CHEM-313 SYLLABUS
Instructor: Dr. J. L. Lyle
Office: NSM D-323
Phone: (310)243-3388;243-3376
Office Hours: Will be announced in class; open-door policy
Required Texts:
Introduction to Organic Laboratory Techniques Pavia, Kriz, Lampman & Engel.
CRC Handbook of Chemistry and Physics (highly recommended)
Lab notebook
Safety goggles
1. Grading: Traditional letter grades will be assigned on the same basis as in CHE-312.
Lab reports 75%, Notebook 10%, Evaluation 15%
2. Lab reports and prelabs. A pre-lab is to be turned in 24 hours before the scheduled lab (see father below for format). A typed lab report will be required for each experiment. The report is due one week after the scheduled completion of the lab. These reports are due at the scheduled start time for the lab. Late reports will be penalized one letter grade for the first 24 hours. Lab reports that are submitted more than 24 hours late will not be accepted!
Please note that lab reports are not written in the lab notebook, but are separate requirements. You will be given explicit instructions about what each lab report is to contain. Lab reports are to be your own work and not plagiarized from some other student or lab report. Academic dishonesty will not be tolerated!
3. Notebook. A written record of what you are doing in the lab will be kept in your notebook. You are expected to have your notebook with you in the lab. Failure to do so can affect your grade. The notebook entries will be written in ink. The carbon copies that you make will be submitted with your lab reports.
4. Evaluation. Part of your grade will be an evaluation of your lab technique, preparedness, punctuality, etc. by the instructor.
5. Safety. You must wear approved eye protection at all times in the lab. Failure to do so will result in expulsion from the lab.
6. Prerequisite. You must have completed CHE-310 and CHE-311. Co-requisite is enrolment in CHE-310.
8. Attendance. You are expected to attend all laboratory sessions. Make-ups will only be allowed if arrangements are made prior to the missed lab and for good reason.
9. Course goals, objectives, and requirements are covered elsewhere in this syllabus.
CHE-313 TENTATIVE SCHEDULE Spring '04
section topic reference
313-01 313-02
1. 1/26 1/27 check-in
2. 1/28 1/29 oxidation/IR & nmr supplement
3. 2/2 2/3 cont. p. 842-845
Appendix 3
4. 2/4 2/5 cont. p. 855-858
Appendix 4
5. 2/9 2/10 ID of unknown ketone supplement
6. 2/11 2/12 cont. p. 888-889
2/16 2/17 no lab
7. 2/18 2/19 Reduct. of acetophenone supplement
8. 2/23 2/24 cont.
9. 2/25 2/26 Grignard synthesis supplement
10. 3/1 3/2 of toluic acids supplement
11. 3/3 3/4 Esterification p. 96-99
3/8 3/11 cont.
13. 3/12 3/11 Aldol condensation p. 409-411
14. 3/15 3/16 cont.
15. 3/17 3/19 Diels Alder supplement
16. 3/22 3/23 cont.
17. 3/24 3/25 α,β-unsaturated ketone p. 413-417
3/29,3/31 3/30,4/1 no lab Spring Break
18. 4/5 4/6 cont.
19. 4/7 4/8 Lidocaine supplement
20. 4/12 4/13 cont.
21. 4/14 4/15 cont.
22. 4/19 4/20 Qualitative analysis p. 485-533
23. 4/22 4/23
24. 4/26 4/27
25. 4/28 4/29
26. 5/3 5/4
27. 5/5 5/6
28. 5/10 5/11
29. 5/12 5/13
Pre-labs:
For each preparative lab you are required to submit at least 24 hours before the lab a pre-lab write-up. The pre-lab is to be written in your lab notebook and the carbon copies submitted for review. These carbon copies will later be attached to your lab report.
1. Title (be specific, eg. "Reduction of Acetophenone with Sodium Borohydride"), name & date.
2. Balanced chemical equation(s) for the reaction(s) that you are going to carry out.
3. Table of Physical Properties summarizing the physical properties of the reactants, solvents, and products. Make photocopies of the sample provided, or make up your own.
4. A step-by-step procedure for the reaction, separation, and purification. Be specific as to amounts (moles & weight or volume).
5. For multi-step syntheses prepare a separate Table of Physical Properties for each reaction in the sequence.
You may turn in pre-labs directly to the instructor or they may be placed in his mailbox in the Chemistry Office (NSM B-302). If you have not submitted a pre-lab before the lab you will not be allowed to begin the experiment until the pre-lab has been completed and okayed. Failure to submit pre-labs on time can severely affect your grade.
