HandlingChromatography Hazard AwarenessIR GC

• Introduction to Environmental Contamination & Chemical Exposure

• Introduction to Green Chemistry• Traditional vs Green Approaches• 12 Principles of Green Chemistry

• It’s important for students to apply Green Chemistry• Analyze greenness of current experiments

• Percent Yield, Atom Economy, Atom Efficiency, Effective Mass Yield, E-Factor

• Revise/design experiments

• Important to build-up as semester progresses

Creating a Green Chemistry Culture

Techniques used:• Solubility• Recrystallization• Melting point• Mixed melting point

How it’s Green:• Not explicitly green

Recrystallization & Mixed MPs

Modified from a procedures acquired from Prof. Jim Patterson, Seattle Community College.

Techniques used:• Liquid-liquid extraction• Recrystallization• Mixed solvent

recrystallization

How it’s Green:• Benign extraction

solvents

Acid/Base Extraction

Biosynthesis of EthanolIsolate/purify ethanol produced by yeast fermentation. This experiment is used to introduce Green Chemistry.

How it’s Green:

• Benign reagents

• Renewable feedstocks

• Ethanol used later

• Atom economy

Techniques used:

• Simple distillation

• Fractional distillation

• gas chromatography

Adapted from experiment by J. Thompson, Lane Community College, GEMS database, July 2006.

Friedel-Crafts Acetylation

Adapted from: Mohrig et al. Modern Projects & Experiments in Organic Chemistry: Miniscale and Standard Taper Microscale, 2nd ed. W.H. Freeman: New York: 2003, 173-176.

Techniques used:• EAS• Column

chromatography• Thin layer

chromatography• Melting point• IR spectroscopy

How it’s Green:• Greener reagents

Isolation of the Three Components of Spearmint Oil

Experiment adapted from Don R. Davies; Todd M. Johnson. J. Chem. Ed. 2007, 84, 318-320.

How it’s Green:• Greener reagents

Techniques used:• Column chromatography• Thin layer chromatography• IR spectroscopy

• Capstone experiment• Students APPLY Green

Chemistry Knowledge• Focuses on choosing

greener methods• Emphasizes

Techniques from previous experiments

Synthesis of 1,2-dibromo-1-phenylpropane

In the Classroom• Students research methods for each step • Required to bring at least one potential procedure for

each reaction to the lab lecture • Class explores different methods using Green Metrics

Techniques used:• Liquid-liquid extraction• IR spectroscopy• BP determination

How it’s Green:• Atom economy• Atom efficiency

Experiment basics:• Ethanol from biosynthesis• CH2Cl2 used for extraction• Can experiment with

greener solvents• Product verified by BP & IR

Other Reagents• Baker’s Yeast• Carrot Reduction• LiAlH4

Experiment adapted from N. Pohl et al. J. Chem. Ed. 2002, 79, 727–728.

Reduction of Propiophenone

Techniques used:• Distillation• IR spectroscopy• BP determination

How it’s Green:• Greener reagents• Atom economy• Atom efficiency

Experiment basics:• H3PO4 vs H2SO4

• Distillation purifies as well as drives rxn

• No work up necessary• Pdt verified by BP and IR

Experiment adapted from: Doxsee et al. Green Organic Chemistry. Thomson 2004. 129-134.

Elimination of 1-phenyl-1-propanol

Experiment basics:• Opportunity to work with

strong acids

Other Reagents• Pyridinium tribromide• Br2 in CH2Cl2• Br2 in Me-THF

Techniques used:• Recrystallization• IR spectroscopy

How it’s Green:• Greener reagents• Atom economy

Experiment adapted from: McKenzie et Al. J. Chem. Ed. 2005, 82, 306-310.

Bromination of trans-β-methylstyrene

Summary• Laboratory emphasizes applying green chemistry • Exposed to different chemical methods and challenged

to ‘think green’• Exposed to a wide variety of techniques• Final synthesis provides a venue for applying Green

Chemistry to a synthetic protocol• Analysis by NMR can easily be added if desired

What’s Next?• We are now having students “Green” the synthesis of

Aromatic Sulfa Drug Analogs in Organic II Lab

AcknowledgementsKaitlyn GerhartOrganic Chemistry students:

Fall 2007, 2009Summer 2008, 2009

Krishna BhatIrina Knyazeva

UO GCEWA&S Summer Housing

FellowshipWidener Faculty Development

GrantChemistry, biochemistry, and

biology faculty

“There’s nothing that unusual about what I’m doing……. What is unusual is that I had the privilege to be shown it as a young man.” – Al Gore