What is the result of azo dye test?

(e) Azo-Dye Test: This test is performed in order to confirm the presence of aromatic amines. Aromatic amines forms a diazonium salts when treated with HNO2. These diazo compounds couple with phenols like β-naphthols forms an orange azo dye which is insoluble in water.

What is the reaction taken place in azo dye formation?

Azo dyes are prepared in a two step reaction, the first being the synthesis of an aromatic diazonium ion from an aniline derivative. The next step is coupling of the diazonium salt with an aromatic compound (shown below is the preparation of methyl yellow).

Which will not answer azo dye test?

Aniline and benzylamine cannot be distinguished by azo dye test.

Which is the best test for azo dye?

Azo dyes test is used for detarmine the value of aromatic amines. Azo dye test is given aromatic amines. such as, aniline. it is an aromatic amine. Aniline is easily diazotized on coupling reaction gives azo dyes. This test is given yellow colour azo dyes but it turn red brown with contact of air or light. Azo dye test for phenol

What is the coupling reaction of azo dye?

Experiment 8 Synthesis of an azo dye – the coupling reaction of benzenediazonium ion with naphthalene-2-ol Co-produced by The Chinese University of Hong Kong, Education and Manpower Bureau and Hong Kong Examinations and Assessment Authority 54 The unit containing the nitrogen-nitrogen double bond is called an azo group.

How are diazonium salts converted to azo dyes?

Diazotization. The process of conversion of primary aromatic amines into its diazonium salt is called diazotization. Diazonium salts are important synthetic intermediates that can undergo coupling reactions to form azo dyes and electrophilic substitution reactions to introduce functional groups .

How to prepare azo dye from phenol-textilesgreen?

Preparation of an azo dyes from aniline is, first aniline is react in the presence of NaNO2/HCl at temperature 0-5°C. After this reaction,it is given benzene Diazonium chloride (diazonium salt). and then, coupling reaction is carried out with phenol then result azo dyes is formed as a product.