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1.
Studies on the fractional sublimation of various metal β-diketone chelates have been extended to include the chelates of thenoyltrifluoroacetone (TTA). Many of the common metal chelates were found to be stable, to sublime readily, and to form well-defined zones in the vacuum fractional sublimator. Of the 17 chelates reported only those of manganese (II) and iron(II) were not volatile. The chelates of UO2(II), Zr(IV), Pb(II), and Cr(III) partially decomposed during sublimation and their recovery was incomplete. The recovery of the sublimed chelates of Ni(II), Mg(II), Al(III), Pd(II), Co(II), Cu(II). Fe(III), Tl(III), Zn(II) and Be(II) ranged from 87 to 100%, with most recoveries being quantitative. The sublimation recrystallization zone temperatures of the various chelates are compared to those of the metal acetylacetonates and the benzoyltrifluoroacetonates; in general, the metal chelates of TTA sublime more readily than those of benzoyltrifluoroacetone but are potentially less useful for fractional sublimation separations than the corresponding metal acetylacetonates. Even so, a quantitative separation of iron(III) from Ni(II), Al(III), Mn(II), and Fe(II) is proposed that depends upon the fractional sublimation of the TTA chelates.  相似文献   

2.
Stability constants for Al(III), Cd(II), Co(II), Cu(II), Fe(III), Hg(II), La(III), Nd(III), Er(III), Mg(II). Mn(II), Ni(II), Pb(II), Th(IV) and Zn(II) complexes of triethylenetetraminehexaacetic acid (TTHA) have been evaluated from data obtained by pH and pM measurements. The pM method based on measurements with the mercury electrode and the redox system Fe(III)/Fe(II) proved to be very useful when binuclear complexes are formed.  相似文献   

3.
The preparation and thermal analysis of the metal chelates of N-benzoyl-N-phenylhydroxylamine (BPHA) with Al(III), Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Ni(II) and Zn(II) is discussed. The differential thermal analysis apparatus is described in detail. DTA and TGA curves of BPHA arid the chelates from 25 to 700° in oxygen and in nitrogen are presented.  相似文献   

4.
The thermal behaviour of the chelates of 5,5′-methylendisalicylhydroxamic acid with Pb(II), Zn(II), Ni(II), Cd(II), Fe(III), Cr(III), Al(III), Ti(IV), V(V), Mo(VI) and Cu(II) has been studied by thermogravimetry (TG), differential thermal analysis (DTA), IR spectroscopy and X-ray diffraction.The compounds decompose through three major steps, dehydration, transformation of the anhydrous hydroxamates to intermediate N-hydroxylactams, which decompose to yield metal oxides as the final products.  相似文献   

5.
A reversed-phase liquid chromatographic method for the determination of trace amounts of vanadium is described. Metal ions are converted into 2-(8-quinolylazo)-5-N,N-diethylaminophenol chelates in an off-line system. The chelates are injected onto a Zorbax CN column and separated with an aqueous acetonitrile mobile phase containing no chromogenic reagent. Unter these conditions, only vanadium(V) is spectrophotometrically detected at 540 nm among the metal ions Al(III), Ba(II), Ca(II), Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Ga(III), Hg(II), Mg(II), Mn(II), Ni(II), Pb(II), V(V) and Zn(II). Amounts of 8.0–200 pg of vanadium(V) in 100-μl injections can be determined without interference from 10-fold molar excesses of many cations. At 0.001 a.u.f.s., the detection limit (twice the peak-to-peak noise) for vanadium(V) is 8.0 pg in 100 μl of injected solution and the relative standard deviation at 120 pg of vanadium(V) in a 100-μl injection is 3.5%. The proposed method is applied to the determination of vanadium in rain water and airborne particulates.  相似文献   

6.
    
