Transforming the organic chemistry laboratory

experience with greener laboratory experiments

The challenge of greening the chemistry curriculumUO green organic chemistry curriculum: Keys to our successRecent developments - experiments and momentum

http://greenchem.uoregon.edu

Department of Chemistry and Materials

Science Institute

University of Oregon

Green chemistry offers many practical and

fundamental advantages for chemistry education

Table 1 Starting Material Employed in Classic Organic Laboratory Syntheses

1902-1980

Date Author

Acetanilide 4-Bromoacetanilide Benzoin

Starting Materials Required (grams)

Aniline Acetanilide Benzaldehyde

1902 Levy, 4th ed. 46.2 50.0

1915 Cohen, 3rd ed. 25.0 5.0 25.01933 Adkins 28.0 13.5 10.0

1941 Fieser, 2nd ed. 18.2 13.5 25.0

1963 Adams 20.0 13.5 16.0

1980 Drust 10.0 5.2 10.0

Adapted from: From Microscale Organic Laboratory by D.W. Mayo, R.M. Pike and S.S.

Butcher, 1985

• Alternative processing methods. Rapid, high yield transformationsat room temperature - catalysis

• Better understanding of how molecular structure dictates desirableand undesirable properties - Structure-Activity Relationships (SARs)

Hazardless, completely recyclable products

• “Waste” or renewable resources as raw materials

• Integrating green chemistry into the curriculum

Green chemistry challenges for the academic

community

Green chemistry is a multidisciplinary field, involvingfundamental sciences, business, law and engineering

How can we bring green chemistry into an already

crowded chemistry curriculum?

Challenges• Overcoming the misconception that

green chemistry is less rigorous• Finding experiments that illustrate

green chemistry concepts and areeffective in the teaching labs

• Involving students in the process ofgreening the curriculum

• Building a community to support thedevelopment and use of the curriculum

Strategies• Replace rather than add course material• Modernize the curriculum using the

latest green chemistry developments• Ensure quality through thorough testing• Provide a wide range of choices• Help others learn from our experience

Process used to develop and teach greener

laboratory procedures

We teach this simple process to

our students as we implement it.

Identify hazards

or inefficiencies

Find/develop

alternative methods

Test efficacy

of new procedure

Assess existing

procedure

Greener

alternative

Reed, S.M.; Hutchison, J.E. J. Chem. Ed. 2000, 77, 1627-1629.

H

H

Br+ Br

2

BrH

H

CCl4 or CH2Cl2

N H N H +Br3 Br Br2

H

H

ethanol

ethanol

TRADITIONAL

GREEN

Laboratory Skills:

Reaction set-up

Vacuum filtration

Melting point determination

Green Lessons Taught:

Less toxic solvents can be selected

Hazardous reagents can be generated in situ

Djerassi, C; Scholz, C.R. J. Am. Chem. Soc. 1948, 70, 417.

H

H

HBr

H Br

1. HBr2. 30% H2O2

ethanol, reflux

GREENER

A safer bromination of an olefin

McKenzie, L. C.; Huffman, L. M.; Hutchison, J. E. J. Chem. Ed. 2005, 82, 306-310.

Analysis using green metrics

• Appropriate metrics for teaching laboratories:

– Enhance student safety

– Reduce the volume and hazard of the wastestream

– Ease reliance on environmental controls

– Improve reaction efficiency

McKenzie, L. C.; Huffman, L. M.; Hutchison, J. E. "The evolution of a green

chemistry laboratory experiment greener brominations of stilbene," Journal of

Chemical Education 2005, 82, 306-310.

• Atom economy, percent experimental atom

economy, E factor, effective mass yield

Solventless Aldol Condensation

O

O

OCH3

OCH3

H3CO OCH3

O

+

1. NaOH2. H3O+ workup

mp 40-42 oCmp 42-45 oCmp 178 - 181 ° C

Rothenberg, G.; Downie, A. P.; Raston, C. L.; Scott, J. L.

J. Am. Chem. Soc. 2001, 123, 8701-8708.

Raston, C. L.; Scott, J. L. Green Chemistry 2000, 2, 49-52.

Chemical Concepts:

Melting point determination

and depression

Aldol condensation reaction

Recrystallization skills

Green Lessons:

Solventless reactions

Atom economical reactions

Liquid CO2 as a green extraction solvent

Chemical Concepts:

Solid/liquid extraction

Natural products (terpenes)

Spectroscopy

Phase transitions

Green Lessons:

Use of safer solvents

Prevention of waste

Green materials processing

Traditional Method

Green Method

McKenzie, L. C.; Thompson, J. E.; Sullivan, R.; Hutchison, J. E. "Green

chemical processing in the teaching laboratory: A convenient liquid CO2

extraction of natural products," Green Chem. 2004, 355-358.

