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Meeting #13
General Announcements
1. The next quiz (=quiz 5) will be administered on November 7, 2007 at 10 am. It will cover the Grignard reaction and the esterification. Make sure that you show up on time. Otherwise you will not be allowed to take the quiz.
2. Please look start looking for a partner for the last project. Your partner should be in a different time slot than yourself e.g. if you are in T/R morning section, your partner should be in section in the T/R afternoon section or in the W/F afternoon section. The proposal will be due on November 21, 2007 at 5 pm.
3. If possible both reactions (esterification and nitration) should be carried out in this lab. This will give you more time to recrystallize the final product and get better quality crystals. The final product has to be turned in to the TA by November 14, 2007.
Homework questions
1. Referring to the Esterification carried out in the lab, answer the following questions. Show chemical equations where appropriate.
a. Why is it imperative to dry the benzoic acid thoroughly before carrying out the esterification?
b. What is the function of the sulfuric acid in this reaction? Show appropriate intermediates here.
c. Why is methanol used in excess in this reaction?
d. After the reaction is terminated, the reaction mixture is cooled and poured into water. Explain briefly why.
e. Why is the organic layer extracted with sodium bicarbonate?
f. What does the final product look like?
2. Referring to the Nitration reaction carried out in the lab, answer the following questions. Show chemical equations where appropriate.
a. Why is it important that the ester is dissolved in sulfuric acid first?
b. Why is temperature control crucial in this reaction? How is this accomplished?
c. How is the electrophile in this reaction obtained?
d. A student attempts to recrystallize the crude product from hot water. What would he observe?