The condensation reactions are chemical reactions that occur due to the combination of two molecules or functional groups. The combination of these molecules forms a new molecule with the loss of a small molecule. In case, if that small molecule is water then these condensation reactions are known as dehydration reaction. Similarly, there are some more types of these reactions which are termed on the basis of particle lost during the formation of a new molecule. These small molecules could be methanol, hydrogen chloride or acetic acid.
Basically, if we go to the meaning of condensation, then the word condensation refers to a procedure in which something is lost. In case of condensation reactions that something is small molecule that is lost. Furthermore, these reactions could also be termed on the basis of the molecules participating into it too. Take, for instance, if two separate molecules react with each other then such condensation reactions are known as intermolecular reactions. Now let’s look at the example of these reactions which is the condensation of two amino acids. These two molecules of amino acid, form the peptide bond, which is the major characteristic of proteins.
To know more about condensation reactions, it is important to look on other facts related to them. To begin with the condensation reactions are quite different from the process of hydrolysis where a separate chemical entity is split into two parts with the help of the molecule of polar water.
Now, if we talk about the condensation between two groups of the same molecule or two atoms, then these condensation reactions are termed as intermolecular reactions, which generally lead to form a ring formation. If we talk about the example of such a type of reactions, then Dieckmann condensation is the best approach to understand the ethics of condensation reactions. In this reaction two ester group which belongs to the identical di-ester molecule, react with each other eliminating a small alcohol molecule and forming a β-keto-ester molecule.
Usually, all the condensation reactions complete successfully in the presence of some catalysts which include bases, acids, metal ions and cyanide ion etc. Well, that was all about the properties of these reactions, now let’s consider the mechanism of these reactions. Most of the condensation reactions follow an aldol condensation or a nucleophilic acyl substitution mechanism. Whereas some other condensations including acyloin condensations; are triggered by single electron transfer mechanisms.
These condensation reactions play a vital role in polymer chemistry too as a series of condensation steps occurs in polymerization reactions. In these reactions various monomer chains or monomers combine with each other in order to form a long chain which is termed as condensation polymerization. The example of this type of reactions is a synthesis of nylons or polyesters. Well, it’s time to consider the most crucial applications of these condensation reactions. As mentioned above these reactions are the basis of many essential polymers such as polyesters, nylon and various epoxies. They also play a vital role in the laboratory development of polyphosphates and silicates. Moreover, most of the reactions which form acid anhydrides from their ingredient acids; belong to the category of condensation reaction.