Potentiometric study on the complex equilibria between ni(ii) and mn(ii) and 3-(2-furyl)-2-mercaptopropenoic and 3-(2-furyl)-2-mercaptopropanoic acids

Complex formation between Ni(II), Co(II) and Mn(II) and 3-(2-furyl)-2-mercaptopropenoic and 3-(2-furyl)-2-mercaptopropanoic acids has been studied using glass electrode potentiometry. Ligand-metal ion mixtures in 10% (v/v) ethanol-water containing 0.1 mol dm^–3KNO₃ were titrated with potassium hydroxide. The e.m.f. data obtained have been analyzed using the linearization method, and initial estimates of protonation constants for the ligands and complex formation constants have been refined with the MINIQUAD program.     

Solvent extraction and spectrophotometric determination of titanium(IV) with 3-phenyl-3-methyl-2-mercaptopropenoic acid

The distribution equilibria of 3-phenyl-3-methyl-2-mercaptopropenoic acid (PhMMP) and the titanium(IV)-PhMMP complex have been studied. An extraction-photometric method for the determination of microamounts of titanium has been developed. We have investigated the influence of pH, the reagent, and the presence of electrolytes and masking agents in the aqueous phase on the equilibrium. From the slope analysis of the distribution curves the composition of the extracted species has been found to be Ti(OH)₂(HR)₂. The complex is extracted quantitatively. Beer's Law is followed over the range 0.09–3.74 μg ml^?1 of titanium(IV), the molar absorptivity is 1.65 × 10⁴ liters mol^?1 cm^?1, and the Sandell sensitivity is 2.8 ng cm^?2 at 439 nm. This method has been applied to the determination of titanium in a bauxite.     

Spectrophotometric study of the complex formation of 3-(2-hydroxyphenyl)-2-mercaptopropenoic acid with Ni(II) and Zn(II)

The dissociation and complex formation equilibria between Ni(II) and Zn(II) with 3-(2-hydroxyphenyl)-2-mercaptopropenoic acid, at 25 degrees in aqueous 0.1 and 1.0M sodium perchlorate solutions, containing about 1% ethanol, have been studied spectrophotometrically. The data were connected directly from the spectrophotometer to an IBM-PC via a serial interface, using the DUMOD program (written in BASIC), described in the paper. The obtained spectra were treated by the factor analysis program NIPALS in order to determine the number of absorbing species and the experimental error. Dissociation constants of ligand (H(3)L), and formation constants for the complexes Ni(HL), Ni(HL)(2), Zn(HL) and Zn(HL)(2) at 0.1 and 1.0M ionic strengths, refined by the SQUAD program, are reported.     

Solvent extraction and spectrophotometric determination of titanium (IV) with 3-phenyl-3-methyl-2-mercaptopropenoic acid by use of the synergistic effect of pyridine

Summary The distribution equilibria of 3-phenyl-3-methyl-2-mercaptopropenoic acid (PhMMP), pyridine and the titanium (IV)-PhMMP complex in the presence of pyridine have been studied in the chloroform-water system. An extraction-photometric method for the determination of micro amounts of titanium has been developed. The synergistic effect of pyridine, and the influence of pH, the reagent concentration and the presence of electrolytes and masking agents on the equilibrium have been determined. From slope analysis of the distribution curves, the composition of the extracted species has been found to be Ti(OH)₂(HR)₂·py. The complex is extracted quantitatively. Beer's law is obeyed over the range 0.09–4.30g/ml titanium (IV) and the molar absorptivity is 1.30×10⁴1·mole^–1·cm^–1 at 447 nm. The method has been applied to the determination of titanium in ceramics.

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Über die Extraktion und spektrophotometrische Bestimmung von Titan(IV) mit 3-Phenyl-3-methyl-2-mercaptopropensäure mit Hilfe der synergistischen Wirkung des Pyridins

Zusammmenfassung Das Verteilungsgleichgewicht von 3-Phenyl-3-methyl-2-mercaptopropensäure (PhMMP), Pyridin und Titan-PhMMP-Komplex in Gegenwart von Pyridin wurde in einem Wasser-Chloroform-System untersucht. Eine extraktionsphotometrische Methode für die Bestimmung von Mikromengen Titan(IV) wurde ausgearbeitet. Die synergistische Wirkung des Pyridins sowie der Einfluß des pH, des Reagens und der Gegenwart von Elektrolyten und maskierenden Reagenzien in der wäßrigen Phase auf das Gleichgewicht wurden bestimmt. Aus der Richtung der Verteilungskurven wurde für den extrahierten Komplex die Zusammensetzung Ti(OH)₂(HR)₂·py ermittelt. Der Komplex wird quantitativ extrahiert. Das Beersche Gesetz ist von 0,09–4,30g·ml^–1 Ti(IV) erfüllt, der molare Absorptionskoeffizient ist 1,13·10⁴1·mol^–1·cm^–1; die Sandell-Empfindlichkeit beträgt 3,7ng·cm^–2 bei 447 nm. Diese Methode wurde für die Bestimmung von Titan in keramischem Material verwendet.

