Direct Yellow 21
Name:C.I.Direct Yellow 21,C.I.40045
Molecular Structure: Stilbenes
Molecular Formula:
Molecular Weight:
CAS Registry Number:1325-46-8
Manufacturing Methods : (E)-2-(2-sulfo-4-nitrostyryl)-5-nitrobenzenesulfonic acid sodium sodium hydroxide solution together with aniline backflow heating.
Properties and Applications: soluble in water to pure yellow, slightly soluble in ethanol for yellow. The strong sulfuric acid in red orange for, for the yellow brown after diluted, precipitation. The dye solution to join a light yellow brown hydrochloric acid precipitation; Add sodium hydroxide have orange precipitation.
| Standard | Acid Resistance | Alkali Resistance | Light Fastness | Soaping | Water | ||
| Fading | Stain | Fading | Stain | ||||
| ISO | 5 | 3 | 2 | 3 | 3-4 | ||
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Diphenyl Citronine G( Geigy Co. Ltd )