Solvent Yellow 7

Solvent Yellow 7 is an aromatic organic molecule and a common azo dye with a formula of C₆H₅N₂C₆H₄OH.^[3] It has a phenolic hydroxyl and an azo group in the same molecule.^[4]

Solvent Yellow 7^[1]

Names
Preferred IUPAC name 4-(Phenyldiazenyl)phenol
Other names 4-Hydroxyazobenzene Solvent Yellow 7 Simpsol Yellow
Identifiers
CAS Number	1689-82-3
3D model (JSmol)	Interactive image
ChEBI	CHEBI:82475
ChEMBL	ChEMBL1525953
ChemSpider	10296254
ECHA InfoCard	100.015.346
EC Number	216-880-6
KEGG	C19433
PubChem CID	15529
UNII	VX4306NSH1
CompTox Dashboard (EPA)	DTXSID70942923 DTXSID3022160, DTXSID70942923
InChI InChI=1S/C12H10N2O/c15-12-8-6-11(7-9-12)14-13-10-4-2-1-3-5-10/h1-9,15H Key: BEYOBVMPDRKTNR-UHFFFAOYSA-N InChI=1S/C12H10N2O/c15-12-8-6-11(7-9-12)14-13-10-4-2-1-3-5-10/h1-9,15H
SMILES C1=CC=C(C=C1)N=NC2=CC=C(C=C2)O
Properties
Chemical formula	C12H10N2O
Molar mass	198.225 g·mol−1
Appearance	An orange solid[2]
Melting point	155 °C (311 °F; 428 K)
Solubility in water	Slightly soluble in hot water
Solubility in other solvents	Soluble in ethanol, acetone
Acidity (pKa)	8.2 (from the hydroxyl group)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Irritant
Related compounds
Related compounds	Benzenediazonium chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Like most azobenzenes, Solvent Yellow 7 can be synthesized by the reaction of the phenyldiazonium salt with phenol. The optimal pH value for this azo coupling is 8.5-10. The reaction is carried out in water, since sodium chloride (or potassium chloride) formed in the reaction is soluble in water, while the product precipitates.^[5]

As azo dyes are not usually water soluble, the effect of various solvents on them has been studied analytically, and likewise analytical methods and calculations for the color concentration developed.^[6][7]

Further reactions

The molecule can be further reacted including with bromine,^[8] and other halogens.^[9] Other reactions include nitration.^[10] The reactivity with Grignard reagents has also been studied.^[11]

Toxicology

The toxicology has been extensively studied,^[12] including IARC studies.^[13] There have been other extensive reviews.^[14]