Methyl Benzoate by Fischer Esterification - What are two things you could do to
ID: 1057531 • Letter: M
Question
Methyl Benzoate by Fischer Esterification - What are two things you could do to improve the yield of this reaction?
Here is the actual procedure we did:
1. Place 10.0 g of benzoic acid and 25 mL of methanol in a 100-mL round bottomed flask. In the fume hood, pour 3 mL of concentrated sulfuric acid slowly and carefully down the walls of the flask, and then swirl to mix the components.
2. Attach a reflux condenser, add a boiling stone, and reflux the mixture gently for 1 hour.
3. Cool the solution and decant into a separatory funnel containing 50 mL of water, and rinse the flask with 35 mL of diethyl ether. Add this ether to the separatory funnel, shake thoroughly, and drain off the water layer, which contains the sulfuric acid and the bulk of unreacted methanol.
4. Wash the ether in the separatory funnel with 25 mL of water followed by 25 mL of 5% sodium bicarbonate to remove any remaining traces of sulfuric acid and unreacted benzoic acid. Again shake, with frequent release of pressure by inverting the separatory funnel and opening the stopcock, until no further reaction is apparent; then drain off the bicarbonate layer into a beaker. If this aqueous material is made strongly acidic with hydrochloric acid, unreacted benzoic acid may be observed.
5. Wash the ether layer in the separatory funnel with saturated sodium chloride solution and dry the solution over anhydrous magnesium sulfate so that it no longer clumps together on the bottom of the flask. After 10 minutes, decant the dry ether solution into a flask, wash the drying agent with an additional 5 mL of ether, and decant again. Remove the ether using the rotary evaporator.
Explanation / Answer
To improve the yield.
1. You can reflux the reaction mixture for over night or 24 hours.
2. After completion of the reaction evaporate the methanol layer. if you do directly workup with water. your compound in methanol will go into water layer. it may decrease your yield.
3. Please increase the volume of methanol. if methanol is more it reacts fastly.
4. Reflux the reaction mixture fast not gently (higher temperature)