1. General

You will have to start the experiment in the lab first before you go to the computer lab. 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 posted on the web site (meeting 4, Parts II-III). If you do not finish the assignment during the alloted time, you need to come back later.

The GC-spectra 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.

The IR assignment for this quarter has been posted. It is due by January 23, 2009 at 5 pm in YH 3077E. Make sure that you start working on it asap and that you do not forget to turn it in either since no late assignments will be accepted. Submissions via email are not acceptable! If you are not in school on Friday, you are welcome to turn in the assignment on Thursday (or earlier!).

2. Safety notes

Bleach causes stains on clothes since it oxidizes the dyes very quickly. Any spills should be avoided.

Ethyl acetate is flammable. It might catch fire if you spill it on the hot plate. Therefore, be careful when you evaporate off the solvent. Do not forget to add a boiling stick to prevent it from bumping (=spilling). It would also be advisable to place it under the hood at your bench to avoid exposure to the solvent.

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! FYI, a separatory funnel costs more than $80 these days!

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!

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. What is the advantage of PTC reactions?

c. Which properties does a solvent have to have in order to be 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. Why?

e. What is the main use for ethyl acetate in the "real world"?