Solutions Of 8-hydroxyquinoline Research Articles

Highly efficient purification of the process solution when producing lithium hydroxide by caustification

Relevance. The need to develop highly effective methods for purifying the process solution from impurity calcium and aluminum ions for the industrial production of lithium hydroxide at the Chemical Metallurgical Plant JSC in Krasnoyarsk. Aim. Development of methods for reducing the content of impurity calcium and aluminum ions in the process solution of lithium hydroxide after caustification to a concentration of 5–10 mg/l. Methods. Evaporation and crystallization, precipitation of colloidal sediments of aluminum and calcium with an ammonia buffer solution, chemical precipitation with 8-hydroxyquinoline. Results and conclusions. The effectiveness of the applied methods for purifying a process solution of lithium hydroxide from calcium and aluminum ions was shown: evaporation followed by crystallization, precipitation with an ammonia buffer solution, precipitation in the form of hydroxyquinolates. It was experimentally established that when using the evaporation method followed by crystallization, the degree of extraction of impurity aluminum ions Al3+ is achieved 29%; and calcium ions Ca2+ – 56%. When cleaning the process solution by precipitation of aluminum hydroxide colloid with an ammonia buffer solution, the degree of extraction for aluminum ions Al3+ was 96%; for calcium ions Ca2+ – 67%. The use of the chemical precipitation method with 8-hydroxyquinoline in an alkaline solution showed the degree of extraction of aluminum ions Al3+ 20%; and calcium ions Ca2+ – 76%. It was established that the method of evaporation and crystallization of the process solution does not require the use of special reagents. A method using an ammonia buffer solution to remove impurity calcium and aluminum ions shown to be simple and effective. For the first time, a method was proposed for cleaning the process solution after caustification using an aqueous-alkaline solution of 8-hydroxyquinoline, excluding the use of organic, flammable and toxic solvents.

Cobalt(II) Metal-organic Framework as Scintillating Material

Novel cobalt(II) metal-organic framework was grown by the reaction of a methanol solution of 8-hydroxyquinoline and benzoic acid with aqueous solution of cobalt(II) chloride hexahydrate using slow solvent evaporation. The X-ray luminescence of the synthesized compound showed vibronic peaks: one with λmax at 489 nm and shoulders at 424 and 531 nm, respectively, which compare favorably with best organic scintillators such as anthracene –447 nm and stilbene –410 nm currently in application. The elemental analysis of the metal complex suggests a metal to ligands ratio of 1:1:1. Conductance measurement shows a nonelectrolytic nature of the synthesized compound. The SEM studies give the surface morphology of the complex. The observed emission bands with different dynamics in response to temperature change suggest that the Co-MOF exhibits scintillation properties. Electronic spectrum and magnetic moment studies were used to determine the geometry of the Co-MOF molecule. Thermal analysis data reported displayed the extent of stability of the Co-MOF compound. PXRD data revealed the nanocrystalline nature of the complex. Energy resolution peak observed at 2535 KeV, suggest the synthesized compound can be used as a scintillator.

Highly Active and Chemoselective Reduction of Halogenated Nitroarenes Catalyzed by Ordered Mesoporous Carbon Supported Platinum Nanoparticles

Highly dispersed Pt nanoparticles (∼2.2 nm) on ordered mesoporous carbon (Pt/CMK-3–HQ) were first prepared through a two-step impregnation route with aqueous solutions of 8-hydroxyquinoline (8-HQ) ...

Formation and Entrapment of Tris(8-hydroxyquinoline)aluminum from 8-Hydroxyquinoline in Anodic Porous Alumina.

The formation and entrapment of tris(8-hydroxyquinoline)aluminum (Alq3) molecules on the surface of anodic porous alumina (APA) immersed in an ethanol solution of 8-hydroxyquinoline (HQ) were investigated by absorption, fluorescence, and Raman spectroscopies. The effects of the selected APA preparation conditions (galvanostatic or potentiostatic anodization method, anodizing current and voltage values, one- or two-step anodizing process, and sulfuric acid electrolyte concentration) on the adsorption and desorption of Alq3 species were examined. Among the listed parameters, sulfuric acid concentration was the most important factor in determining the Alq3 adsorption characteristics. The Alq3 content measured after desorption under galvanostatic conditions was 2.5 times larger than that obtained under potentiostatic ones, regardless of the adsorbed quantities. The obtained results suggest the existence of at least two types of adsorption sites on the APA surface characterized by different magnitudes of the Alq3 bonding strength. The related fluorescence spectra contained two peaks at wavelengths of 480 and 505 nm, which could be attributed to isolated Alq3 species inside nanovoids and aggregated Alq3 clusters in the pores of APA, respectively. The former species were attached to the adsorption sites with higher binding energies, whereas the latter ones were bound to the APA surface more weakly. Similar results were obtained for the Alq3 species formed from the HQ solution, which quantitatively exceeded the number of the Alq3 species adsorbed from the Alq3 solution. Alq3 molecules were formed in the HQ solution during the reaction of HQ molecules with the Al3+ ions in the oxide dissolution zone near the oxide/electrolyte interface through the cracks and the Al3+ ions adsorbed on surface of pore and cracks. In addition, it was suggested that HQ molecules could penetrate the nanovoids more easily than Alq3 species because of their smaller sizes, which resulted in higher magnitudes of the adsorption.

