Condensation Reaction

The condensation reaction definition as any class of reactions where two molecules combine, generally in the presence of a catalyst, with an elimination of water or a few other simple molecules. The combination of two identical molecules is called self-condensation. Aldehydes, esters, ketones, alkynes (or acetylenes), and amines are the examples (or the condensation reaction example) of organic compounds that interact with one another and, with the exception of amines, among themselves to form larger molecules, the majority of which are useful intermediates in organic synthesis. 

The condensation reactions of Catalysts that are commonly used include acids, bases, complex metal ions, and cyanide ions.

Example

The addition of the two molecules proceeds in a step-wise fashion, typically to the addition product, generally in the equilibrium, and with a loss of water molecule (thus the name condensation). The reaction can otherwise involve the functional groups of the molecules, and it is a versatile class of reactions that can take place either in acidic or basic conditions or in the catalyst presence. This class of reactions is said to be a vital part of life as it is important to the peptide bond formation between amino acids and also to the biosynthesis of fatty acids.

An idealized scheme representing the condensation of two amino acids to form a peptide bond is chemically shown below:

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Several variations of condensation reactions still exist. Some of the common examples are the Knoevenagel condensation and aldol condensation, where both form water as a by-product, and the Claisen condensation, the Dieckman condensation (which is an intramolecular Claisen condensation) as well that form alcohols as by-products.

Basic Process of Condensation

Condensation of water takes place when the water changes its phase from a gaseous state to either a liquid or a crystal shape. At low temperature and high pressure, any gas can condense. Technically, the condensation process may take place at any temperature as long as the pressure of the liquid state of the gas signifies less than the condensing gas pressure. In the matter, the molecules slow down during the condensation process due to the heat energy is taken away, which in turn causes a change within the three states of matter, which means it changes the matter into a solid state.

A condensation reaction is given as a chemical reaction, where two molecules combine to produce a larger one and also a molecule of water. Condensation reactions involving alcohols and a variety of other molecular forms are typical in living organisms.

In any of the condensation reactions, the removed hydroxide and hydrogen come from various molecules, whereas in the case of a dehydration reaction, the removed OH and H come from a similar molecule.

In a condensation reaction, the Hydrogen (H) can be removed from an electronegative atom. Whereas, in the case of dehydration reaction, the Hydrogen (H) can be removed from a C atom.

Key Points

• During a condensation reaction, two molecules combine to produce a single molecule with a small molecule loss; in the dehydration reaction, this particular lost molecule is given as water.

• When two separate molecules come together, intermolecular condensation occurs, while intramolecular condensation occurs when groups or atoms of similar molecules come together, resulting in a ring formation.

• As a series of condensation steps are used to form long chains in condensation polymerization, condensation reactions may be used; this reaction can be either a homopolymerization of one monomer or copolymerization of two co-monomers; several biological transformations are given as the condensation reactions.

Terms

• Monomers react first to form dimers, then longer oligomers, trimers, and finally long-chain polymers in the condensation polymerization process.

• A condensation reaction occurs when two molecules react, resulting in the loss of a water molecule (or other small molecules); formal hydrolysis is the reversal of this reaction. 

• A dehydration reaction is an elimination (or condensation) reaction, where the small molecule, which is removed is water

Condensation Polymerization Reactions

A series of condensation steps occurs in one polymerization reaction type, in which monomer chains or monomers add to each other to form longer chains. This is named either “step-growth polymerization” or “condensation polymerization” and takes place in such processes as the synthesis of nylons or polyesters.

Nylon is given as a silky material, which is used to make clothes - made of repeating units linked by the amide bonds, and it is frequently known as polyamide. This reaction can be either a homopolymerization of a single monomer A-B including two varied end groups that condense, or copolymerization of the two co-monomers, both A-A and B-B. Usually, the small molecules are liberated in these steps of condensation, unlike the polyaddition reactions.

The condensation of diamine and diacid is an example of A-B polymerization, which is represented below:

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Condensation polymers also require heat to shape, are slower to form than addition polymers, and have a lower molecular weight. This reaction type can be used as a basis for forming several essential polymers, such as polyester, nylon, and other different epoxies. Also, it is the basis for the laboratory formation of polyphosphates and silicates. Condensations are a type of biological transformation that includes polyketide synthesis, polypeptide synthesis, phosphorylation, terpene syntheses, and glycosylations.