scholarly journals Liquid-liquid extraction of ion-association complexes of cobalt(II)-4-(2-pyridylazo)resorcinol with ditetrazolium salts

2015 ◽  
Vol 80 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Vidka Divarova ◽  
Kirila Stojnova ◽  
Petya Racheva ◽  
Vanya Lekova ◽  
Atanas Dimitrov
Keyword(s):  
Equilibrium Constants ◽  
Ion Association ◽  
Liquid Extraction ◽  
Tetrazolium Chloride ◽  
Molar Ratios ◽  
Liquid Liquid Extraction ◽  
Blue Tetrazolium ◽  
Blue Tetrazolium Chloride ◽  
Extraction Equilibria ◽  
Ditetrazolium Salts

The formation and liquid-liquid extraction of ion-association complexes between Co(II)-4-(2-Pyridylazo)resorcinol (PAR) anionic chelates and cations of three ditetrazolium chlorides were studied: Blue Tetrazolium chloride (BTC), Neotetrazolium chloride (NTC) and Nitro Blue Tetrazolium chloride (NBT). The optimum conditions for the formation and solvent extraction of the ion-association comlpex chelates were determined. It has been found that in the systems of Co(II)-PAR-DTS, the reactants are reacted in molar ratios 1:2:1 and the general formula of complexes was suggested. The extraction equilibria were investigated and quantitatively characterized by the equilibrium constants and the recovery factors. The analytical characteristics of the complexes were calculated.

scholarly journals Phenylmethoxybis(tetrazolium) ion-association complexes with an anionic indium(III) — 4-(2-pyridylazo)resorcinol chelate

2013 ◽  
Vol 11 (2) ◽  
pp. 280-289 ◽  
Author(s):  
Teodora Stefanova ◽  
Kiril Gavazov
Keyword(s):  
Limit Of Detection ◽  
Ion Association ◽  
Molar Absorptivity ◽  
Tetrazolium Salt ◽  
Limit Of Quantification ◽  
Tetrazolium Chloride ◽  
Liquid Liquid Extraction ◽  
Blue Tetrazolium ◽  
Blue Tetrazolium Chloride ◽  
Molar Absorptivity Coefficient

AbstractComplex formation and liquid-liquid extraction were studied in systems containing indium(III), 4-(2-pyridylazo)resorcinol (PAR), phenylmethoxybis(tetrazolium) salt (MBT), water and chloroform. The following MBTs, which differ only by the number of -NO2 groups in their cationic parts, were used: 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)bis(2,5-diphenyl-2H-tetrazolium chloride) (Blue Tetrazolium chloride, BT), 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)bis[2-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride] (Nitro Blue Tetrazolium chloride, NBT) and 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)bis[2,5-di(4-nitrophenyl)-2H-tetrazolium chloride] (Tetranitro Blue Tetrazolium chloride, TNBT). The composition of the formed ternary complexes was determined, In:PAR:MBT=1:2:2, and the optimum conditions for their extraction found: pH, shaking time, concentration of the reagents and the sequence of their addition. Some key constants were estimated: constants of extraction (Kex), constants of association (β) and constants of distribution (KD). BT appears to be the best MBT for extraction of the In(III)-PAR species, [In3+(OH)3(PAR)2]4−, (Log Kex=10.9, Log β=9.8, Log KD=1.12, R%=92.7%). Several additional characteristics concerning its application as extraction-spectrophotometric reagent were calculated: limit of detection (LOD = 0.12 µg cm−3), limit of quantification (LOD = 0.40 µg cm−3) and Sandell’s sensitivity (SS =1.58 ng cm−2); Beer’s law is obeyed for In(III) concentrations up to 3.2 µg mL−1 with a molar absorptivity coefficient of 7.3×104 L mol−1 cm−1 at λmax=515 nm.

scholarly journals Complex Formation in a Liquid-Liquid Extraction System Containing Cobalt(II), 4-(2-Pyridylazo)resorcinol, and Nitron

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Petya Vassileva Racheva ◽  
Kiril Blazhev Gavazov ◽  
Vanya Dimitrova Lekova ◽  
Atanas Nikolov Dimitrov
Keyword(s):  
Complex Formation ◽  
Limit Of Detection ◽  
Equilibrium Constants ◽  
Ion Association ◽  
Molar Absorptivity ◽  
Liquid Extraction ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Liquid Liquid Extraction ◽  
Experimental Parameters

Complex formation and liquid-liquid extraction were studied in a system containing cobalt(II), 4-(2-pyridylazo)resorcinol (PAR), 1,4-diphenyl-3-(phenylamino)-1H-1,2,4-triazole (Nitron, Nt), water, and chloroform. The effect of some experimental parameters (pH, shaking time, concentration of PAR, and concentration of Nt) was systematically investigated, and the optimum conditions for cobalt extraction as an ion-association complex, (NtH+)[Co3+(PAR)2], were found. The following key equilibrium constants were calculated: constant of association (Log β=4.77±0.06), constant of distribution (LogKD=1.34±0.01), and constant of extraction (LogKex=6.11±0.07). Beer’s law was obeyed for Co concentrations up to 1.7 μg mL−1 with a molar absorptivity of 6.0×104 L mol−1 cm−1 at λmax=520 nm. Some additional characteristics, such as limit of detection, limit of quantification, and Sandell’s sensitivity, were estimated as well.

