Preparing Banana Oil (Isoamyl Acetate) – Rate, Catalyst and Yield
ChemistryOrganic ChemistryAges 16–17Virtual lab
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Organic Chemistry
Heat acetic acid with isoamyl alcohol to prepare banana oil, tracking how much ester forms minute by minute. Toggle concentrated H₂SO₄ to see that the catalyst only speeds up how fast equilibrium is reached, not the final yield; only using excess alcohol or continuously removing water actually shifts the equilibrium toward the ester, matching how a real organic chemistry practical is set up. A second screen compares this acid route with acetic anhydride, for banana oil and for aspirin: it plots the amount of ester against time and compares yield and atom economy.
Lesson: Practical experience in organic chemistry
What it shows
Isoamyl acetate, the ester that smells of banana, forms when acetic acid reacts with isoamyl alcohol (3-methylbutan-1-ol) in a reversible esterification with an equilibrium constant close to 4. The model separates two ideas students often mix up: rate and extent. Concentrated H₂SO₄ speeds up both the forward and reverse reactions, so equilibrium arrives sooner, yet the final yield at a 1 : 1 ratio stays near 67%. Only an excess of alcohol or removing water as it forms shifts the position of equilibrium, as Le Chatelier's principle predicts. The second screen compares the anhydride route, which is fast and practically complete but has a lower atom economy.
How to use
Set the Alcohol : acid mole ratio to 1, switch on the Concentrated H₂SO₄ catalyst and press Heat; watch the ester curve level off at the equilibrium line. Then switch the catalyst off and compare with the dashed curve for the other setting. Next raise the ratio or turn on Continuous water removal (Dean–Stark trap) and note the new plateau. Change the Heating time to read the yield at a chosen moment. On Acid or anhydride, choose the Product, press Heat and compare the two curves and the table.
Parameters you can change
- Screen Banana oil, Acid or anhydride
- Product Banana oil, Aspirin
- Alcohol : acid mole ratio 0.5–5
- Concentrated H₂SO₄ catalyst
- Continuous water removal (Dean–Stark trap)
- Heating time 0–180 min
Questions to explore
- Does concentrated H₂SO₄ change the final yield of ester, or only how quickly that yield is reached?
- Why does continuously removing water push the yield of ester close to 100%?
- Once equilibrium has been reached, what happens to the mass of ester if you keep heating for longer?
- Which route gives the higher yield and which the higher atom economy, and which gives more ester from 100 g of reactants?
