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Example Iupac Nomenclature of Organic Chemistry

The chemical compounds which are mainly composed of carbon atoms are called as organic compounds. They play an important role in the living organisms and also in our atmosphere. There are more than thousand organic compounds which are named in different manners. Initially chemical compounds are named according to their origin or their nature.  Later trivial system provided a new direction in the naming of chemical compounds. Let’s have a look on the example of IUPAC nomenclature of organic compounds with the help of simplest organic compound called as alkyl halide or haloalkane.

They have long parent chain of carbon atom with halogen group as functional group directly bonded on the carbon atom.  In trivial system, the monohalogen derivatives of haloalkanes are called as Alkyl halides. For example; methyl chloride According to the IUPAC nomenclature rules, the term haloalkane is used for an alkyl halide. In the IUPAC the root name is based on the longest carbon chain containing the halogen. This root gives the alkane part of the name. The type of halogen defines the halo prefix such as chloro-, fluoro-, bromo- etc.

The chain is numbered in such a way that the halogen will get the lowest possible number. For example in tert-butyl bromide, the longest carbon chain has 3 carbon atoms therefore the root word will be propane. It has one methyl group as side chain and one bromo- group as prefix at second carbon atom.

Hence the name will be 2-bromo-2-methylpropane. We know that dihalogen derivatives can be three types on the basis of position of halogen atoms in compound:
  1. Alkylidene dihalide
  2. Alkyliene dihalide
  3. Polymethylene dihalide

The alkylidene dihalide are germinal dihalides in which both the halogen atoms are bonded to the same carbon atom.  For example in ‘Isopropylidene dichloride’ there is 3 carbon atoms so suffix will be propane. Both the Chloro groups are bonded to the same carbon atom. Hence IUPAC name will be 2,2-dichloropropane. Alkyliene dihalides are vicinal dihalides in which the two halogen atoms of same type are bonded on the adjacent carbon atoms such as Propylene dichloride. According to IUPAC nomenclature rules, the position of halo groups is prefixed to the name of dihaloalkane. Here 2 Cl-groups are bonded on carbon 1 and carbon 2.

Therefore the IUPAC name of the compound is 1,2-dichloropropane.  Dihalogen derivative of alkane, in which same halogen attached on terminal carbon atoms of the carbon chain are known as polymethylene dihalide such as tetramethylene dichloride. Haloalkanes with more than two halo groups are known as polyhaloalkanes. In IUPAC system, the location of halo groups is prefixed to the name of Haloalkanes. Aryl halides are known as haloarenes in IUPAC as well as in trivial system. In dihalogen derivatives of haloarene , the prefixes ortho, meta and para are used for 1,2 ; 1,3; and 1,4 positions respectively.

Hydrocarbons without any functional groups are named with the help of root words and primary suffix. Here root word indicates the number of carbon atoms in parent chain and primary suffix indicates the saturation and unsaturation in the molecule. For example primary suffix for alkane is –ane, for alkene it is –ene and –yne for alkyne.