What is aromaticity in organic chemistry?
In chemistry, aromaticity is a property of cyclic (ring-shaped), typically planar (flat) structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to other geometric or connective arrangements with the same set of atoms.
What makes an organic molecule aromatic?
The condition that aromatic molecules must have [4n+2] pi electrons is sometimes called “Hückel’s rule”. So the cyclopentadiene anion has six pi electrons – 4 from the two double bonds, and two from the lone pair on carbon.
How do you make a benzene ring?
Benzene is prepared from ethyne by the process of cyclic polymerization. In this process, Ethyne is passed through a red-hot iron tube at 873 K. The ethyne molecule then undergoes cyclic polymerization to form benzene.
What compound is Synthesised from benzene?
More than half of the entire benzene production is processed into ethylbenzene, a precursor to styrene, which is used to make polymers and plastics like polystyrene and EPS. Some 20% of the benzene production is used to manufacture cumene, which is needed to produce phenol and acetone for resins and adhesives.
What causes aromaticity?
Aromaticity results from particular bonding arrangements that cause certain π (pi) electrons within a molecule to be strongly held. Aromaticity is often reflected in smaller than expected heats of combustion and hydrogenation and is associated with low reactivity.
What is the criteria for aromaticity?
An aromatic must follow four basic criteria: it must be a ring planar, have a continuous chain of unhybridized p orbitals (a series of sp2-hybridized atoms forming a conjugated system), and have an odd number of delocalized electron pairs in the system.
How do you identify aromatic hydrocarbons?
Which is a characteristic of aromatic hydrocarbons?
General properties of aromatic hydrocarbons: They display aromaticity. The carbon–hydrogen ratio is high. They burn with a strong sooty yellow flame because of the high carbon–hydrogen ratio.
Why is gasoline called benzene?
In many languages, the name of the product gasoline is derived from benzene, such as Benzin in German, and benzina in Italian. This does not necessarily mean it contains any benzene, and actually it should contain as little benzene as possible.
How do you make aniline?
Aniline is prepared by the reaction of nitrobenzene and Sn / concentrated HCl / excess NaOH with nitrobenzene. In this reaction, nitrobenzene is reduced to aniline salt by Sn / concentrated HCl. Then aniline is recovered by adding NaOH.