Zusammenfassung Es wird die Optimierung der Extraktion von Metallkationen [Sc(III), Cr(III), Mn(II), Fe(III), Co(II), Cu(II), Zn(II), Y(III), Ag(I), Cd(II), La(III), Ce(III), Eu(III), Yb(III), Hg(II), Pb(II), Th(IV), U(IV, VI) und Am(III)] in Form gemischter Komplexe mit Hexafluoracetylaceton und neutralen Donatoren mit Stickstoffatomen bzw. P = O-Gruppen beschrieben. Über thermische und gaschromatographische Eigenschaften der extrahierten flüchtigen Verbindungen wird berichtet. Optimale Ergebnisse wurden mit Tri-n-butylphosphinoxid als Donator erzielt.
Volatile hexafluoroacetylacetonates for the isolation and gas-chromatographic determination of trace metals
Summary The optimization of the extraction of metal cations [Sc(III), Cr(III), Mn(II), Fe(III), Co(II), Cu(II), Zn(II), Y(III), Ag(I), Cd(II), La(III), Ce(III), Eu(III), Yb(III), Hg(II), Pb(II), Th(IV), U(IV, VI) and Am(III)] in the form of mixed-ligand complexes with hexafluoroacetylacetone and neutral donators with nitrogen atoms or P = O-groups is described. The thermal and gas-chromatographic characteristics of the extracted volatile compounds are reported. Optimal results were achieved using tri-n-butylphosphine oxide as donator.
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7.
Thiacalix[4]arenetetrasulfonate (TCAS) has been examined as a pre-column chelating reagent for the determination of trace metal ions by kinetic differentiation mode (KD) ion-pair reversed-phase high-performance liquid chromatography (HPLC) with spectrophotometric detection. Among 14 kinds of common metal ions tested here, viz. Al(III), Ca(II), Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Hg(II), Mg(II), Mn(II), Ni(II), Pb(II), V(V), and Zn(II) ion, only Ni(II) ion was detected as the TCAS chelate in the HPLC separation stage in spite of TCAS forming the chelates with various metal ions except for Al(III), Ca(II), and Mg(II) at the pre-column chelation stage. The undetected metal-TCAS chelates seemed to be dissociated on an HPLC column where no added TCAS was present in the mobile phase because of their kinetic unstability. The calibration graph for Ni(II) ion gave a wide linear dynamic range (40-20,000 nM) with the very low detection limit (DL) (3σ base-line fluctuation) to be 5.4 nM (0.32 ng ml−1). The practical applicability of the KD-HPLC method with TCAS was demonstrated with the determination of trace Ni in coal fly ash.  相似文献   

8.
Nan Z  Yuan-Xiang G  Zhi-Ren L  Eei-Yong C 《Talanta》1985,32(12):1119-1124
A rapid chelatometric method for the determination of Al (4–20%) in magnesium, copper and chromium-aluminium-iron alloys is proposed. HEDTA is used as titrant and Zn solution as back-titrant, with hydrazidazol as indicator. Mn(II), Cu(II), Cd, Zn, Pb, Co(II), Ni, Hg(II), Fe(III), Bi, Cr(III), Sb(III), Ce(III), La, Sn(IV), Ti(IV), Zr and Mo(VI) do not interfere. High selectivity is achieved by a combination of group separation, masking and interference correction. The coefficient of variation varies from 0.2 to 1%.  相似文献   

9.
A new adsorbent is synthesized on the basis of silica consecutively modified by polyhexamethylene guanidine and 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron) for the group preconcentration of Fe(III), Al(III), Cu(II), Pb(II), Zn(II), and Mn(II) followed by determination by inductively coupled plasma atomic emission spectrometry. The adsorbent in the batch mode quantitatively (recovery 98?99%) extracts Fe(III), Al(III) and Cu(II) ions at pH 4.0 and Fe(III), Al(III), Cu(II), Pb(II), Zn(II), and Mn(II) ions at pH 7.0; the time of attainment of an adsorption equilibrium does not exceed 10 min. Consecutive preconcentration at pH 4.0 and 7.0 in the batch and dynamic modes ensures the quantitative separation of Fe(III), Al(III), and Cu(II) from Pb(II), Zn(II), and Mn(II) and their separate determination. The quantitative desorption of metals was attained with 0.5?1.0 M HNO3 (5 or 10 mL). In preconcentration from 200 mL of solution with 5 mL of a desorbing solution, the preconcentration coefficient was equal to 40. The developed procedure was used for the determination of metal ions in river waters of Krasnoyarsk Krai. The results obtained were verified by the added?found method.  相似文献   