Lab Reports
A typed lab report is required for each experiment. Reports are due one week after the scheduled completion of the experiment at 1:00 pm for section 01 and 9:00 am for section 02. Labs turned in after these times will be penalized 10% per day late.
Follow the following format for preparative reports:
1. Title, name & date (unknown #)
2. Balanced equation(s) for the reaction(s) you carried out.
3. Step-wise mechanism(s) for the reaction(s).
4. Physical data for your product(s) (weight, mp or bp, %yield, & literature mp or bp for comparison).
5. Tabulation of spectral data. (Tables summarizing the IR and nmr spectra and your interpretation). see attached.
6. Conclusions, comments, deviations, etc. Discuss your results.
7. Answers to the questions at the end of each preparation.
8. Attach to the end of the report:
a) the pre-lab including table of physical properties
b) any additional carbon copies from your lab notebook
c) IR & nmr spectra, glc's, etc.
Products
With your lab reports you are to turn in the products that you have synthesized in the laboratory. Note, the labels must contain your name, the date, the identity of the contents, the net weight, and the mp or bp. Solid products should be in wide-mouth bottles and liquids in narrow-mouth containers.
TABLE OF PHYSICAL PROPERTIES (This table must be completed before coming to lab!)
Reactants and fw Moles weight volume density bp mp solubility
solvents (g) (mL) (g/mL)
Product(s)
TABLE OF PHYSICAL PROPERTIES (This table must be completed before coming to lab!)
Reactants and fw Moles weight volume density bp mp solubility
solvents (g) (mL) (g/mL)
Product(s)
CHE-313 Reporting IR and nmr spectra
Report the results of infrared and nmr spectroscopy in tabular form. See example below:
For the nmr:
1. Draw the structure of the compound and label the groups of hydrogens that give rise to each signal using a, b, c ... (let a = most up-field).
2. Make a table showing the chemical shift, integration and splitting pattern for each group of hydrogens assigned to the structure.
example: ethoxybenzene Ph-O-CH2CH3
c b a
a 1.3 ppm 3H triplet
b 3.9 ppm 2H quartet
c 6.6-7.2 ppm 5H complex
For the IR:
Make a table listing in decreasing order all of the absorbances and identify those that are important.
example: ethoxybenzene
frequency (cm-) interpretation
3040 C-H stretch unsaturation, Ar-H
3000
2940 C-H stretch saturation
1600 C=C stretch, aromatic ring
1580
1500 C=C stretch, aromatic ring
1480 C-H bend, saturated
1390 " " "
1300
1240
1170
1120 C-O stretch, ether
1050
880
800 C-H out of plane bend -
750 mono-substitution
690
Oxidation of a side chain & introduction to IR and nmr
You will oxidize an unknown arene with KmnO4 to a benzoic acid. See the procedure in this supplement. Because the starting material is an unknown, the table of physical properties is a little different from the ones you have previously prepared. You will be given (on the unknown bottle) the molecular formula of your unknown. Calculate the gram formula weight and the number of moles contained in 1.0 grams. The amount of KMnO4 you will use is based on the formula of your unknown.
You will identify the unknown arene from the melting point of the acid product and the IR and nmr spectra of the unknown. Be sure to balance your chemical equations correctly. No mechanism is required for this report. Include the answers to the following questions in your report.
Answer the following questions:
1. Write a balanced chemical equation for the permanganate oxidation of p-xylene under basic conditions. See your general chem text for review of balancing oxidation-reduction equations.
2. Write a balanced chemical equation for the permanganate oxidation of tolune.
3. Write chemical equations to show how you would oxidize toluene to benzaldehyde rather than benzoic acid. see M&B
4. Why is benzoic acid more soluble in base than in aced?
What is this difference in solubility used for?
5. Tert-butylbenzene is not oxidized by permanganate to benzoic acid. Why not?
6. a) Draw all of the arenes with formula C7H7Br and show the products of oxidation for each one. b) Look up the mp of each product. c) Can you identify every isomer based on the melting point of the carboxylic acid derivative? Explain.
7. Write a balanced equation for the reaction of potassium permanganate with sodium bisulfite.
Identification of an unknown arene by oxidation to the carboxylic acid; introduction to IR and nmr spectroscopy.
