A qualitative reaction of primary and secondary amines

KAMIYA Shozo

doi:10.2116/bunsekikagaku.9.26

Primary and secondary aromatic and aliphatic amines react with carbon disulfide and each of them forms a different compound which gives a characteristic color reaction with 2, 6-dibromoquinonechlorimide, and the reagent can be used for a qualitative test of primary and secondary amines. Namely, 1) aromatic primary amines form a durable red-purple coloration of thiourea derivatives, 2) aliphatic primary amines form salts with dithiocarbamic acid of red coloration which discolor immediately or turn yellow. Aliphatic secondary amines are converted into yellow colored salts of corresponding dithiocarbamic acid. Similarly, methyl (or ethyl) aniline gives green coloration, and dimethyl (or ethyl) aniline gives blue colored indamine pigment without the reaction with carbon disulfide. Amino acids in water react with a drop of pyridine to give a red coloration. In general, aromatic primary amines with substituting group having - M effect show negative reaction. About 13mg of a free amine or its alcoholic or ethereal solution is taken in a micro test tube, 0.7 cc carbon disulfide is added and evaporated to dryness on a water bath by heating at 8090°C. In case the sample is insoluble to carbon disulfide, it is dissolved by adding one or two drops of alcohol. Following the addition of 0.5 cc alcohol, the solution is colored by the addition of a drop of 5% sodium acetate and 12 drops of 0.1% 2, 6-dibromoquinonechlorimide. In case of amino acids, the sample is reacted after dissolving it in one drop each of water and pyridine, and three drops of 2, 6-dibromoquinonechlorimide reagent are added.

A qualitative reaction of primary and secondary amines

Bibliographic Information

Search this article

Description

Journal

Keywords

Details 詳細情報について

Export

Report a problem