Synthesis of Butyl Benzoate Using Phase Transfer Catalysis
The objective of the experiment is to synthesize the butly benzoate by nucleophilic substitution and characterize it by IR spectroscopy. The percent yield of the final product is determined after the synthesis.
2.0 mL of 1-bromobutane, 3.0 g of sodium benzoate, 5.0 mL of water, 4 drops of Aliquat 336, and a boiling stone were placed in a 50mL round-bottomed flask. The reaction mixture was refluxed for 1 hour and the flask was cooled in a beaker in the water of room temperature. The solid was formed in the mixture and the flask was shaken until it dissolved. The flash was rinsed with 15 mL dichloromethane and it was added to the separating funnel. 10 mL of water was added to the funnel and shaken to mix the layers. The lower organic phase was drained into the Erlenmeyer flask and the aqueous phase out of the funnel. After that, the organic layer was returned to the separating funnel and washed with 15% NaCl solution. Anhydrous sodium sulfate was used as the drying agent and allowed the solution to stay for 15 minutes. The Erlenmeyer flask was weighed and the pipet was used to transfer the solution from the drying agent to the flask. Finally, the hood was used to remove the dichloromethane with a stream of nitrogen in the beaker of water at the temperature 50°C. The flask was weighed again to determine the final product after the nitrogen was blown over the solution after the another minute.
1) Percent Yield:
Weight I (beaker) = 30.02 g
Weight II (beaker + 1-bromobutane) = 30.64g
Weight of 1-bromobutane = WII - WI = 30.64 - 30.02 = 0.62 g
Molar Mass of 1-bromobutane (C4H9Br) = 137.02 g/mol
Molar Mass of butyl benzoate (C11H14O2) = 178.23g/mol
Mole ratio = 1:1
Limiting agent: 1-bromobutane
Density of 1-bromobutane= 1.27g/ml, Volume = 2.0ml
Mass of 1-bromobutane = 1.27 x 2.0 = 2.54g
Theoretical mass of 1-bromobutane = 2.54 / 137.02x 178.23...
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