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Skeletal formula of 8-hydroxyquinoline
Ball-and-stick model of the 8-hydroxyquinoline molecule
IUPAC name
Quinolin-8-ol, 8-Quinolinol
Other names
1-azanaphthalene-8-ol, Fennosan H 30, hydroxybenzopyridine, hoxybenzopyridine, oxychinolin, oxyquinoline, phenopyridine, quinophenol, oxine
148-24-3 YesY
ChEBI CHEBI:48981 YesY
ChEMBL ChEMBL310555 YesY
ChemSpider 1847 YesY
Jmol 3D model Interactive image
Interactive image
KEGG D05321 YesY
PubChem 1923
Molar mass 145.16 g/mol
Appearance White crystalline needles
Density 1.034 g/cm3
Melting point 76 °C (169 °F; 349 K)
Boiling point 276 °C (529 °F; 549 K)
ATC code G01AC30
A01AB07 D08AH03 R02AA14
Vapor pressure {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

8-Hydroxyquinoline is an organic compound with the formula C9H7NO. It is a derivative of the heterocycle quinoline by placement of an OH group on carbon number 8. This light yellow compound is widely used commercially, although under a variety of names.[2][3]


It is usually prepared from quinoline-8-sulfonic acid and from a Skraup synthesis from 2-aminophenol.[4]

As a chelating agent

8-Hydroxyquinoline is a monoprotic bidentate chelating agent. In neutral solution, the hydroxyl is in the protonated form (pKa=9.89) and the nitrogen is not protonated (pKa=5.13).[5] However, an excited-state zwitterionic isomer exists in which H+ is transferred from the oxygen (giving an oxygen anion) to the nitrogen (giving a protonated nitrogen cation).[6]


The complexes as well as the heterocycle itself exhibit antiseptic, disinfectant, and pesticide properties,[7][8] functioning as a transcription inhibitor.[9] Its solution in alcohol is used in liquid bandages. It once was of interest as an anti-cancer drug.[10]

The reaction of 8-hydroxyquinoline with aluminium(III)[11] results in Alq3, a common component of organic light-emitting diodes (OLEDs). Variations in the substituents on the quinoline rings affect its luminescence properties.[12]

The roots of the invasive plant Centaurea diffusa release 8-hydroxyquinoline, which has a negative effect on plants that have not co-evolved with it.[13]

Hydroxyquinoline was used as a stabilizer of hydrogen peroxide in a rocket fuel oxidizer (T-Stoff) for the German Messerschmitt Me 163 Komet in World War 2.[citation needed]

Related compounds

Related ligands include the Schiff bases derived from salicylaldehyde, such as salicylaldoxime, salen, and salicylaldehyde isonicotinoylhydrazone (SIH). 8-Mercaptoquinoline is the thiol analogue of 8-hydroxyquinoline.


  1. Nanjing Odyssey Chemicals
  2. "8-Hydroxyquinoline Safety Data". Oxford University. [dead link]
  3. "8-Hydroxyquinoline". PAN Pesticides Database. 
  4. Collin, G.; Höke, H. (2005), "Quinoline and Isoquinoline", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a22_465 
  5. Albert, A.; Phillips, J. N. (1956). "264. Ionization Constants of Heterocyclic Substances. Part II. Hydroxy-Derivatives of Nitrogenous Six-Membered Ring-Compounds". Journal of the Chemical Society (Resumed). 1956: 1294–1304. doi:10.1039/JR9560001294. 
  6. Bardez, E.; Devol, I.; Larrey, B.; Valeur, B. (1997). "Excited-State Processes in 8-Hydroxyquinoline: Photoinduced Tautomerization and Solvation Effects". The Journal of Physical Chemistry B. 101 (39): 7786–7793. doi:10.1021/jp971293u. 
  7. Phillips, J. P. (1956). "The Reactions of 8-Quinolinol". Chemical Reviews. 56 (2): 271–297. doi:10.1021/cr50008a003. 
  8. "8-Hydroxyquinoline". Medical Dictionary Online. 
  9. "8-Hydroxyquinoline". Sigma-Aldrich. Retrieved 2012-05-23. 
  10. Shen, A. Y.; Wu, S. N.; Chiu, C. T. (1999). "Synthesis and Cytotoxicity Evaluation of some 8-Hydroxyquinoline Derivatives". Journal of Pharmacy and Pharmacology. 51 (5): 543–548. PMID 10411213. doi:10.1211/0022357991772826. 
  11. Katakura, R.; Koide, Y. (2006). "Configuration-Specific Synthesis of the Facial and Meridional Isomers of Tris(8-hydroxyquinolinate)aluminum (Alq3)". Inorganic Chemistry. 45 (15): 5730–5732. PMID 16841973. doi:10.1021/ic060594s. 
  12. Montes, V. A.; Pohl, R.; Shinar, J.; Anzenbacher, P. Jr. (2006). "Effective Manipulation of the Electronic Effects and Its Influence on the Emission of 5-Substituted Tris(8-quinolinolate) Aluminum(III) Complexes". Chemistry - A European Journal. 12 (17): 4523–4535. PMID 16619313. doi:10.1002/chem.200501403. 
  13. Vivanco, J.M.; Bais, H.P.; Stermitz, F.R.; Thelen, G.C.; Callaway, R.M. (2004). "Biogeographical variation in community response to root allelochemistry: novel weapons and exotic invasion". Ecology Letters. 7 (4): 285–292. doi:10.1111/j.1461-0248.2004.00576.x.