ACKNOWLEDGEMENT
I would like to express my sincere gratitude to
my Chemistry teacher, _____________________,
for providing me with the opportunity to work
on this fascinating project on “Synthesis and
Decomposition of Aspirin.” Her valuable
guidance, constant encouragement, and
constructive feedback throughout the duration
of this project have been instrumental in its
successful completion. I am also thankful to my
school laboratory assistant for helping me with
the apparatus and chemicals required for the
experimental work. I extend my appreciation to
my classmates and family members for their
support.
CERTIFICATE
This is to certify that _____________________, a
student of Class XII-_____ of
_____________________________________, has
successfully completed the Chemistry project on
“Synthesis and Decomposition of Aspirin”
during the academic year
_____________________.
Internal Examiner:_____________________
External Examiner: _____________________
Principal: _____________________
AIM & THEORY
AIM
1.To synthesize aspirin from salicylic acid
using acetylation reaction
2.To purify the synthesized aspirin through
recrystallization
3.To determine the yield and purity of the
synthesized product
4.To study the decomposition behavior of
aspirin under different conditions
THEORY / BACKGROUND
Historical Background: Aspirin (C₉H₈O₄) is an
important pharmaceutical compound
belonging to NSAIDs. It was first synthesized by
Felix Hoffmann at Bayer in 1897.
Synthesis Reaction:
Salicylic Acid + Acetic Anhydride → Aspirin + Ac
etic Acid
C₇H₆O₃ + (CH₃CO)₂O → C₉H₈O₄ + CH₃COOH
Mechanism: The concentrated sulfuric acid acts
as catalyst by protonating acetic anhydride,
making it more electrophilic for nucleophilic
attack by salicylic acid’s hydroxyl group.
Decomposition Reactions: - Hydrolysis: C₉H₈O₄
+ H₂O → C₇H₆O₃ + CH₃COOH - Thermal:
Aspirin decomposes at elevated temperatures
forming salicylic acid and acetic acid
APPARATUS & CHEMICALS
APPARATUS
Glassware: • Conical Flask - _____ mL • Beakers
- _____ mL, _____ mL
• Measuring Cylinders - _____ mL, _____ mL •
Glass Rod - for stirring • Funnel - for filtration •
Watch Glass
Equipment: • Water Bath - for controlled
heating • Hot Plate - with magnetic stirrer •
Thermometer - _____°C range • Analytical
Balance - precision ±0.001 g • Melting Point
Apparatus • Büchner Funnel - for vacuum
filtration • Vacuum Pump
CHEMICALS / REAGENTS
Primary Chemicals: • Salicylic Acid (C₇H₆O₃) -
_____ g
• Acetic Anhydride ((CH₃CO)₂O) - _____ mL
• Concentrated Sulfuric Acid (H₂SO₄) - _____
drops
Purification & Testing: • Ethanol (C₂H₅OH) -
_____ mL
• Distilled Water (H₂O) - _____ mL
• Ferric Chloride Solution (FeCl₃) - 0.1 M, _____
mL
• Ice-cold Water - _____ mL
Safety Note: All chemicals used were of
analytical grade (AR) with purity ≥ 99%
PROCEDURE
SYNTHESIS PROCEDURE
Step 1: Preparation 1. Weigh _____ g salicylic
acid using analytical balance 2. Transfer to dry
_____ mL conical flask 3. Add _____ mL acetic
anhydride carefully 4. Add _____ drops
concentrated H₂SO₄ as catalyst
Step 2: Reaction 5. Place flask in water bath at
_____°C 6. Heat for _____ minutes with gentle
swirling 7. Continue heating for additional
_____ minutes
Step 3: Crystallization 8. Remove from heat and
cool to room temperature 9. Slowly add _____
mL ice-cold water while stirring 10. White
aspirin crystals precipitate immediately
PURIFICATION PROCEDURE
Step 4: Filtration & Recrystallization 11. Filter
crude aspirin using Büchner funnel 12. Wash
crystals with cold distilled water (3 × _____ mL)
13. Dissolve in minimum hot ethanol (_____ mL)
14. Cool slowly for recrystallization 15. Filter
pure crystals and dry
CHARACTERIZATION
Step 5: Testing 16. Melting Point: Determine
using capillary method 17. FeCl₃ Test: Add 2-3
drops to aspirin solution 18. Decomposition
Studies: Test at different pH and temperatures
OBSERVATIONS
SYNTHESIS OBSERVATIONS
Stage Observation Inference
Initial ______________ ______________
mixing ___ ___
After ______________ ______________
heating ___ ___