     

Spectrophotometric study of the complex formation of 3-(1-naphthyl)-2-mercaptopropenoic acid with nickel(II), palladium(II) and hydrogen ions

The equilibria between 3-(1-naphthyl)-2-mercaptopropenoic acid (H(2)NMP) and nickel, palladium and hydrogen ions at 25 degrees in aqueous 0.1 M NaClO(4) solution containing 1-2% ethanol have been studied spectrophotometrically. Protonation constants for the ligand and formation constants for the complexes Ni(NMP), Ni(NMP)(2-)(2), Pd(NMP) and Pd(NMP)(2-)(2), refined by the SQUAD program, are reported.     

2-(5-Bromo-2-furyl)quinoxaline and 3-(5-bromo-2-furyl)-2-quinoxalone

2-(5-Bromo-2-furyl)quinoxaline and 3-(5-bromo-2-furyl)-2-quinoxalone were obtained by the action of bromine on the corresponding quinoxaline derivatives and also by condensation of o-phenylenediamine with, respectively, (5-bromo-2-furyl)glyoxal or (5-bromo-2-furyl)glyoxylic acid esters.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 404–406, March, 1973.     

Darzens synthesis of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid derivatives

Esters and amides of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid were prepared by the reaction of furfural with dichloroacetic acid derivatives under the conditions of the Darzens condensation. The structures of the reaction products were confirmed by their¹H NMR and IR spectra and chemical transformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1444–1448, August, 1994.     

Spectrophotometric studies on ion-pair extraction equilibria of the iron(ii) and iron(III) complexes with 4-(2-pyridylazo)resorcinol

The ion-pair extraction equilibria of the iron(II) and iron(III) chelates of 4-(2-pyridylazo)resorcinol (PAR, H(2)L) are described. The anionic chelates were extracted into chloroform with benzyldimethyltetradecylammonium chloride (QC1) as counter-ion. The extraction constants were estimated to be K(ex1)(Fe(II)) = [Q{Fe(II)(HL)L}](0)/[Q(+)][{Fe(II)(HL)L}(-)] = 10(8.59 +/- 0.11), K(ex2)(Fe(II)) = [Q(2){Fe(II)L(2)}](o)/ [Q(+)](2)[{Fe(II)L(2)}(2-)] = 10(12.17 +/- 0.10) and K(ex1)(Fe(III)) = [Q{Fe((III))L(2)}](o)/(Q(+)][{Fe(III)L(2)}(-)] = 10(6.78 +/- 0.15) at I = 0.10 and 20 degrees , where [ ](o) is concentration in the chloroform phase. Aggregation of Q{Fe(III)L(2)} in chloroform was observed and the dimerization constant (K(d) = [Q(2){Fe(III)L(2)}(2)](o)/[Q{Fe(III)L(2)}](o)(2)) was evaluated as log K(d) = 4.3 +/- 0.3 at 20 degrees . The neutral chelates of {Fe(II)(HL)(2)} and {Fe(III)(HL)L}, and the ion-pair of the cationic chelate, {Fe(III)(HL)(2)}ClO(4), were also extracted into chloroform or nitrobenzene. The relationship between the forms and extraction properties of the iron(II) and iron(III) PAR chelates are discussed in connection with those of the nickel(II) and cobalt(III) complexes. Correlation between the extraction equilibrium data and the elution behaviour of some PAR chelates in ion-pair reversed-phase partition chromatography is also discussed.     

Solvent extraction of gallium(III) as the monothiodibenzoylmethane complex

Gallium(III) can be quantitatively extracted at trace levels with monothiodibenzoylmethane in benzene at pH 5.0. It is then determined spectrophotometrically as its Rhodamine B complex in the organic phase, at 570 nm. The system conforms to Beer's law at 570 nm, in the range 1.4-26 mug of gallium. The absorbance is stable for 24 hr. Gallium can be extracted and determined in the presence of several elements with which it is generally associated in minerals and other products.     

