1. General

Review the following topics: NMR spectroscopy, IR spectroscopy, Recrystallization

It might be good to read the following paper: Vogel G.G., Perry, W.D., J.Chem.Educ. 1991, 68(7),607.

2. Experiment

Safety note: Petrol ether and cyclopentadiene are highly flammable. It should kept away from all ignition sources. Make sure that the monomer is stored on dry ice at all times.

Don't touch the dry ice with your bare hands. This will cause severe burns due to the low temperature.

Potassium hydroxide is a very strong base. It should only be handled wearing nitrile gloves.

Dimethyl sulfoxide (DMSO) is suspected carcinogen.

The potassium hydroxide has to be ground up in a mortar. Make sure to do this quickly since the fine powder is extremely hygroscopic. The powder is suspended in DMSO and the cyclopentadiene monomer is added. The flask is closed tight!

After 15-20 minutes of stirring, the potassium hydroxide is usually dissolved to yield a brown or purple solution, depending on how much air leaked into the container.

To this solution, a solution of 3 g of FeCl₂*4H₂O in DMSO or DME is added.The mixture is stirred for ~30 minutes during which a orange brown precipitate forms. The mixture is poured in ice water and the resulting precipitate is isolated by filtration on a Buechner funnel.

The crude product is dried under the heating lamp and then recrystallized from high-boiling petrol ether or hexane. Make sure to use a minimum quantity of solvent and to place the solution in acetone/dry ice bath (~-78 ^oC).

Make sure that you complete the experiment, so that you can continue with the acylation during the next lab period.