Discovery (?) Group Projects in the Organic Laboratory

Martin B. Jones Adams State College Alamosa, CO

Discovery (Guided-Inquiry) Experiments

• Predetermined outcome (but only the instructor knows) • Inductive reasoning required of the students • Procedure is given by instructor Domin, D. S. J. Chem. Educ. 1999 ,

76

, 543

Sources of Organic Chemistry Discovery Experiments

Journal Articles (examples)

Mohan, R. S. and coauthors, 6 papers in J. Chem. Educ. 1999-2005 ; Reeve, A. M. J. Chem. Educ. 2004 ,

81

, 1497; Adrian, J. C. Jr; Hull, L. A. J. Chem. Educ. 2001 ,

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, 529; Horowitz, G.

J. Chem. Educ

.

2003

,

80

, 1039; Moroz, J. S.; Pellino, J. L.; Field, K. W.

J. Chem.

Educ. 2003 ,

80

, 1319.

Textbooks (examples)

Pavia, Lampman, Kriz, Engle “Introduction to Organic Lab Techniques – A Microscale Approach”; Schoffstall, Gaddis, Druelinger “Microscale and Miniscale Organic Chemistry Lab Experiments”; Mohrig, Hammond, Morrill, Neckers “Experimental Organic Chemistry: A Balanced Approach”

History of Chemistry Group Projects Labs at ASC

• Summer 2000 – ACS Gen Chem workshop • Fall 2000 – Project Labs implemented in General Chemistry at ASC • Fall 2001 – Project Labs implemented in Organic Chemistry at ASC • Summer 2002 – Workshop on Organic Discovery Experiments at BCCE

Group Projects in Organic Chemistry at ASC

• Fall Semester: Effect of Acid on Dehydration of 2-Methylcyclohexanol (adapted from Taber, R. L.; Champion, W.C.

J. Chem. Educ

.

1967

,

44

, 620; Moeur, H. P.; Swatik, S. A.; Pinnell, R. P.

J. Chem. Educ

.

1997

,

74

, 833.) • Spring Semester: Directing Influences in Electrophilic Aromatic Substitution Reactions (adapted from “Introduction to Organic Laboratory Techniques – A Microscale Approach”, 3 rd Ed. Pavia, Lampman, Kriz, Engel; Saunders; 1999; Exps 39 & 40)

Common Features of Each Project

• Students get a handout that describes the project in general, including the rubric I use for grading.

• Groups of 4 preferred.

• Molecular Modeling.

• Two weeks for laboratory work, one additional week to prepare report.

• One formal report per group; individual duplicate notebook pages also included.

• Group members evaluate each other and themselves.

Rubric for Group Lab Report

E G F P Incorrect Format (5) Introduction (10) Clear purpose; reactions shown Procedure (20) Detailed; observations given; duplicate pages present Results (20) Discussion (30) Ref’s (5) Calculations shown; instrumental and modeling data included Clear and based on correct interpretation of actual results Pertinent ref’s cited properly Readability (10) Correct Good organization; <3 spelling/grammar errors Unclear; no reactions Brief; no observations; no duplicate pages No calculations, instrumental data, or modeling data present.

Based on incorrect interpretation of actual results No ref’s Poor organization; many spelling/grammar errors

Peer and Self Evaluation Rubric

Score

yourself and your team members

in each category using

E

xcellent,

G

ood,

F

air,

P

oor or

N

o participation.

Please mark your own name with an asterisk (*).

Be honest when you mark your ratings. If you have any comments to make, use the space below the rubric.

Evaluation Category Names of Group Members Participation in planning/ design of experiments Participation in actual experiments Efficiency in completing all data collection Participation in discussion of results Participation in writing of group report

Peer and Self Evaluation Rubric

Evaluation Category Participation in planning/design of experiments Participation in actual experiments A G,E,E,G G,E,E,E Efficiency in completing all data collection P,E,E,E Participation in discussion of results F,E,E,G Participation in writing of group report P,E,G,F Sum Scaling Factor 17.9

0.918

Names of Group Members B G,E,E,G C G,E,E,G D G,E,G,G G,E,E,E G,E,E,E G,E,E,E E,E,E,E 19.5

1.00

G,E,E,E G,E,E,E G,E,E,E G,E,E,E 19.4

0.995

G,E,E,E G,E,E,E G,E,G,G G,E,G,F 18.7

0.959

Dehydration of 2-Methylcyclohexanol

OH Acid, heat + - H 2 O CH 3 CH 3 • Objectives • Determine if Zaitsev's rule regarding product distribution in dehydration reactions is valid.

