AP Chemistry: Formation
of Esters
530763WW
Frey Scientific
$47.95
Overview
 AP Chem is a year 2 Chem class!!
Organic lab possibilities?
 For AP Chemistry class
(Demo/Combination of labs?)
Organic Review (1)
 Acetic Acid
 Butyric Acid
Organic Review (2)
 These acids will react with different alcohols
[methyl (1), ethyl (2),
butyl (4) & octyl (8)], forming ESTERS (and
water).
 ESTER:
 Esters tend to have sweet, fruity smells,
which we will detect in the lab today.
Organic Review (3)
 Example Reaction:
CH3COOH + CH3OH -> CH3COOCH3 + H2O

Concentrated Sulfuric Acid will:
1. Act as a Catalyst (make the carbonyl group
more electrophilic)
2. Dehydrate the reaction (removing water so
more ester can be formed -- LeChatelier)

CAUTION! Use gloves, goggles, and safe
lab practices - Conc Sulfuric Acid is 18 M!!
What We’ll Discover Today
 How well/long do the esters keep? (Can this
work as a demo in class? Pre-made
samples?)
 Are all of the scents differentiable? (For
future lab modifications - determining
identities of unknowns)
 Do we REALLY need to pour samples into
water? (Just waft, right?! H2O Drives
reaction to break down the ester! On the
other hand, unreacted sulfuric acid may be a
problem if not diluted 1st.)
Lab Setup
1. Break into 8 (EIGHT) groups [1 sample/gp]
-- Group # = Sample #
2. Follow procedure steps 3-7 ONLY!
3. <We’ll do steps 8-9 ONLY if necessary.>
4. Waft. Write scent description.
5. Rotate to all groups - waft & write scent
description. ARE THEY DIFFERENTIABLE?!
Concluding Thoughts
1. Lab procedure and analysis is pretty light
for AP Chemistry. (It takes more than C to
make a lab worthy of AP Chemistry.)
2. Students synthesizing all samples is a waste
of time.
3. Could be modified/added to to bulk up the
difficulty & analysis. Unknown samples?
End of year lab?
Suggestions? Ideas?
Modifications?
Ref
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http://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/Acetic_acid_atoms.svg/8
00px-Acetic_acid_atoms.svg.png
http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons
/2/24/Butyric-acid-2Dskeletal.png&imgrefurl=http://commons.wikimedia.org/wiki/File:Butyric-acid-2Dskeletal.png&usg=__ysSaPc_P1BeP6q54i03joE0qbI=&h=576&w=1100&sz=20&hl=en&start=3&um=1&itbs=1&tbnid=KreQ1
sPhh4D_AM:&tbnh=79&tbnw=150&prev=/images%3Fq%3Dbutyric%2Bacid%26um%3D1%26hl%
3Den%26client%3Dsafari%26sa%3DN%26rls%3Den%26tbs%3Disch:1
http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons
/9/99/Ester-skeletal.png&imgrefurl=http://commons.wikimedia.org/wiki/File:Esterskeletal.png&usg=__KXMDdMXsC_ghX4Hqvb-B8VI_D4=&h=744&w=969&sz=11&hl=en&start=3&um=1&itbs=1&tbnid=gmd_CISuVsAuAM:&tbnh=1
14&tbnw=148&prev=/images%3Fq%3Dester%26um%3D1%26hl%3Den%26client%3Dsafari%26s
a%3DN%26rls%3Den%26tbs%3Disch:1