what is Liebermannsnitrosobromo reaction

Libermann’s nitroso reaction: The yellow oily nitrosamines when heated with phenol and a few drops of conc. H₂SO₄ give a green solution. When the green solution is made alkaline with NaOH ,the colour of the solution changes to deep blue. On diluting the blue coloured solution, the colour again changes to red.

 

                              C6H5OH+H2SO4                   NaOH                                Dilution

N-nitsoamine            green solution         deep blue         red solution

 

 

This reaction is called Libermann’s nitroso reaction and is used as atest for secondary amine.