Bcce Lab2008

New Model for Organic Laboratory

Dell Jensen, Ph.D.

Richard Narske, Ph.D.

Commentary -The Problem with Organic Chemistry Labsby Jerry R. Mohrig

Mohrig, Jerry R. J. Chem. Educ. 2004 81 1083.

How to extract knowledge fromexperimental results is at the heart of science,

yet for the most part we don’t attemptto teach this skill in traditional labs.

Problems with Verification Experiments

• Lack of comprehension and purpose of lab• Lack of student engagement/motivation

• Poor communication skills• Discrepancy between lecture and lab

performance/grades

Commentary -The Problem with Organic Chemistry Labsby Jerry R. Mohrig

Mohrig, Jerry R. J. Chem. Educ. 2004 81 1083.

How to extract knowledge fromexperimental results is at the heart of science,

yet for the most part we don’t attemptto teach this skill in traditional labs.

“What we need is to bring thinking about experimentalchemistry back into our introductory organic chemistry labs”

Commentary -The Problem with Organic Chemistry Labsby Jerry R. Mohrig

Mohrig, Jerry R. J. Chem. Educ. 2004 81 1083.

How to extract knowledge fromexperimental results is at the heart of science,

yet for the most part we don’t attemptto teach this skill in traditional labs.

Goals•Interpret results•Draw conclusion (extract knowledge)•Develop procedures

Recent LiteratureA New Model for Transitioning Students from the Undergraduate Teaching

Laboratory to the Research Laboratory. Hollenbeck, Jessica J.; Wixson, Emily N.; Geske, Grant D.; Dodge, Matthew W.; Tseng, T. Andrew; Clauss, Allen D.; Blackwell, Helen E. J. Chem. Educ. 2006, 83, 1835.

A Research-Based Laboratory Course in Organic Chemistry Newton, Thomas A.; Tracy, Henry J.; Prudenté, Caryn. J. Chem. Educ. 2006, 83 ,1844.

The State of Organic Teaching LaboratoriesHorowitz, Gail. J. Chem. Educ. 2007, 84, 346.

Incorporating Guided-Inquiry Learning into the Organic Chemistry LaboratoryGaddis, Barbara A.; Schoffstall, Allen M. J. Chem. Educ. 2007, 84, 848.

On the Successful Use of Inquiry-Driven Experiments in the Organic Chemistry Laboratory Mohrig, Jerry R.; Hammond, Christina Noring; Colby, David A. J. Chem. Educ. 2007, 84, 992.

Laboratory Models

• Verification (Cookbook)

• Discovery (Guided-inquiry)

• Inquiry (Open-ended)

• Research Based (Projects)

• Literature Based

Goals for New Laboratory

• Increase Student Engagement

• Develop Independence

• Improve Communication Skills

• Close the Grade Gap

A New Model

• Read Experiments from the Literature

• Maintain Detailed Notebook

• Build Lab Skills through trial and error

• Write Formal Reports

Fall Term• Three Techniques Labs (Quals)

– Unknown Solid and IR spectroscopy– Unknown Liquid and NMR Spectroscopy– Mixture, Chromatography, and Mass Spectra

• Mohrig, et. al., Techniques in Organic Chemistry, 2nd Ed., W.H. Freeman, 2006

• Two Experiments– Separation Experiment (choose one of 3)– Synthesis Experiment (choose one of 3)

What does this look like?Solid Unknown and IR Spectroscopy:• Student will obtain a melting point range of the impure solid and then

recrystallized the unknown twice, first in a large test tube (500mg) and then in a Craig Tube (100 mg). The purity will be verified by a constant melting point range of the recrystallized solid. The solid may need additional recrystallization to achieve a constant mp. A solid thin film IR will be taken of the solid and used to characterize the unknown. The collected data will be used to identify the unknown from a list of possible compounds.

• Students’ product grade will be based on accuracy of mp, calculation of percent recovery, quality of IR, assignment of the IR peaks and identification of unknown.

• References: Melting Point, Mohrig, Chapt. 10, p93-103, Recrystallization, Mohrig, Chapt. 9, p78-92, Infrared, Mohrig, Part 3, Chapt. 18, Solid Film IR, Feist, P.J.; “Sampling Techniques for Organic Solids in IR Spectroscopy: Thin Solid Films as the Method of Choice in Teaching Laboratories” J. Chem. Ed., 78, 2001, 351.

Choose an ExperimentComplete one of the following three separation experiments

(only 6 student per experiment per lab section)Exp. 1: Distillation of a Three Component Mixture

Craig J. Donahue; "Fractional Distillation and GC Analysis of Hydrocarbon Mixtures." J. Chem. Ed., 79, 2002, 721-723.

Exp. 2: Isolation of RubberL. Volaric and J. Hagen; "The Isolation of Rubber from Milkweed Leaves"; J. Chem. Ed., 79, 2002, 91-93.

Exp. 3: Extraction of Chlorophyll from Spinach LeavesQuach, Hao T.; Steeper, Robert L.; Griffin, G. William; “An Improved Method for the Extraction and Thin-Layer Chromatography of Chlorophyll a and b from Spinach“ J. Chem. Educ., 81, 2004 385.

