Week 7 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. One of the reactants is used in excess here in this reaction. Which one and how much in excess is appropriate here?
b. Why is concentrated sulfuric acid added to the reaction mixture? Show the appropriate intermediate.
c. After the reaction is terminated, water is added to the chilled mixture. Explain.
d. Why is the reaction mixture extracted with sodium bicarbonate during the work-up? Show pertinent chemical equations.
e. Many of the crude products are light tan or yellow in color. How is the product prurified further?
2. A student refluxes a mixture of 1.52 g of p-methoxybenzoic acid, 3.50 mL of iso-propanol and 0.5 mL of concentrated sulfuric acid for two hours. After the work-up, the student isolated 1.80 g of the ester.
a. Show a balanced chemical equation for the reaction.
b. Determine the yield of the reaction. Show all calculations.
c. Predict the boiling point of the compound at p=30 mmHg.
d. The student observes refractive index of nD23= 1.5120. Which conclusion can he draw from this observation?
e. Predict the 1H-NMR spectrum for the product. Include the multiplicity, the chemical shift and the integration in the table.
3. Extraction
a. Construct a flow diagram to separate m-nitroaniline, p-cresol and naphthalene.
b. Construct a flow diagram to separate benzoic acid, benzil and benzoin.