Advertisements
Advertisements
प्रश्न
Explain why Lewis acid is not required in bromination of phenol?
Advertisements
उत्तर
Usual halogenation is carried out in the presence of Lewis acid, \[\ce{FeBr3}\] which polarises the halogen molecule. In case of phenol, the polarisation of bromine occurs even in the absence of Lewis acid. This is because of highly activating effect of –OH group on the benzene ring. The reaction follows:
Note: In aqueous solution, phenol ionizes to give phenoxide ion. Due to the presence of the negative charge, the oxygen atom of the phenoxide ion donates electrons to the benzene ring to a large extent. As a result, the ring gets highly activated leading to the formation of trisubstituted product. On the other hand, in the non-polar solvents, the ionization of phenol does not occurs to a large extent. As a result, the -OH group donates electrons to the benzene ring only to a small extent. Consequently, the ring is activated slightly and, therefore, only monosubstitution occurs.
APPEARS IN
संबंधित प्रश्न
Name the following compound according to the IUPAC system.
\[\begin{array}{cc}
\phantom{..................}\ce{CH2OH}\\
\phantom{.........}|\\
\ce{CH3 - CH2 - CH - CH - CH - CH3}\\
\phantom{.........}|\phantom{...................}|\\
\phantom{.............}\ce{CH2Cl}\phantom{..........}\ce{CH3}\phantom{}
\end{array}\]
Write the IUPAC name of the following compound:
\[\begin{array}{cc}
\ce{H3C - CH - CH2 - CH - CH - CH2 - CH3}\\
|\phantom{....................}|\phantom{.........}|\phantom{.............}\\
\ce{OH}\phantom{................}\ce{OH}\phantom{...}\ce{C{_2}H5}\phantom{.........}\\
\end{array}\]
Write the IUPAC name of the following compound:
Write the IUPAC name of the following compound:
Write structures of the compounds whose IUPAC names are as follows:
3-Chloromethylpentan-1-ol.
Which of the following compounds is NOT prepared by the action of alcoholic NI3 on alkyl halide?
(a) CH3NH2
(b) CH3- CH2- NH2
(c) CH3 - CH2 - CH2 - NH2
(d) (CH3)3 C- NH2
How is phenol converted into the following?
Benzene
How is phenol converted into the following?
picric acid
Write the IUPAC name of the following compound:
Write IUPAC names of the following
In a carbinol system of nomenclature tert.butyl alcohol is named as _______________
Isopropyl alcohol on oxidation forms:
Give IUPAC names of the following compound:
\[\begin{array}{cc}
\phantom{..}\ce{H}\phantom{...}\ce{CH3}\phantom{.}\ce{H}\phantom{..}\\
\phantom{}|\phantom{....}|\phantom{....}|\phantom{}\\
\ce{H - C - C - C - H}\\
\phantom{}|\phantom{....}|\phantom{....}|\phantom{}\\
\phantom{.}\ce{H}\phantom{...}\ce{OH}\phantom{.}\ce{H}\phantom{.}\\
\end{array}\]
Butane-2-ol is ____________.
IUPAC name of the compound is:
\[\begin{array}{cc}
\ce{CH3-CH-OCH3}\\
|\phantom{....}\\
\ce{CH3}\phantom{..}
\end{array}\]
IUPAC name of the compound \[\begin{array}{cc}
\ce{CH3 - CH - OCH3}\\
\phantom{}|\phantom{....}\\
\phantom{}\ce{CH3}\phantom{..}
\end{array}\] is ______.
What happens when benzene diazonium chloride is heated with water?
Write complete reaction for the bromination of phenol in aqueous and non-aqueous medium.
Convert the following:
Ethyl alcohol into ethyl acetate.
