Meeting 5 Problem Set 30 BL (Esterification Reaction)

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. Show pertinent chemical equations where appropriate.

1. What is the role of the concentrated sulfuric acid in this week's experiment?

2. Explain how the workup serves to isolate the ester. Supply a flow chart indicating in which layer the ester can be found at each step. (Hint: What organic compounds are present after the reflux?)

3. Extraction with sodium bicarbonate

a. Why is it necessary to be careful in the beginning?

b. Could you replace it by Na₂CO₃ solution?

4. Refractive index

a. Which information do you get from the refractive index?

b. A student observes a refractive index of n_D²²=1.3502. What is the refractive index at 20 C?

5. A student refluxes a mixture 10 mL of glacial acetic acid, 7.5 g of butanol and 2 mL of concentrated sulfuric acid for two hours. After the work-up, the student isolated 9 mL of the ester.

a. Show a balanced equation for this reaction.

b. Determine the yield of the reaction. Show all the calculations.

c. How could the student improve the yield?

6. Do questions 4, 7, 8 and 11 on p. 140 in Landgrebe.