A classical approach to the identification of some aromatic compounds is the oxidation of side chains to carboxylic acid groups. Measurement of the derivative's melting point and comparison with the known melting points of different benzoic acids provided a means of identifying or eliminating certain possible structures. For example: if a compound was found to have the formula C8H10, it could be four different compounds: ethyl benzene, o-xylene, m-xylene, or p-xylene. If you look up the boiling points of these four compounds, they are very close to each other. On the other hand, the melting points of the corresponding carboxylic acids produced from the oxidation of the side chains are distinctly different. When combined with additional information, such as the IR and nmr spectra, the melting point of the derivative will usually be sufficient to determine the structure of the unknown.
You will be given a small sample of an unknown arene for which the only information provided is the molecular formula. You are to carry out the permanganate oxidation in alkalai solution and isolate the carboxylic acid. You will measure the melting point of the acid and compare it to the melting points of the possible derivatives from your molecular formula. In addition, you will obtain the IR spectrum of your original uknown and the nmr spectrum.
procedure:
1. The apparatus consists of a 250 mL round-bottom flask fitted with a reflux condenser.
2. Place about 1 gram (40 drops) of the unknown into the flask.
3. Add approx. 80 mL of water and 1-2 mL of 6M NaOH to the flask.
4. Using the powder funnel, introduce the required amount of potassium permanganate (see table below) into the flask and add a couple of boiling chips.
compound formula g KMnO4/g unknown
C7H8 4 g
C8H10 6 g
C9H12 8 g
5. Attach the reflux condenser and begin heating the mixture with a heating mantle. Be careful when the mixture first starts to boil as it has a tendency to "bump".
6. Continue the reflux for 2-3 hours. At the end of the first period, cool the flask, label it, cork it, and place it in one of the hoods until next lab.
7. Suction filter the contents of the round-bottom flask to remove the solid MnO2.
8. Transfer the filtrate to a 250 mL beaker. Place the beaker in a ice bath, and after the solution has cooled for 10 minutes, acidify with 10 mL of 6 M H2SO4, while stirring. (If the solution is still purple due to excess permanganate, destroy it by adding no more than about 2 mL of 20% sodium bisulfite.
9. Test the solution with litmus to verify that it is acidic; if not add more sulfuric acid.
10. Filter the precipitated acid with suction through a small buchner funnel and wash with a few mL of cold water. (If no acid has precipitated, consult with the instructor).
11. Recrystallize the acid from a suitable solvent (try water first).
12. Let the product air dry, weigh it, package it, and obtain its melting point.
Identification of an unknown carbonyl
In this experiment you will be given an unknown aldehyde or ketone. You will obtain the IR and nmr spectra, do the Tollen's test, and prepare two solid derivatives. In the report, identify the unknown and compare the experimental values with the ones given in the text; make a TABLE for comparison. Be sure to include balanced equations for the Tollen's test, the preparations of the derivatives, as well as appropriate mechanisms. Do not weigh derivatives or calculate % yield.
Prepare the 2,4-dinitrophenylhydrazone derivative of your unknown. The reagent is already prepared. Mix 10 drops (0.5 mL) of your unknown in 20 mL of 95% ethanol. To this solution, add 15 mL of the 2,4-DNPH reagent. Shake the mixture vigorously. If a precipitate does not form immediately, let it stand for 15 minutes. Suction filter the solid derivative and recrystallize from 95% ethanol. After air drying, obtain the mp.
Make an additional derivative, the semicarbazone, according to the directions on page 888 and obtain the mp.
Test the unknown with Tollen's Reagent (p 511) to see if it is a ketone or an aldehyde. Page 878-879 lists possible aldehydes in increasing order of boiling point and the melting points of easily prepared derivatives. Ketones are listed in the table on pages 879-880.
Do a simple distillation to measure the boiling point of your unknown carbonyl compound.
Obtain the IR and nmr spectra of your unknown carbonyl compound.
Answer the following questions:
1) An unknown organic compound (b. 212-216 oC) gives a positive 2,4-DNPH test and is positive with Tollen's reagent. A semicarbazone derivative is made that melts at 228-232 oC. What is the identity of the unknown? What would you do next?
2) Predict the products of the reaction of the following with silver nitrate in ammonium hydroxide:
cylcohexanone
formaldehyde
acetone
acetophenone
butyraldehyde
3) In the reaction of an aldehyde or ketone with derivatives of ammonia, the reaction can be catalyzed by sulfuric acid. However, it is important that the pH not be too low since the reaction will slow down at very high acid concentrations. Explain.