Purpose: To synthesize, and detect the odours of several esters.
Hypothesis: Each of the three esters would have its own unique smell. As mentioned in the previous handout, propyl ethanoate would have a pear odour, pentyl ethanoate would have a banana odour, and octyl ethanoate would have an orange odour.
Materials: (refer to handout)
Procedure:
- A hot-water bath was prepared by half filling a 500mL beaker with water and heating it carefully on a hot plate until it comes to a gentle boil.
- Three test tubes were numbered: the first one was filled with 1mL of 1-octanol, second with 1mL of 1-propanol, and third with 1mL of 1-pentanol.
- In the fume hood, a pipet was used to add 1mL of glacial acetic acid (CH3COOH) and 0.5mL of H2SO4 to each test tube. The tubes were gently shaken in order to mix the substances.
- The test tubes were returned to lab bench and placed into the hot-water bath, pointing away from the group members. After 5 minutes of heating, the test tubes were removed from the heat and put back into the rack.
- The contents of the first test tube was poured into an evaporating dish half filled with cold water; the odour of the ester was wafted and identified as instructed by the teacher. The same process was repeated for the second and third ester.
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