Direct Red 31 Chemical Properties

EPA Substance Registry System

2-Naphthalenesulfonic acid, 7,7'-iminobis[4-hydroxy-3-(phenylazo)-, disodium salt (5001-72-9)

Direct Red 31 Usage And Synthesis

Chemical Properties

Reddish brown powder. Water solubility is still good, aqueous solution is bluish red, add concentrated hydrochloric acid to produce date red precipitate, add concentrated alkali to orange-brown. Soluble in ethylene glycol ether, slightly soluble in ethanol, reddish orange, insoluble in other organic solvents. Orange to brown in concentrated sulfuric acid, produces dark blue-red precipitate after dilution; brown solution with precipitate in concentrated nitric acid. Insoluble in concentrated alkali; date red in concentrated ammonia.

Uses

Direct red 31 is a good dyeing agent for cotton fabrics.

Properties and Applications

References

[1] Sawada K, Ueda M. Adsorption behavior of direct dye on cotton in non-aqueous media[J]. Dyes and pigments, 2003, 58(1): 37-40.

Direct Red 31(5001-72-9)Related Product Information

• Direct Red 13
• Direct Red 75 tetrasodium salt
• DIAMINE GREEN B
• CHLORAZOL VIOLET N
• Direct Yellow 12
• Direct Black 19
• BRILLIANT YELLOW
• Direct Black 38
• DIRECT FAST BROWN M
• STILBENE YELLOW
• CI NO 22610
• Direct Red 23
• Direct Orange S
• DIRECT BLUE 15
• Direct Blue 86
• Direct Grey D
• DIRECT YELLOW 27
• DIANIL BROWN 3GN