• Investigate the effect of dehydrating agent on product distribution and yield in dehydration reactions.

• Timing of Experiment • Typically the first non-technique based experiment in the course CH 3

Directing Influences in EAS Reactions

• Objectives • Determine the directing influences of two different substituents in typical electrophilic aromatic substitution reactions • Timing • Second semester, just prior to discussion of EAS reactions

Directing Influences in EAS Reactions

NH O NH Br 2 , HBr, HOAc O Br O O OCH 3 HNO 3 , H 2 SO 4 OCH 3 NO 2

“Group” Aspect of the Experiment

SA A D SD N/ A 7 My group worked well together for each experiment.

5 My group worked well together for at least one experiment.

6 I would have preferred to have been assigned to a group rather than to have selected my own.

2 5 4 3 2 1 1 I think it’s a good idea to have my peers evaluate me on my contributions to the project.

5 6 1 My group graded me fairly in the peer and self evaluation rubric.

8 3 1

Selected Comments

• I think peer evaluations are generally good & most students (at least in a class like this) are honest & thoughtful.

• Having groups picked for us is good because we learn to work with new people.

• It’s always easier to work with people you get along with, rather than being assigned to a group of people who may or may not work well together.

“Discovery” Aspect of the Experiment

SA A D SD N/ A 3 9 I already knew exactly how the experimental results would turn out (i.e., product distributions) prior to conducting the experiment and analyzing the results.

The molecular modeling portions of the experiments helped me predict the outcome of the experiments.

Conducting the experiment and analyzing the results helped me remember Zaitsev’s rule for dehydration reactions and the directing influence of different substituents in EAS reactions better than just looking at reactions written on the board.

These experiments should be done before any discussion of dehydration (fall) and EAS (spring) reactions in the lecture portion of the course.

5 7 1 6 5 1.5

1 7.5

2

Selected Comments

• A little discussion should be done so that students have a clue about what is going on.

• Doing the experiments before could help but I think it works well either way.

• I believe the experiment should be utilized at approximately the same time lecture covers the material. It would better reinforce the concepts learned.

Experimental Design

I think it’s a good idea for us to come up with our own experimental procedure, as we did in the fall.

I prefer to have the exact procedure spelled out in the lab text, as it was in the spring.

4 1 SA A D 6 1 SD N/ A 1 6 5

Selected Comments

• I like the challenge of coming up with the procedure. It is also helpful to have some direction as in the spring. I think a combination of both would be better.

• I think we learn more when we need to think about it.

• Designing the experiment is half the fun.

Group Project Report

SA A D I enjoyed writing a formal report in the format of a journal article.

4 1 6 SD N/ A 1 I think it is beneficial for me to write a formal report in the format of a journal article.

I think we should have just written the report as a normal report in our lab notebooks.

6 6 1 10 1

Selected Comments

• This was the first time I really took a look at the journal, since then I have looked at many articles. In writing a report like the journal I learned how to effectively read a journal article.

• While I didn’t enjoy the journal format, I think it is beneficial to learn the scientific journal article format.

• I don’t enjoy writing formal reports but the importance of knowing their format supercedes my laziness

Successful or Not?

• The group projects were nice because it gave a variation in the schedule so that it never got monotonous.

• Overall, a well worthwhile and engaging activity. Would prefer not to do it in groups.

• Sometimes the group projects were frustrating, but it is also a real life situation. Not only did we learn from the experiment, but we learned from each other as well.

Average project score (Fall ’05) – 85.5

Average project score (Spring ’06) – 90.3

Acknowledgements

Chemistry 321 and 322 students at Adams State College from 2001 to present; especially students from 2005-2006.

Jerry Bell, Melanie Cooper, and the rest of the ACS GenChem “team”.

Allen Schofftstall, Barbara Gaddis, Connie Pitman, and Susan Schelble for a workshop on discovery experiments at the 17 th BCCE.