1. General

Make sure that you finish up your report for the epoxidation project. The report will be due on May 9, 2003 at 5 pm in YH1217.


2. Experiment

Step 1:

During the second part, make sure that you allow the mixture to cool first before you extract it with ether (Hint: You can use an ice bath to speed things up.). Ether will build up a significant pressure in your separatory funnel if the solution to be extrated is too warm.

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. If the product is wet, it will cause problems in the isolation of the final product. USe a fritted funnel (to be checked out from the lab support) for the filtration.


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.

Use a fritted funnel for the filtrations (to be checked out from the lab support) .

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?