This is the lab assignment: Oxidation of Secondary Alcohol OBJECTIVES: 1. To ill
ID: 830817 • Letter: T
Question
This is the lab assignment:
Oxidation of Secondary Alcohol
OBJECTIVES:
1. To illustrate reactions 3 and 8 of the citric acid cycle in the laboratory.
2. Be able to follow the reaction progress using the TV monitor and TLC.
3. To analyze the product using 1H NMR and IR spectroscopy.
INTRODUCTION:
Two reactions (3 and 8) of the citric acid cycle involve the oxidation of a secondary alcohol to a ketone. The oxidation of the secondary alcohol to a ketone in reaction 3 was very important as in the next step, the high-energy thioester was formed. Both reactions are catalyzed by a different enzyme.
While we are unable to oxidize a secondary alcohol to a ketone via an enzymatic pathway in our laboratory setting, we are able to accomplish this reaction using a very powerful oxidizing agent. This oxidizing agent is pyridinium chlorochromate (PCC).
PROCEDURE:
1. Record all information and data collected in your laboratory notebook, which is simply a spiral notebook or a piece of notebook paper. You do not need to use the notebook in the virtual laboratory for observations but you may want to use the virtual lab notebook to save TLC, IR and NMR spectra.
2. Enter the stockroom and click on the clipboard. Select Alcohol Oxidation.
3. Choose the starting materials: 1-phenylethanol, and diethyl ether, which is the solvent.
4. Return to the lab and build the experiment apparatus, which includes a heater, condenser, nitrogen gas.
5. Add the reagent, pyridinium chlorochromate (PCC) to the reaction flask.
6. You will monitor the reaction progress using the pull down TV and TLC.
7. Run a TLC sample before you start the reaction and either sketch it in your lab notebook or save it in the virtual notebook. (To save the TLC plate in your virtual notebook click on the save option at the bottom of the TLC plate. Every time you save a TLC plate it will be recorded as TLC1, TLC2, etc. If you record the TLC number in your notebook, this will allow you to go back and review a TLC plate if you wish.)
8. Remember that every time you run a TLC sample the laboratory clock will advance by 5 minutes.
9. Some reactants may not show up on TLC so make sure that you notice the contents of the reaction vessel on the TV monitor.
10.Note the time on the laboratory clock and start the reaction by turning on the stir plate.
11.Advance the laboratory clock by a one minute intervals and note the time at the first sign of product.
12.Take another TLC sample and be sure to sketch the plate in your notebook or save it in your virtual notebook.
13. Advance the laboratory clock by ten minute intervals and continue to monitor the reaction progress by watching the TV monitor until all the starting material is gone.
14.Run another TLC sample and be sure to sketch the plate in your notebook or save it in your virtual notebook.
15.Note the time when all the starting material has been converted to product.
16.Be sure to make an observation about the material present in your reaction flask in your notebook.
17.Transfer the reaction mixture to a separatory funnel by double clicking on the separatory funnel in the drawer.
18.Extract the reaction mixture with HCl. Notice which layer your final product is in by mousing over the layers and viewing the TV monitor. Failure to save the correct layer will result in you having to repeat the procedure.
19.Separate the layers and discard the layer that does not contain your product in the waste container.
20.Transfer your final product to a round bottom flask.
21.Analyze your product by IR and 1H NMR. Be sure to name and save the spectra in your virtual notebook. (To save the IR in the virtual notebook for later review if you wish click on the save button on the bottom of the spectrum. The spectra will be saved similarly to the TLC plates as IR1, IR2 etc. If you note which spectra goes with which lab, you will be able to open up a particular spectra if needed. You may also save the NMR in your virtual notebook by clicking on the saved button. NMRs will be saved as NMR1, NMR2, etc.)
22.Make structural assignments to both your IR and NMR
23.Clean up the laboratory bench by dragging the flask to the waste container.
Question:
Which proton absorption appears the furthest upfield at ~ 2.5 ppm?
ortho protons
meta protons
para proton
methyl protons
a.ortho protons
b.meta protons
c.para proton
d.methyl protons
Explanation / Answer
Which proton absorption appears the furthest upfield at ~ 2.5 ppm?
ortho protons
meta protons
para proton
methyl protons
it's because it's not in the ring. Ortho, meta and para protons are in the ring.
a.ortho protons
b.meta protons
c.para proton
d.methyl protons
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