CH344, Organic Chemistry Lab 2, Spring 2007Instructor: Dr. Bruce A. HathawayOffice: Rhodes 201EPhone: 651-2370Office Hours: MWF 9-10:30 AM, and by appointmentCourse Web Page: http://cstl-csm.semo.edu/Hathaway/CH344/E-mail: bahathaway@semo.edu

Pre- or corequisites: CH-343, or consent of instructor.If you drop CH-343, you must drop this course as well!

Assignments and ValueAssigned Lab Reports & Products: 50%Student Project Reports: 20%Student Project Presentation: 10%Student Research Conference Work: 5%Pre-lab Write-ups: 5%Comprehensive Written Final Exam: 10%

Grading Scale

A: ≥ 90%; B: 80-89.9%; C: 70.79.9%; D: 60-69.9%; F: <60%

Required Materials:

Text: John W. Lehman, “Multiscale Operational Organic Chemistry”, 2002.Safety Goggles: May be obtained at the Chemical Storeroom.Bound Notebook: May be purchased at University Bookstore, K-Mart, Wal-Mart, etc.

General Course Procedures:

In this course, I emphasize identification and preparation of organic compounds. For you to get the most out of lab, you need to be prepared before you come into the lab. Therefore, I will have you look up certain information before you come to lab. This information will be checked, and will be part of your lab grade. This will also help you to work safely in the lab, since you will know what you are working with.

You are required to work during your assigned laboratory period: this is not an “open lab” like some courses. If you come to lab prepared, you will be able to finish during the time allotted. If you have to miss your lab for some reason, please contact me in advance, if possible, and I will work out a time to make it up. Medical reasons will require some verification.

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Report Formats:

I will give you a report format for each lab experiment. When you write up each report, carefully follow the format, give me what I ask for, and don’t include things I don’t ask for. Always save your products from each experiment, and turn them in to the appropriate boxes in the lab - they are part of your lab report grade.

The Grignard Project:

The goal of this project is to find Grignard reactions that yield liquid products that are easily isolated and purified by distillation. The alcohol products should boil in the 140-200 ºC range (so that they can be easily distilled, but not removed on the rotary evaporator), as well as having a significantly different boiling point than the starting alkyl halides and aldehydes or ketones (so that the starting materials can be easily separated from the product alcohol). It is possible that products with higher boiling points could be prepared, but distillation of things with boiling points of over 200 ºC sometimes don’t work as well, unless done under reduced pressure. The reactions should be run on a scale large enough to permit convenient distillation of the alcohol products.

Available Aldehydes: propanal, butanal, pentanal

Available Ketones: acetone, 2-butanone, 2-pentanone, 3-pentanone, cyclohexanone

Available Organic Halides: 1-bromopropane, 2-bromopropane, 1-bromobutane, bromocyclohexane, bromobenzene

You will have five weeks to work on your project. Each individual student will write up an intermediate progress report after three weeks of work, and will write up a final written report at the end.

On March 28&29, you will be presenting posters of what you did to the rest of the students in the course. These posters will be similar in format to the ones posted in the hall near MG213. You will receive more instructions on these later.

On April 18 and/or 19, you will attend the Student Research Conference (SRC), either as a presenter of your project, or as a member of the audience. If Dr. Hathaway thinks you did well enough on your project, you may elect to present it at the SRC. If you present your project, you will get a 100% for the SRC part of your grade. You will need to turn in your poster or overheads or slides or PowerPoint presentation for me to look at. If you do not present, you will need to attend five science presentations (not ones made by CH344 people on their projects), and write up a 100-200 word summary of each presentation. I take a really dim view of several people handing in essentially identical summaries of the same five presentations.

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Schedule of Topics

All Experiments are done on the “Standard Scale”, unless otherwise indicated.

Date Experiment (Experiment # in text, page number) Report Due Date*

Jan. 17, 18 Introduction to Lab, Discussion of “The Grignard Project”, Check-in.

