Q. 255.0( 2 Votes )
(a) Identify A –
(a) A = AgNO2
reacts with AgNO2 to give
reacts with tin in an acidic medium to give
reacts with bromine in the presence of NaOH to give
reacts with CHCl3 and KOH to give
(c) A =
Step 1:Ethane nitrile on reduction with lithium aluminium hydride produces primary amine – propylamine.
Step 2: Propyl amine on reaction with nitrous acid prepared in situ by reaction of sodium nitrite and hydrochloric acid gives propyl alcohol.
(a) (i) The anilinium ion formed in a strongly acidic medium is by the protonation of aniline during nitration os meta - directing.
Primary aromatic amines cannot be prepared by Gabriel phthalimide synthesis because aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.
1. Ethanoic acid is first converted into into an ethanamide by the action of ammonia.
2. Hoffman bromamide degradation reaction:
The amide produced from the first step is used to make a primary amine by the Hoffman bromamide degradation reaction. An amide is treated with bromine in an aqueous or ethanolic solution of sodium hydroxide.
In this reaction, an alkyl or aryl group migrates from the carbonyl atom to the nitrogen atom. The amine formed methanamine.
(ii) This reaction can be carried out by a process called bromination. Simple bromination produces only ortho and para products. To produce a product with only a single substituted product, a special reaction is carried out-
The amine is first treated with pyridine to get acetanilide. This reacts with bromine in the presence of ethanoic acid which is then treated in an acidic or alkaline medium to get 4-Bromoaniline.
(c) p – nitroaniline < aniline < p - toluene.
IMPORTANT: Basic strength is proportional to the electron-density of the atom
In p-toluene, there is the presence of electron donating CH3 group. This increases the electron-density of the N-atom Therfore p-toluene is more basic than aniline.
The presence of electron-withdrawing group NO2 IN p-nitroaniline decreases the electron density of the N atom, therefore it is less basic than aniline.
Hence the order is Aniline, p - nitroaniline, and p - toluene.
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