Week 5 Problem Set 30 BL (Esterification Reaction)
Useful Link: Refractometer
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. Reaction planning of esterification carried out in the lab
a. Which container is used for the reaction? Which implication does this have?
b. Which reactant is used in excess here? Why?
c. What is the function of the sulfuric acid in this reaction?
d. Why is the reaction mixture refluxed? Which setup is used here?
e. Why is the product distill in the end? What changes in the setup compared to e.?
2. A student refluxes a mixture 12.0 g of butyric acid, 20 mL of ethanol and 2 mL of concentrated sulfuric acid for two hours. After the work-up, the student isolated 15.5 ml of the ester.
a. Show a balanced chemical equation for the reaction.
b. Determine the yield of the reaction. Show all calculations.
c. Which potential problems do you see with the reaction setup?
d. The student observes refractive index of nD17= 1.3936. Which conclusion can he draw from this observation?
e. How does the compound smell?
3. Extraction
a. Construct a flow diagram to separate p-aminophenol, benzoic acid and graphite.
b. Construct a flow diagram to separate a aspirin, salicylic acid and ethyl-3-hydroxybenzoate.
c. If sodium bicarbonate is used for extraction, certain precaution have to be taken. Explain.