last updated Thursday, May 22, 2003

Problems Set #9

1. Referring to the esterification,

a. why do you add an excess of methanol and do not use an excess of the benzoic acid?

b. why do you add water after the reaction?

c. why do you add sulfuric acid to the mixture? Show appropriate intermediates.

d. why is it important the the benzoic acid used in this reaction is dry?

2. Outline a separation scheme for the isolation of the ester.

3. What is the common name for the ester? What is it used for?

4. Referring to the nitration experiment, answer the following questions:

a. How do you generate the nitronium ion?

b. During the nitration step, explain why does the amount of the dinitro derivative increases with increase in temperature of the reaction mixture? How can you prevent this from happening? Explain.

c. What is the function of the sulfuric acid? Explain.

5. Why is the nitronium ion a stronger electrophile than a acylium ion? How can you prove this statement?

6. Suggest a pathway to synthesize m-ethylaniline starting from benzene.