Question

Lap questions, please provide the answers in steps.

1)Write the balanced equation for the synthesis of Aspirin    (with Structural formula, Mol. formula, Catalyst and names of reactants & products). Classify the reaction that takes place.

2)After synthesis of Aspirin, Suggest an experiment or technique based on what you have learned last few weeks to confirm the preparation of Aspirin. (Give full details) Hint: (you are provided with pure sample of Aspirin)

3)Suppose you started with 30 g of salicylic acid and an excess of acetic anhydride was used to prepare Aspirin. If you prepared 21.0 g of acetyl salicylic acid (aspirin), calculate the yield of this reaction. (Show your calculations)

Answer 1

1. Aspirin synthesis from salicylic acid is esterification reaction. The balnced equation with catalyst, reactant and products is given in figure.

2. If you have pure aspirin you can confirm your product by taking TLC of your product and pure aspirin provided to you.

3. MW of salicylic acid: 138; Molecular weight of Aspirin: 180; amount of Salicylic acid taken: 30 g

Theoretical yield: amount of reactant x MW of product/MW of reactant = 30 x 180/138 = 39.13 g

Practical yield: 21.0 g

% yield: 100 x practical yield/theoretical yield = 100 x 21.0/39.13 = 53.7 %