Solvent dyes are the class of dyes that gets soluble in the solvents of organic nature. They are generally introduced in the organic solvent as a solution. As a general tendency the solvent dyes do not ionise. Many of the solvent dyes are typically the Azo dyes that has in fact lost the ability for ionising due to change in their molecular arrangement.
But in the process they gained the ability to get dissolved in
non-polar materials like triglycerides. Because of this the solvent dyes
are also called lysochrome dyes.
The Solvent dyes are specifically recognised as dyes of the stated
colour, whose method of staining is by dissolving. Some of the popular
Solvent Dyes are Solvent Red 26, Solvent Red 24, Solvent Red 164 etc. It
is pertinent here that the names of the solvent dyes follows the generic
pattern of the scheme, like solvent "color" "number".
When we talk about chemical structures some of the popular chemical
structures are the Azo structure that imparts the solvent dyes
yellow-red color, Anthraquinone structure solvent dyes that results in
green-blue. Other structures for solvent dyes include among others
heterocyclic rings, metal complex, pyrazolone, xanthene and ketoamin.
One of the prominent application of solvent dye is the Fuel dye.