7590. Ponceau 3R

Nomenclature

CAS number: 3564-09-8
3-Hydroxy-4-[(2,4,5-trimethylphenyl)azo]-2,7-naphthalenedisulfonic acid disodium salt; sodium cumeneazo-β-naphthol disulfonate; C.I. Food Red 6; C.I. 16155; FD & C Red no. 1; Ext. D & C Red no. 15.
C19H16N2Na2O7S2; mol wt 494.45.
C 46.15%, H 3.26%, N 5.67%, Na 9.30%, O 22.65%, S 12.97%.

Description and references

Prepn: Colour Index vol. 4 (3rd ed., 1971) p 4092. Toxicity studies: Hansen et al., Toxicol. Appl. Pharmacol. 5, 105 (1963).

Chemical structure

Properties

Dark red powder. Soluble in water with cherry-red color, slightly in alcohol. Addition of HCl to its aq soln does not change the color, but NaOH produces a yellow ppt. It dissolves in concd H2SO4 to a cherry-red soln which does not change color on dilution.

Use

Dyeing wool. Colorant in food, drugs and cosmetics.