Ingredient Dictionary

DIRECT RED 81

Sirius red 4B is an organic sodium salt resulting from the formal condensation of Sirius red 4B (acid form) with two equivalents of sodium hydroxide.

Definition

Sirius red 4B is an organic sodium salt resulting from the formal condensation of Sirius red 4B (acid form) with two equivalents of sodium hydroxide. Used as the plasma stain in some trichrome staining methods. It has a role as a fluorochrome, a poison, a histological dye and an environmental contaminant. It contains a Sirius red 4B(2-).

Source: PubChem

US FDA substance register · UNII 7E49Q56PNB · registered name DIRECT RED 81 · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Cosmetic roles

Dyes hairHAIR DYEING

Safety & regulatory references

Banned: Argentina · ASEAN · Brazil · China · European Union · South Korea · Taiwan · United Kingdom

Source: ASEAN Cosmetic Directive · EU Cosmetics Regulation · MFDS (Korea) cosmetic regulatory information · Taiwan FDA cosmetic ingredients · UK cosmetics regulations (OPSS)

Not classified under Korea’s toxic-substance GHS list · existing chemical substance

Source: Korea toxic substances GHS register (NIER)

EU Cosmetics Regulation, Annex II (prohibited substances), entry 1267

Source: EU prohibited substances (Annex II)

Restriction II/1267

Source: EU CosIng ingredient list

More data — names, identifiers, properties, test records, literature

Names & identifiers

DIRECT RED 81INCI2-Naphthalenesulfonic acid, 7-(benzoylamino)-4-hydroxy-3-[[4-[(4-sulfophenyl)azo]phenyl]azo]-, disodium saltSynonym다이렉트적색81호Korean label name (MFDS standard)

CAS No.chemical registry number: 2610-11-9
EC No.EU chemical inventory number: 220-028-9
DTXSIDUS EPA chemical ID: DTXSID5041726
DTXCIDUS EPA compound ID: DTXCID3021726

IUPAC: Disodium 7-benzamido-4-hydroxy-3-({4-[(4-sulfonatophenyl)diazenyl]phenyl}diazenyl)naphthalene-2-sulfonate
Molecular formula: C29H19N5Na2O8S2
Molecular weight: 675.6 g/mol

Measured properties

Appearance: solid
Melting/freezing point: 240 ℃(exp)
Initial boiling point and range: 1142.75 ℃(est)
Vapour pressure: 0.00000000000000000000000000000142 ㎜Hg (1.42E-30 est)
Water solubility: 2.805 ㎎/ℓ (est)
n-Octanol/water partition coefficient (Kow): 1.65
Molecular weight: 675.6

Values measured on the substance itself. The KOSHA data are a reference for writing and reviewing safety data sheets, not a specification for a commercial raw material.

Source: KOSHA safety data sheets (Korea)

What products actually use it for

What the 4 products reported to the US EPA with this ingredient use it for. Products outside cosmetics are included, so the top few rows are its main uses.

Dye3
Pigment1

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

1 skin studies and 0 eye studies are on record.

Classed as low1

The study conclusions largely agree (100%). These tests are on the raw material itself; irritation at the amount in a finished product is a different question.

See all 1 studies

Not likely to be sensitizing
skin sensitisation: in vivo (non-LLNA) · Screening · according to OECD Guideline 406 (Skin Sensitisation)