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Investigation of an Unknown Ester
1. “Investigation for an unknown substance”
An Investigational Project for the
Partial Fulfillment of Requirements in Organic
Chemistry
Submitted by: Daniel Thomas A. Berberabe
BSP-2A
Centro Escolar University
Submitted to: Mrs. Gliceria Masicap
2. Abstract of Study
The Study is intended for the identification of an unknown substance
which is provided by the instructor. The purpose of the study is to
apply different tests and methods learned from Organic Chemistry
11 in detecting the functional group and compositions of unknown
substances provided.
Based on physical tests,
The unknown substance provided by the instructor was a colorless
liquid with a characteristic sweet odor. It is highly volatile and
flammable. Care must be exercised in handling the substance due to
possible fire hazards. The first physical test used is the ignition test
which confirmed that the substance is highly flammable. The odor
was tested using the wafting method to determine the characteristic
odor of the substance (Wafting method is important so that mild
irritations associated with chemicals can be avoided). Solubility of
the substance was tested in Ethyl Alcohol, Acetone and water. The
substance was insoluble in water and soluble in both Ethyl Alcohol
and Acetone. The last physical test is the test for Boiling point. The
test for the boiling point was done three times yielding an average of
78 degrees Celsius.
Based on the results of the physical tests, the unknown substance
exhibits properties similar to an ester. The odor of the substance also
resembles an acetate group because of its similarities with paint,
lacquers and plastic balloon odors. To validate the theory of the
compound being an ester, hydroxamic test for esters is employed.
The hydroxamic test for the unknown substance provided positive
results and confirmed that the substance is an ester. To further
recognize the specific composition of the ester, the physical tests
were linked with some examples of acetate groups widely used in
paints, lacquers and plastic balloons. The final result confirmed that
the unknown substance was ETHYL ACETATE
3. METHODOLOGY AND RESULTS
Physical Tests
1. Ignition test
A small amount of substance
(preferably 1 drop) is put into a Water SLIGHTLY
watch glass. The substance is SOLUBLE
Ignited using a lighted
matchstick. The substance
burned with a yellow flame.
Acetone SOLUBLE
Ethyl Alcohol
SOLUBLE
2. Wafting method (odor test)
The compound is held near the 4. Boiling point
Nose avoiding direct contact and
slowly wafting so that the odor can
be easily detected. The substance 1st TRIAL 80 degrees
contains a sweet odor similar to Celsius
paints, lacquers and plastic balloon.
2nd TRIAL 77 degrees
3. Solubility Celsius
The solubility of the substance is
tested with Ethyl Alcohol, Acetone 3rd TRIAL 78 degree
Celsius
4. and Water. 1 ml of the unknown
substance is dissolved in 3ml of each
compounds.
Chemical Test AVERAGE- 78 degrees celsius
1. Hydroxamic test for esters
a.) Preliminary test
1 drop of the unknown substance is
dissolved in 1ml of 95% ethyl alcohol
and 1ml of 1N HCl. By adding 1 drop
of 5% FeCl3,the substance will
produce a yellow color.
b.) Final test
1 drop of the unknown substance is
Mixed with 1ml of hydroxylamine HCl
Saturated alcoholic solution and adding
0.2ml of 6N NaOH. The mixture is
Heated in a water bath. The mixture
Is cooled slightly after heating. By adding
2ml of IN HCl and 5% ferric chloride, a
Magenta or burgundy color is produced
The magenta or burgundy color produced
Compared to the yellow color of the
Preliminary test is a positive result. The
Unknown substance is an ester
5. ANALYSIS AND CONCLUSION
The unknown substance’s physical characteristics are the key
element in determining the composition of the compound. The
chemical test however is vital to prove that the unknown substance is
an ester. Esters with low molar mass and derived from carboxylic
acids are generally flammable that is why the compound ETHYL
ACETATE is positive in the ignition test because ethyl acetate is a
low molar mass ester and it is also derived from acetic acid and
ethanol. One of the main characteristics of ethyl acetate is its sweet
odor similar to plastic balloons, this sweet odor is present if the ester
has lower molar mass.
Solubility is also a good test for determining an unknown compound.
Ethyl acetate is slightly soluble in water and soluble in ethanol and
acetone. Ethyl acetate is slightly soluble in water because of absence
of –OH group and an increase in carbon chain length. Boiling point is
the test that specifically identifies the unknown compound because
the acetate groups have definite boiling points. Based on the
experimental result, the unknown substance yield an average 78
degree Celsius boiling point close to the theoretical boiling point of
ethyl acetate.
The hydroxamic test for ester is a chemical test used to prove that the
unknown substance is an ester. The test is used when an ester is
reacted with a hydroxylamine hydrochloride saturated alcoholic
solution to and then reacting with ferric chloride to form a ferric
hydroxamate which is an indicator that an ester is present.
These evidences lead to the conclusion that the unknown substance
is ethyl acetate because of the solid evidences provided by physical
tests such as boiling point, solubility and the hydroxamic test.