Benzoin Condensation

Many reasons focus on the importance of chemistry reactions in our daily life. The chemical reactions tell us about the formation of matter, how the new substances formed and the results of these reactions. Chemistry reactions help us in understanding the properties of matter and their chemical properties that are required to identify any unknown specimen or even make predictions on the types of matter.

By understanding these chemical reactions, we get to understand the natural world and as to what makes it happen. The Benzoin Condensation is one of the chemical reactions; that explains the formation of Benzoin from the aldehydes. In 1832, Justus von Liebig and Friederich Woehler were the persons who, the reaction is named.

Definition and Meaning of Benzoin Condensation

DefinitionBenzoin condensation reaction or also called as condensation reaction is defined as the reaction between two kinds of aromatic aldehydes especially benzaldehyde, in the presence of some catalyst (either nucleophile or heterocyclic) to form an aromatic parent compound.

Condensation reactions are mainly used to create carbon to carbon bonds, polymers, new monomers, production of polypeptides, etc.

Benzoin condensation reaction is nothing but the coupling reaction that occurs between aldehydes for the formation of parent benzoin. In this case, the benzaldehyde is involved in this homocoupling process.

Mechanism of Benzoin Condensation Reaction

Benzoin Condensation

The general form of this condensation reaction is below-

Benzoin Condensation

The mechanism of Benzoin condensation reaction is as in the steps below-

  1. The first phase of the process includes the reaction of cyanide ions with the benzaldehyde to form the product called cyanohydrin. In this step, the cyanide ion or sodium cyanide takes part in the nucleophilic addition reaction, and it is a reversible reaction. The cyanide ion helps the reaction to occur by acting as a nucleophile and facilitating the abstraction of protons, thus forming cyanohydrin. The cyanide ions serve as a catalyst in the reaction.

  2. The second step is the condensation reaction that occurs between the cyanohydrin and the benzaldehyde.

  3. In the third phase, rearrangement occurs and also the removal of the cyanide ions occurs resulting in the formation of benzoin. The Rearrangement process results in the reversal of polarity of the carbonyl group, later adding to the second group of carbonyl atom in the second nucleophilic addition.

In the reaction, a strong base deprotonates the former carbonyl C-atom and the second kind of an equivalent aldehyde reacts with the carbanion, thus eliminating the catalyst and regenerating the carbonyl compound at the end of the condensation reaction.

In this Benzoin Condensation reaction, the two different aldehydes serve two purposes. One aldehyde in the reaction donates the protons and whereas the other aldehyde accepts the protons.

Application of Benzoin and Benzoin Condensation Reaction

  • 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.

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