Jan. 24, 25 Determination of the Structure of a Natural Product in Anise Oil (36, 291-7); IR Demonstrations

Feb. 2

Jan 31, Feb. 1 Preparation of a Phenylalcohol by a Grignard Reaction (29A, Handout: Read Experiment 29 for background)

Feb. 16

Feb. 7, 8 Finish Preparation of a Phenylalcohol by a Grignard Reaction; NMR Demonstrations

Feb. 14, 15 The Grignard ProjectFeb. 21, 22 The Grignard ProjectFeb 28, Mar. 1 The Grignard Project Progress Report

due March 5Mar. 7, 8 The Grignard ProjectMar. 14, 15 The Grignard Project Final Report Due

March 30Mar. 21, 22 Spring Break Mar. 28, 29 Project Presentations; Start Wittig Synthesis of 1,4-

Diphenyl-1,3-butadiene (38A, 305-312)April 11

Apr. 4, 5 Finish Wittig Synthesis of 1,4-Diphenyl-1,3-butadiene (38B, 305-312)

Apr. 11, 12 Start Synthesis and Identification of an Unknown Carboxylic Acid (42, 338-343),and A Diazonium Salt Reaction of 2-Aminobenzoic Acid (Minilab 40, 505-6)

Apr. 18, 19 Student Research ConferenceApr. 25, 26 Finish Synthesis and Identification of an Unknown

Carboxylic Acid (42, 338-343), and A Diazonium Salt Reaction of 2-Aminobenzoic Acid (Minilab 40, 505-6)

May 3

May 2, 3 Check-OutFinal Exam - Weds. Lab: Monday, May 7, 2 PM Thurs. Lab: Tuesday, May 8, 2PM

*Lab reports are due by NOON on or before the date indicated. Late lab reports, if accepted, will be penalized severely.

If you do not check out of lab, you will be charged $20, plus the cost of any missing or broken items, if I have to check you out!

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The Laboratory Notebook

Your laboratory notebook is THE place where you record ALL information about the experiments you perform. It is meant to be a permanent record; therefore, all entries are to be in INK. If you make a mistake, just draw a line through it - you may discover later that it was correct, and need to see it.

Pre-laboratory Preparation

Before you come to lab, you MUST have certain information in your laboratory notebook. This way, I know you have read the lab, and are ready to work. Having this information in your lab notebook before you come to lab also earns you points toward your lab grade. You can find the information you need in the CRC Handbook of Chemistry and Physics and/or in the Merck Index, or other on-line sources .

Start each new experiment on a new page.

Each experiment must have:

1. A Title

2. A Main Reaction, in those experiments where you are preparing a compound from other compounds.

3. Table of Chemical Data - for starting materials, products, and solvents.

a. Nameb. Molecular weight (Formula weight)c. Boiling point or melting pointd. Density (for liquids)e. Solubility in water and other solventsf. Toxicity

4. Calculation of Theoretical Yield, in those experiments where you are preparing a compound from other compounds.

5. The procedure briefly written out, with room left for observations. This is most easily done by writing the procedure in one column, and leaving another column for observations next to it. You don’t need to copy the procedure word-for-word, but can abbreviate it as you see fit, as long as it is complete.

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Lab Handouts and Lab Report Formats

CH344, Spring 2007Dr. Hathaway

Look at these before you come to lab, to be sure you catch any changes in the procedure, or things you need to make sure you do during the lab.

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Modifications for Determination of the Structure of a Natural Product in Anise Oil

We will set this reaction up in a reflux apparatus using a 25 mL round-bottomed flask. Zero your round-bottomed flask on a balance, and add five drops of anisene to the flask, recording its mass. Add the water, the KMnO4, and the Aliquat 336, attach the water-cooled condenser, and heat the reaction at reflux using a thermowell for at least 20 minutes. Then proceed as instructed in the second paragraph on page 295.

Report Format

1. Title Page

a. Descriptive title with between 15 & 25 words.b. Course and section number.c. Dates the experiment was performed.d. Your name.

2. Body of the report

a. Chemical equation for the reaction, with chemical structures, not just formulas. A balanced chemical equation earns a bonus!

b. Important observations and possible interpretations. Color changes are important in this lab.

c. Weight and melting point of the product.d. Calculation of theoretical and % yields. Show the calculations of the numbers of moles

of all reactants from the grams you actually started with.e. Include your IR spectrum with your report

3. Questions

a. Interpret the IR spectrum of anisene, explaining what the major peaks are.b. Draw out the four possible C=C containing side chains with the formula C3H5.c. What is the structure of anisene? Explain your reasoning completely, using the data you

collected. How did you distinguish your choice from all of the other choices?d. Do exercises 4 & 6 on page 296.

