The benzoin condensation is a reaction between two molecules of benzaldehyde catalyzed by cyanide ions to form benzoin. It was first reported in 1832 by Liebig and Wöhler. It involves a cyanide ion forming a cyanohydrin intermediate with benzaldehyde, followed by a condensation reaction between the cyanohydrin and another benzaldehyde molecule. This forms benzoin along with the removal of cyanide ions. Benzoin condensation is useful for organic synthesis and producing polymers.

1. BENZOIN CONDENSATION
PRESENTED BY: MR K V NANDA KUMAR
ASSOCIATE PROFESSOR
KRISHNA TEJA PHARMACY COLLEGE, TIRUPATHI-517506
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2. CONTENTS
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History
General principle
Requirements for the reaction
Reaction mechanism
Applications

3. HISTORY
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The Benzoin condensation is a condensation reaction between two
aromatic aldehydes, especially benzaldehyde that is catalyzed by a
cyanide.
The reaction product is an aromatic acyloin with benzoin as the parent
compound.
The history of this reaction goes back to 1832 when it was reported by
German scientists Justus von Liebig and Friedrich Wöhler.

4. GENERAL PRINCIPLE
• The benzoin condensation is the condensation
between two molecules of benzaldehyde to form
benzoin in the presence of a cyanide catalyst (e.g.,
NaCN and KCN) or thiamine (vitamin B).
• The structure of benzoin is that of a ketone.
• It consists of acetophenone bearing hydroxy and
phenyl substituents at the alpha-position
(α‐hydroxyl ketone).
• Its IUPAC name is 2-hydroxy-1,2-diphenylethanone
with a molecular mass of 212.24 g/mol.
• A cyanide ion usually catalyzes benzoin
condensation.
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5. REQUIREMENTS OF THE REACTION
• Two molecules of benzaldehyde
• A cyanide ion usually catalyzes benzoin
condensation.
• Cyanide is used because it is a good
nucleophile, can stabilize the
intermediate ion, and is an excellent
leaving group.
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6. MECHANISM OF
THE REACTION
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• STEP 1:
The standard method for performing the benzoin
condensation begins with benzaldehyde treated with a
catalytic amount of sodium cyanide in the presence of a base.
The cyanide ion forms a stable cyanohydrin intermediate

7. MECHANISM OF
THE REACTION
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• STEP 2:
The second step is the condensation reaction that occurs
between the cyanohydrin and the benzaldehyde.

8. MECHANISM OF
THE REACTION
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• STEP 3:
In the third phase, rearrangement occurs and also the removal
of the cyanide ions occurs resulting in the formation of
benzoin.

9. USES AND APPLICATIONS OF BENZOIN CONDENSATION
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The benzoin condensation reactions find uses in various organic synthesis and
reactions.
The product benzoin is made use in hardening of different polymers by making
use of microemulsion.
The reaction is helpful in the synthesis of heterocyclic compounds and also
extends to the aliphatic form of aldehydes.
These reactions also find its applications in the poly chemistry, for the production
of polymers as well in the condensation of new monomers.

10. QUESTIONS
• What is benzoin condensation?
• Write the general principle involved in benzoin condensation.
• Explain the mechanism involved in benzoin condensation?
• What are the important applications of benzoin condensation?
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Thank you Any questions