Name: _________________
Date: _________________
SCH4U Lab: Preparation of Esters Lab
Purpose: Why are we doing this lab?
Introduction:
What is an ester? Draw the general formula.
Draw a generic reaction equation for the synthesis of an ester. What type of reaction is
it? What are the reactants? Is a catalyst required?
Prediction: What do you predict the 5 esters you have chosen will smell like? Use the
following format:
Alcohol
Carboxylic Acid
Ester
Predicted Scent
Materials:
Alcohols
A. methanol
Acids
V. salicylic acid
B.
C.
D.
E.
W. acetic acid
X. benzoic acid
Y. propanoic acid
Z. formic acid
ethanol
1-propanol
1-butanol
1-pentanol
F. 1-octanol
Research ester fragrances that can
be made with these materials.
Pick 5 esters for the lab.
**Note some of the names are not IUPAC,
in your report, use IUPAC naming
Procedure:
1)
Set up a 400mL beaker, half full with water, as a hot bath (75o-80oC)
2)
Obtain two clean test tubes. Into one test tube add ~10 drops of the desired
alcohol; into the second test tube add approximately 5 drops of the desired
carboxylic acid. Carefully, waft the vapours of each tube towards your nose and
record the odour of each reactant.
3)
Mix the contents of the two test tubes together. Using a dropper add 4 drops of
concentrated sulfuric acid to the mixture. Carefully, mix the solution.
4)
Place the test tube containing the reactants into the hot bath for about 5 minutes.
Do not let the water or the contents of the test tube boil.
5)
Remove the test tube from the water bath and carefully waft the vapours towards
your nose. If you have trouble detecting the odour of the ester follow the next
step.
6)
Add approximately 20mL of water to a 100mL beaker. Pour the contents of your
test tube into the beaker containing water. Carefully, waft the vapours towards
your nose.
7)
Name the ester and describe its odour.
8)
Discard the contents of your beaker into the organic waste container.
Name: _________________
Date: _________________
Observations: Prepare a table to record your observations before and after the
reaction has occurred
Analysis: Draw structural diagrams for each reaction. Name the compounds using
IUPAC conventions
Discussion:






Sources of error? What challenges did you face? Did the esters smell as you
expected?
Why would putting the ester reaction mixture in water help us smell the ester?
Why did we use a hot plate rather than a Bunsen burner?
What would happen if you forgot to add sulfuric acid?
Describe some commercial and biological applications of esters.
Do you think all schools and hospitals should implement a scent-free policy?
Research how fragrances affect our health and our environment.

End with a concluding statement that reflects back on the purpose of the lab.
Due: ______________________________
Lab: _________________________
Name: ______________________
Level R
insufficient
Initiating & Planning
Use of critical/creative thinking skills
Initiating, planning, predicting, processing
Use of prior knowledge (facts, terminology, definitions,
theories, ideas, principles)
e.g. purpose, hypothesis, introduction, procedure
Performing & Recording
A1/B2
Safe & proper use of equipment
e.g. lab skills, procedure, observations
Analysing & Interpreting
Analysing, synthesizing, researching, interpreting
Evaluating sources of bias/error, suggesting improvements
Justifying conclusions, making connections
e.g. analysis, discussion
Communicating
Expression & organization of ideas
Clarity & use of scientific vocabulary and conventions (e.g.
significant figures)
e.g. overall lab report
B1
Connections to Technology, Society, & the
Environment
Assessing the impact of science on technology, society &
environment
Proposing courses of action
e.g. discussion
Level 1
limited
Level 2
approaching
Level 3
considerable
Level 4
insightful