Quinoline was first extracted from coal tar in 1834 by German chemist Friedlieb Ferdinand Runge; he called quinoline leukol ("white oil" in Greek). Coal tar remains the principal source of commercial quinoline. In 1842, French chemist Charles Gerhardt obtained a compound by dry distilling quinine, strychnine, or cinchonine with potassium hydroxide; he called the compound Chinoilin or Chinolein. Runge's and Gephardt's compounds seemed to be distinct isomers because they reacted differently. However, the German chemist August Hoffmann eventually recognized that the differences in behaviors was due to the presence of contaminants and that the two compounds were actually identical. The only report of quinoline as a natural product is from the Peruvian stick insect
Oreophoetes peruana. They have a pair of thoracic glands from which they discharge a malodorous fluid containing quinoline when disturbed.
(Eisner, T; Morgan, R.C.; Attygalle A.B., Smedley, S.R.; Herath, K.B., Meinwald, J. (1997) "Defensive Production of quinoline by a phasmid insect (Oreophoetes peruana) J. Exp. Biol. 200, 2493-2500).
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 its 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.
Quinolines are present in small amounts in crude oil within the virgin diesel fraction. It can be removed by the process called hydrodenitrification.
Quinolines are often synthesized from simple anilines using a number of named reactions.
Quinoline is mainly used as in the production of other specialty chemicals. Approximately 4 tonnes are produced annually according to a report published in 2005. 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".
^F. F. Runge (1834) "Ueber einige Produkte der Steinkohlendestillation" (On some products of coal distillation), Annalen der Physik und Chemie, 31 (5) : 65-78 ; see especially p. 68: "3. Leukol oder Weissöl" (3. White oil [in Greek] or white oil [in German]). From p. 68: "Diese dritte Basis habe ich Leukol oder Weissöl genannt, weil sie keine farbigen Reactionen zeigt." (This third base I've named leukol or white oil because it shows no color reactions.)
^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.
^GRIBBLE, Gordon W.; HEALD, Peter W. (1975). "Reactions of Sodium Borohydride in Acidic Media; III. Reduction and Alkylation of Quinoline and Isoquinoline with Carboxylic Acids". Synthesis. 1975 (10): 650-652. doi:10.1055/s-1975-23871. ISSN0039-7881.
^Xu, L.; Lam, K. H.; Ji, J.; Wu, J.; Fan, Q.-H.; Lo, W.-H.; Chan, A. S. C. Chem. Commun.2005, 1390.