Organic Reactions

Organic reactions are chemical processes that organic molecules go through. Organic compounds are those chemical compounds that contain carbon. The various types of organic reactions are discussed in this article.

Organic reaction

Organic reactions are chemical processes that organic molecules go through. In organic reactions, certain patterns recur often, many of which represent the interactions between nucleophiles and electrophiles. Many sorts of reactions have already been discussed, including the production of peptides through the removal of water, oxidation-reduction events that generate a voltage in batteries, and chain reactions involving organic radicals.

Substitution reactions, addition reactions, elimination reactions, oxidation-reduction reactions, and radical reactions are the five types of organic reactions covered in this section. 

1. Substitution reactions

To generate new material, one atom or a group of atoms is exchanged for another atom or a group of atoms in a substitution reaction.

Considering an example, a C-Cl bond, wherein the carbon atom has a partial positive charge because of the extremely electronegative chlorine atom present. The nucleophile in a nucleophilic substitution reaction must have a pair of electrons and a high affinity for the electropositive species when compared to the substituent that was initially present.

The reaction in which the chlorine atom in the chloromethane molecule is displaced by the hydroxide ion, resulting in the formation of methanol, is another example:

CH3Cl  +  OH−  →  CH3OH  +  Cl–

2. Addition reactions

The addition reaction is the complete antithesis of the elimination reaction. The molecules A and B are joined with the carbon-carbon multiple bonds in an addition reaction, which is referred to as an addition reaction. For example, whenever H2 is added to ethylene in the reaction below, it produces ethylene chloride.

H2 + CH2=CH2→ CH3CH2Cl

3. Elimination Reactions

Some reactions necessitate the deletion or removal of neighbouring atoms. Following the formation of several bonds, tiny molecules are released as products. The conversion of ethyl chloride to ethylene is an example of an elimination reaction.

CH3CH2Cl → CH2=CH2 + HCl

The molecule that is eliminated in the aforementioned reaction is HCl, which is created by combining H+ from the carbon atom on the left side with Cl– out from the carbon atom on the right side.

4. Redox Reaction

The name “redox” combines the terms “reduction” and “oxidation.” A redox reaction is a chemical reaction in which electrons are transferred between two substances.

Redox reactions have two parts: a reduced half and an oxidised half that always happen at the same time. The oxidation number drops as the reduced half obtains electrons, while the oxidised half loses electrons as the oxidation number rises.

The thermite reaction is an exothermic (heat-releasing) reaction involving ferrous oxides and aluminium. It is a notable example of a redox reaction, wherein iron atoms in ferric oxide lose (or give up) O atoms to Al atoms, forming Al2O3.

Fe2O3 (s) + 2Al (s)  →  Al2O3 (s) + 2Fe (l)

5. Radical Reaction

Radicals are involved in many organic processes. A free radical mechanism is involved when a halogen is added to a saturated hydrocarbon.

A radical substitution reaction is one in which one or more of the atoms or groups available in the substrate are replaced by different atoms or groups by a free radical mechanism.

Initiation, propagation, and termination are the three phases of a radical chain reaction.

• The initiation phase is the first step in the creation of a radical species. Because of the enormous energy barriers involved, this is usually a homolytic cleavage event that occurs only rarely. To overcome the energy barrier, UV light, or a metal-containing catalyst are frequently used. When exposed to heat or light, both molecular chlorine and bromine undergo homolytic cleavage and generate radicals.

• The ‘chain’ aspect of chain reactions is described by the propagation phase. Once a reactive free radical has been produced, it can combine with stable molecules to produce other reactive free radicals. Hydrogen abstraction or radical addition to double bonds are frequently used in propagation phases.

• When two free radical species combine to generate a stable, non-radical adduct, chain termination occurs.

Conclusion

Organic reactions are those chemical processes that comprise organic compounds. The most prevalent types of organic chemistry reactions include addition reactions, elimination reactions, substitution reactions, pericyclic events, rearrangement processes, photochemical reactions, and redox reactions. In organic synthesis, organic processes are used to create new organic molecules. Organic methods are used to synthesise many man-made chemicals, including medications, polymers, food additives, and textiles. The same variables that drive chemical reactions also influence organic reactions. Conjugation, hyperconjugation, and aromaticity are all variables that influence reactant and product stability, as well as the occurrence and stability of reactive intermediates such as free radicals, carbocations, and carbanions.