Study on the structure and luminescence properties of the coordinated ZnO crystallites

The coordinated ZnO nanoparticles and crystallites have been produced by focused pulsed laser ablation of ZnO target submerged in the ethanol solution of 8-hydroxyquinoline. The structure of the nanoparticles was characterized by high-resolution transmission electron microscopy (HRTEM). The ZnO crystallites properties were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis coupled to differential scanning calorimetry (TG/DSC), X-ray photoelectron spectroscopy (XPS) and luminescence spectrometry. The results show the surface Zn2+ ions of the ZnO nanoparticles are coordinated by the 8-hydroxyquinoline. The crystal class and the space group of the coordinated ZnO crystallites are triclinic and P-1(2), respectively. The lattice parameters are refined to a=1.1904 nm, b=1.2135 nm, c=0.8586 nm, α=108.28∘,β=100.27∘ and γ=85.50∘, respectively. The coordinated ZnO crystallites have better thermo stability than bis(8-hydroxyquinoline)zinc and can emit yellow-green light under UV and visible radiations.

Dehydration and volatilization non-isothermic kinetic of the solid state aluminium 8-hydroxyquinolinate

Al(C9H6ON)3.2.5H2O was precipitated from the mixture of an aqueous solution of aluminium ion and an acid solution of 8-hydroxyquinoline, by increasing the pH value to 9.5 with ammonia aqueous solution. The TG curves in nitrogen atmosphere present mass losses due to dehydration, partial volatilisation (sublimation plus vaporisation) of the anhydrous compound followed by thermal decomposition with the formation of a mixture of carbonaceous and residues. The relation between sublimation and vaporisation depends on the heating rate used. The non isothermic integral isoconventional methods as linear equations of Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose (KAS) were used to obtain the kinetic parameters from TG and DTA curves, respectively. Despite the fact that both dehydration and volatilisation reactions follow the linearity by using both methods, only for the volatilisation reaction the validity condition, 20£ E/RT£ 50, was verified.

Dehydration and volatilization non isothermic kinetic of the solid state aluminium 8-hydroxyquinolinate

Al(C9H6ON)3.2.5H2O was precipitated from the mixture of an aqueous solution of aluminium ion and an acid solution of 8-hydroxyquinoline, by increasing the pH value to 9.5 with ammonia aqueous solution. The TG curves in nitrogen atmosphere present mass losses due to dehydration, partial volatilisation (sublimation plus vaporisation) of the anhydrous compound followed by thermal decomposition with the formation of a mixture of carbonaceous and residues. The relation between sublimation and vaporisation depends on the heating rate used. The non isothermic integral isoconventional methods as linear equations of Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose (KAS) were used to obtain the kinetic parameters from TG and DTA curves, respectively. Despite the fact that both dehydration and volatilisation reactions follow the linearity by using both methods, only for the volatilisation reaction the validity condition, 20<= E/RT<= 50, was verified.

Quantitative Determination of Mg in Ai-Alloys by Ion-Exchange TLC

Abstract Analytical procedure for the quantitative determination of Mg in Al-alloys using ion-exchange thin layer chromatography is described. Chromatographic plates were coated with Amberlite IRP-69 (strong-acid cation exchanger in H+-form) mixed in different ratios with microcristalline cellulose. Solutions of HCI and HNO3 respectively, in the concentration range from 0.5 – 2.0 mol dm−3 were used as developers. Chromatograms were visualized by spraying with ethanolic solution of 8-hydroxyquinoline and spots were scanned using Camag Turner Fluorometer 111. The optima separation was obtained on TLC plates containing 23 % of ion-exchanger (particle size <60 μm) and by eluting with 1.25 M HCI. RF (Al)=0.12, RF(Mg)=0.41.

