Ponceau colorants
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Description
Scarlet red synthetic Azo dyes first made in 1878 by a secret process developed by Brooke, Simpson, and Spiller. Ponceau colorants were used to dye wool and silk without a mordant. These water-soluble dyes were formerly used for coloring maraschino cherries prior to being removed from the FDA approved list for food in 1976.
- Ponceau 2R: Acid Red 26; CI 16150; Xylidine ponceau; Ponceau G; a red azo dye used in histology for staining; water soluble; usually a disodium salt
- Ponceau 3R: discontinued
- Ponceau 4R: Acid Red 18; CI 16255; Pigment Red 274; a crimson azo dye often used as a food coloring (not allowed in US, Canada, or Japan; Stable to light heat and acid
- Ponceau 6R: Acid Red 44; CI 16250; Crystal Ponceau 6R; a red azo dye used for food coloring and histology staining; soluble in water; usually a disodium salt
- Ponceau S: Acid Red 112; CI 27195; a sodium salt of a disazo dye used for histological staining of proteins
- Ponceau SX: Scarlet GN; Food Red 4; once used as a food dye (E number-E125)
Synonyms and Related Terms
Ponceau Reds; ponceaux; Ponceau 2R; Ponceau SX; Ponceau 4R; Ponceau 6R
Physical and Chemical Properties
- Soluble in water.
- Slightly soluble in alcohols.
- Insoluble in oils.
- High heat resistance and good lightfastness.
Resources and Citations
- Wikipedia: Ponceau
- CHSOS: Spectra (Reflectance, XRF, Raman, FTIR) for PR 274 Ponceau 4R
- E. Hagan, I. Castro-Soto, M. Breault, et al. The lightfastness of early synthetic organic dyes. Herit Sci 10, 50 (2022).