Type of organic reaction:
The reaction in organic compounds can be classified into following categories-
1) Substitution reactions:
The reactions in which an atom or group of atoms in a molecule is replaced or substituted by different atoms or group of atoms are called substitution reactions. For example, in the reaction between bromo methane with sodium hydroxide, bromine atom is replaced by hydroxide group.
CH3Br + NaOH —-> CH3OH + NaBr
In this reaction, a nucleophile (-OH) substitutes the bromide in the substrate and hence this reaction is also called nucleophilic substitution reaction.
2) Addition reactions:
The organic reactions in which two molecules react to form a single product having all the atoms of the combining units are called addition reactions. For example,
CH2 = CH2 + Br2 ——> BrCH2—CH2Br
3) Condensation reactions:
In these reactions, two different or same organic reactants combine with or without the elimination of a simple molecule to give a product. For example, two molecules of acetaldehyde (CH3CHO) condense in the presence of a base (NaOH) to form 3-hydroxybutanal. This reaction is called aldol condensation. The product then loses a water molecule to form but-2-enal.
2CH3CHO + aq. NaOH —>CH3—CH(OH)—CH2—CHO —–> CH3—CH = CH—CHO + H2O
3-hydroxybutanal But-2-enal
4) Rearrangement reactions:
These reactions involve the migration of atoms or group of atoms to another position within the molecule under suitable conditions. For example,
CH3CH2CH2CH3 ——-> CH3 CH (CH3) CH3
n-Butane Isobutane
5) Elimination reactions:
The reactions in which two atoms or groups of the molecule are removed are called elimination reactions. For example,