D-limonene

Orange Peel Steam distilland/or

Organic solvent

Orange PeelCO2(liquid)

No organic solvent

Liquid CO2 extraction in the teaching laboratory

Target audience: Sophomore-level organicchemistry laboratory

• Introduction• Identification of Chemical Hazards• Chemical Exposure and

Environmental Contamination• Evaluation of Chemical Hazards• Introduction to Green Chemistry• Alternative Solvents• Alternative Reagents• Reaction Design and Efficiency• Alternative Feedstocks and Products

Plus 19 Green Organic Chemistry Experiments

Green Organic Chemistry Laboratory Manual

Fall term 2003

Synthesis, separations, spectroscopy

1. Solventless Aldol condensation

2. Bromination of an alkene

3. Preparation/distillation of

cyclohexene

4. Synthesis of adipic acid

5. Oxidative coupling of alkynes

6. Gas phase porphyrin synthesis

7. Solvent effects on kinetics

8. Molecular mechanics modeling

Winter term 2004

Synthesis, spectroscopy, applications

1. Electrophilic iodination with KI/NaOCl

2. Palladium-catalyzed aryl halide/alkyne

coupling

3. Polymer-supported oxidation chemistry

4. Friedel-Crafts acylation of ferrocene

5. Thiamine-mediated benzoin condensation

6. Self-assembled monolayers/patterning

7. Combinatorial synthesis of antibiotics

Laboratory curriculum project implementation

0

50

100

150

200

250

97-

98

98-

99

99-

00

00-

01

01-

02

04-

05

Number of

Students

"After taking this course I have a much better opinion of chemistry .... I feel likeI am learning something that has an actual important application to the realworld."

"I have decided to get a minor in chemistry so I can make more consciousdecisions regarding chemistry and avoid destructive practices for my health orthe environment."

• Teaches students a rational procedure for analyzing/minimizing

hazards

• Empowers students to use chemistry to solve environmental

problems - "Ambassadors of Green Chemistry"

• Changes the way students and society view chemicals, chemistry

and chemists - "Know the hazards, not all chemicals are hazardous"

The approach changes the way students think about

chemical hazards and chemistryWe are generating less waste and a less hazardous waste stream.

Winter term disposal numbers (14.2L of aqueous, 1L of flammableorganic and 1kg of solid waste for 180 students)

The project has been great for University public relationsMore than 20 articles have now been published around the world

Enhances student recruitingWe have seen strong interest from undergrads and grads who want tobe part of green chemistry

Opportunity to upgrade curriculum and facilitiesUniversity invested in a showcase lab facility to highlight the program

Improved educational atmosphereThe new lab setting is an excellent learning environment

Our experience introducing green chemistry - there

are many incentives

The new green chemistry labGreen chemistry offers many practical and

fundamental advantages for chemistry education

Table 1 Starting Material Employed in Classic Organic Laboratory Syntheses

1902-1980

Date Author

Acetanilide 4-Bromoacetanilide Benzoin

Starting Materials Required (grams)

Aniline Acetanilide Benzaldehyde

1902 Levy, 4th ed. 46.2 50.0

1915 Cohen, 3rd ed. 25.0 5.0 25.01933 Adkins 28.0 13.5 10.0

1941 Fieser, 2nd ed. 18.2 13.5 25.0

1963 Adams 20.0 13.5 16.0

1980 Drust 10.0 5.2 10.0

Adapted from: From Microscale Organic Laboratory by D.W. Mayo, R.M. Pike and S.S.

Butcher, 1985

Next steps

More labs!

Disseminate our and other’s labs via the GEMs

database

Promote the community through workshops,

symposia and collaborations

Build the “business case” for green chemistry

Workshop participants 2001-present

“Green chemistry will be more expensive”

Must carefully consider costs of reagents, solvents, disposal, engineeringcontrols, new labs, etc.

“There are no lab exercises available and I don’t have time to develop my own”

A wide range of experiments are now in development around thecountry. There should be a lot of choice soon.

“There is no room in the curriculum for new material”

Don’t add, replace.

“The curriculum will not train students to work with hazardous materials”

Most students will not work with hazardous substances after organic.Don’t have to work with hazardous substances to learn proper technique.

“Green is political, not scientific…green chemistry is not rigorous”

Designing better products and better processes is what synthetic chemistsdo. Green chemistry provides a new challenge.

Addressing the case for green chemistry

Prof. Ken Doxsee

Dr. Scott Reed

Ms. Lallie McKenzie

Mr. Marvin Warner

Ms. Lauren Huffman

Dr. Julie Haack

Dr. Rob Gilbertson

Mr. Gary Succaw

Dr. John Thompson

Ms. Kathryn Parent

Ms. Anna Shope

Dr. Leif Brown

Mr. Gerd Woehrle

and the Students of CH337G and CH338G

Acknowledgments

The Alice C. Tyler Perpetual Trust

The University of Oregon