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Not to be confused with quinolone.
Quinoline chemical structure part1.png
Quinoline molecule
Quinoline molecule
IUPAC name
Systematic IUPAC name
  • 2-azabicyclo[4.4.0]deca-1(6),2,4,7,9-pentaene
  • 2-azabicyclo[4.4.0]deca-1,3,5,7,9-pentaene
  • benzo[b]azine
  • benzo[b]azabenzene
Other names
  • 1-azanaphthalene
  • benzo[b]pyridine
  • 1-benzazine
  • benzazine
  • benzazabenzene
  • benzopyridine
  • 1-benzine
  • quinolin
  • chinoline
  • chinoleine
  • chinolin
  • leucol
  • leukol
  • leucoline
91-22-5 YesY
3DMet B00959
ChEBI CHEBI:17362 YesY
ChemSpider 6780 YesY
EC number 202-051-6
Jmol-3D images Image
KEGG C06413 YesY
MeSH Quinolines
PubChem 7047
RTECS number VA9275000
UNII E66400VT9R YesY
UN number 2656
Molar mass 129.16 g/mol
Appearance yellowish oily liquid
Density 1.093 g/mL
Melting point −15 °C (5 °F; 258 K)
Boiling point 237 °C (459 °F; 510 K) /760 mm Hg, 108 to 110 °C/11 mm Hg
Slightly soluble
Solubility Soluble in alcohol, ether, and carbon disulfide
Acidity (pKa) 4.85[2]
174.9 kJ mol−1
R-phrases R21, R22
S-phrases S26, S27, S28, S29, S30, Template:S31, Template:S32, S33, Template:S34, S35, S36
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 101 °C (214 °F; 374 K)
400 °C (752 °F; 673 K)
Lethal dose or concentration (LD, LC):
331 mg/kg
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 YesY verify (what isYesY/N?)
Infobox references

Quinoline is a heterocyclic aromatic organic compound with the chemical formula C9H7N. It is a colorless hygroscopic liquid with a strong odor. Aged samples, especially if exposed to light, become yellow and later brown. Quinoline is only slightly soluble in cold water but dissolves readily in hot water and most organic solvents. Quinoline itself has few applications, but many of its derivatives are useful in diverse applications. A prominent example is quinine, an alkaloid found in plants. 4-Hydroxy-2-alkylquinolines (HAQs) are involved in antibiotic resistance.

Occurrence and isolation[edit]

Quinoline was first extracted from coal tar in 1834 by Friedlieb Ferdinand Runge.[3] Coal tar remains the principal source of commercial quinoline.[4]

Like other nitrogen heterocyclic compounds, such as pyridine derivatives, quinoline is often reported as an environmental contaminant associated with facilities processing oil shale or coal, and has also been found at legacy wood treatment sites. Owing to it relatively high solubility in water, quinoline has significant potential for mobility in the environment, which may promote water contamination. Quinoline is readily degradable by certain microorganisms, such as Rhodococcus species Strain Q1, which was isolated from soil and paper mill sludge.[5]

Quinolines are present in small amounts in crude oil within the virgin diesel fraction. It can be removed by the process called hydrodenitriification.


Quinolines are often synthesized from simple anilines using a number of named reactions.

Quinoline from aniline.png

Going clockwise from top these are:

A number of other processes exist, which require specifically substituted anilines or related compounds:


Quinoline is used in the manufacture of dyes, the preparation of hydroxyquinoline sulfate and niacin. It has also used as a solvent for resins and terpenes.

Quinoline is mainly used as a feedstock in the production of other specialty chemicals. Approximately 4 tonnes are produced annually according to a report published in 2005.[4] Its principal use is as a precursor to 8-hydroxyquinoline, which is a versatile chelating agent and precursor to pesticides. Its 2- and 4-methyl derivatives are precursors to cyanine dyes. Oxidation of quinoline affords quinolinic acid (pyridine-2,3-dicarboxylic acid), a precursor to the herbicide sold under the name "Assert".[4]

See also[edit]


  1. ^ "QUINOLINE (BENZOPYRIDINE)". Chemicalland21.com. Retrieved 2012-06-14. 
  2. ^ Brown, H.C., et al., in Baude, E.A. and Nachod, F.C., Determination of Organic Structures by Physical Methods, Academic Press, New York, 1955.
  3. ^ "Quinoline". Encyclopædia Britannica. 1911. 
  4. ^ a b c Gerd Collin; Hartmut Höke (2005), "Quinoline and Isoquinoline", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a22_465 
  5. ^ O'Loughlin, Edward J.; Kehrmeyer, Staci R.; Sims, Gerald K. (1996). "Isolation, characterization, and substrate utilization of a quinoline-degrading bacterium". International Biodeterioration & Biodegradation 38 (2): 107. doi:10.1016/S0964-8305(96)00032-7. 

External links[edit]