Meeting 8 Problem Set

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

1. Referring to the Grignard reaction, answer the following questions.

a. Which one is the limiting reagent in this experiment? Show your calculations.

b. Why is it appropriate to use anhydrous diethyl ether for this reaction?

c. During the work-up, a student is asked to add 10% sulfuric acid to the reaction mixture. Which precautions have to be taken in this step? Show pertinent equations.

d. During the recystallization step, why is the solution not placed in ice-bath?

e. A student uses low-boiling petroleum ether as solvent. What would he observe?

2. What are the most important changes in the IR spectrum going from the reactant to the product?

3. How can you determine in the GC spectrum which peak belongs to your desired product?

4. Why does the reaction of esters with Grignard reagents lead to the formation of tert. alcohols as the major product?