Addition of ______________ ______________
water ___ ___
Crystallizati ______________ ______________
on ___ ___
PURIFICATION OBSERVATIONS
Process Observation
Crude filtration _________________
Recrystallization _________________
Final crystals _________________
Final yield _____ g obtained
CHARACTERIZATION RESULTS
Observatio Standard
Test n Value Inference
Meltin _____°C 138-140°C _________
g Point ________
Observatio Standard
Test n Value Inference
FeCl₃ __________ No color _________
Test _______ change ________
(Aspiri
n)
FeCl₃ __________ Purple color _________
Test _______ ________
(Salicyl
ic
Acid)
DECOMPOSITION STUDIES
pH
Conditio Temperatur
n e Time Observation
pH _____ _____°C ____ _______________
(Acidic) _ __
min
pH _____ _____°C ____ _______________
(Neutral) _ __
min
pH _____ _____°C ____ _______________
(Basic) _ __
min
Thermal Temperat Change
Study ure Duration Observed
Sample 1 _____°C 1 hour ___________
______
Sample 2 _____°C 1 hour ___________
______
Sample 3 _____°C 1 hour ___________
______
CALCULATIONS
THEORETICAL YIELD CALCULATION
Given Data: - Starting material: Salicylic acid =
_____ g - Molecular weight of salicylic acid
(C₇H₆O₃) = 138.12 g/mol - Molecular weight of
aspirin (C₉H₈O₄) = 180.16 g/mol
Step 1: Calculate moles of salicylic acid
Moles of salicylic acid = Mass ÷ Molecular weigh
t
Moles of salicylic acid = _____ g ÷ 138.12 g/mol
= _____ mol
Step 2: Theoretical yield calculation
Theoretical moles of aspirin = _____ mol (1:1 sto
ichiometry)
Theoretical mass of aspirin = _____ mol × 180.1
6 g/mol = _____ g
PERCENTAGE YIELD CALCULATION
Actual yield obtained = _____ g
Percentage yield = (Actual yield ÷ Theoretical yi
eld) × 100
Percentage yield = (_____ g ÷ _____ g) × 100 = _
____%
PURITY ASSESSMENT
Based on melting point comparison: - Observed
melting point: _____°C - Literature value: 138-
140°C - Purity estimate: ≥ _____%
SAMPLE CALCULATION
If starting with different amount:
For _____ g salicylic acid:
Moles = _____ g ÷ 138.12 g/mol = _____ mol
Theoretical aspirin = _____ mol × 180.16 g/mol
= _____ g
At ____% yield: Actual yield = _____ g
RESULTS, DISCUSSION & CONCLUSION
RESULTS
• Synthesis Success: Aspirin successfully
synthesized with ____% yield • Product Purity:
Melting point _____°C indicates _____ purity •
Characterization: FeCl₃ test result:
_________________ • Recrystallization:
_________________ crystals obtained •
Decomposition: Most stable at pH _____, least
stable at pH _____ • Thermal Stability: Stable up
to _____°C, decomposes above _____°C
DISCUSSION
The achieved yield of ____% demonstrates the
effectiveness of the synthetic method. The
melting point determination revealed _____
purity of synthesized aspirin. The _____ ferric
chloride test confirms complete consumption of
salicylic acid.
Decomposition studies showed pH-dependent
stability with fastest hydrolysis under _____
conditions due to base-catalyzed ester
hydrolysis mechanism. Thermal studies indicate
proper storage temperature should be _____.
Factors affecting yield: - Incomplete reaction
completion - Product loss during filtration and
purification - Side reactions at high temperature
- Experimental handling errors
CONCLUSION
This project successfully demonstrated the
synthesis of aspirin through acetylation of
salicylic acid achieving ____% yield with _____
purity. The experiment illustrated key
pharmaceutical synthesis principles, purification
through recrystallization, and stability
assessment techniques.
The decomposition studies provided valuable
insights into aspirin’s storage requirements and
degradation pathways. This work enhanced
practical skills in organic synthesis, analytical
characterization, and pharmaceutical chemistry
applications essential for advanced chemistry
studies.
BIBLIOGRAPHY
1.Morrison, R.T. and Boyd, R.N. Organic
Chemistry, 7th Edition. Pearson Education
India.
2.NCERT Chemistry Textbook for Class XII
Chemistry Part II, Chapter 16.
3.Clayden, J., et al. Organic Chemistry, 2nd
Edition. Oxford University Press.
