Quinoline Yellow SS is a bright yellow

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...

with green shade. It is insoluble in water, but soluble in nonpolar organic solvents. Quinoline yellow is representative of a large class of quinophthalone pigments. It is suggested that quinoline yellow exhibits

excited-state intramolecular proton transfer Excited state intramolecular proton transfer (ESIPT) is a process in which photoexcited molecules relax their energy through tautomerization by transfer of protons. Some kinds of molecules could have different minimum-energy tautomers in different ...

(ESIPT) behavior and the behavior might be the cause of its decent photostability, by recent spectroscopic study.

Synthesis and reactions

As first described in 1878, the dye is prepared by the fusion of phthalic anhydride and

quinaldine Quinaldine or 2-methylquinoline is an organic compound with the formula CH3C9H6N. It is one of the methyl derivatives of the heterocyclic compound quinoline. It is bioactive and is used in the preparation of various dyes. It is a colorless oil ...

. The compound exists as a mixture of two tautomers. Using other anhydrides and other quinaldine derivatives other dyes in the quinophthalone family can be prepared. When

sulfonated Aromatic sulfonation is an organic reaction in which a hydrogen atom on an arene is replaced by a sulfonic acid functional group in an electrophilic aromatic substitution. Aryl sulfonic acids are used as detergents, dye, and drugs. Stoichiomet ...

, it converts to a water-soluble derivative, Quinoline Yellow WS.

Uses and safety

Quinoline Yellow SS is used in spirit

lacquer Lacquer is a type of hard and usually shiny coating or finish applied to materials such as wood or metal. It is most often made from resin extracted from trees and waxes and has been in use since antiquity. Asian lacquerware, which may be ca ...

polystyrene Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a ...

polycarbonate Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily work ...

s, polyamides, acrylic resins, and to color hydrocarbon solvents. It is also used in externally applied drugs and cosmetics. Quinoline Yellow SS is used in some yellow colored smoke formulations. It may cause contact dermatitis. It has the appearance of a yellow powder with a melting point of .

References

{{reflist Quinoline dyes Staining dyes Solvent dyes Indandiones