Aura Ochoa
April 15, 2011
Chemistry
Liz Schibuk
Synthesis of Esters Lab Report
GSEs:
Science Process Skills 2:11:5.5 Students will discover how the composition of a molecule affects
its interactions with other molecules.
Science Process Skills 4:12:2.2 Students will create written reports and journals to share and
communicate scientific ideas, plans, results, and conclusions resulting from observations and
investigations.
Physical Science 1(Ext)– 4bb Given specific reactants in a chemical reaction, students will
determine the products, type of compound formed (ionic or molecular), and the properties
of the compound.
Purpose,

To synthesize an ester out of an alcohol and a carboxylic acid.
Introduction
Everything that has scent is made up of molecules. Their scent is determined by the
functional group each molecule contains, which is connected to an organic compound, a
carbon-based molecule. These functional groups can determine whether a molecule is an
alcohol, if it smells putrid (a carboxylic acid), or if it smells sweet (an ester). However,
there are more than just three functional groups. When different functional groups react
with one another, a new functional group is formed. For example, if an alcohol reacts
with a carboxylic acid, an ester is formed. For this lab, this is exactly what we had to do.
The class was assigned to combine alcohols and carboxylic acids in order to create
different type of esters. If reacted correctly, the different properties of the different
alcohols and carboxylic acids could make scents such as apple, strawberry, and banana.
Materials
 Various Alcohols
 Various Organic Acids
 Test Tubes (5-8)
 Hot Plate
 Gloves
 Goggles
 Pipettes
 Stirring Rods
Procedure
Wintergreen:
1. Put 0.2 grams of salicylic acid into a 10 cm test tube.
2. Add 6 drops of methyl alcohol add shake the tube until mixed.
3. Add 1 drop of concentrated sulfuric acid.
4. Shake the tube again and place it in a beaker of boiling water for three minutes.
5. After heating is complete, remove the tube from beaker and add 15 drops of
water.
6. Hold the ester away from your face and waft the scent towards you.
Grape:
1. Place 0.2 grams of anthranilic acid into a 10-cm test tube.
2. Add 6 drops of methyl alcohol and agitate the tube until the contents are well
mixed.
3. Add 1 drop of concentrated sulfuric acid.
4. Shake the tube and place it in a beaker of boiling water for three minutes.
5. After heating is complete, remove the tube from breaker and add 15 drops of
water.
6. Hold the ester away from your face and waft the scent towards you.
Banana
1. Put 6 drops of isoamyl alcohol in a 10-cm test tube.
2. Add 2 drops of glacial acetic acid.
3. Add 1 drop of concentrated sulfuric acid.
4. Shake the tube and place it into boiling water.
5. Remove the test tube from boiling water and add 20 drops of water. Shake tube.
6. Wave the vapor of the scent towards you.
Strawberry:
1. Put 6 drops of ethyl alcohol into a 10-cm test tube.
2. Wearing gloves, add 2 drops of butyric acid.
3. Add 1 drop of concentrated sulfuric acid,
4. Shake tube, and place into boiling water.
5. Remove test tube from boiling water and add 20 drops of water. Shake the tube.
6. Smell ester by wafting the vapor towards you.
Apple:
1. Put 6 drops of methyl alcohol in a 10-cm test tube.
2. Wearing gloves, add 2 drops butyric acid.
3. Add 1 drop of concentrated sulfuric acid.
4. Shake tube and place it into boiling water.
5. Remove test tube from boiling water and add 20 drops of water. Shake the tube.
6. Smell ester by wafting the vapor towards you.
Results
Ester
Wintergreen
R-OH
Methyl Alcohol
R-COOH
Salicylic Acid
Banana
Isoamyl
Alcohol
Acetic Acid
Strawberry
Ethyl Alcohol
Butyric Acid
Apple
Methanol
Butyric Acid
Grape
Methyl Alcohol
Anathrnic Acid
Analysis of Results
Odor
There‟s a hint of mint. It‟s very
faint, but the scent of the ester is
mostly foul.
It actually smells like banana.
You really can‟t smell the other
chemicals.
It smells like strawberry. You
can still smell a very small hint
of the acid.
It smells a little bit like apple. At
first, you couldn‟t smell it, but
after a while the scent
It smells nothing at all like
grape. It smells plain foul.
Part 1: Reactions
Ester
Synthesis
Wintergreen
Alcohol
Carboxylic Acid
Reaction
Banana
Strawberry
Apple
Grape
Part 2: Questions
1. What evidence do you have that an ester was produced in each of your reactions?
The evidence that I have that an ester was produced is most of my reactions is the
way the esters smell. If the products of the reactions smell sweet, than you know it is an
ester. If the products of the reactions smell foul, than you know it is not an ester.
2. What is the role of sulfuric acid in this reaction? How come it isn’t listed with the
other reactants?
The role of sulfuric acid in a reaction is to work as a catalyst, which helps speed
up the reaction. The reason why sulfuric acid is not listed with the other reactants is
because sulfuric acid is not a reactant, which means it‟s not part of the production.
Sulfuric Acid, the catalyst, does not undergo a chemical reaction, it does not change.
3. In your own words, describe what happens at a molecular level when an alcohol
and a carboxylic acid react?
When an alcohol and a carboxylic acid react, one hydrogen from the alcohol
combines with an „OH‟ from the carboxylic acid. Both the “H” and “OH” are connected
to organic compounds. Therefore, parts of the functional groups of these molecules have
reacted with one another and created a new molecule, called an ester. An ester has a
specific functional group (“O” double bonded to another “O,” then bonded to another
“O”) that determines its smell.
Conclusion:
The GSE that my work on this lab demonstrates mastery in is Science Process Skills
2:11:5.5. In order to meet proficiency in this GSE, students will discover how the composition of
a molecule affects its interactions with other molecules. In order to conduct the lab, my partners
and I had to combine different types of chemicals made up of different structures, which would
react, and result in an ester. For example, in order to make an ester smell like banana, we had to
combine methyl alcohol (an alcohol) and acetic acid (a carboxylic acid). The compositions
of these chemicals were different, but once they we combined them and heated them up,
they produced a sweet-smelling molecule. Although in class we had learned about the
process, but it wasn‟t until the actual lab that I discovered and witnessed that when you
combine an alcohol and a carboxylic acid (which smells putrid), you get a sweet-smelling
compound. The other way my work on this lab shows proficiency in this GSE are the
chemical reactions. In doing the reactions, I was able to show the way an ester looks once
the alcohol and carboxylic acid react in the form of a skeletal structure.
Alcohol
Carboxylic Acid
Methyl
Salicylic Acid
n-Propyl
Isoamyl
Anthranilic Acid
Octyl
n-Butyl
Acetic Acid
Ethyl
Butyric Acid