Hydroxyquinoline oxine

Hydroxyquinoline ( oxine ). The technique adopted in this preparation is based upon the fact that, in general, the reactants glycerol, amine, nitro compound and sulphuric acid can be mixed with temperature control, and then maintained at any convenient temperature below 120° without any appreciable chemical reaction taking place. A pre-mix of the amine, glycerol and sulphuric acid, maintained at a temperature which keeps it fluid (60-90°), is added in portions to a reaction vessel containiug the nitro compound and warmed with stirring to 140-170° at which temperature the Skraup reaction takes place. 

Hydroxyquinoline (oxine, 8-quinolinol) [148-24-3] M 145.2, m 71-73 , 75-76 , 76 , b 267 pKj 4.91, pK 9.81. Crystd from hot EtOH, acetone, pet ether (b 60-80 ) or water. Crude oxine can be purified by pptn of copper oxinate, followed by liberation of free oxine with H2S or by steam distn after acidification with H2SO4. Stored in the dark. Forms metal complexes. [Manske et al. Can J Research 27F 359 1949 Phillips Chem Rev 56 271 1956.]... 

Determination of molybdenum with 8-hydroxyquinoline (oxine) Discussion. 

Hydroxyquinoline ( oxine) solution, 5 per cent. Dissolve 5.0 g oxine in 12 g glacial acetic acid and dilute to 100 mL with distilled water. 

Van den Berg [510] carried out direct determinations of molybdenum in seawater by adsorption voltammetry. The method is based on complex formation of molybdenum (VI) with 8-hydroxyquinoline (oxine) on a hanging mercury drop electrode. The reduction current of adsorbed complexions was measured by differential pulse adsorption voltammetry. The effects of variation of pH and oxine concentration and of the adsorption potential were examined. The method was accurate up to 300 nmol/1. The detection limit was 0.1 nmol/1. 

Hydroxyphenylarsonic acid, C6H4(OH)AsO(OH)2 (aqueous) 8-Hydroxyquinoline (oxine), C9H6NOH, (alcohol)... 

Among the most important indirect methods of analysis which employ redox reactions are the bromination procedures for the determination of aromatic amines, phenols, and other compounds which undergo stoichiometric bromine substitution or addition. Bromine may be liberated quantitatively by the acidification of a bromate-bromide solution mixed with the sample. The excess, unreacted bromine can then be determined by reaction with iodide ions to liberate iodine, followed by titration of the iodine with sodium thiosulphate. An interesting extension of the bromination method employs 8-hydroxyquinoline (oxine) to effect a separation of a metal by solvent extraction or precipitation. The metal-oxine complex can then be determined by bromine substitution. 

The use of an organic precipitant may be exemplified by reference to the employment of 8-hydroxyquinoline (Oxine), to determine aluminium. Aluminium oxinate, Al(C9H6NO)3, can be quantitatively precipitated from... 

There are many interesting derivatives of quinoline and acridine obtained by substitution. In particular, 8-hydroxyquinoline (oxine) is the second complexing agent in importance after EDTA. Sulfonation in position 5 leads to a compound which is soluble in water and that exhibits outstanding fluorogenic properties (i.e. fluorescence enhancement) on complexation with metal ions (e.g. aluminum). 

Class 2 fluorophores that can reversibly bind an analyte. If the analyte is a proton, the term fluorescent pH indicator is often used. If the analyte is an ion, the term fluorescent chelating agent is appropriate. Fluorescence can be either quenched upon binding (CEQ type Chelation Enhancement of Quenching), or enhanced (CEF type Chelation Enhancement of Fluorescence). In the latter case, the compound is said to be fluorogenic [e.g. 8-hydroxyquinoline (oxine)]. 

Such a fluorescence enhancement in these compounds 32-34 is similar to that observed in metal chelates with 8-hydroxyquinoline (oxine) and its derivatives but is not fully understood yet. 

Kinetic studies of the oxidation of some a-hydroxy acids with pyridinium dichromate (PDC) are consistent with a mechanism involving the loss of H2O from the pro-tonated substrate in the rate-determining step. The oxidation of 8-hydroxyquinoline (oxine) by PDC has been studied. The intermediacy of an acetochromate ion in the oxidation of some acetophenone oximes with PDC is suggested. 

The stability constants821 for the 8-hydroxyquinoline (oxine) complexes have been questioned owing to the ease with which the VIV complexes undergo oxidation, even by atmospheric o2.355,687 However, adducts [VO(oxine)2L] (L = py or other nitrogen bases) were more stable towards oxidation. The Viv oxine complex gradually turns magenta black when extracted into a nonpolar solvent, indicating formation of the Vv oxine complex in air, but in... 

The handling and disposal problems associated with the use of liquid solvent extractors have resulted in increased attention to the separation and preconcentration of organic compounds in water by collection in synthetic polymers followed by elution with an organic solvent (2). For example, selective collection and concentration of organic bases on methylacrylic ester resin from dilute water samples have been reported (3). Such collection techniques are especially well-suited to flow-injection measurement techniques. In this study, ionizable organic analytes such as salicylic acid and 8-hydroxyquinoline (oxine) were extracted into a polymer and then back extracted by an aqueous solution. Amperometric measurement using a flow-injection technique was employed to monitor the process. 

The Br2 can be used to analyze many unsaturated oiganic compounds. Al3+ was analyzed as follows An unknown was treated with 8-hydroxyquinoline (oxine) at pH 5 to precipitate aluminum oxinate, AI(C9H6ON)3. The precipitate was washed, dissolved in warm HC1 containing excess KBr, and treated with 25.00 mL of 0.020 00 M KBr03. 

Hydroxyquinoline (oxine, 6), one of the earliest analytical reagents, also is one of the most widely studied N—O bidentates. Its early coordination chemistry was reviewed by Phillips.19 Its use as an in vivo agent in microbiological systems has been reviewed by Schulman and Dwyer.20 The extensive use of oxine and substituted forms, and closely related bidentates, for the analytical solvent extraction and colorimeteric determination of metal ions has been comprehensively reviewed.21 An unusual bridged bonding mode for oxine has been reported in which N monodentate and O... 

Hydroxyquinoline oxine ). Place 170 ml (3.18 mol) of concentrated sulphuric acid in a 1-litre three-necked flask provided with a stirrer, and add 112.5g (1.03 mol) of o-aminophenol, followed by 287g (3.12mol) of anhydrous glycerol maintain the temperature below 80 °C by cooling, if necessary. Keep the mixture in a fluid state by placing the flask on a steam bath. 

The Influence of Chemical Constitution on Antibacterial Activity. Part III. A Study of 8-Hydroxyquinoline (oxine) and related Compounds. 

The bromination of 8-hydroxyquinoline (oxine) is applicable to the indirect determination (after separation) of various metals. Each mole of oxine consumes 2 moles of bromine, or 4 equivalents of oxidant ... 

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