AS- Esterification – Making Esters

ESTERIFICATION: MAKING ESTERS LAB

Purpose:

……………………………………………………

Materials:

Procedure:Hot water bath:

• Hot water bath:

1. 1. Fill a ¼ of a 150 cm³ beaker with water.
   2. Place it on the hot plate.
   3. Using a thermometer, regulate the hot plate so the water does not exceed 65ºC. (around #6?)
   4. One of the students in the group must control the hot bath at all times.

• Isopentylacetate:

1. 1. Label the test tube “A”
      1. 1.0mL (20 drops) of acetic acid – record the smell
      2. 1.0mL (20 drops) of isopentanol – record the smell
      3. 3 drops of sulfuric acid was added – do not smell
   2. Bring back the test tube to the lab bench and place it in the hot water bath
   3. Heat the mixture for a minimum of 10 minutes.
   4. Mix the mixture from time to time using a glass rod. DO NOT CONTAMINATE by switching the glass rods.
   5. The longer the mixture is heated the better results.
   6. Take out of the water bath, allow cooling down.
   7. Pour the liquid OVER 5 mL concentrated solution of NaHCO₃ to neutralize the remaining acids.
   8. Add 1 mL of NaHCO3 at a time until fizzing stops.
   9. Carefully pipette ONLY the organic layer and place it on a piece of paper and smell.
   10. Record your observations

• N-octylacetate:

1. 1. Label the test tube “B”
      1. 1.0mL/20 drops Acetic acid
      2. 1.0mL/20 drops n-octanol
      3. 3 drops sulfuric acid
   2. Bring back the test tube to the lab bench and place it in the hot water bath
   3. Repeat steps c to i from the first experiment.
   4. Record your observations.

• Methylsalicylate:

1. 1. Label the test tube “C”
      1. 1.0 cm high of salicylic acid
      2. 1.0mL/20 drops methanol
      3. 3 drops sulfuric acid
   2. Bring back the test tube to the lab bench and place it in the hot water bath
   3. Repeat steps c to i from the first experiment.
   4. Record your observations.

Analysis Questions:

 

1. What is the purpose of the hot water bath and concentrated acid?
2. What is significant about the temperature of 65°C
3. Why are all test tubes dry before starting?
4. Use structural or line diagrams to represent each reaction. Include names of all reactants and products and all reaction conditions. Indicate the theoretical odor of each ester produced.

 

Reaction 1:

Reaction 2:

Reaction 3:

The ester responsible for the odour of a lily is 2-phenylethlypropanate

The odour of pineapple is characteristic of an ester produced from n-butanol and butanoic acid

Ethylcinnamate is the ester responsible for the scent of cinnamon. The IUPAC name for cinnamic acid is 3-phenylprop-2-enoic acid.