Definition of Organic Chemistry
The branch of chemistry which deals with the study of carbon-containing compounds, their structure, properties, reactions, preparation, composition, and derivatives is called organic chemistry.
What are Organic Compounds?
The compounds that contain carbon, carbon atoms, or some other atoms by making covalent bonds are called organic compounds. Those other atoms may be hydrogen, oxygen, nitrogen, Sulphur, etc. Organic compounds are found in living organisms because the cells of living organisms are also organic in nature.
Examples of Organic Compounds
The basic molecules of life like carbohydrates, fats, lipids, proteins, and nucleic acids are examples of organic compounds in addition to these examples fossil fuels natural gas and petroleum are also examples of organic compounds.
Do you want to know some important history about Organic Compounds?
Organic compounds were thought to be synthesized in plants and animals
due to vital force present in them. But in 1828, F. Wholer prepared urea by
heating ammonium cyanate in the laboratory and disproved the vital force
theory.
Sources
- The important sources of organic compounds are plants, animals, coal,
natural gas, and petroleum. - Coal is present in the earth’s crust and has a vegetable origin. The wood was
converted into peat and then lignite, which was converted to bituminous coal
and finally anthracite. - Bituminous coal is taken in iron retorts and destructive distillation is
performed between 1000 – 1400°C. One of the important fractions obtained
is coal tar, which has more than 215 organic compounds. - Natural gas is also present in the earth’s crust and has 80 – 95 % methane.
Natural gas is formed from the remains of marine animals and plants and is
always associated with petroleum. - Natural gas is used to produce carbon black which is used as a filler in the
manufacture of tires. - Natural gas is one of the raw materials for the manufacture of urea and is
used for power generation in the cement and fertilizer industries. - Petroleum is a mixture of saturated hydrocarbons from C₁ – C40. Small
amounts of some other compounds may contain N2, S, and P. These
compounds may be present in petroleum. - Petroleum has a biological origin and is formed due to the decay and
decomposition of marine animals. - Petroleum has a biological origin and is formed due to the decay and
decomposition of marine animals. - The fractional distillation of petroleum gives us many important fractions
which are used by modern society for different purposes.
Characteristics
- Organic compounds are studied as a separate branch of chemistry because carbon has a property of catenation.
- These compounds are covalent in character.
- The existence of isomerism and the slow rates of organic chemical reactions are the unique properties of these compounds.
- Organic compounds are closely related to the activities of daily life. e.g. the substances like our food, clothing, materials of cleanliness, cosmetics, things of decoration, etc. are consisted of organic compounds.
- The higher hydrocarbons present in petroleum are cracked into smaller hydrocarbons. In this way, the quantity and quality of petrol are improved.
- Cracking is of three types i.e. thermal, catalytic, and steam cracking.
- The gasoline which is used in internal combustion engines should have high octane number to decrease the knocking property of petrol. The best compound available with the most suitable octane number is iso-octane.
- Regular gasoline which is used in motor cars or in buses has an octane number of 74. However, the octane number can be improved by the processes like reforming, isomerization, alkylation, hydroforming, and the addition of antiknock fluid.
- Reforming petroleum is done from the gasoline fraction, which has various saturated hydrocarbons ranging from C5H12 to C3H18.
- Gasoline heated to a temperature of 100°C in the presence of AICI, or platinum, and a pressure of 28 – 50 atm. is maintained. In this way, octane is converted to iso-octane.
Structure
In order to understand the structures of organic compounds, we should understand the nature of hybridization associated with the carbon atom.
- In saturated hydrocarbons, carbon is sp³-hybridized. Four bonds are attached to carbon in a tetrahedral manner. Methane is perfectly tetrahedral in structure. It has four faces, four corners, six edges, and six angles. Each angle is 109.5°. The molecules of propane, butane, etc. are not linear but, they have zig-zag structures.
- Those organic compounds in which carbon makes a double bond with carbon, oxygen, or nitrogen, undergo sp²-hybridization. In a double bond between two carbon atoms, one of the bonds is sigma and the other is. T-bond is weaker than o, and all the sigma bonds of ethene lie in one plane.
