Problems Set - Meeting #2
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 Tuesday, October 6, 2009 at 11:00 am covering the resolution, polarimetry and introduction to asymmetric synthesis. Bring a ruler, non-graphing calculator and pen 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. The initial stage of the reaction the tartrate salt is reacted with potassium carbonate in water. Provide a balanced equation and rationalize the choice of solvent.
b. Next, the 95% ethanol is added to the mixture obtained in a.. Explain.
c. Upon addition of the aldehyde to the solution obtained in b., which observation should the student make?
d. Before allowing the reaction mixture to cool to room temperature, water is added. Why?
e. The IR spectrum of the ligand seems to be missing the characteristic broad OH stretching mode of phenols. Rationalize this observation.
f. 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?
g. The student acquires the optical rotation for the ligand. Which solvent and which concentration should be used for this measurement?
h. A student observes a specific optical rotation for his ligand of [a]= -288o. Determine the optical purity of the ligand. Comment on the result.