Question

Fischer esterification lab question, Please help. Thank you in advance

1) In the synthesis of isopentyl ethanoate, whose reaction is shown below

0 cat. H2S04 reflux 1 h O tH20

a) what is the purpose of the sodium bicarbonate solution in the isolation step?

b) what is the purpose of adding molecular sieves to the reaction?

c) what is the purpose adding sulfuric acid to the reaction?

d) why is acidic acid added in excess?

e) what is the purpose of conducting a semi-micro distillation in the second week of this experiment?

Answer 1

a) In this reaction acetic acid is used in excess .so to remove it from reaction mixture sodium bicarbonate solution is used.

b) while performing esterification reaction water is generated.which is trapped in a molecular sieves.trace amount of water can decompose ester found during reaction hens molecular sieves is used.

c) sulfuric acid act as a catalyst in the esterification reaction . which drives the reaction towards the product formation by activating acid.

d) acetic acid play duel role in reaction ,it act as a reagent as well as a reaction medium.it is less expensive than isopentyl alcohol, and easily removed from reaction mixture.

e)semimicro fractional distillation is used to distilled out product isopentyl ethanoate form reaction mixture.as starting isopentyl alcohol boiling point 131°C very close to boiling point of isopentyl ethanoate ( 141°C). Normally moisture sensitive or air sensitive reagent distilled out using this method.