Study of heterogeneous equilibria in saturated solutions of some sparingly soluble 8-hydroxyquinolines

Heterogeneous equilibria in saturated aqueous solutions of 8-hydroxyquinoline (A), 2-methyl-8-hydroxyquinoline (B) and 5-chloro-8-hydroxyquinoline (C) were investigated at constant ionic strength (1 M sodium chloride), at 25.0 ± 0.1°, by the application of the following methods: the formation function method, the method of bound protons, the method of free proton sites and the solubility method. The following equilibrium constants were determined: K s1=[H 2A +]/[H 3O +], K s2=[HA] and K s3=[H 3O +] [A −]. Their mean pK values are: −2.88, 2.42 and 12.09 for A, −3.27, 2.71 and 12.73 for B, and −0.34, 3.88 and 12.75 for C. In addition, the acidity constants of investigated 8-hydroxyquinolines were determined by pH-metric titrations. The values obtained for these constants were consistent with those calculated on the basis of corresponding equilibrium constants determined in heterogeneous systems.

Fluorescent technique for macroscopic detection of electrical metallization.

A fluorescence method for the detection of trace metals was investigated to visualize in situ latent current marks or electrical metallic traces on cloth. The main electrodes metallization (iron, copper, zinc, aluminum, nickel, chromium, and brass) can be identified by spraying a 0.2% solution of 8-hydroxyquinoline in ethanol followed by observation under shortwave UV light. Advantages and disadvantages of this technique are compared with previously described methods.

The kinetics and mechanism of solvent extraction of Fe(III) and Cu(II) by oxine reagents—II: The extraction of Fe(III) into a toluene solution of 8-hydroxyquinoline

The kinetics of the extraction of Fe(III) from an aqueous nitrate solution into a toluene solution of 8-hydroxyquinoline have been examined in a constant-interfacial-area device. During the course of this reaction a competitive reaction takes place in the aqueous phase. This reaction involves transfer of the reagent to the bulk aqueous phase, and the contribution of this pathway to the kinetics of extraction is assessed. The effect of temperature, agitation and the concentration of ferric ions, protons, and reagent on the kinetics of the extraction reaction are considered, and a mechanism is presented.

The kinetics and mechanism of solvent extraction of Fe(III) and Cu(II) by oxine reagents—I: The aqueous-phase reaction between Fe(III) and 8-hydroxy quinoline

The kinetics of extraction of Fe(III) from an aqueous nitrate solution into toluene or chloroform solutions of 8-hydroxyquinoline have been studied in a constant interfacial area cell. During this reaction a green ferric-oxine complex is formed in the aqueous phase, and the kinetics of this reaction are reported here. Activation energies for the reaction under various conditions have been calculated, and a detailed reaction mechanism is presented. It is shown that the reaction is controlled by diffusion in both the organic phase and the aqueous phase and that the relative contributions of organic and aqueous phase diffusion to the overall rate are a sensitive function of the iron and proton concentrations.

Determination of mononuclear dissolved aluminum in near-neutral waters

Concentrations of mononuclear dissolved Al are determined in samples of natural waters and of solutions separated from experimental suspensions of clay minerals, by solvent extraction and spectrophotometry of aluminum 8-hydroxyquinoline. Samples are treated with a solution of 8-hydroxyquinoline buffered at pH 5.0 by sodium acetate-acetic acid. The resulting Al-hydroxyquinoline complex is extracted immediately into 2.00 ml toluene, to prevent inclusion of secondary mononuclear Al released from poly-nuclear Al(OH) x ions or aluminous solids. After centrifugation-separation of the toluene and aqueous phases, the overlying toluene layer is transferred to a spectrophotometer equipped with a miniature fixed quartz cell. A detection limit of 0.2 μg Al l −1 can be attained with 100-ml samples, and at 1.0 μg Al l −1, the analytical uncertainty is ± 10% or less. Preliminary extractions with chloroform solutions of diethylammonium diethyldithiocarbamate eliminate interferences due to dissolved V, Fe, Ni, Cu, Ga, Mo and U. Extracting the Al-hydroxyquinoline complex at pH 8.3 eliminates any interference due to F. The procedure was used to measure the solubility of gibbsite over the pH range 5–8.

A New Trace Ferrous Metal Detection Reagent

Abstract Since the early 1970s there has been substantial use of the 8-hydroxyquinoline test for determining whether a person has handled a weapon [1]. This test, now generally referred to as the TMDT test [2], involves spraying the hands of a person suspected of handling a weapon with a 0.2% solution of 8-hydroxyquinoline in isopropanol and observing the sprayed area with ultraviolet light. If a person has handled a weapon to the extent that oxidized ferrous ion is transferred to the hands, a dark area is noted in those areas of contact. Often a pattern of the object handled will be apparent. A positive reaction must be recorded by photography, however, and attendant complications exist in the ultraviolet fluorescent photography which must be employed [3].

