Overview of Basic Dyes

Basic dyes, also known as base dyes, are salts formed by aromatic bases and acids (organic acids, inorganic acids), that is, salts of colored organic bases. Its basic group is generally amino group, which is -NH2·HCl salt group after being formed into a salt. It dissolves in water and dissociates into dye cation and acid anion. Also known as cationic dyes.
In 1856, H.W.perkin synthesized the world’s first synthetic dye, aniline violet, which is a basic dye. After that, basic fuchsin (C.I. Basic Violet 14), Basic Blue (C.I. Basic Blue 9), Crystal Violet (C.I. Basic Violet 3), Malachite Green (C.I. Basic Green 4) and Rhodamine appeared one after another. (C.I. Basic Violet 10) and many other varieties. The chemical structure types of basic dyes include diarylmethane, triarylmethane, azo type and nitrogen-containing heterocyclic compounds (such as xanthene, oxazine and thiazine, etc.).
Basic dyes have less hydrophilic groups, so they are insoluble in water. When dissolving, first dissolve with alcohol or acetic acid, and then dilute with water. Basic dyes are more sensitive to temperature, so the temperature of dissolving dilution and dyeing bath should not be too high. Basic dyes have affinity with negatively charged leather, so they are suitable for dyeing vegetable tanned leather. It is mainly used for dyeing leather with anions (vegetable tanned leather), and its binding force is strong. Cationic chrome tanned leather is less used because of its poor light fastness.
Basic dyes are salts of organic bases, which dissociate into pigment cations and acid anions in solution, so they are also called basic dyes. Its molecular structure generally contains primary amines, secondary amines, tertiary amines or nitrogen-containing heterocycles, so it is weakly cationic in acidic baths.
Basic dyes have strong tinting strength and bright shades. However, the light fastness and washing fastness of such dyes are poor. It is now rarely used for coloring on fibers. Mainly used for the coloring of paper, ribbons and biological materials. Dyes such as crystal violet, rhodamine and oxazine can also be used as heat-sensitive dyes, pressure-sensitive dyes and dye lasers.