Hawler medical university
College of pharmacy
1
st
stage
Group:4
SYNTHESIS OF ACETYL
SALICYLIC ACID (ASPIRIN)
Prepared by:
Rawsht Rzgar
Didar Karzan
Muhammad Ayiub
Sahand Soran
Date:9\12\2024
Definition:
The synthesis of acetylsalicylic acid (aspirin) involves a chemical
reaction that converts salicylic acid into aspirin. This is achieved
through a process called esterification, where the hydroxyl group (-
OH) of salicylic acid is replaced with an acetyl group (-COCH3)
from acetic anhydride. The reaction is typically catalyzed by a
strong acid, such as sulfuric acid.
Principle:
The basic principle of aspirin synthesis lies in a chemical reaction called
esterification. Here's a simplified breakdown:
Starting Material: The process begins with salicylic acid, a compound that
naturally occurs in some plants.
Key Reaction: Salicylic acid has a hydroxyl group (-OH) attached to a
benzene ring. In the presence of an acid catalyst (like sulfuric acid) and a
reagent called acetic anhydride, this hydroxyl group is replaced with an
acetyl group (-COCH3).
Product Formation: This reaction transforms salicylic acid into
acetylsalicylic acid, which is the chemical name for aspirin.
Information:
Aspirin, or acetylsalicylic acid, has a long history dating back to ancient
civilizations, where willow bark, containing salicin (a precursor to salicylic
acid), was used for its pain-relieving properties.
In the late 19th century, Felix Hoffmann, a chemist at Bayer, synthesized
aspirin in its current form, revolutionizing pain management and fever
reduction.
Reference:Pubmed.com
Glassware & Equipment:
1. Conical flask
2. Hood
3. Graduated cylinder
4. Water bath
5. Papper filter
6. Funnel
7. Oven
8. Sensitive balance
9. Spatula
Procedure:
1- In a conical flask containing (1.5g) of SALICYLIC ACID, add
(3ml) of ACETIC ANHYDRIDE in a small portion using a burette
for such addition.
2- Add (3-5)drops of conc. SULFURIC ACID to the solution.
3- Enclose the conical flask, then heat the solution in a water bath to
about (5) minutes.
4- Add (3ml) of DISTILLED WATER to the hot solution.
5- In continuous process add (25ml) of DISTILLED WATER to the
solution.
6- Cool the MIXTURE at room temperature until the white crystals
formed inside the solution.
7- Separate the crystals (ASPIRIN) from the solution by filtration
process.
8- Dry the CRYSTALS then calculate the percentage yield of the
prepared aspirin.
