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In a substitution reaction, a functional group in a particular chemical compound is replaced by another group.
In organic chemistry, the electrophilic and nucleophilic substitution reactions are of prime importance. Organic substitution reactions are classified in several main organic reaction types depending on whether the reagent that brings about the substitution is considered an electrophile or a nucleophile, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical or whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to predict the product outcome in a reaction. It also is helpful for optimizing a reaction with regard to variables such as temperature and choice of solvent.
A good example of a substitution reaction is:
CH4 + Cl2 ? CH3Cl + HCl (in the presence of sunlight)
Nucleophilic substitutions
Electrophilic substitutions
Radical substitutions
A radical substitution reaction involves radicals.
Substituted compounds
Substituted compounds are chemical compounds where one or more hydrogen atoms of a core structure have been replaced with a functional group like alkyl, hydroxy, or halogen.
For example benzene is a simple aromatic ring and substituted benzenes are a heterogeneous group of chemicals with a wide spectrum of uses and properties:
Further reading
- Is This Reaction a Substitution, Oxidation-Reduction, or Transfer? / N.S.Imyanitov. J. Chem. Educ. 1993, 70(1), 14 – 16.
- Unimolecular Nucleophilic Substitution does not Exist! / N.S.Imyanitov. SciTecLibrary
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