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Acid
A
B
C
D
E
F
G
H
I
Nam
#1
#1
#2
#2
#3
#3
#4
#5
#6
Smell
Name
#1
#2
#1
#3
#4
#5
#1
#1
#6
INSTRUCTIONS FOR SCENT OF ESTER LABORATORY PREPARATION
Materials:
small test tubes
hot plates
small labels
filter paper
Beryl pipettes
Chemicals
Name
Label on Jar
salicylic acid
Acid #4
2-amino benzoic acid
Acid #5
(o-aminobenzoic acid)
Label on Beryl Pipette
isopentyl alcohol (isoamyl) Alcohol #1
ethyl alcohol
Alcohol #2
methyl alcohol
Alcohol #3
benzyl alcohol
Alcohol #4
propyl alcohol
Alcohol #5
isobutyl alcohol
Alcohol #6
acetic acid
Acid #1
pentanoic acid (valeric)
Acid #2
propanoic acid
Acid #3
formic acid
Acid #6
Concentrated Sulfuric Acid which will be on teacher’s bench.
THE SCENT OF ESTERS
11/2005
Horace-Mann Chemistry
Name _______________________________ Partner _________________________
The overall purpose of this laboratory is to synthesize a series of esters and to use your
olfactory senses to identify the alcohol and acid which reacted to produce each ester.
PRELABORATORY EXERCISES
1. Draw flat line structures for the following organic acids
a. formic (methanoic)
b. acetic (ethanoic) c. propanoic (propionic)
d. pentanoic
e. benzoic
f.o-aminobenzoic
g. salicylic (o-hydroxybenzoic)
2. Make flat line structures for the following organic alcohols
a. methyl (methanol)
b. ethyl (ethanol)
c. propyl (1-propanol)
d. isobutyl (2-methyl-1-propanol)
e. isopentyl (3-methyl-1-butanol)
f. benzyl
3. Write a balanced equation for the reaction between ethyl alcohol and propanoic acid to
form the ester, ethyl propionate (ethyl propanoate). Draw a line structure for the ester
produced.
PROCEDURE:
1. Write the letters A through I on the tops of 9 small test tubes with a wax marking
pencil. Place the labeled test tubes in a test tube rack.
2. Each of the nine test tubes will be filled with different combinations of organic
alcohols and acids. These combinations for each test tube are listed in the table below.
Place the reaction components in each test tube. Use the numbered dropper bottles for the
liquids and be very careful to use the correct number of drops.
Test
Tube
A
B
C
D
E
F
G
H
I
Organic
Alcohol
Alcohol #1 (5 drops)
Alcohol #1 (5 drops)
Alcohol #2 (5 drops)
Alcohol #2 (5 drops)
Alcohol #3 (4 drops)
Alcohol #3 (5 drops)
Alcohol #4 (5 drops)
Alcohol #5 (5 drops)
Alcohol #6 (5 drops)
Organic
Acid
Acid #1 (2 drops)
Acid #2 (2 drops)
Acid #1 (2 drops)
Acid #3 (2 drops)
Acid #4 (small pellet, 0.1 g)
Acid #5 (small pellet, 0.4 g)
Acid #1 (2 drops)
Acid #1 (2 drops)
Acid #6 (2 drops)
3. Come to the teacher’s bench and watch your teacher carefully place one drop of
concentrated sulfuric acid into each small test tube. The acid acts as a catalyst. This is
concentrated acid. Use caution.
4. Place each small test tube in the boiling water bath (250 ml beaker in the hood on hot
plates) for five minutes. Each test tube must be immersed in the boiling water bath for a
total of five minutes.
5. Use a clean stirring rod to transfer a drop of the reaction mixture to a clean piece of
filter paper. Gently waft the vapors toward your nose and determine the characteristics of
the odor. WAFT JUST ENOUGH TO GET A GOOD SMELL. Each ester should
correspond to one of these odors listed below. All of these odors should be familiar to
you.
FRAGRANCE LIST
CORRESPONDING ESTER
COMMON NAME
benzyl acetate
ethyl propionate
isopentyl pentanoate
ethyl acetate
methyl-2-aminobenzoate
propyl acetate
methyl salicylate
isopentyl acetate
isobutyl formate
peach
rum
apple
nail polish remover
grape
pear
wintergreen
banana
rasberry
SYSTEMATIC NAME
benzyl ethanoate
ethyl propanoate
3-methyl-butyl-1-pentanoate
ethyl ethanoate
methyl-2-aminobenzoate
propyl ethanoate
methyl salicylate
3-methyl-butyl ethanoate
2-methyl-propyl methanoate
6. Record your observations in the space provided on the data sheet below. Place the
used small test tubes into the waste container on the teacher’s bench. Use the information
given above to identify the esters and the unknown alcohols and acids.
Test
Alcohol
Tube #
Name
A
1
#
1
B
1
2
C
2
1
D
2
3
E
3
4
F
3
5
G
4
1
H
5
1
I
6
6
Acid
Name
Smell
Ester
Name