Problems Set - Meeting #3
Announcements:
1. Make sure that you make progress on your formal report as well in terms of literature search and writing the parts that you completed already in the lab.
2. The first quiz will be administered on Monday, January 11, 2010 at 11:00 am covering the resolution, polarimetry and introduction to asymmetric synthesis. Bring a ruler, non-graphing calculator and pen/pencil (blue or black) with you. Please make sure that you arrive on time (this means that you are seated by 10:55 am!!!). Late arrivals will not be allowed into the class room since they disturb the rest of the class!! This also means that you will not be allowed to take the quiz!!!
ATTN: answers to the below questions are due at the start of your lab period; these answers should be part of your pre-lab write-up.
Referring to the synthesis and characterization of the Jacobsen ligand, answer the following questions.
a. Why is water used in the initial stage of the reaction?
b. It is very important that a little more than two equivalents of potassium carbonate are used above. Provide a balanced chemical equation for this part of the reaction.
c. How many equivalents of the aldehyde are required for the reaction? Which observation should the student make here?
d. Before allowing the reaction mixture to cool to room temperature after the reaction is completed, water is added. Why?
e. The solvent is removed using a rotavap. Why is this a better way to remove the solvent?
f. What are the characteristic peaks in the IR spectrum of the ligand?
g Which solvent is used to acquire the UV-Vis spectrum of the ligand? Which type of cuvette should be used here? Where is the UV-Vis spectrometer located that is used in this lab course?
h. The student acquires the optical rotation for the ligand. Which solvent and which concentration should be used for this measurement? Where is the instrument used that is used for this measurement? How is this instrument called?
i. A student observes a specific optical rotation for his ligand of [a]= -240o. Determine the optical purity of the ligand. Comment on the result. How should the student proceed?