2) Changes to published procedure
We used 9 mL of isopentyl alcohol (3-methyl-1-butanol), 12 ml acetic acid, and 3 mL H2SO4.
Reflux was done for 40 min.
The routine liquid-liquid washings were done.
The ester was distilled to its final purified form.
We performed an IR spectrum of the products.
3) Positive
+ A classic experiment that covers an important reaction.
+ The product is easy to put between salt plates for the IR.
+ It smells nice.
4) Neutral
± It seems like a lot of acid is needed. Isn’t excess acetic acid enough acid?
± During reflux the mixture turns a dark color. Is this because of impurities in the alcohol?
5) Negative
- This would be much more interesting if the students could mix-and-match several alcohols and carboxylic acids. Wade P.A.; Rutkowsky
6) Inquiry & Extension ideas.
● The combinatorial approach is very cool. Any carboxylic acid matched with a primary alcohol should give a decent yield. At a certain point it would be impractical to distill the resulting esters, possibly.
● Acid-catalyzed reactions have the option of changing the acid.
● Acid-catalyzed reactions always have the possibility of interesting side reactions occurring: eliminations, polymerization, etc…
Student Comments 2008: Synthesis of Isopentyl Acetate (Banana Oil)
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