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Preparation of a Phenylalcohol by a Grignard Reaction

You will be using 20.0 mmol one of the following ketones in your experiment. So, all of you need to calculate the amount of each of these reagents needed in grams before coming to lab.

benzophenone acetophenone propiophenone

Safety Issues

Bromobenzene causes eye and skin irritation, and inhalation, ingestion, or skin absorption may be harmful. Avoid contact with the liquid and do not breathe its vapors.

Ethyl ether is extremely flammable and may be harmful if inhaled. Do not breathe its vapors and keep it away from flames and hot surfaces.

Magnesium can cause dangerous fires if ignited; keep it away from flames and hot surfaces.

Hexanes is extremely flammable and can be harmful if inhaled or absorbed through the skin. Avoid inhalation and prolonged contact, and keep it away from flames and hot surfaces.

Procedure

Reaction of Bromobenzene. It is essential that all glassware used during this reaction step he clean and scrupulously dried, especially your 100 mL round-bottomed flask. Assemble the apparatus as shown. Add a crystal of iodine to the round-bottomed flask. Weigh out about 0.7 -0.8 grams of magnesium turnings into a weigh boat. Transfer them to a mortar, and grind them for about a minute, to expose the shiny magnesium. Weigh 25.0 mmol of clean, dry magnesium turnings and transfer then to the round-bottomed flask. Weigh 25.0 mmol of dry bromobenzene into the dried Erlenmeyer flask and dissolve it in 5.0 mL of anhydrous ethyl ether. Then transfer this solution to the separatory-addition funnel and stopper it, placing a tiny strip of filter paper between the stopper and the neck of the funnel. Add the bromobenzene solution all at once to the

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reaction flask and replace it in the addition funnel by 8 mL of anhydrous diethyl ether. Begin stirring the solution, and observe the reaction mixture closely for evidence of a reaction, such as cloudiness and the evolution of bubbles from the magnesium surface. If the reaction does not begin within 5 minutes or so, consult your instructor. When the reaction mixture begins to boil quite vigorously without external heating, add the ether drop by drop at a rate just sufficient to keep the reaction mixture boiling. When all the ether has been added, let the reaction continue until the boiling has nearly stopped, then use a heating mantle or thermowell to heat the reaction mixture under gentle reflux for another 15-20 minutes. The reflux ring of condensing ether should be in the lower third of the condenser. If a significant amount of ether evaporates, reducing its volume in the reaction flask, replace it with fresh anhydrous ether. Do not stop at this point, because the phenylmagnesium bromide solution will not keep for long. Remove the thermowell, but keep the reaction stirring while you do the next part.

Reaction of Phenylmagnesium Bromide. Dissolve 20.0 mmol of your assigned ketone in 10 ml of anhydrous diethyl ether in a dry Erlenmeyer flask and place it in the separatory-addition funnel. When the reaction mixture has cooled so that the ether is no longer boiling, add this solution drop by drop to the reaction mixture with shaking or magnetic stirring. The addition rate should be sufficient to keep the ethyl ether boiling gently without external heating. When the addition is complete, use a heating mantle or thermowell to heat the reaction mixture under gentle reflux for another 30 minutes.

After the reaction mixture has cooled to room temperature, add 5.0 mL of water drop by drop through the separatory-addition funnel while shaking or stirring, and then add 25 mL of 5% (1.4 M) hydrochloric acid. Wait for the reaction to subside and continue stirring or shaking until most or all of the white solid has dissolved (some magnesium may remain undissolved). If any undissolved white solid remains, detach the reaction flask from the apparatus and use a spatula to break up the solid, then shake the capped flask, adding enough diethyl ether or 5% HCl as needed to dissolve all of the solid. There should be at least 20 mL of ether in the reaction mixture at this time; if necessary, add diethyl ether to replace any ether that evaporated.

