Physical and chemical properties: white needle like crystal. Melting point 76 ℃, boiling point 266.6 ℃ (100.3kpa). It is soluble in ethanol, benzene, chloroform, acetone and dilute acid, but insoluble in water
Application: the product is an intermediate of halogenated quinoline anti amebic drugs, including quiniodoform, chloroiodoquinoline, diioquinoline, etc. This kind of drugs can inhibit the intestinal symbiosis and play an anti amebic effect, which is effective on amebic dysentery, but has no effect on extraintestinal amoeba protozoa. In recent years, it has been reported that this kind of drugs can cause subacute spinal optic neuropathy, so it has been banned in Japan and the United States
8-Hydroxyquinoline Usage And Synthesis
Chemical Properties：8-Hydroxyquinoline is a white to cream-colored crystal or crystalline powder that is insoluble in water or ether and freely soluble in ethanol, acetone, chloroform, benzene, and aqueous mineral acids. It readily forms stable metal chelates, which are soluble or precipitable in organic solvents, depending on the pH of the solution (Hollingshead, 1954).
OriginatorChinosol,Chinosolfabrik
Uses：Oxine is an almost universal complexing agent; it reacts with very many metal ions to give water-insoluble precipitates. It has been used so far for the determination of aluminium, antimony, beryllium, bismuth, cadmium, cerium, cobalt, chromium, copper, gallium, germanium, lanthanum, lithium, magnesium, manganese, molybdenum, nickel, ruthenium, thorium, titanium, uranium, vanadium, tungsten, zinc and zirconium.
With the exception of the aluminium, bismuth, gallium, indium, lead and thallium complexes, the oxinate precipitates contain water of crystallization. The majority of the complexes are of stoichiometric composition (either with or without water of crystallization), and therefore subsequent to drying at suitable temperature the precipitates are ready for direct weighing. The precipitates containing water of crystallization are usually dried at 100-105°C and weighed as such, or dried at 130-140°C when the water of crystallization is eliminated.
The complexes can be decomposed with strong acids, and the oxine liberated in an amount equivalent to the metal may be determined by bromatometric titration.
The electrically neutral oxinate complexes are sparingly soluble in water whereas they readily dissolve in apolar solvents immiscible with water, for instance chloroform. Hence this ligand is useful for the solvent extraction enrichment and the subsequent spectrophotometric determination of metal ions. The optimum pH range for complex formation is dependent upon the stabilities of the oxinate complexes. Accordingly, divalent metals are usually precipitated quantitatively in neutral or slightly alkaline media. Adjustment of the suitable pH may be made with various tartrate buffers, for example with ammonia-ammonium tartrate in the pH range 6-10, and with sodium hydroxidesodium tartrate buffers for the pH range 10-13. Complexes of tri- and tetravalent metals are more stable, and thus can be precipitated quantitatively even at about pH 4. In these cases the pH of the solution is adjusted to the desired value with acetic acid-sodium acetate buffers. The copper(II) and iron(III) complexes precipitate quantitatively even at pH 2.7, as does vanadium(V) as an oxinate complex of uncertain composition.
Uses：8-Hydroxyquinoline has a wide variety of uses. Primarily because of their metal chelating properties, 8-hydroxyquinoline and its salts, halogenated derivatives, and metal complexes have been used as analytical reagents (Hollingshead, 1954) and as antimicrobial agents in medicine, fungicides, and insecticides (Harvey, 1975). It is also used as a preservative in cosmetics and tobacco, a chemical intermediate in dye synthesis (IARC, 1977), and a precipitating reagent for uranium and other radioactive metals in nuclear power plant liquid waste effluent. It is used in nuclear medicine with indium-111 (Davis et al., 1978).
8-Hydroxyquinoline may be used as a chelating ligand in the preparation of tris-(8-hydroxyquinoline)aluminum (Alq3), an organic electroluminescent compound used in organic light-emitting devices (OLEDs).
DefinitionChEBI: A monohydroxyquinoline that is quinoline substituted by a hydroxy group at position 8. Its fungicidal properties are used for the control of grey mould on vines and tomatoes.
Manufacturing Process：The mixture of 1.4 kg o-nitrophenol, 2.1 kg o-aminophenol, 6 kg glycerine (d = 1.26) and 5 kg sulfuric acid (d = 1.848) was heated at reflux to temperature 130°-140°C. This temperature was kept for 1.5 hours. The obtained oxyquinoline precipitated, the liquid was removed with water-steam distillation. The residue was diluted with water and alkalized with sodium hydroxide and sodium carbonate to the strong alkaline reaction. The repeated distillation with water steam gave the oil, which hardened as the long needles by cooling. MP: 75°-76°C recrystallized from diluted ethanol.
In practice it is usually used as sulfate salt
Brand name：Aci-jel;Benzease;Chinosol;Cp-cap;Dermacid;Dermoplast;Fennosan h 30;Heriat;Hydroxybenoxopyridine;Medicone derma-hc;Oxykin;Oxyquinoline-rhp;Pedivol;Phenopyridine;Preconsol;Quinoderm;Quinoped;Quinophenol;Recta medicone-hc;Semori;Serohinol;Serorhinol;Superol;Trimo-san;Triva douch powder;Triva jel.
Therapeutic FunctionAntiseptic
World Health Organization (WHO)Halogenated hydroxyquinoline is structurally related to clioquinol. See WHO comment for clioquinol. (Reference: (WHODI) WHO Drug Information, 77.1, 9, 1977)
General Description：White to off-white or faintly yellow crystalline powder. Phenolic odor.
Air & Water ReactionsInsoluble in water.
Reactivity Profile8-Hydroxyquinoline darkens on exposure to light. 8-Hydroxyquinoline readily forms stable metal chelates. 8-Hydroxyquinoline is incompatible with strong oxidizers. 8-Hydroxyquinoline is also incompatible with many metal ions.
HazardToxic by ingestion. Questionable carcinogen.
Fire HazardFlash point data for 8-Hydroxyquinoline are not available; however, 8-Hydroxyquinoline is probably combustible.
Clinical UseOxine, quinophenol, or oxyquinoline is the parent compoundfrom which the antiprotozoal oxyquinolines havebeen derived. The antibacterial and antifungal properties of oxine and its derivatives, which are believed to result fromthe ability to chelate metal ions, are well known. Aqueoussolutions of acid salts of oxine, particularly the sulfate(Chinosol, Quinosol), in concentrations of 1:3,000 to1:1,000, have been used as topical antiseptics. The substitutionof an iodine atom at the 7-position of 8-hydroxyquinolinesyields compounds with broad-spectrum amebicidalproperties.
Safety ProfilePoison by intraperitoneal and subcutaneous routes. Moderately toxic by ingestion. Questionable carcinogen with experimental carcinogenic, neoplastigenic, and tumorigenic data. Experimental reproductive effects. A central nervous system stimulant. Human mutation data reported. Combustible when exposed to heat or flame. When heated to decomposition it emits hghly toxic fumes of NOx.
Purification MethodsCrystallise oxine from hot EtOH, acetone, pet ether (b 60-80o) or water. Crude oxine can be purified by precipitation of copper oxinate, followed by liberation of free oxine with H2S or by steam distillation after acidification with H2SO4. Store it in the dark. It forms complexes with many metals. [Manske et al. Can J Research 27F 359 1949, Phillips Chem Rev 56 271 1956, Beilstein 21 III/IV 1135, 21/3 V 252.]
