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. Which reactant should be used in excess here? In which ratio and why?
b. Why is concentrated sulfuric acid used in this reaction? Could concentrated hydrochloric acid be used instead?
c. Why is the reaction mixture refluxed? Which setup is used here?
d. Why is an extraction with sodium bicarbonate used during the work-up? How does the student know that he extracted often enough?
e. What is the final purification step for the product?
2. A student refluxes a mixture 1.35 g of L-(+)-tartaric acid, 2.00 mL of ethanol and 0.3 mL of concentrated sulfuric acid for two hours. After the work-up, the student isolated 1.50 g of the ester.
a. Show a balanced chemical equation for the reaction.
b. Determine the yield of the reaction. Show all calculations.
c. The student observes refractive index of nD18.7= 1.4470. Which conclusion can he draw from this observation?
3. Extraction
a. Construct a flow diagram to separate o-cresol, anthranilic acid and graphite.
b. Construct a flow diagram to separate p-diacetylbenzene, acetophenone and acetyl chloride.