Question

This is a Fischer Esterification using the alcohol, methanol, and the carboxylic acid, butyric acid, to create the ester, methyl butanoate (smells like apple). After refluxing methanol, butyric acid, and concentrated sulfuric acid, a separatory flask was used and the ester was extracted using ice water, then diethyl ether, then 2 portions of sodium carbonate, and a saturated sodium chloride brine solution. Anyhydrous sodium sulfate was used after separation to dry the ester. Please help!!

4. Read about infrared spectroscopy in your IR tutorial. Look at the reaction; what functional group number range in the IR spectrum does the peak appear and what will it look like? is present in the reactants but not in the ester? At what wave 5. What is the purpose of the sodium sulfate? Write the hydrate interaction to show the role of sodium sulfate. If sodium sulfate was not used what unwanted peak might be observed in the ester's IR spectrum?

Answer 1

In the acid there is -COOH group and in ester it is -COOR. So in the reactant there will be peak near 3200-3300 cm^-1 for -OH group present in -C - OH group. But in the product ester it is absent. 5) Anhydrous Na_2 SO_4 is used to dry the ester by absorbing H_2 O. If H_2 O is present, then ester may undergo hydrolysis to give acid again. If Na_2 SO_4 was not used, then we will see -OH peak at 3200-3300 cm^-1.