1. General

You will have to start the experiment in the lab first before you go to the computer room. The reaction will take about 60-90 minutes and does not need to be supervised if set up properly (the Erlenmeyer flask has to be clamped down and covered with parafilm. No heat!). During this time, you will work on the molecular modeling assignment (part II) posted on the web site (meeting 4, Part IIa, IIb and IIc). If you do not finish the assignment during the alloted time, you need to come back later.

The gas chromatogram from your camphor reduction experiment can be picked up in the instructor's office (usually the day after you submitted the sample). Please make sure that you have your bar code with you. No bar code number= no spectrum= low score in post-lab since it is incomplete! You cannot share the data with somebody else! That is considered cheating and will be dealt with accordingly.

2. Safety notes

Bleach causes stains on clothes because it oxidizes the dyes very quickly. Thus, any spills should be avoided.

Ethyl acetate is flammable (flash point: -4 ^oC). Thus, the rotary evaporator is used to remove the solvent.

95 % Ethanol is flammable (flash point: 62 ^oC) . Be careful when you heat it because it will catch fire as well if gets in contact with the hotplate.

2. Experiment

Before using the separatory funnel, you should make sure that it is working properly. If you do not have one in your desk already, check one out from the lab support. In some cases, the stopcock plug is leaking or the stopper on top does not fit tightly. If this is the case, ask your teaching assistant for help. Make sure that you return it after the experiment since we have very limited equipment. Bottom line: If you break it, you will have to pay for it! A separatory funnel costs more than $120!

For the column chromatography, it is very important that you pack the column well. If you have cracks or air bubbles in your column, you will have a poor separation. Place only a very small amount of cotton in the tip of the pipette. Why?

During the recrystallization step, make sure that you do not use too much solvent (how can you minimize the amount?) and that you allow the solution to cool down slowly (Why?). Do not overdo it with the rinsing of the product and make sure that you use ice-cold solvent in this step!

The student will have to submit a HPLC sample of the final product. The concentration of the sample should be 1 mg/mL isopropanol.

Place your final product in a vial, label it and keep it in your desk. It will be the starting material for the Aldol reaction later on the quarter.

3. Critical Thinking

a. How can you verify that you have an excess of oxidative reagent?

b. How could you determine if the reaction was completed?

c. What constitues a good solvent for recrystallization?

d. The label of a bleach bottle usually tells you not to mix it with other cleaners, which contain acids or ammonia. Why?

e. What is the main use for ethyl acetate outside the Chem 30BL lab?