Common Types of Organic Reactions- Substitution and Addition Reactions

Conditions for the Substitution reaction

The conditions necessary for a substitution reaction to occur are

1. The temperature during the experiment must be low or at room temperature.
2. The solution must be in an aqueous state like water.
3. If a strong base is taken, then it must be diluted. Like if NaOH is taken it should be diluted to avoid the chances of halogenation.

Addition Reaction

Addition reactions are referred to as reactions in which two reactive molecules combine to form a single product molecule. Compounds with numerous (double and triple) bonds are susceptible to such reactions. Whereas different reactions are further divided into three parts based on the nature of the attacking species. Those are electrophiles, nucleophiles, or free radicals.

Main features of an addition reaction

• whenever there is an addition of an atom leading to the formation of a double or triple bond it is termed as an addition reaction.
• Such reactions are linked to unsaturated molecules ( hydrocarbons that have double or triple bonds).
• After the completion of the reaction, there is no residual reactants or products left.

Example of addition reaction

A typical common example of an addition reaction is halogenation: Halogenation involves the addition of a halogen atom. The halogen is simply added to the functional group of an alkene (carbon-carbon double bond). The above-described reaction has also been termed a combination of electrophilic and halogenation reactions. Another example of an addition reaction is the hydration reaction. It involves the addition of water in alkenes Which occurs in the presence of a catalyst. The alkenes form alcohol as a product by reaction with water. Here water is directly injected into a carbon-carbon double bond). Generally, addition reactions are classified as-

• Electrophilic addition reaction and
• Nucleophilic Addition reaction

But while considering polarity, the non-polar addition reactions can be classified as-

• Free radical addition reaction and
• Cyclo-addition reactions

1. Electrophilic Addition Reaction-

The electrophilic addition reactions are addition reactions caused by electrophiles. They are typical alkene and alkyne reactions.

2. Nucleophilic Addition Reaction-

The nucleophilic addition reactions are those that are caused by nucleophiles. It’s a normal aldehyde and ketone reaction.

3. Free Radical Addition Reaction-

The free radical addition reactions are addition reactions caused by free radicals.

1. Initiation: At this point, free radicals are formed.
2. Propagation- At this point, the propagation phase explains the ‘chain’ component of the chain reaction.
3. Termination- At this point, two free radical species react with each other to form a stable, non-radical adduct.

Elimination Reactions-

This is the reaction in which two atoms or groups either from the adjacent position or from the exact position get eliminated or removed, leading to formatting multiple bonds. Elimination reactions are classified into two types. Those are:

1. β– Elimination reactions:

In elimination reactions, the loss of two atoms or groups occurs from adjacent carbon atoms in the molecule.

2. α– Elimination reactions:

In elimination reactions, there is the loss or elimination of two atoms or groups from the same carbon atom in the molecule. Rearrangement Reactions It’s a reaction that involves the migration of an atom or a group from one atom to another from the same molecule is called a rearrangement reaction.

Conclusion:

While concluding we can say that Organic reactions are chemical reactions in which organic compounds are involved ( compounds that have covalently bonded carbon atoms). Every organic reaction has been divided into different types. Important organic reactions are as follows: Substitution, Addition, elimination, and rearrangement reactions depending upon whether the groups are added, eliminated or replaced or substituted.  Since addition and substitution reactions are both a type of chemical reactions but the basic difference in both is that in addition reactions a group/s is added and in substitution reactions, a group/s is replaced by another group/s. In both reactions, the electrophilic and nucleophilic group plays an important role.