Chemistry

Substitution Reactions


Substitution reactions are those where one atom or group of atoms of an organic molecule is replaced by another atom or group of atoms.

The main substitution reactions are:

- halogenation
- nitration
- sulfonation

Halogenation

Halogens used in substitution reactions should be chlorine (Cl) and bromine (Br).

Reactions with fluorine (F) are very dangerous due to the high reactivity of this element and with iodine (I) the reactions become very slow.

Alkanes can be transformed into alkyl halides.

Examples:

From methane, performing successive halogenations (excess halogens) catalyzed by light and heat, we can obtain:

This reaction may be called Chain reaction.

Chloroform was widely used as an anesthetic in surgery. Currently, its use has been abolished because it is very toxic and dangerous to health, and can cause serious damage to the liver.

The order of ease with which hydrogen "exits" from the hydrocarbon is:

ÇTERTIARY > CSECONDARY > CPRIMARY

Nitration

The nitration reaction is where we react a hydrocarbon with nitric acid (HNO).3).

Example:

Sulfonation

The sulfonation reaction is one where we react a hydrocarbon with sulfuric acid (H2ONLY4).

Example: