Organic compounds are mainly composed of carbon atom. There are several common examples of organic compounds which we can observe in our surroundings. Crude oil is a mixture of many compounds. These compounds are known as hydrocarbons, because their molecules contain carbon and hydrogen elements bonded together. They are asphalt, grease and wax, naphtha, diesel fuel, heating oil, aviation fuel, gasoline or petrol and gases. Separating them is quite easy as each compound has progressively higher boiling points. So, crude oil is heated and each component is captured at their respective boiling points.
Hydrocarbons are organic compounds which are one of the Earth's most important energy resources. Volatile hydrocarbons are organic compounds in the atmosphere which are present in the form of vapour at room temperature. Propellant for aerosol spray uses mixtures of volatile hydrocarbons instead of chlorofluorocarbons. Freon is an example of chlorofluorocarbons (CFC's) which is mainly used in air-conditioners and refrigerators as refrigerants. At the same time, it causes damage to the ozone layer.
Similarly, Butane made of 4 carbons, can be converted to liquid easily, provides a safe, volatile fuel for small pocket lighters. Pentane made of 5 carbons is a clear liquid at room temperature. It is mainly used as a powerful, odourless solvent for waxes and other heavy organic compounds. Hexane is a hydrocarbon with 6 C-atoms, is used as non-polar solvent.
The general definition of an organic compound is "any compound of carbon with covalent bonding related to the living organisms present in nature is called an organic compound."
A more detailed definition in the light of petrochemical revolution the definition of the organic compounds is extended up to those compounds that are derived from the decayed organic matter, extracted and synthesized apart from those compounds which are derivatives of those compounds that are having an organic origin. This definition covers the pesticides, medicines and plastics
How to Name Organic Compounds?
Since there are more than a million organic compounds existing and more and more are being synthesized everyday, it is a major task to address the nature of naming the organic compounds.
- Some compounds derived their name from their source.Urea from Urine, formic acid from ants citric acid from fruits etc. Some are due to their properties like glucose (sweet tasting), Olefin ( Oil forming). Some compounds are named from their parent source For example Chlorophyll, Hemoglobin, Petrol,etc.
- Some compounds are given the names of their discoverer. For example Grignards reagent, Pelleterine, Fehlings B reagent, Tollens reagent etc.
- These names are generally termed as trivial names. Some common names which are used even today are Benzene, Toluene, Aniline, cresol, Catechol, resorcinol, Kerosene, naphthalene , anthracene, Camphor, etc.,
- Some common names are based on their action in medicinal value Example. Interferon, aspirin, tincture benzoin and tincture iodine etc.,
- Early system of systematic naming of organic compounds are based on the number of carbon atom in a straight chain. Methane, ethane, propane, butane, pentane.........nonane and decane etc., In a straight chain they are termed with a prefix "n-". If the compound is branched "iso" and "neo" were used.
- The saturated hydrocarbons are called alkanes, Those unsaturated compounds with double bond are called alkens and with triple bonds alkynes. eg. n-pentane, iso-pentane,neo-pentane for saturated straight and branched chain compounds and pentene for double bonded compound and pentyne for triple bonded straight chain compound.
- Iso pentene and iso pentyne is possible but not neo pentene or neo pentyne.
- This nomenclature for organic compounds is not enough with the increasing number of compounds being discovered on a daily basis. As a result International Union of Pure and Applied Chemistry (IUPAC) proposed common rules to name the compounds.
- They used the most popular and common names as it is without changing their names but for all others followed a pattern.
Without going into much detail the nomenclature is based on the number
of carbon atoms, with all the additional groups as derivatives of the
parent compound. The reactive groups which are called functional groups
are given preferences in the naming if more than one group is present
in a single molecule.The naming is divided into pre-prefix (a number) prefix ( branching) root word ( Parent chain) suffix( functional group). For closed chain 'cyclo' is used before the root word by far this is the method which can address the principle of no two compounds shall have same name and no single compound can be drawn with more than one name.
Organic compounds are having a carbonbased structure with covalent bonding
. Most of the organic compounds are nonpolar and hence are bad conductors of heat and electricity. Some organic compounds get ionized when dissolved in water or subjected to electrolysis due to the polar substituents but the main end product will be non polar carbon di oxide.
The molecular weights of organic compounds have an unlimited range. They range from single carbon atom compound to million + carbon atom chains. This is due to the catenation property of carbon atom.
Most Abundant Organic Compound on Earth
- Organic compounds have relatively low melting points and boiling points in comparison to the inorganic compounds of a similar molecular mass. They are soft and have a flexible lattice structure to its crystalline compounds. This is attributed to the non-ionic nature of the bond.
- Organic acids and bases are less stronger and they have a limited dissociation in aqueous medium.
- Organic compounds with metal combinations are called organometallic compounds which are industrially very important compounds as catalysts, promoters, analyzers and stabilizers.
The most abundant organic compound on earth is the Cellulose
. It is a macro molecular structure. It is composed of thousands of glucose molecules and is called a poly saccharide
. Cell wall is composed of cellulose and cells are the basic units of all organisms.
Organic compounds are classified in to various groups on the basis of a number of factors. viz.nature of bonding, types of chains of atoms, their properties, functional groups present and types of molecules etc
., The classification that is based on Chains of atoms in an organic compound can be summarized as follows.
Organic compounds can be broadly divided in to open chain or acyclic or aliphatic compounds and closed chain or ring or cyclic compounds. The closed chain or ring compounds are further classified as homocyclic or carbocyclic compounds where the closed chain is linked with carbon atoms only and heterocyclic compounds where the chain closes by any other atom like O,N,S etc., other than carbon atom.
- Homocyclic or carbocyclic compounds are further classified into alicyclic and homocyclic aromatic compounds while heterocyclic compounds are classified in to saturated heterocyclic compounds or hetero paraffins and heterocyclic aromatic compounds.
- Open chain compounds are called aliphatic compounds and they are further classified as saturated compounds called Alkanes. These compounds undergo substitution reactions. Saturated compounds burn with non sooty flame.
- Unsaturated compounds are again divided in to compounds with double bonded carbon atom called alkenes and triple bonded carbon atoms called alkynes. These compounds under go addition reactions to get saturated. These burn with sooty flame and decolorize bromine water.
- Open chain compounds can be straight chains (unbranched) and branched chain compounds. Both straight chain and branched chain compounds that posses only carbon and hydrogen atoms are called hydrocarbons.
Cyclic compounds or closed chain compounds are limited to closed chains with 8 carbon atoms forming a ring. However there are cyclic compounds with more than one rings attached to one another. Cyclic compounds if they are saturated behave like alkanes and if they are unsaturated behave like alkenes. Aromatic compounds are those homo and heterocyclic compounds that are unsaturated but still shows the properties of saturated compounds. Organic compounds undergo substitution and addition reactions.The compounds with only carbon and hydrogen are called hydrocarbons. The compounds with other elements in addition to C and H are
Apart from these, there are organometallic compounds like Grignards reagent, Chlorophyll etc.
- Carbon, Hydrogen, and Oxygen compounds: Alcohols (primary, secondary and tertiary), aldehydes, Ketones, carboxylic acids, Esters and Ethers.
- Carbon, Hydrogen, and Nitrogen compounds: Amines ( Primary, Secondary,Tertiary), Cyanides, Isocyanides,
- Carbon, Hydrogen, Nitrogen and Oxygen compounds: Nitro, Amide, Imido, Nitroso compounds.
- Carbon, Hydrogen, and Sulphur compounds: thio cyclic compounds
- Carbon, Hydrogen, Sulphur and Oxygen compounds: Sulphuryl, sulphonyl compounds.
- Organic compounds are of varied characteristics. hydrocarbons up to 4 carbon atoms are generally gases.
- Hydrocarbons from 5 to 7 are volatile liquids above are all solids with increasing melting points. These are most applicable to homologous straight chain hydrocarbons.
- With functional groups Lower ethers alcohols and ketones are volatile while benzene is also volatile. The physical state changes from gaseous to solids with increase in molecular weight.
- Long chain compounds are generally solids. Some of the organic compounds are complicated chains with metal atoms interspersed. Deoxyribonucleic acid (DNA) is a helical structured long chain organic molecule.
- Some of the carbohydrates although are non polar are soluble in water. This is due to the formation of glucosidic ring. Glucose, C6H12O6 is an organic molecule soluble in polar solvent like water.
The major difference between the Organic and Inorganic compounds is the nature of bonding. Essentially the organic molecules are formed with covalent bonds while the inorganic compounds are bonded with ionic bonds. This makes inorganic compounds in solution or in molten state to become ions and conduct electricity. Organic compounds even though in liquid state will not conduct electricity unless they are salts formed with inorganic acids or bases.
Many organic compounds are volatile in nature
. Those organic liquids that have smaller molecular masses are volatile. The property of volatility is increasing where the molecule fails to have intermolecular attractive forces like hydrogen bonding, or weak van Der Waal forces.Some of the volatile compounds are Ethyl alcohol, Ether ( Di ethyl ether), Acetone, Benzene Chloroform etc., Organic Compounds Composition
- A typical organic compound contains a molecule formed out of combination of atoms held together by covalent bonds.
- Most of the organic compounds contain carbon in its hybridized state, hydrogen and non metals like oxygen, sulfur, nitrogen, halogens.
- There are organic compounds which are called organometallic compounds that are formed due to the replacement of hydrogen with electropositive metallic ions.
- Although organic compounds are basically called as carbon compounds, there are some non carbon organic compounds that are also categorized as organic compounds due to their similarity of properties to the organic compounds.
Is DNA an Organic Compound?
DNA is an organic compound because it is basically a carbon skeleton sugar molecule with nitrogen containing amino acids and with phosphorus substitutions. A large molecule with coded and specific arrangement of amino acids gives rise to a DNA molecule.
Is Glucose an Organic Compound?
Glucose is a carbohydrate which is one of the functional groups of the carbon compounds. Glucose is an organic compound formed by the catalytic presence which influences the combination of carbon in the form of carbon di oxide with water in the plants.
These form large molecules of starch which on break up forms glucose molecules in presence of enzymes.
Organic vs Inorganic Compounds
As the very name suggests that organic compounds are derived from organic matter and inorganic compounds are derivatives of mineral sources. Broadly we can say that the compounds formed from carbon in its hybridized state by covalent bonding with mostly non metals are organic compounds and the compounds that contain an easily replaceable hydrogen ion with a metal or a hydroxide ion with non metal are the in organic compounds. This suggests that ionic compounds based on predominantly electrovalent bonding are inorganic compounds and non ionic compounds with predominantly covalent bonding are organic compounds.