10.
The thioderivative of 2-thenoyltrifluoroacetone, 1,1,1-trifluoro-4-(2-thienyl) 4-mercaptobut-3-en-2-one (STTA) was prepared. NMR and infrared spectra confirmed the previously suggested structure2. The sulfur is attached to the carbon adjacent to the thienyl group and exists almost entirely in the thio-enolic form. The chelates of STTA with Ni(II), Cu(II), Pb(II), Zn(II). Co(II), Cd(II). Pd(II) and Hg(II) were prepared in a neutral to slightly basic medium, and characterized by analysis. NMR, infrared, visible and ultraviolet spectra, DTA, TGA and fractional sublimation. The chelates are relatively stable, insoluble in water, soluble in non-polar and some polar organic solvents, sublimable, and intensely colored compared to their normal diketone analogs. The selectivity of the reagent has not been completely established but divalent ions chelate more readily than trivalent ions; Fe(III), Al(III), Cr(III) apparently do not chelate. The new chelon may be useful as a color-developing reagent for the colorimetric analysis of such ions as Zn(II), Cd(II), Hg(II) and Pb(II). The molar extinction coefficients are given for the chelon and the chelates investigated  相似文献   

11.
Vapor pressure-temperature data, molar heats of sublimation, and sublimation temperatures are given for 29 metal β-diketone chelates. The chelatcs studied were these of Be(II), Al(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) with acetyl-acetone, acetyltrifluoroacctone, benzoylacetone, benzoyltrifluoroacetone, 2-furoyl-trifluoroacetone, and 2-thenoyltrifluoroacetone. The observed difference in volatilities of the various metal chelatcs of a given ligand is the basis for a suggestion that various mixtures of metal ions can be resolved by a fractional sublimation scheme.  相似文献   

12.
Molodovan Z  Vlãdescu L 《Talanta》1996,43(9):1573-1577
Chrome Azurol S (CS) was mobilized on an strongly basic anion-exchange resin (Dowex 2 x 4, in Cl(-) form) by batch equilibration. The modified resin was stable in acetate buffer solution and in 0.1 M HCl and H(2)SO(4), but it was readily degraded with 2-6 M HCl and HNO(3). Retention of Ba(II), Sr(II), Ca(II), Mg(II), Al(III), Cr(III), Zn(II), Fe(III), Ti(IV), Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) was studied using the batch equilibration method. The uptake and recovery yields were determined by using inductively-coupled plasma atomic emission spectroscopy (for Mg, Al, Cr, Ti, Fe, Mn, Ni, Zn, Cu, Cd and Pb) and atomic absorption spectrophotometry (for Ba, Sr, Ca and Co). The optimum pH value was established for performing a selective separation of Al(III) from the other metal ions. The sorption capacities of the CS-loaded resing for Al(III), Cr(III), Mg(II) (at pH 6), Fe(III) (at pH 5) and Ti(IV) (at pH 4) were 14, 2.9, 0.3, 3 and 3.9 mumoles g(-1) respectively. On this basis a method for separating Al(III) from other cations was established.  相似文献   

13.
A series of Cu(II), Co(II), Mn(II), Fe(III), and La(III) chelates with unsymmetrical fluorinated -keto esters, taken separately and in mixtures with tertiary amines, were tested as catalysts in urethane formation and in synthesis of network elastomers.  相似文献   

14.
Grdinić  V.  Tabor  Z.  Gertner  A. 《Mikrochimica acta》1975,63(4):433-436
Microchimica Acta - Ein Trennungsschema für Cs(I), Ag(I), Ba(II), Zn(II), Cd (II), Mn(II), Pb(II), Cu(II), Ni(II), Co(II), Bi(III), Al(III) und Fe(III) unter Verwendung von Dithiooxamid als...  相似文献   

15.
Abstract

Dark colored chelates of p-dimethylaminoanil of 3-benzoyl-methylglyoxal bidentate ligand with Sb(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), ZrO(II), Y(III), La(III), Pr(III), Nd(III) Sm(III), Gd(III) and Dy(III) have been chromatographed on starch bound silica gel thin layers. New correlations of I.R. with Rf (resolving solvent) have been used to ascertain the colored spots.