Write a ReportTitleIntroductionExperimental (Not a procedure)ResultsDiscussion/ConclusionsReferencesFocus on grammar and proper writing style

-ACS Style Guide

Formal Report Grading Sheet Notebook Sheets – 50 points• Procedure & Reagent Table (10 pts)• Observations and Details (10 pts)• Sign and date each day (5 pts)• Characterization data (10 pts) • Calculations (10 pts)• Summary/Conclusion (5 pts)

Formal Report – 150 points• Type-written/double-spaced (10 pts)• Chemical structures w/ computer (10 pts)• Title – descriptive and concise (10 pts)• Introduction – (20 pts)• type of experiment and mechanism• discussion of theory of reaction• Experimental – (30 pts)• 3rd person• appropriate detail

Product – 100 points• Percent Recovery or Yield (20 pts)• Purity (mp, GC) (10 pts)• Quality of Spectra (10 pts)• Characterization (20 pts)• Effort (40 pt)

• Writing style and grammar (30 pts)• Results – (30 pts)• relevant data included• tables where appropriate• no calculations• Discussion – (40 pts)• explanation and interpretation • discussion of results• conclusions• focused

Winter Term• Complete five experiments from 4 areas

– Alkenes– Alcohols– Gringards– Dienes & AromaticsTotal of sixteen experiments

• Some double experiments • Formal Reports for all experiments

– Focus on technical writing– Characterization and analysis (interpret)

What does this look like?Alkenes• Exp. 1: Poon, T., et al. “Kinetic vs. Thermodynamic Control in Dehydration

of 2-Methylcyclopentanol” J. Chem. Ed., 1997, 74, 1218. Double Exp. see Grignards; use GCMS

• Exp. 2: Centko, R. S., and Mohan, R. S. “Epoxidation of p-Methoxy-trans-b-methylstyrene” J. Chem. Ed., 2001, 78, 77. Complete both reactions; complete NMR

• Exp. 3: Chatla, N., et.al, "An Operationally Simple Hydroboration Experiment.", J. Chem. Ed., 1990, 67, 975.

• Exp. 4: Bromination of Stilbene: "The Evolution of a Green Chemistry Laboratory Experiment: Greener Bromination of Stilbene." Hutchison, J.E., et.al, J. Chem. Ed., 2005, 82, 306. Double Exp.

• Exp. 5: Duty, R.C., and Ryder, B.L., "Grignard Dehydration Reactions.", J. Chem. Ed., 1976, 53, 456. Double Exp., see Grignards, complete at 1/10th in 25 mL RB flask scale, do not flame dry glassware, use oven. GCMS analysis of both products.

• Exp. 6: Tomsho, John; McKee, James R.; Zanger, Murray; “A Microscale Synthesis of the Diastereomers of 2,3-Dibromosuccinic Acid” J. Chem. Ed., 76, 1999, 73.

Spring Term

• Complete two multi-step synthesis experiments– Choice of twelve experiments

• Polished Formal Reports (10-15 pages)

• Focus on Detailed Discussion and Explanations (Drawing Conclusions)

1. “Convergent Synthesis of Betaine-30, a Solvatochromic Dye: An Advanced Undergraduate Project and Demonstration”; Osterby, Bruce R.; McKelvey, Ronald D.; J. Chem. Educ. 1996, 43, 260.

2. “Microscale Synthesis of 1-Bromo-3-chloro-5-iodobenzene: An Improved Deamination of 4-bromo-2-chloro-6-iodoaniline”; Peter, M.W.; et.al.; J. Chem. Educ. 2004, 80, 111; Ault, A.; Kraig, R.; J. Chem. Educ. 1966,43, 213. - Begin this synthesis with the bromination of acetanilide from Ault article and the chlorination is completed using Procedure b.

3. “A Series of Small Scale, Discover Based Organic Laboratory Experiments Illustrating Concepts of Addition, Substitution, and Rearrangement”; Moroz, J.S.; et.al. J. Chem. Educ. 2003, 80, 1319.

4. “Bromination, Elimination, and Polymerization: A 3-Step Sequence for The Preparation of Polystyrene from Ethylbenzene” Sanford, E. M. and Hermann, H. L.; J. Chem. Ed., 2000, 77, 1343. & Slough, Greg A. “A Simple, Discovery-Based Laboratory Exercise: The Molecular Mass Determination of Polystyrene” J. Chem. Ed., 1995, 72, 1031. Characterize the molecular weight of your product using TLC procedure from the Slough article, requires drawing a graph.

Pros & Cons

• Fine Line between Order & Chaos

• More initial prep time – no weekly setups

• More Time Grading Reports, but Fewer Reports

• Selection of Labs – Flexible and Dynamic

• No Separate Lab Manual

Results• Students more engaged – learn more?• Students work independently• Students have a choice - ownership• Students writing is better

– Quality of writing improved– Rational of arguments stronger

• Performance better represents ability– Stronger correlation between lecture

and laboratory

Assessment• 5 years of this new Model Literature

– Refinements each year• No change in ACS Organic Exam

– All organic students take the Organic Exam• Student Evaluations are higher• Improvement in Literature Research Course

– Paper and Oral Presentation

In Closing

• Copies of the Lab Syllabi• Thanks to

– Tredway Library, Augustana College– Chemistry department colleagues– Augustana students

• Contact us at:[email protected]@augustana.edu