Toluidine red

Toluidine red
Names
	Other names Pigment Red 3, 1-(4-Methyl-2-nitrophenylazo)-2-naphthol
Identifiers
CAS Number	2425-85-6;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:82428;
ChEMBL	ChEMBL2138372;
ChemSpider	13615376;
ECHA InfoCard	100.017.612
EC Number	219-372-2;
KEGG	C19373;
PubChem CID	17047;
UNII	7K26S08256;
CompTox Dashboard (EPA)	DTXSID8021226 ;
	InChI InChI=1S/C17H13N3O3/c1-11-6-8-14(15(10-11)20(22)23)18-19-17-13-5-3-2-4-12(13)7-9-16(17)21/h2-10,21H,1H3 Key: ZLFVRXUOSPRRKQ-UHFFFAOYSA-N;
	SMILES CC1=CC(=C(C=C1)N=NC2=C(C=CC3=CC=CC=C32)O)[N+](=O)[O-];
Properties
Chemical formula	C17H13N3O3
Molar mass	307.309 g·mol−1
Appearance	red solid
Density	1.434 g/cm3
Melting point	269 °C
Solubility in water	low
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H318, H410, H413
Precautionary statements	P264+P265, P273, P280, P305+P354+P338, P317, P391, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Toluidine red is an organic compound with the formula C₁₀H₆(OH)(N₂C₆H₃(NO₂)CH₃). A dark red solid, the compound is classified as a azo dye consisting of a 2-naphthol group linked to a 2-nitro-4-methylphenyl substituent.^[3] Toluidine red is a traditional pigment, found in oil paints.^[4] Although once popular, it suffers as a pigment owing to "insufficient lightfastness and bleeding when incorporated into a paint system."^[1]

Safety

It is classified as carcinogenic, a property that it shares with many azo dyes.^[5]

References

^ ^a ^b Chung, F. H. (1971). "Crystallography of Toluidine Red". Journal of Applied Crystallography. 4 (1): 79–80. Bibcode:1971JApCr...4...79C. doi:10.1107/S0021889871006307.
^ "Toluidine red". pubchem.ncbi.nlm.nih.gov.
^ Jaffe, Edward E. (2004). "Pigments, Organic". Kirk-Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.151807011001060605.a01.pub2. ISBN 978-0-471-48494-3.
^ Scherrer, Nadim C.; Stefan, Zumbuehl; Francoise, Delavy; Annette, Fritsch; Renate, Kuehnen (2009). "Synthetic Organic Pigments of the 20th and 21st Century Relevant to Artist's Paints: Raman Spectra Reference Collection". Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 73 (3): 505–524. Bibcode:2009AcSpA..73..505S. doi:10.1016/j.saa.2008.11.029. PMID 19136293.
^ Møller, Peter; Wallin, Håkan (2000). "Genotoxic hazards of azo pigments and other colorants related to 1-phenylazo-2-hydroxynaphthalene". Mutation Research/Reviews in Mutation Research. 462 (1): 13–30. doi:10.1016/s1383-5742(99)00090-3. PMID 10648921.

[AC-1] Chung, F. H. (1971). "Crystallography of Toluidine Red". Journal of Applied Crystallography. 4 (1): 79–80. Bibcode:1971JApCr...4...79C. doi:10.1107/S0021889871006307.

[2] "Toluidine red". pubchem.ncbi.nlm.nih.gov.

[3] Jaffe, Edward E. (2004). "Pigments, Organic". Kirk-Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.151807011001060605.a01.pub2. ISBN 978-0-471-48494-3.

[4] Scherrer, Nadim C.; Stefan, Zumbuehl; Francoise, Delavy; Annette, Fritsch; Renate, Kuehnen (2009). "Synthetic Organic Pigments of the 20th and 21st Century Relevant to Artist's Paints: Raman Spectra Reference Collection". Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 73 (3): 505–524. Bibcode:2009AcSpA..73..505S. doi:10.1016/j.saa.2008.11.029. PMID 19136293.

[5] Møller, Peter; Wallin, Håkan (2000). "Genotoxic hazards of azo pigments and other colorants related to 1-phenylazo-2-hydroxynaphthalene". Mutation Research/Reviews in Mutation Research. 462 (1): 13–30. doi:10.1016/s1383-5742(99)00090-3. PMID 10648921.

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