Separation. If there is undissolved magnesium present, remove it by gravity filtration through your Hirsch funnel without filter paper, washing the magnesium with a small amount of diethyl ether. Transfer the reaction mixture to a separatory funnel, shake gently to mix the layers thoroughly, then drain out and discard the aqueous layer. Carefully wash the ether layer with 15 mL of 5% aqueous sodium bicarbonate. Then wash it with 15 mL of saturated aqueous sodium chloride. Dry the ether solution over anhydrous magnesium sulfate, and filter it into a dry round-bottomed flask. Evaporate the ether using a rotovap.

Add about 10 mL of "hexanes" to the round-bottomed flask, and swirl it for a couple minutes. The hexanes will dissolve some of the impurities. Collect the solid (crude phenylalcohol) by suction filtration, and wash it with a little "hexanes". Save the "hexanes" filtrate for TLC. Allow the product to dry on a watch glass for a few days, then weigh it and take a melting point.

Check the purity of your solid and the contents of the filtrates by thin-layer chromatography (TLC). Draw a pencil line 1 cm from the bottom of a silica-gel TLC plate. Make 4 tic marks on the line. Dissolve a tiny amount of your product in several drops of acetone, and spot it on one

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of the tic marks. Dissolve a tiny amount of your starting ketone in several drops of acetone, and spot it on another tic marks. Spot the hexanes filtrate on another tic mark. Finally, spot TLC standard of biphenyl on the remaining tic mark. Make sure you write down what compound is spotted on each tic-mark in your notebook. Check the TLC plate under a UV lamp to determine if you spotted enough material. Put a folded piece of filter paper in a 400 mL beaker, and add 10 mL of 1:19 ethyl acetate:hexane solvent. Swirl the beaker to wet the filter paper, and then place the TLC plate in the beaker. Cover the beaker with a watch glass, and allow the solvent to rise within 1-2 cm of the top of the plate. Remove the plate, draw a pencil line at the solvent front, wave the plate in the air to evaporate the solvent off of it, and check the plate under a UV lamp. Be sure to circle all of the spots. Pour the solvent into the "Water-Insoluble Organic Waste" bottle.

When you are finished with the hexanes filtrate, pour it into the "Water-Insoluble Organic Waste" bottle in the hood. I will collect your product during the next lab period. Turn it in in a product vial labeled as follows:

Product nameWeightMelting point rangeYour name

You will take an IR spectrum of your dry product. Your instructor will take you down in groups of 3-4 to see how NMR spectra are taken.

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Report Format for Preparation of a Phenylalcohol.

A. Title Page:

1. Descriptive title containing 15-25 words.2. Your name.3. Course and section numbers.4. Dates the experiment was performed.5. Tape your TLC plate to the bottom of the page. Clearly label each column so I know

what it is.

B. Body of the Report (Start a new page)

1. Balanced chemical equation, using structures.2. Observations (things seen, smelled, etc.), with possible explanations.3. Weight and melting point of product.4. Calculations of moles of all reactants from the grams or milliliters you started with,

theoretical yield, and percent yield. Show your work.5. Calculate the Rf values for each of the spots on your TLC plate.6. Attach your NMR and IR spectra, and interpret them.

C. Questions

1. Write a balanced chemical equation for the formation of biphenyl from bromobenzene and magnesium.

2. What do you think are the major sources of loss of yield in your experiment? Explain why you think so, citing any evidence from observations you made. What could you have done differently to minimize these losses of yield?

3. Write an arrow-pushing mechanism to show how your ketone reacted with phenyl magnesium bromide, followed by addition of water, to form your product.

4. Each of the products we made could have been made by the reaction of a Grignard reagent with an ester. What other different Grignard reaction could you have used to make your product?

5. Following the format in Appendix V, construct a flow diagram for the formation of your phenyl alcohol.

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Apparatus for Addition with Reflux and Drying Tube

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Grignard Project Progress Report FormatThis report must be typed or word-processed. Chemical equations may be hand-written in neatly.

A. Title Page

1. Descriptive title with between 10-25 words.2. Dates the experiment(s) was (were) performed.3. Course and section numbers.4. Your name.5. Your group member(s) name(s).

B. For each experiment, include the following items (start a new page for each experiment).

1. Literature used. Include author, journal or book, title of article, volume number, page number, and year. Indicate how you used each piece of literature.

