1. General

Review the following topics from Chem 30BL: distillation, extraction with separatory funnel, recrystallization theory, vacuum filtration, ¹³C-NMR, HETCOR and DEPT spectroscopy


2. Experiment

Step 1:

Make sure that you allow the mixture to cool first before you extract it with ether.

Try to avoid the use of an excessive amount of drying agent? Why?

The setup for the distillation should look like below.

The distillation setup consists of a flask (containing the solution), a three-way adapter, a water condenser, a vacuum adapter and a round-bottom flask to collect the liquid that condenses. The water supply (inlet) is connected on the bottom (lower) end, while the outlet goes either back to the sink or to the inlet of another condenser. Make sure that you have an opening at the end of your setup to release the pressure that will build up when you start to heat. Before you start, let the TA check on the setup.


Step 2:

a-Chloroacetyl chloride is very corrosive and sensitive to moisture. Make sure that all the glassware in the experiment is dry.

You will need to get the solid product during the first lab section because it has to air-dry for some time.


Step 3:

Make sure that all the glassware in the experiment is dry. Why?

If needed, the reflux time can be shortened to 60 minutes. Make sure that the hoses are properly attached before you leave to the computer lab.

In some cases, the crude Lidocaine does not crystallize. If this is the case, use the following procedure:

1. Extract the crude oil using small portions of petroleum ether (careful!).

2. Add and a spatula of char coal and heat this mixture to a gentle boil for five minutes.

3. Filter the hot suspension using a warm glass funnel with filter paper.

4. Reduce the volume of the solvent to ~5 mL, then allow the solution to cool down to room temperature before placing it in an ice bath.

3. Things to think about

a. How does the procedure in Step 3 (above) help to crystallize the Lidocaine?

b. How would the ¹H-NMR and the ¹³C{¹H} for the compounds (3), (4) and (5) look like?

c. What are the characteristic changes in the IR spectra going from (3) over (4) to (5)?

d. Why do you always connect the water inlet to the lower end of your condenser?

e.