The document discusses the preparation and synthesis of aspirin. Aspirin, also known as acetylsalicylic acid, is synthesized through the esterification reaction of salicylic acid and acetic anhydride. This reaction converts the hydroxyl group of salicylic acid into an ester group, yielding aspirin and acetic acid as a byproduct. A small amount of sulfuric or phosphoric acid is used as a catalyst. The document also outlines the history, uses, and potential side effects of aspirin.

1. Chemical Process Industr ies
Topic: Preparation of Aspirin
Prepared By:

2. Details of aspirin:
o It is also commonly known by the name Acetyl Salicylic Acid and its IUPAC name
is: 2- Acetyloxybenzoic Acid
o Its molecular formula s: C9H8O4 and molecular weight is: 180.157 g/mol.
o Structural Formula of aspirin is :
o In 1853 Charles F. Gerhardt synthesized a primitive form of aspirin, derivative
of salicylic acid.
o In 1897 Felix Hoffmann working at Bayer, Germany derived a better way to
synthesize the aspirin.
o It was the first NSAID (non steroidal anti-inflammatory drug) and still is most
effective drug.
o It was mainly developed as an analgesic drug (pain killer).

3. Synthesis of aspirin:
o It is synthesised by the esterification reaction.
o The rectants used are salicylic acid and acetic anhydride.
o Here the salicylic acid is treated with acetic anhydride which results in chemical reation
turning the hydroxyl group of salicylic acid into ester group (R-OH -> R-OCOCH3).
o This yields aspirin and acetic acid, which is regarded as by product.
o Small amount of sulphuric acid (H2SO4) or phosphoric acid (H3PO4) are used as catalyst.
Chemical Reaction:
O
C-OH
OH
salicylic acid
O O
CH3C-O-CCH3
acetic anhydride
O
C-O-H
O C-CH3
O
aspirin
O
CH3C-OH
+
H

4. MECHANISM
••
••
••
••
O O
••
CH3C-O-CCH3
••
+
H
H

••
••
••
O O
••
••
CH3C-O-CCH3
H
••
••
••
••
O O
••
CH3C-O-CCH3
 ••
H
••
••
••
••
O O
••
CH3C-O-CCH3

H
••
••
••
••
O O
••
CH3C-O-CCH3
 ••
O
C-OH
•• C-OH
OH
••
O
H
••
••
••
••
CH3C-O-CCH3
OH
O O

••
••
••
O
C-OH
H
••

CH3C-O-CCH3
O
O O
H
••
••
••
••
••
••
O
C-OH
O
H

O
CCH3
••
••
••
O
C-OH
O
O
H
CCH3

••
••
••
••
O
C-OH
H
••

CH3C-O-CCH3
O
O O
H
••
••
••
••
••
••
••
O
••
HO-CCH3
••
••
O
C-O-H
O C-CH3
O

5. SYNTHETIC ASPIRIN
Synthesis from petroleum

6. FLOW CHART SCHEME FOR PURIFICATION
O O
CH3C-O-CCH3
O
C-OH
OH
H3PO4
heat 10 min add H2O cool
ppt
filter
O
C-O-H
O C-CH3
O
unreacted
salicylic acid
polymer
O
CH3C-OH
H3PO4
H2O
O
C-O–Na+
O C-CH3
NaHCO3 O
*
sodium
salicyate
polymer
NaHCO3 H2O
vacuum
filter *
polymer
O
C-O–Na+
O C-CH3
O
sodium
salicyate
NaHCO3 H2O
HCl
-CO2
O
C-O-H
O C-CH3
O
unreacted
salicylic acid
HCl NaCl H2O
O
C-O-H
O C-CH3
O
vacuum
filter
unreacted
salicylic acid
HCl NaCl H2O

7. Final Recrystallization of Crude Aspirin
O
C-O-H
O C-CH3
O
unreacted
salicylic acid
recytal.
ethyl
acetate
vacuum
filter
dry
O
C-O-H
O C-CH3
O
mp 135°C
unreacted
salicylic acid
ethyl
acetate

8. Industrial Scale Production of aspirin

9. Uses of aspirin:
o Over-the-counter pain relief, especially for headaches.
o Reduction of swelling and inflammation in arthritis and
injuries.
o Anti-coagulant given to sufferers of heart attack.
o Can reduce severity of heart attack if taken at first symptoms.
o Recovery after cardiovascular surgery.
o Treatment of rheumatoid arthritis, osteoarthritis and other
rheumatoid diseases

10. SIDE Effects:
o Risk of increase in gastrointestinal bleeding.
o It inhibits the ability of kidney to excrete uric acid and
exacerbate these conditions.
o Large dosages results in tinnitus (ringing in ears).
o May result in fatty liver and acute encephalopathy.
o May cause swelling of skin tissues.
o It increases the risk of cerebral microbleed.

11. Thank you