- The compounds having carbon-carbon triple bonds have sp-hybridization associated with carbon. In a triple bond, one is a sigma bond and two are it. The molecule of ethyne is linear.
Classification of Organic Compounds
Organic compounds are classified in two ways. The first one is called an open chain or Acyclic compound and the second one is called a closed chain or a Cyclic compound. Let’s discuss the details of these two categories of organic compounds.
Open chain (Acyclic Compounds)
The compounds in which ended carbons of the chain are not connected with each other to form a ring or a cycle are called open-chain organic compounds. These compounds are also called Acyclic compounds and aliphatic compounds. These compounds may be saturated or unsaturated compounds having branched chains or linear chains in structure.
Examples of Open chain compounds
The most common examples of Open chain compounds are :
- Oxide.
- Thiadiazoles.
- Reagent.
- Benzoic Acid.
- Solvent.
- Indazole Derivative.
- Lactam.
Types of open-chain compounds
On the basis of structure, open-chain compounds are of two types. It can be an unbranched chain or a branched chain.
Unbranched chain compounds
Those compounds in which carbon atoms are attached to each other to form a linear chain are called unbranched chain compounds. For example; methane ( CH ), ethane (CH2), propane (CH3) and butane (CH4).
Branched-chain compounds
The chain of organic compounds in which one carbon is attached with at least 3 to 4 other carbon atoms to form a chain is called a branch chain compound. For example; Iso-butane, Iso-butene and Methyl propanoic acid.
Closed-chain compounds ( Cyclic Compounds )
The organic compounds in which ended carbons of the compound are connected with each other to form a ring or a cycle are called Closed chain compounds. These are also called Cyclic organic compounds. Closed-chain organic compounds may be homo-cyclic or heterocyclic in nature.
Examples of Closed chain compounds
The most common examples of Closed chain compounds are :
- Cyclohexane.
- Cyclohexene.
- Cyclopropane.
Types of Closed chain compounds
On the basis of structure, open-chain compounds are of two types. It can be homo-cyclic or heterocyclic in nature.
Homo-cyclic Closed chain compounds
Those closed-chain compounds in which only carbon atoms are present and are attached with only hydrogen atoms are called homo-cyclic compounds. These compounds are also called carbocyclic compounds. For example; Benzene and derivatives of Benzene, Cyclohexadiene, Cyclohexene, Cyclohexane, etc.
Hetero-cyclic Closed chain compounds
Those closed-chain compounds in which carbon atoms are attached with different elements to form a ring or a cycle are called heterocyclic compounds. For example; Pyridine, Furan, Thiophene, Tetrahydrothyphine, etc.
Flow chart for the classification of organic compounds
FAQ’s
What is the main class of organic compounds?
Proteins, carbohydrates, lipids, and nucleic acids are the four main categories of organic substances that make up all living organisms. The most prevalent organic substance on Earth is cellulose. Plants have 33% of it on average, with cotton having the purest form at 90%. It is the major component of plant fiber. Up to 10,000 D-glucose units make up the linear polymer known as cellulose.
How did organic compounds get their name?
Organic chemicals are so-called because they are linked to living beings. Carbohydrates, lipids, nucleic acids, and proteins are all examples of significant organic molecules. The concept of organic compounds is one of the more fundamental principles in Biological Chemistry.
What are simple organic compounds called?
Hydrocarbons are the most basic organic molecules, containing simply carbon and hydrogen. Alkanes have only single carbon-hydrogen and carbon-carbon bonds, whereas alkenes have at least one double carbon-carbon bond and alkynes have one or more triple carbon-carbon bonds.
Why are the organic compounds classified?
Organic compounds are classified by chemists based on bonding patterns in their structures. These patterns are significant because structure dictates function. That is, these structural patterns govern the qualities of a molecule as well as the sorts of chemical interactions in which it can engage.
Who is the father of organic chemistry?
Friedrich Wöhler is widely regarded as the father of organic chemistry. He was a German scientist who was the first to isolate several elements. Wohler initially focused on inorganic chemistry subjects, and he was the first to produce pure Beryllium and Yttrium.
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