Classification of Organic Compounds

Introduction

As Friedrich Wohler demonstrated in the early 1800s, organic chemicals can be synthesised in a laboratory from minerals and other non-organic materials. The first organic compound synthesized is urea.

Organic chemistry was once assumed to be limited to the study of molecules formed as part of the natural processes of living creatures. For the creation of synthetic chemicals, insecticides, and a variety of other things, modern chemistry and materials sciences have focused on the extraordinary capabilities of carbon atoms. The carbon in organic molecules is usually always linked to another carbon atom or hydrogen.

Define Organic Compounds?

Any kind of chemical complex, whether it has one or more carbon atoms, is considered to be organic if its atoms are covalently connected to those of the other elements. If you want to put it simply, you may say that an organic compound is any chemical compound that contains carbon.

However, not all compounds containing carbon are organic, such as cyanides, carbonates, and carbides. Methane is the purest illustration of an organic substance. Ethyne, cyclohexane, ethane, and ethane are a few examples of organic molecules.

Classification of Organic compounds

Organic compounds can be divided into two categories. Based on "Structure," and then based on "Functional groups."

Classification based on the structure

Based on structure organic compounds are of two types: Acyclic and cyclic compounds.

Acyclic or Open-chain Compounds

Due to the lack of ring formation in their molecules, acyclic compounds are the exact opposite of cyclic compounds. They are known as open-chain compounds because of their linear form. Acyclic aliphatic molecules and alkanes are the most effective examples of these substances. Straight-chain and branched-chain compounds can both be used to understand open-chain molecules. In contrast to branched-chain compounds, which have one or more side chains connected to their atoms, straight-chain compounds have no side chains.

Cyclic or Closed-chain Compounds

The term "Ring compounds" also applies to cyclic compounds. Cyclic compounds, as their second name implies, are those in which one or more atoms are linked together to form a closed ring. These compounds' rings don't necessarily need to be the same size on either side. Due to the frequent exposure to these substances in daily life, cyclic or closed-chain compounds have a prior place in human existence. They are divided into two groups as well. "Heterocyclic" is the topic of the first division, and "Homocyclic" is the topic of the second division.

Classification based on Functional group

Based on different functional groups attached to compounds, there are different organic compounds like acid, aldehyde and amine etc.

What do you mean by Heterocyclic Compounds?

Heterocyclic compounds are a subclass of cyclic chemicals that contain a ring structure. It must be noted that even though they contain carbon atoms, they also contain at least one atom of another element. Synthetic colours, nucleic acids, and most medications are all well-known examples of these molecules. Tetrahydrofuran, furan and thiophene are examples of heterocyclic compounds.

Classification of Heterocyclic Compounds

• Alicyclic Heterocyclic Compounds − These chemicals can be explained using just a few lines. One or more heteroatoms can be found in the rings of these compounds. A few examples, such as tetrahydrothiophene, tetrahydrofuran, and others, can help us grasp these substances.

• Aromatic Heterocyclic Compounds − These substances can be simply understood and defined. These compounds, unlike alicyclic heterocyclic compounds, have one or more heteroatoms in their molecules. These substances include thiophene, furan, and others.

What do you mean by Homocyclic or Carbocyclic Compounds?

Homocyclic compounds are the sort of cyclic compounds that, in contrast to heterocyclic compounds, in which the ring structure is created by the atoms. The same elements' atoms make up this ring structure, and this element is carbon. Carbocyclic compounds are what these are. This chemical cannot include any element besides carbon. The greatest examples of this substance include benzene, naphthalene, and tetracene.

Classification of Homocyclic Compounds

• Alicyclic Compounds − An alicyclic compound is both cyclic and aliphatic. This chemical has one or more saturated or unsaturated all-carbon rings. Any kind of bond, including single, double, and triple bonds, may be present in pairs of atoms.

• Aromatic Compounds − Contrary to alicyclic compounds, which can either be saturated or unsaturated, aromatic compounds are those cyclic compounds that are unsaturated. Benzene and toluene are a couple of examples of these chemicals.

What do you mean by Aromatic Compounds?

Aromatic compounds have a cyclic structure with unsaturation in the ring. These compounds are additionally known as aromatics or arenas. They have a lovely aroma, as their Greek definition of "aroma" implies. These compounds are categorised as Benzenoid Aromatic Compounds and Non-Benzenoid Aromatic Compounds, respectively.

Classification of Aromatic Compounds

• Benzenoid Aromatic Compounds − The main source of these aromatic compounds is benzene. One or more benzene rings that are fused or isolated, as well as their derivatives, make up the extra structural features that set these molecules apart. Depending on how many benzene rings are fused in the structure, these compounds can be categorised as monocyclic, bicyclic, or tricyclic. Phenanthrene, naphthalene, and anthracene are a few examples of these substances.

• Non-benzenoid Aromatic Compounds − Instead of benzene rings, these aromatic compounds have additional unsaturated rings. The stability of these aromatic compounds is unique. Tropolone and Azulene are a couple of examples of these substances.

Classification based on the functional groups

The process through which one or more of the molecule's atoms acquire the molecule's distinctive chemical properties is known as a functional group. We must now comprehend why it is necessary to categorise organic molecules according to their functional groups. Because it categorises an organic compound's chemical behaviour, the answer is straightforward.

Understanding that functional groups have effects on compounds' reactions, and, to some extent, their physical properties are important. Numerous organic reactions that entail functional group change and don't affect the other molecules are common. Some functional groups are given below:

Class	Functional Group
Alcohol	$\mathrm{-OH-}$
Acid	$\mathrm{-COOH-}$
Aldehyde	$\mathrm{-CHO-}$
Amine	$\mathrm{-NH_{2}-}$
Ether	$\mathrm{-OR-}$

Conclusion

Organic chemicals are those that have carbon in their molecules and can exist as solid, liquid, or gaseous states. A precise, systematic classification of organic compounds was necessary due to their abundance and variety. Acyclic (compounds with an open chain) and cyclic (compounds with a closed chain) are two general categories of organic compounds.

FAQs

1. The first organic compound synthesized?

Urea was the first organic compound prepared in the laboratory.

2. What are the organic compounds found in living things?

Lipids, carbohydrates, nucleic acid, and proteins are the organic compounds found in living things.

3. Which is the most abundant organic compound on the earth?

Cellulose and starch are two abundant organic compounds on earth.

4. What is the importance of aromatic compounds?

They are essential in the production industry of medicine and polymers.

5. Which heterocycle is the least aromatic?

Thiazole and oxazole are found to be the least aromatic heterocyclic compounds.