Article · Wikipedia archive · Last revised Jul 5, 2026

Solvent Yellow 7

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

Last revised
Jul 5, 2026
Read time
≈ 3 min
Length
585 w
Citations
14
Source
Wikipedia ↗
Solvent Yellow 71
source ↗
Names
Preferred IUPAC name
4-(Phenyldiazenyl)phenol
Other names
4-Hydroxyazobenzene
Solvent Yellow 7
Simpsol Yellow
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.015.346
EC Number
  • 216-880-6
KEGG
UNII
  • 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
  • C1=CC=C(C=C1)N=NC2=CC=C(C=C2)O
Properties
C12H10N2O
Molar mass 198.225 g·mol−1
Appearance An orange solid2
Melting point 155 °C (311 °F; 428 K)
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).

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

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

source ↗

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.67

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

References

References

  1. "4-PHENYLAZOPHENOL". www.chemicalbook.com. Retrieved 2019-04-08.
  2. Solomons, T.W Graham (2017). Organic chemistry (10 ed.). John Wiley and sons. p. 941. ISBN 978-1119248972. OCLC 973372285.
  3. "4-Phenylazophenol - PubChem Compound - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2024-01-15.
  4. "4-PHENYLAZOPHENOL | 1689-82-3". ChemicalBook. Retrieved 2024-01-15.
  5. Estibaliz, Merino. "Synthesis of azobenzenes: the coloured pieces of molecular materials" (PDF).
  6. Brode, W. R. (1926-01-01). "The Effect of Solvents on the Absorption Spectrum of a Simple Azo Dye". The Journal of Physical Chemistry. 30 (1): 56–69. doi:10.1021/j150259a006. ISSN 0092-7325.
  7. Moir, James (1922-01-01). "CLXXXV.—The calculation of the colour of the azo-dyes and related coloured substances". Journal of the Chemical Society, Transactions. 121: 1555–1562. doi:10.1039/CT9222101555. ISSN 0368-1645.
  8. Hewitt, J. T.; Aston, W. G. (1900-01-01). "LXI.—Bromination of benzeneazophenol". Journal of the Chemical Society, Transactions. 77: 712–716. doi:10.1039/CT9007700712. ISSN 0368-1645.
  9. Hodgson, Herbert H.; Turner, Gerald (1942-01-01). "82. The coupling of m-halogenophenols with diazotised aniline, and the existence of chromoisomerism among the 3-halogeno-4-benzeneazophenols". Journal of the Chemical Society (Resumed): 433–435. doi:10.1039/JR9420000433. ISSN 0368-1769.
  10. Hewitt, J. T. (1900-01-01). "X.—Preparation of benzeneazo-o-nitrophenol". Journal of the Chemical Society, Transactions. 77: 99–103. doi:10.1039/CT9007700099. ISSN 0368-1645.
  11. Gilman, Henry; Bailie, J. Clyde (March 1937). "Relative Reactivities of Organometallic Compounds. Xvii. The Azo Linkage". The Journal of Organic Chemistry. 02 (1): 84–94. doi:10.1021/jo01224a010. ISSN 0022-3263.
  12. Smith, J. N.; Williams, R. T. (1951-05-01). "Studies in detoxication. 36. A note on the glucuronides of benzeneazophenol and benzeneazoresorcinol". Biochemical Journal. 48 (5): 546–547. doi:10.1042/bj0480546. ISSN 0306-3283. PMC 1275371. PMID 14838898.
  13. "4-Hydroxyazobenzene (IARC Summary & Evaluation, Volume 8, 1975)". inchem.org. Retrieved 2024-01-15.
  14. Walker, R. (1970-01-01). "The metabolism of azo compounds: a review of the literature". Food and Cosmetics Toxicology. 8 (6): 659–676. doi:10.1016/S0015-6264(70)80455-2. ISSN 0015-6264. PMID 5500003.
See also

See also

External Websites