scholarly journals Ternary complexes of vanadium(IV) with 4-(2-pyridylazo)-resorcinol (PAR) and ditetrazolium chlorides (DTC)

2010 ◽  
Vol 8 (2) ◽  
pp. 461-467 ◽  
Author(s):  
Fatma Genç ◽  
Kiril Gavazov ◽  
Murat Türkyilmaz
Keyword(s):  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Extraction Constant ◽  
Ternary Complexes ◽  
Limit Of Quantification ◽  
Tetrazolium Chloride ◽  
Liquid Liquid Extraction ◽  
Blue Tetrazolium ◽  
Blue Tetrazolium Chloride ◽  
Molar Absorptivity Coefficient

AbstractComplex formation and liquid-liquid extraction have been studied for ternary complexes of vanadium(IV) with 4-(2-pyridylazo)-resorcinol (PAR) and ditetrazolium chlorides (DTC) in a water-chloroform medium. The specific ditetrazolium compounds investigated were i) 3,3′-(4,4′-biphenylene)-bis(2,5-diphenyl-2H-tetrazolium) chloride (Neotetrazolium chloride, NTC); ii) 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)-bis(2,5-diphenyl-2H-tetrazolium) chloride (Blue Tetrazolium chloride, BTC); and iii) 3,3′-(3,3′-dimetoxy-4,4′-biphenylene)-bis[2-(4-nitrophenyl)-5-phenyl-2H-tetrazolium] chloride (Nitro Blue Tetrazolium chloride, NBT). Molar absorptivity coefficients and the composition of the complexes have been calculated. Association constants (β) have also been obtained for the interactions between the vanadium(IV) — PAR anionic chelates [VO(PAR)2]2− (I) and [VO(OH)2(PAR)2]4− (II), and ditetrazolium cations (DT2+). Some special features of NBT as an extraction-spectrophotometric reagent for vanadium(IV) have been discussed. Unlike NTC and BTC which form complexes with both I and II, NBT associates only with II. The pH interval for complete extraction of (NBT2+)2[VO(OH)2(PAR)2] is broader and allows work at lower pH values the other ion-associates of V(IV,V)-PAR that were studied. NBT is -therefore the appropriate reagent both for direct V(IV) determination and for V(IV)/V(V) separation. Some additional characteristics for the V(IV)-PAR-NBT-water-chloroform system have been determined: extraction constant, distribution constant, recovery factor, limit of detection and limit of quantification. Beer’s law is valid up to 1.4 μg mL−1 vanadium(IV) with molar absorptivity coefficient of 3.55×104 L mol−1 cm−1 at λmax=559 nm.

scholarly journals Ternary ion-association complexes between the indium(III) - 4-(2-pyridylazo)resorcinol anionic chelate and some tetrazolium cations

2011 ◽  
Vol 9 (6) ◽  
pp. 1143-1149 ◽  
Author(s):  
Galya Toncheva ◽  
Kiril Gavazov ◽  
Vanya Lekova ◽  
Kirila Stojnova ◽  
Atanas Dimitrov
Keyword(s):  
Complex Formation ◽  
Ternary Complex ◽  
Ion Association ◽  
Liquid Extraction ◽  
Extraction Time ◽  
Tetrazolium Salt ◽  
Optimum Conditions ◽  
Tetrazolium Chloride ◽  
Tetrazolium Bromide ◽  
Liquid Liquid Extraction

AbstractComplex formation and liquid-liquid extraction were studied in systems containing indium(III), 4-(2-pyridylazo)resorcinol (PAR), tetrazolium salt (TZS), water and chloroform. Two different TZS were used: 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT). The optimum conditions for extraction of In(III) as a ternary complex, (TT+)[In(PAR)2] or (MTT+)[In(PAR)2], were found: pH, extraction time, concentration of PAR and concentration of TZS. The constants of extraction (Kex), constants of association (β), constants of distribution (KD) and recovery factors (R%) were determined. The apparent molar absorptivities in chloroform were calculated to be ɛ′520=6.6×104 L mol−1 cm−1 and ɛ′515=7.1×104 L mol−1 cm−1 for the systems with TTC (I) and MTT (II), respectively. Beer’s law was obeyed for In(III) concentrations up to 3.4 µg mL−1 in both the cases. The limits of detection (LOD=0.07 µg mL−1I and LOD=0.12 µg mL−1II), limits of quantification (LOQ=0.24 µg mL−1I and LOQ=0.41 µg mL−1II) and Sandell’s sensitivities (SS) were estimated as well.