2. Balanced chemical equation, using structures (can be hand-written neatly in ink).3. Procedure and observations.4. Physical data determined (such as boiling points, melting points, Rf values, GC results).5. Calculations of grams and moles of reactants, and theoretical and percent yields of

product. Show your work.6. Include any NMR and IR spectra with the report, along with their interpretations.7. How successful was your experiment? Where do you think you lost yield of your

product? Be specific! Is there any evidence for these places of loss?8. How pure was your product? What evidence do you have for this level of purity?

C. What experiment(s) will you be doing for the next two weeks? How confident are you that they will succeed? Explain your reasoning

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Grignard Project Final Report FormatThis report must be typed or word-processed. Chemical equations may be hand-written in neatly.

Title Page

1. Descriptive title with between 10-25 words.2. Dates the experiment was performed.3. Course and section numbers.4. Your name.5. Names of group members.

Body of report (start a new page)

Write up each step separately, using the following format. If you did the same reaction several times, and just varied the starting materials or conditions, you just need to write up the procedure the first time, and just list amounts of reactants and any changes in procedure for each additional reaction.

1. Literature used. Include author, journal or book, title of article, volume number, page number, and year. Indicate how you used each piece of literature.

2. Balanced chemical equation, using structures (can be hand-written neatly in ink).3. Experimental procedure written concisely, with any important observations.4. Physical data determined (such as boiling points, melting points, Rf values, GC results).5. Calculations of theoretical and percent yield of product. 6. Include new copies of your NMR and IR spectra with the report, along with their

interpretations.

Questions

1. What alcohol did your group try to synthesize? What variations did you do?2. What difficulties did you encounter in your project? How did you try to overcome them?

How successful were you in overcoming these difficulties? 3. How could you improve the yield of your Grignard reaction? Explain your reasoning in

detail.4. How pure was your product? What evidence do you have for this level of purity?5. Following the format in Appendix V, construct a flow diagram for the formation of your

alcohol.

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Report Format for the Wittig Synthesis of 1,4-Diphenyl-1,3-butadiene

1. Title Page

a. A descriptive title with between 15-25 words.b. Dates the experiment was performed.c. Course and section numbers.d. Your name

2. Body of the report (start a new page)

Part A

a. Balanced chemical equation using structures, not formulas. b. Important observations and their interpretations, if possible.c. Weight of product collected.d. Show your calculations of moles of starting materials from the grams and mLs you

started with, the theoretical yield of product, and the percent yield you recovered.

Part B

a. Balanced chemical equation using structures, not formulas.b. Important observations and their interpretations, if possible.c. Weight of product collected.d. Melting point range of product.e. Show your calculations of moles of starting materials from the grams and mLs you

started with, the theoretical yield of product, and the percent yield you recovered.

3. Exercises

Do Exercises 1, 3, and 4 on page 312.

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Report Format for the Synthesis and Identification of an Unknown Carboxylic Acid

1. Title Page

a. A descriptive title with between 15-25 words.b. Dates the experiment was performed.c. Course and section numbers.d. Your name

2. Body of the report (start a new page)

a. Balanced chemical equation using structures, not formulas.b. Important observations and their interpretations, if possible.c. Weight of product collected.d. Melting point range of product.e. Show your calculations of moles of starting materials from the grams and mLs you

started with, the theoretical yield of product, and the percent yield you recovered.f. Data and calculations for determining the neutralization equivalent: show your work.

3. Exercises

a. What is the identity of your unknown acid? Explain in detail how you determined it.b. Exercise 1, p. 342.c. Exercise 6, p. 343.

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Report Format for a Diazonium Salt Reaction of 2-Aminobenzoic Acid

1. Title Page

a. A descriptive title with between 15-25 words.b. Dates the experiment was performed.c. Course and section numbers.d. Your name

2. Body of the report (start a new page)

a. Balanced chemical equation using structures, not formulas.b. Important observations and their interpretations, if possible.c. Weight of product collected.d. Melting point range of product.e. Show your calculations of moles of starting materials from the grams and mLs you

started with, the theoretical yield of product, and the percent yield you recovered.

3. Exercises

a. What is the identity of your unknown acid? Explain in detail how you determined it.b. What is the gas that was given off? What test could you have done to support this

conclusion?

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