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Dec 3, 2018 · 4. Bonus Reaction: Diazo Coupling. There’s one last reaction of diazonium salts which is worth mentioning. A surprising number of dyes in our daily experience are derivatives of diazobenzene, the essential structure of which is two benzene molecules joined by a nitrogen-nitrogen double bond. See this article on azo dyes, for instance. Yellow ...
Jan 23, 2023 · Coupling reactions of diazonium ions. The reaction with phenol; The reaction with naphthalen-2-ol; The reaction with phenylamine (aniline) The use of an azo dye as an indicator - methyl orange; Contributors; This page looks at some typical reactions of diazonium ions, including examples of both substitution reactions and coupling reactions.
Aryl diazonium salts may be reduced to the corresponding hydrazines by mild reducing agents such as sodium bisulfite, stannous chloride or zinc dust. The bisulfite reduction may proceed by an initial sulfur-nitrogen coupling, as shown in the following equation. Ar-N 2(+) X (–) NaHSO 3. Ar-N=N-SO 3 H.
Azo N-coupling under basic condition. In alkaline media, diazonium salt can react with most primary and secondary amines, which exist as a free base to produce triazene. This chemical reaction is called azo N-coupling, or the synthesis of azoamines. The dye called aniline yellow is produced by the reaction of aniline and a diazonium salt.
Diazonium salts undergo two types of reactions: Reactions which involve the replacement of nitrogen. Reactions which involve retention of the diazo group. This article deals with the reactions which involve the replacement of nitrogen. Diazonium group is a good leaving group.
The diazonium coupling may simply be defined as the reaction between a diazonium salt and an aromatic compound to give rise to an azo compound.
show how the removal of an amino (or nitro) group from an aromatic ring through the reaction of an arenediazonium salt with hypophosphorous acid (H 3 PO 2) can sometimes be of use in organic synthesis. write a general equation to represent a diazonium coupling reaction.
7.3.2 Coupling Reactions Diazonium ions are weak electrophiles, however, they undergo coupling with activated aromatic nuclei such as aryl amines, phenols and aromatic heterocyclic compounds.
Both steric and electronic factors play a role in this reaction. Resonance structures such as those shown below favor electrophilic attack (the diazonium ion is an electrophile) at the ortho and para positions.
diazonium salt acts as an electrophile in a coupling reaction. Many of the products of coupling reactions are important dyes. A coloured precipitate of azo compound is formed immediately on reaction of diazonium salt with amines or phenols. 4.3.1 Examples of coupling reactions:
