Wednesday, November 21, 2012

Organic Chemical Reactions

The term organic nowadays arouses lot of curiosity because of the term organic produce.
Whereas the meaning imbibed in this term relates to purity of agricultural produce  sans fertilizers or insectisides.
However in chemistry it applies to a wider term  that is connected to carbon.
Organic chemistry is the chemistry of carbon and its compounds, their preparations, physical and chemical  properties, reactions and everything about them.
The arena of this branch of chemistry has grown to such extent that a separate branch had to be earmarked for the study of these compounds.

Why Carbon?

Carbon is the important element to organic chemistry. But why?
It is because of the electronic configuration of carbon.
As it is having two 2p electrons, one 2p orbital is vacant and the valency of 4 can be obtained by carbon by the rearrangement of the orbitals.
As a result carbon can form single, double and even triple bonds with atoms like hydrogen, oxygen, nitrogen,etc.as well as other carbon atoms.
It can arrange itself in chained, cyclic, acyclic, branched and unbranched compounds.
It can even form hitherto unknown aromatic compounds where specific phenomena called resonance exists. In this type of structure as is in the benzene, the 3 pi bonds lie alternately in a aromatic ring.
This in turn facilitates nucleophilic as well as electrophilic additions to the aromatic ring.
Not only this, the s and p orbitals can mix up and get rearranged to give special 'hybridized' bonds like sp, sp2 and sp3.

Types of Organic Chemical Reactions

There are various types of organic chemical reactions. A few are as under.
Addition: It takes place across unsaturated double or triple bond.
e.g.CH2=CH2 + Cl2   ---------------->  ClCH2-CH2Cl
Substitution When a species is substituted for another.
CH3SH  + O2    --> CH3OH
Elimination When certain species is altogether removed.
ClCH2-CH3    ---------------> CH2=CH2 + HCl
Re-arrangement
When the compounds change the structure.
BrCH2-CH2 -CH2Cl     <=======>  ClCH2-CH2-CH2Br

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