Organic chemistry deals with carbon-containing compounds and their reactions. There are different types of reactions that occur in organic chemistry. Let's discuss each type of reaction in more detail along with some examples:
Addition Reactions
Addition reactions occur when a molecule is added to a carbon-carbon double or triple bond. One of the most common examples of addition reactions is the reaction between an alkene and hydrogen gas in the presence of a catalyst to form an alkane. This reaction is called hydrogenation of alkenes and can be represented as follows:
H2 + CH2=CH2 → CH3-CH3
Another example is the reaction between an alkene and water in the presence of an acid catalyst to form an alcohol. This reaction is called hydration of alkenes and can be represented as follows:
H2O + CH2=CH2 → CH3-CH2OH
Elimination Reactions
Elimination reactions involve the removal of a molecule from a carbon-carbon double or triple bond. For instance, the dehydrohalogenation of alkyl halides, where a hydrogen halide molecule is removed from the alkyl halide, to form an alkene. This reaction can be represented as follows:
CH3-CH2-Br → CH2=CH2 + HBr
Another example of an elimination reaction is the dehydration of alcohols, where a water molecule is removed from the alcohol to form an alkene. This reaction can be represented as follows:
CH3-CH2-OH → CH2=CH2 + H2O
Substitution Reactions
Substitution reactions involve the replacement of one atom or group of atoms with another atom or group of atoms. In organic chemistry, substitution reactions are divided into two categories: nucleophilic substitution and electrophilic substitution.
An example of nucleophilic substitution is the reaction between an alkyl halide and a nucleophile to form an alkyl group. This reaction can be represented as follows:
CH3-CH2-Br + NaOH → CH3-CH2-OH + NaBr
On the other hand, electrophilic substitution occurs when an electrophile attacks an electron-rich carbon atom, resulting in the substitution of one atom or group of atoms with another atom or group of atoms. For example, the nitration of benzene to form nitrobenzene:
C6H6 + HNO3/H2SO4 → C6H5NO2 + H2O
Oxidation-Reduction Reactions
Oxidation-reduction reactions involve the transfer of electrons from one atom or molecule to another. In organic chemistry, the most common example of an oxidation-reduction reaction is the combustion of hydrocarbons. Hydrocarbons are oxidized to form carbon dioxide and water. This reaction can be represented as follows:
CH4 + 2O2 → CO2 + 2H2O
Rearrangement Reactions
Rearrangement reactions involve the rearrangement of atoms within a molecule to form an isomer. One example of a rearrangement reaction is the Pinacol-Pinacolone rearrangement, which involves the rearrangement of a pinacol molecule to form a ketone. The reaction can be represented as follows:
(CH3)2C=C(CH3)-CHOH-CHOH-(CH3)2 → (CH3)2C=O + CH3C(CH3)=CH2
These reactions are just a few examples of each type of reaction in organic chemistry. There are many more reactions that occur in organic chemistry, and they are crucial for understanding the behavior of organic compounds.
