colorant azoïque

Traductions

• anglais

  Date : 1984

  Définition

  The most versatile and widely used group of dyestuffs; the term azo refers to the nitrogen content of the molecule. Two reactions are involved in their formation.

  Note :

  The azo component is derived by reacting a primary aromatic amine with nitrous acid, plus a mineral acid. This reaction is called diazotization.It yields a compound containing an -N=N-, or diazo, group which performs the color-imparting function and thus is called a chromophore. The diazo compound then undergoes a second reaction, known as coupling, with other organic compounds, such as phenols or amines. Many azo dyes can be formed by means of diazotization and coupling, producing a wide variety of organic dyes and intermediates, suitable for both natural and synthetic fibers, as well as for nontextile materials. The dyes are bright, light-fast, and resistant to washing.

  Terme :

  1. azo dye