History of Organic Chemistry and classification of organic compounds

history of Organic Chemistry

Organic Chemistry

It is the study of the structure, properties, and reactions of organic compounds. The compounds in which carbon atom is covalently bonding are called organic compounds. The structure of a compound gives its chemical composition and formula. Properties of a compound include its physical and chemical properties. Chemical reactions include the preparation of a compound.

history of Organic Chemistry

Why is it important to study organic chemistry?

Organic compounds give essence to all living things on earth. The majority of chemicals contain organic compounds. Organic compounds form the basis of many industries like pharmaceuticals, petrochemicals, and agrichemicals. Many products such as lubricants, solvents, plastics, fuels, and explosives are made from organic compounds. Organic chemistry explains the chemical reactions occurring in living things.

History of Organic Chemistry

Before the 19th century, it was believed that organic compounds can be obtained from living organisms. These compounds can not be prepared from inorganic compounds in the laboratory. These compounds can be prepared with a vital force that is present in the living organism. This theory is called the vital force theory. In 1816, Michel Chevreul separated fats from soap. He explained that it was possible to make chemical changes in organic compounds without vital force theory. In 1828, Friedrich Wohler made organic compounds (urea) from inorganic materials (potassium cyanate and ammonium sulfate). He disproved the vital force theory. This was the first time in history when the organic compound was prepared in the laboratory.

In 1856, William Henry Perkin accidentally prepared organic dye while manufacturing quinine. This organic dye is called Perkin’s mauve. In 1858, Friedrich August Kekule and Archibald Scott Couper developed independently the concept of chemical structure. They suggested that carbon atoms could link to form a carbon lattice.

In the last decade of the 19th century, Bayer (German pharmaceutical company) developed Aspirin (acetylsalicylic acid). The pharmaceutical industry began with the development of aspirin. In 1910, Paul Ehrlich and his laboratory group developed arsphenamine used for the treatment of syphilis. His lab developed antiserum for diphtheria. 

Classification of Organic Compounds


The compounds containing carbon and hydrogen are called hydrocarbons. Hydrocarbons are divided into two classes: aliphatic hydrocarbons and aromatic hydrocarbons

1). Aliphatic Hydrocarbons

The compounds in which C and H atoms are connected by single, double, or triple bonds to form a non-aromatic structure are called aliphatic hydrocarbons. Aliphatic Hydrocarbons are subdivided into three categories:

Alkanes: These hydrocarbons contain a single bond. e.g. methane.

Alkenes: These hydrocarbons contain a double bond. e.g. ethene

Alkynes: These hydrocarbons contain a triple bond. e.g. ethyne

2). Aromatic Hydrocarbons

The compounds that contain one or more rings with pi electrons delocalized all the way around the rings are called aromatic hydrocarbons. The basic unit of aromatic hydrocarbons is benzene. The structure of the benzene ring is formulated by Kekule. He proposed the resonance concept for explaining its structure.

Heterocyclic compounds

The cyclic compounds that have atoms of different elements as members of their rings are called heterocyclic compounds. e.g. nucleic acid. The atoms other than carbons and hydrogens are heteroatoms. The heteroatoms are generally   N, O, and S. The ring present in these compounds is called heterocycle. Pyridine and furan are examples of aromatic heterocycles. Piperidine and tetrahydrofuran are examples of alicyclic heterocycles. Heterocyclic compounds are present in dyes and medicines.


The substance containing macromolecules composed of many repeating subunits are called polymers.  The word polymer is derived from the Greek words polus meaning many and meros meaning parts. The basic unit of a polymer is called a monomer. Polymers are formed by a process called polymerization. Polymerization is a process in which many monomers joined to form a long chain of the polymer.  Polymers are present in synthetic plastics such as polystyrene as well as biopolymers such as proteins and DNA. Synthetic polymers are prepared artificially while biopolymers are present in nature.

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