Synthesis
of Esters Lab Report
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.
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
Analysis of Results
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
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.
why When different functional groups react to each other, a new functional group is formed?
BalasHapusBacause they from the different reactant so they will form a new functional gruop
HapusWhat causes the ester to have a distinctive odor?
BalasHapusThe term aromaticity originated with the discovery of unusually stable hydrocarbons that also happened to have strong smells. Many hydrocarbons smell, but not all are aromatic.
HapusNowadays, a compound being classified as "aromatic" has little to nothing to do with its smell and everything to do with its electron configuration. There are also non-aromatic compounds and anti-aromatic compounds. If we try to relate these to smell as well, what would an anti-aromatic compound smell like? Bad? But isn't that a little too subjective for science? Doesn't benzene smell "bad" too? Then why is it aromatic (i.e. unusually resistant to chemical change?) Why not anti-aromatic?
Esters smell partly because they exhibit weak intermolecular forces. This allows ester molecules to enter the gas phase and reach your nose. Esters don't exhibit intermolecular hydrogen bonding, unlike alcohols, for example. These are no strongly positively polarized hydrogens in esters to participate in hydrogen bonding. Consider for example ethyl butyrate, which smells like pineapples.
Why the compositions of these chemicals were different? And what the defferent?
BalasHapusBecause to make a different smell we have to react a various alcohol with various carboxylic acid
HapusWhat benefits can be derived from the practicum in your report?
BalasHapusFrom the experiment we know the process of esterification or synthesis of esters
HapusHow many isomers of the ester?
BalasHapusMethyl propanoate (CH3-CH2-COO-CH3)
HapusEthyl ethanoate (CH3-COO-CH2-CH3)
Propyl methanoate (HCOO-CH2-CH2-CH3)
2-methyl-ethyl methanoate (HCOO-CH-(CH3)2)
I just find that sis
Hi mutia, i want to ask. What is the difference of esterification with neutralization?
BalasHapusHello desi,
Hapus1.Esterification involves the reaction between an alkanol and alkanoic acid while neutralization involves an acid and a base.
2. Esterification produces ester and water as product while neutralization produces salt and water only.
3. Esterification is a reversible reaction while neutralization is not.
Esterification occurs in the presence of a mineral acid which act as a catalyst and also a as a dehydrating agent while neutralization can occur without been in the presence of a mineral acid
What is different between Ester and eter?
BalasHapus• Esters have a general formula of RCOOR’. Esters are made by the reaction between a carboxylic acid with an alcohol.
HapusEsters are polar compounds, but they don’t have the capability to form strong hydrogen bonds to each other due to the lack of hydrogen bounded to oxygen. As a result, esters have lower boiling points compared to acids or alcohols with similar molecular weights
Example: (CH3)-COO-(CH3)
• Ether is a type of organic molecule where two alkyl groups, aryl groups, or an alkyl and an aryl group are connected to both side of an oxygen atom.
Ethers can be produces by intermolecular dehydration of alcohols. This usually takes place at a lower temperature than dehydration to the alkene
Example: (CH3)-O-(CH3)
What reaction is used for the identification and separation of carboxylic acids
BalasHapusA carboxylic acid will always have a COOH or carboxyl functional group. When dissociated in solution, it will form a carboxylate ion(COO-) and hydrogen/hydronium ion (H3O+)
Hapuswhy you use Hot Plate in the experiment?
BalasHapusIt is for boiling the water but in the procedure it called beaker of boiling water
Hapus