Dissociation constants, neutralization enthalpies and reactions of 3-styryl-2-mercaptopropenoic and 3-(1-naphthyl)-2-mercaptopropenoic acids

Dissociation constants (pK(a1) and pK(a2) in water-ethanol medium for 3-styryl-2-mercaptopropenoic and 3-(1-naphthyl)-2-mercaptopropenoic acid have been determined potentiometrically, and pK(a2) for both in aqueous medium, spectrophotometrically. Neutralization enthalpies in water-ethanol medium have been determined by thermometric titration. The reactions with metal ions have been studied, and the main reactions are described. The most sensitive reactions are with titanium(IV) (pD = 7.00) and nickel(II) (pD = 6.50).     

Complexation of Ni (II) and Zn(II) ions by 3-(1-naphthyI)-2-mercaptopropenoic acid

The complexation equilibria between Ni(II) and Zn(II) metal ions with 3-(1-naphthyl)-2-mercaptopropenoic acid (H₂NMP) were studied by glass electrode potentiometry, at 25 °C and 1.0 mol·dm^–3 in NaClO₄ as constant ionic medium in 50% (v/v) water-ethanol solutions. Formation constants for the complexes Ni(NMP), Ni(NMP) ₂ ^2– , Zn(NMP) and Zn(NMP) ₂ ^2– , refined by the MINIGLASS program, are reported.     

Solvent effect on ion-pair extraction of 2-(2-pyridylazo)-1-naphthol-4-sulfonate anion with solvated hydroxonium ion using alcohols and 1-octanol/octane mixed solvents.

Extraction of 2-(2-pyridylazo)-1-naphthol-4-sulfonate anion with solvated hydroxonium ion was carried out using 14 kinds of alcohols and 1-octanol/octane mixed solvents as a solvent at 25 degrees C. Alcohols are 1-pentanol, 1-hexanol, 1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol, 1-octanol, 2-octanol, 3-octanol, 1-nonanol, 2-nonanol, 3-nonanol, 5-nonanol and 1-decanol. Among them, 1-octanol was found to be extremely high in extractability for 2-(2-pyridylazo)-1-naphthol-4-sulfonate anion with hydroxonium cation. The extraction equilibrium for the systems using 1-octanol/octane mixed solvents was analyzed in detail in order to examine the extraction mechanism for these extraction systems. 2-(2-Pyridylazo)-1-naphthol-4-sulfonate anion was found to be extracted with the hydroxonium ion solvated by three 1-octanol molecules as an ion-pair. The extraction and partition constants of the ion-pair of 2-(2-pyridylazo)-1-naphthol-4-sulfonate anion with solvated hydroxonium ion were estimated in the 1-octanol/octane mixed solvent systems.     

Synthesis of 1-(2-furyl)-2-nitropropen-3-ones

1-(2-Furyl)-2-nitropropen-3-ones were synthesized by reaction of nitrogen tetroxide with a number of , -unsaturated furylcarbonyl compounds. The 5-nitrofuryl derivative was obtained from 1-(2-furyl)-3-(4-methoxyphenyl)propen-3-one when the excess amount of N₂O₄ was increased. Replacement of bromine by a nitro group in the furan ring is observed in the case of the 5-bromofuryl derivative.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1604–1606, December, 1977.     

Solvent extraction of tetrachloronitridotechnetate(VI) ion with tetraphenylarsonium chloride

Radiochemical and spectrophotometric studies on the solvent extraction of tetrachloronitridotechnetate(VI) ion with tetraphenylarsonium chloride into chloroform have been reported. Analysis of the dependence of the distribution ratio for technetium species on the concentration of hydrogen ion (0.1–1.0M) revealed that an equilibrium between tetrachloronitridotechnetate(VI) ion and [(H₂OCl₃NTc–O–TcNCl₃(H₂O)]^2– is established in the aqueous phase. However, formation of di(-O) dimer was suggested, when the concentration of hydrochloric acid is less than 0.2M. The extraction constant for technetium and formation constant for -oxo technetium nitrido complex were evaluated.     

二氯菊酸2－甲基－3－（2－呋喃基）－2－丙烯酯的合成

报导了一种新拟除虫菊酯的设计和合成。标题化合物是由二氯菊酰氯与新自制的２－甲基－３－（２－呋喃基）－２－丙烯－１－醇酯化合成。