1. General

Make sure that you keep writing your formal report. See your teaching assistant or instructor if you have questions about the format.

Review the following topics: ¹H-NMR and ¹³C-NMR spectroscopy, GC/MS

2. Experiment

a. Jacobsen Catalyst

If you don't have 1.0 g of the Jacobsen ligand, downscale the other reagents accordingly.

Make sure that the air stream and the temperature of the hotplate is not too high during the oxidation reaction . If the solvent level lowers too much, the reaction will not take place anymore. Keep the solvent level around 20 mL in the flask (by adding more solvent if necessary).

The round bottom flask used should only be half-filled. Why?

The evaporation process of the dichloromethane should be done at low heat using an air stream. However, the concentration process should not be too fast. Why?

The IR spectrum of the Jacobsen catalyst has to be run on a different IR instrument (as KBr pellet).

b. Step 3 b (Oxidation of the alcohol with Ce(OH)₃(OOH))

It is important to keep the temperature of the reaction mixture between 50-70 C (monitor the temperature using a thermometer). A water bath might be the best heat source here. Too low of a temperature slows down the reaction too much. A significantly higher temperature causes the Ce(OH)₃(OOH) to decompose without oxidizing the alcohol. Make sure that you collect the solid product (Ce(OH)₃) in a separate container for recycling. If you dump anything else in there, you will be the one that is going to recycle the Ceric salt!

You should perform the actual oxidation reaction this week, maybe even filter off and wash the Ce(OH)₃ and do the rest of work-up next week.

It might be a good idea to monitor the reaction using TLC.

3. Things to think about

a. Why do you have to reflux the ligand initially with 25 mL of ethanol?

b. How could you improve/speaad up the oxidation process?

c. Why is a mixture of dichloromethane and heptane used in the procedure and not dichloromethane and pentane?