Among various mixtures resolved qualitatively a few typical ones have been alanysed quantitatively. Errors in determinations and maximum separation limits have also been deduced.  相似文献   

16.
Beryllium is separated from Mg, Ca, Mn(II), Fe(III), Al, Co(II). Zn. U(VI), La and Gd by elution with 2.0 M nitric acid in 70 % methanol from a column of AG50W-X8 sulphonated polystyrene cation exchanger, while the other elements are retained quantitatively. Sr, Ba, Sc, Y, the other lanthanides, Zr, Hf, Th, Ga, In, Cd and Ni(II) should also be separated according to their distribution coefficients or elution behaviour. Separations are sharp and recoveries quantitative from millimolar amounts down to 10 μg of beryllium. The separation of Ti(IV) and Cu(II) from beryllium is not satisfactory and requires rather large columns. Bi(III), Pb(II), Hg(II) and the alkali metals are eluted together with beryllium, but can be separated by other methods. Typical elution curves and results for the quantitative separation of binary synthetic mixtures are presented.  相似文献   

17.
The titration procedure described in previous papers of this series has been applied to a study of some metallic chelates of dimethylglyoxime and of its O-monomethyl ether. Evidence is presented for the existence of dimethylglyoxime chelates with Zn (II), Pb (II), Cd (II), and La (III) in addition to the known Cu (II), Ni (II), and Co (II) complexes. Formation constants are calculated for these complexes, and for those of dimethylglyoxime O-monomethyl ether, on the basis of their most probable structures. The results indicate that the famed specificity of dimethylglyoxime fur nickel does not lie in any special stability of this chclate. but in some other factor, possibly solubility. A comparison of the chelates of dimethylglyoxime with those of its O-ether is discussed in terms of such structural factors as hydrogen bonding and steric hindrance. Heat content and entropy changes have been calculated for the chelation of dimethylglyoxime with Cu (II) and Ni (II) ions.  相似文献   

18.
1. In citrate or tartrate solutions mercury formed three different compounds with p-dimethyl-amino-benzylidene-rhodanine at pH ~5,~7 and ~9.The composition of the compounds is discussed. 2. Analytical methods are presented for the determination of 0.1 mg mercury in 20 ml solution which contained 99.5–99.9% foreign metals. In most cases the error lay between zero and 1%. The foreign metals were :Ca, Ba, Mg, Zn, Mn, Ni, Co, Al, Cr(III), Fe(III), Cd, Cu, Pb, U(VI), Tl(I), Th, Ce(III), Sb(III) and Bi(III). Methods for the determination of 0.1 mg mercury in gold (III), Pt(VI), Pd(II) and silver are also presented.  相似文献   

19.
Summary New Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) chelates of the Schiff base derived from isatin witho-phenylenediamine have been synthesized and characterized on the basis of elemental analyses, electronic, IR and1H NMR spectra, and also by aid of molar conductivity and magnetic moment measurements. It has been found that the Schiff base behaves as ONNO tetradentate dibasic ligand forming chelates with 1:1 (metal:ligand) stoichiometry. Square planar environment is suggested for nickel(II) chelate. All the metal chelates show non-electrolytic behaviour.
Metallchelate einiger Übergangs- und Nichtübergangsmetallionen mit Isatin-o-Phenylendiamin-Schiff-Basen
Zusammenfassung Es wurden neue Chelate von Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) und Pb(II) mit Schiff-Basen aus Isatin undo-Phenylendiamin hergestellt und mittels Elementaranalysen, Elektronen-, IR- und1H-NMR-Spektroskopie, sowie durch Messung der molaren Leitfähigkeit und der magnetischen Momente charakterisiert. Es wurde festgestellt, daß sich die Schiff-Base als vierzähniger zweibasischer ONNO-Ligand verhält, wobei 1:1-stöchiometrische Metall:Ligand-Komplexe gebildet werden. Für das Nickel(II)-Chelat wird eine quadratisch-planare Geometrie vorgeschlagen. Alle untersuchten Metallchelate zeigen ein nicht-elektrolytisches Verhalten.
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20.
Koshima H  Onishi H 《Talanta》1986,33(5):391-395
Adsorption of microgram amounts of 20 metal species on activated carbon powder from aqueous solutions of pH 1-13 was investigated. The species examined were Cs(I), Y(III), Ce(III), Ti(IV), Zr(IV), Cr(III), Cr(VI), Mn(II), Fe(III), Co(II), Ni(II), Ru(III), Cu(II), Ag(I), Zn(II), Cd(II), Al(III), Pb(II), Sb(III) and Bi(III).  相似文献   

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