AROMATIC COMPOUNDS Irrespective of which theory is used to describe the bonding, benzene is a perfect hexagon where all the bond angles are 120 and where all six C C bonds are identical.
When drawing a benzene molecule, it is common to draw a circle in the centre green oakley sunglasses of the hexagon of carbon atoms. This implies 'delocalisation' of the 6 p electrons around the aromatic ring and indicates the real symmetry of the benzene molecule. The general type of reaction is an electrophilic substitution reaction. Like alkenes, an electron pair from a p bond is available oakley frogskin sunglasses for reaction. However, an addition reaction would result in loss of the "resonance energy" which makes aromatic compounds more stable than the analogous alkenes. Consequently substitution occurs and the net effect preserves the aromatic nature of the compound.
Aromatic hydrocarbons undergo substitution reactions only with extremely powerful electrophiles, which include the nitronium ion (NO2+), the bromonium ion (Br+) the chloronium ion (Cl+) and acylium ion (RCO+). These electrophiles are too reactive to oakley mens sunglasses usa be stable species and are usually generated in situ (within the reaction mixture) immediately before they are required for oakley mens sunglasses aromatic substitution. NO2+ is generated in a mixture of concentrated sulfuric and nitric acid ; Cl+ is generated by reaction of Cl2 with a Lewis acid such as AlCl3; and RCO+ is generated by reaction of RCOCl with AlCl3.
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