Basic Dyes

Basic dye is a stain that is cationic (+ve charged) and so will react with material that is (-ve) negatively charged. This dye is usually synthetic, that act as bases, and which are actually aniline dyes. Their color base is not water soluble but can be made so by converting the base into a salt. The basic dyes, while possessing great tinctorial strength and brightness, are not generally light-fast.

At the chemical level, basic dyes are typically cationic or positively charged. Basic dyes display cationic functional groups like -NR3+ or =NR2+. Since basic dye is a stain that is cationic or positively charged and it is the reason that it reacts well with material that is anionic or negatively charged.

Basic dyes consists of amino groups, or alkylamino groups, as their auxochromes. Synthetic dye that was discovered by Perkin incidentally was a basic dye. Few examples of basic dyes are the following, methylene blue, crystal violet, basic fuchsin safranin, etc. An example of a basic dye that has amino groups as their auxochrome is pararosanilin or basic red 9 (according to the strict color index system of classification) example of alkylamino groups is methylene blue or basic blue 9. Basic Blue 9 is a very popular dye that has vast use. Table given below provides more information about Basic Blue 9:

Common name	Methylene Blue
Other name	Methylene Blue
Suggested name	Swiss blue
C I name	Basic blue 9, Solvent blue 8
C I number	52015
Ionisation	Thiazin
Solubility aqueous	3.55%
Solubility ethanol	1.48%
Class	Basic
Color	Blue
Empirical formula	C16H18N3SCl
Formula weight	319.9

Yes! I am Interested

• Moderate substantivity
• Relatively economical
• High Tinctorial strength
• Wide shade range
• Shows good brightness
• Includes some of the most brilliant synthetic dyes

• High acid content
• Colored backwaters
• Poor shade stability
• Preferential dyeing
• Very poor light fastness

Modified basic dyes have similar chemistry, as of basic dyes. These only show a bit longer molecular structures than the typical conventional basic dyes, thus resulting in significantly improved properties.

Key advantages over conventional basic dyes:-

• Better Lightfastness
• Clear backwaters
• Covers all fibres
• Excellent substantivity

Basic dyes are extensively used for dyeing of jute, cut flowers, dried flower, coir, etc. For dyeing Acrylic Fibres, basic dyes are used widely. Modified basic dyes are used for dyeing of Acrylic Fibre, because these are perfect for this material. If the reason behind the success of Basic dyes is analysed, it would be seen that the positively charged cations of the Basic dyes gets attracted towards the negatively charged anions in the acrylic fibre. Acylic polymers have anionic groups attached to it. They are most commonly the sulphonate group, -SO3-, followed closed by the carboxylate group, -CO2-. This reaction of the cation and anion results in salt linkages. Basic dye do not show absolutely any migration in acrylic fibers under normal dyeing conditions.

Basic dyes are also preferred to dye leather, because they can get combined easily with vegetable-tanned leather thus doing away with mordant. Basic dyes are also used in the coloring of papers.