scholarly journals Extraction-Spectrophotometric Studies on the Complex Formation of Iron(III) with 4-(2-Thiazolylazo)Resorcinol and Tetrazolium Salts

2014 ◽  
Vol 10 (3) ◽  
pp. 2491-2501 ◽  
Author(s):  
Kiril Blazhev Gavazov ◽  
Teodora S. Stefanova ◽  
Galya K. Toncheva
Keyword(s):  
Equilibrium Constants ◽  
Liquid Extraction ◽  
Association Constants ◽  
Molar Ratio ◽  
Tetrazolium Salt ◽  
Optimum Conditions ◽  
Tetrazolium Chloride ◽  
Iron Extraction ◽  
Liquid Liquid Extraction ◽  
Linear Relationships

Four liquid-liquid extraction-chromogenic systems containing Fe(III), 4-(2-thiazolylazo)resorcinol (TAR), tetrazolium salt (TZS), water and chloroform were studied. 2,3,5-Triphenyl-2H-tetrazolium chloride (TTC), 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT), 3-(2-naphtyl)-2,5-diphenyl-2H-tetrazolium chloride (TV), and 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) were the examined TZSs. Optimization experiments for iron extraction were performed and the following parameters were found for each system: pH(opt), CTAR(opt), CTZS(opt), shaking time (opt), and l(opt). Under the optimum conditions, the molar ratio of the reacting Fe(III), TAR and TZS is 1:2:2 and the general formula of the extracted species is (TZ+)2[FeII(TAR2–)2]. Some equilibrium constants (constants of association, constants of distribution, and constants of extraction) and analytical characteristics (molar absorptivities, Sandell’s sensitivities, Beer’s law limits, etc.) were calculated. Linear relationships involving the molecular mass of TZ+ were discussed.

scholarly journals Liquid–liquid extraction of gallium(III) with n-octylaniline from succinate media

2005 ◽  
Vol 70 (6) ◽  
pp. 853-867 ◽  
Author(s):  
T.N. Shilmkar ◽  
S.S. Kolekar ◽  
M.A. Anuse
Keyword(s):  
Extraction Process ◽  
Liquid Extraction ◽  
Tolerance Limit ◽  
Variation Method ◽  
Hydrogen Ions ◽  
Binary Separation ◽  
Liquid Liquid Extraction ◽  
Masking Agents ◽  
Increasing Temperature ◽  
Extraction Equilibria

The distribution equilibrium of gallium(III) between n-octylaniline dissolved in toluene and acidic aqueous succinate media has been investigated as a function of the concentration of extractant in the organic phase and concentration of hydrogen ions and gallium( III) ions in the aqueous phase. The stoichiometry of the extracted species was determined on the basis of slope analysis.Gallium(III) is extracted by the anion exchange mechanism as [RNH3+Ga(succinate)2]org. The temperature dependence of the extraction equilibria was examined by the temperature variation method. The extraction process is favoured with increasing temperature. It was found that a large number of cations and anions have a high tolerance limit. The selectivity of the extraction is increased by the use of suitable masking agents. The method affords the binary separation of gallium(III) from associated elements and was further extended to the analysis of a synthetic mixture.

Thermodynamic parameters for the complexation of Tc(IV) with bromide under aqueous conditions

2020 ◽  
Vol 108 (5) ◽  
pp. 409-414
Author(s):  
Cecilia Eiroa-Lledo ◽  
Donald E. Wall ◽  
Nathalie A. Wall
Keyword(s):  
Working Conditions ◽  
Equilibrium Constants ◽  
Liquid Extraction ◽  
Complexation Reaction ◽  
Hydrolysis Constant ◽  
Carboxylate Ligands ◽  
Liquid Liquid Extraction ◽  
Varied Temperature ◽  
Aqueous Conditions ◽  
Aqueous Complexes

AbstractTechnetium-99 is a long-lived fission product present in nuclear wastes, found mainly as Tc(VII) and Tc(IV) in the environment. The quantification of the equilibrium constants for the formation of Tc(IV) aqueous complexes has been limited to carboxylate ligands and interactions with the halides is mostly unknown. This work reports equilibrium constants of the formation of the TcO(OH)+ complexes with Br−, in a 3 M NaClO4 solution of pcH 2 and varied temperature, using a liquid-liquid extraction system. Neutron activation confirmed the suitability of the extraction technique for this work. Under the working conditions, Br− forms a weak exothermic TcO(OH)Br complex, with a Gibbs free energy (ΔGr) of 3 ± 3 kJ · mol−1 at a temperature of 273.15 K. The values for ΔHr (−32 ± 3 kJ · mol−1) and ΔSr (106 ± 9 J · mol−1 · K−1) of the complexation reaction were quantified using a van’t Hoff analysis. This work also showed that bromide addition does not displace the hydroxide from TcO(OH)+, as the equilibrium constant of bromide addition is much weaker than the first hydrolysis constant of the metal.

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