ESTERIFICATION: MAKING ESTERS LAB
Purpose:
……………………………………………………
Materials:
Procedure:Hot water bath:
- Hot water bath:
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- Fill a ¼ of a 150 cm3 beaker with water.
- Place it on the hot plate.
- Using a thermometer, regulate the hot plate so the water does not exceed 65ºC. (around #6?)
- One of the students in the group must control the hot bath at all times.
- Isopentylacetate:
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- Label the test tube “A”
- 1.0mL (20 drops) of acetic acid – record the smell
- 1.0mL (20 drops) of isopentanol – record the smell
- 3 drops of sulfuric acid was added – do not smell
- Bring back the test tube to the lab bench and place it in the hot water bath
- Heat the mixture for a minimum of 10 minutes.
- Mix the mixture from time to time using a glass rod. DO NOT CONTAMINATE by switching the glass rods.
- The longer the mixture is heated the better results.
- Take out of the water bath, allow cooling down.
- Pour the liquid OVER 5 mL concentrated solution of NaHCO3 to neutralize the remaining acids.
- Add 1 mL of NaHCO3 at a time until fizzing stops.
- Carefully pipette ONLY the organic layer and place it on a piece of paper and smell.
- Record your observations
- Label the test tube “A”
- N-octylacetate:
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- Label the test tube “B”
- 1.0mL/20 drops Acetic acid
- 1.0mL/20 drops n-octanol
- 3 drops sulfuric acid
- Bring back the test tube to the lab bench and place it in the hot water bath
- Repeat steps c to i from the first experiment.
- Record your observations.
- Label the test tube “B”
- Methylsalicylate:
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- Label the test tube “C”
- 1.0 cm high of salicylic acid
- 1.0mL/20 drops methanol
- 3 drops sulfuric acid
- Bring back the test tube to the lab bench and place it in the hot water bath
- Repeat steps c to i from the first experiment.
- Record your observations.
- Label the test tube “C”
Analysis Questions:
- What is the purpose of the hot water bath and concentrated acid?
- What is significant about the temperature of 65°C
- Why are all test tubes dry before starting?
- 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.