Metal ion complexes of cytidinediphosphocholine

Cytidine-5′-diphosphocholine (CDPcholine) forms a complex with Mg 2+ and Mn 2+ ions as indicated by the broadened 31P NMR peaks of CDPcholine in the presence of these ions. Additional evidence for the complex is the decrease in absorption at 360 nm when CDPcholine is added to solutions of 8-hydroxyquinoline and Mg 2+. The stability constant of the Mg-CDPcholine complex was found to be 20 M −1.

Equilibria in uranyl carbonate systems—I: The overall stability constant of UO 2(CO 3) 34−

Solutions of 8-hydroxyquinoline in chloroform have been shown to extract the uranyl(VI) ion from aqueous carbonate media and from aqueous solutions of two phenylarsonic acid derivatives, as the species UO 2(OX) 2HOX. A method for calculating the overall stability constant, β 3( c) , of UO 2(CO 3) 3 4− from the resultant distribution date is outlined. The value obtained is log β 3( c) = 21·54 ± 0·03 at an ionic strength of 0·1 M.

Solute-solvent interactions from relaxation data by a novel procedure

The use of the Bellamy plot in infra-red spectroscopy is extended into the realm of dielectric relaxation studies. The mean relaxation times of a given molecule in a series of solvents are plotted against the mean relaxation times of a suitable reference molecule in the same solvents. The use of these reference-molecule relaxation time plots (RMRT plots) is illustrated for solutions of trichloromethane in several solvents. The plots are then applied to solutions of 2-nitrophenol in several solvents with nitrobenzene as reference molecule, and to solutions of 8-hydroxyquinoline in several solvents with 1-nitronaphthalene as reference molecule. The specific interaction between 1,4-dioxan and the hydroxyl compound is distinctly revealed in each case despite the presence of the strong intramolecular hydrogen bond in the solute molecules. Taking other physical evidence into account, the most comprehensive explanation for 2-nitrophenol is the formation of a bifurcated hydrogen bond between the chelated molecule and the solvent. For 8-hydroxyquinoline the possibility of chelate ring fission and orthodox intermolecular hydrogen bond formation is not eliminated.

Calculation of the rate constant of the extraction of nickel (II) 8-hydroxyquinolinate

1. The results of kinetic experiments on the extraction of nickel by solutions of 8-hydroxyquinoline in chloroform, conducted earlier, were analyzed to develop a method of calculating the rate constant of extraction. The values of the rate constant of extraction were calculated. 2. The conditions of applicability of the method under consideration in the analysis of the kinetic extraction data were substantiated. 3. The interdependence of the rates of chemical reactions occurring in homogeneous and heterogeneous systems under comparable conditions was discussed.

Extraction of tungsten with 8-hydroxyquinoline and some of its derivatives

The extraction of tungsten by chloroform solutions of 8-hydroxyquinoline( I), 2-methyl-8-hydroxyquinoline( II), 5,7-dibromo-8-hydroxyquinoline( III) and 8-mercaptoquinoline( IV), as a function of the concentration of tungsten and reagent and the acidity of the aqueous phase, has been studied. Evidence was obtained for the quantitative extraction of tungsten over a wide range of acidity. The degree of extraction of tungsten at 10 −5 M concentration with I,III and IV gives two maxima when plotted against acidity. The extraction maximum for the more acidic solutions lies in the region where the reagents exist in the protonated form and its position depends on the reagent used. It is suggested that different tungsten complexes are extracted, depending on the acidity of the aqueous phase.

Investigation of the kinetics of the extraction of chromium (III) by 8-hydroxyquinoline

1. The extraction of Cr(III) with solutions of 8-hydroxyquinoline in organic solvents practically cannot be accomplished even at increased temperature as a result of the “inertness” of aquo-complexes of chromium and on account of the formation of incompletely substituted or hydrated hydroxyquinolinates. 2. The rate of extraction and the amount of chromium extracted increases sharply in the presence of salts of formic or acetic acid when the temperature is raised to 50–80°. The significance of the presence of these salts in the aqueous phase is determined by the formation of more labile complexes of Cr(III). 3. Oxygen-containing organic solvents (alcohols) extract chromium more rapidly and completely than “inert” solvents (of the type of chloroform and benzene) for two reasons: in the first place, on account of the lower distribution constant of the reagent in the system water-organic solvent, and in the second place, on account of the possibility of the formation of solvents of the chromium hydroxyquinolate to be extracted.