Oxidations with potassium permanganate in the presence of fluoride

Summary Trivalent chromium and quadrivalent vanadium can be determined with fair accuracy by a method consisting in mixing either with an excess of KMnO₄ in the presence of 0.3 to 1.8 M alkali hydroxide. After leaving the mixture for 5 min, the solution is acidified with sulphuric acid and mixed with 50 to 75 ml of 2% NaF solution. An excess of monovalent mercury Hg₂ ²⁺ solution is then added, the solution heated to 40° C and then titrated with KMnO₄ solution in the presence of Cu²⁺ ions to conceal the pink manganic fluoride colour.Part II: Issa, I. M., and M. Hamdy: Z. analyt. Chem. 172, 162 (1960).     

Oxidations with potassium permanganate in the presence of fluoride

Summary The titration of ferrous iron in presence of fluoride ions in acid medium gives fleeting end points and erroneous results. A method is deviced to overcome this difficulty by oxidising the ferrous with an excess of KMnO₄ in alkaline medium. After mixing the reactants the excess of KMnO₄ is reduced by an excess of Hg₂ ²⁺ ions in presence of H₂SO₄ and fluoride. The remaining mercurous is then titrated with standard KMnO₄ solution.Part III: Issa, I. M., and M. Hamdy: Z. analyt. Chem. 174, 418 (1960).     

Oxidation with manganate solutions

Summary The reaction between Tl⁺ solutions and manganate is sluggish. In the titration of Tl⁺ with manganate solution the end points are always attained earlier than the theoretical. When the reaction is accelerated by NaCl and heating to 45–50° C the end points were found to be concordant with the theoretical values. Titration of manganate with Tl⁺ solutions gives accurate results in presence of telluric acid but not in its absence. It is also possible to determine Tl⁺ by oxidation with an excess of K₂MnO₄ using arsenite as a back titrant for excess oxidant.Part III: Issa, I. M., and M. G. E. Allam: Z. analyt. Chem. 175, 103 (1960).     

A vibrational analysis of the MnO 4 − bands

Teltow'S [14,15] measurements of the permanganate bands are reanalyzed using the level scheme of Ballhausen and Liehr [2]. For KMnO ₄ dissolved in KClO ₄ the components of the first ¹ T ₂ state are found at 18050 cm^–1 18078 cm^–1 and 18043 cm^–1. The breathing frequency of the MnO _– ⁴ unit is in this state 768 ^–1. The electronic origin of the second ¹ T ₂ state is found at 30723 cm^–1 with a breathing frequency of 760 cm^–1.Evidence is further found for a ¹ T ₁ state with its split components located at 14446 cm^–1, 14526 cm^–1 and 14600 cm^–1. The breathing frequency is here found to be 800 cm^–1.Finally for KMnO ₄ dissolved in NaClO ₄ there are indications that one or two spin-triplets are located near 13200 cm^–1.

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Zusammenfassung TeltowS Messungen des Permanganatspektrums [14, 15] werden mit Hilfe des Termschemas von Ballhausen und Liehr [2] von neuem analysiert. Für KMn ₄ in KClO ₄ findet man die zum ersten ¹ T ₂-Zustand gehörenden Komponenten bei 18050, 18078 und 18043 cm^–1. Die Valenzschwingung des MnO _– ⁴ liegt hier bei 768 cm^–1. Der Ursprung des zweiten ¹ T ₂-Systems wird bei 30723 cm^–1 gefunden, die dazugehörige Valenzfrequenz ist 760 cm^–1.Bei 14446, 14526 und 14600 cm^–1 liegen offenbar die Komponenten eines ¹ T ₁-Terms, wozu eine Valenzfrequenz von 800 cm^–1 gehört.Schließlich findet man für KMnO ₄ in NaClO ₄ Anzeichen für ein oder zwei Spin-Tripletts um 13200 cm^–1.

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Résumé Les bandes d'absorption du permanganate, mesurées par Teltow [14,15], sont réanalysées à l'aide d'un système de termes proposé par Ballhausen et Liehr [2]. Pour KMnO ₄ dans KClO ₄, on trouve les composants du premier état ¹ T ₁ à 18050, 18078 et 18043 cm^–1. La vibration symétrique du MnO _– ⁴ dans cet état se situe à 768 cm^–1. L'origine électronique du second état ¹ T ₂ est trouvé à 30723 cm^–1, la fréquence oscillatrice correspondante est de 760 cm^–1.Un état ¹ T ₁ avec ses composants à 14446, 14526 et 14600 cm^–1 est mis en évidence, avec une vibration symétrique de 800 cm^–1.Finalement, au cas du KMnO ₄ dissous dans le NaClO ₄, il y a des indications pour un ou deux triplets de spin vers 13200 cm^–1.

     

Nicotinamidoxime as an analytical reagent

Summary Alkaline solutions of nicotinamidoxime containing traces of nickel(II) give a deep blue color on treatment with iodine. At a p_H of 10.5–11.5 in presence of an excess of the amidoxime the color develops almost instantaneously and is stable for at least 24 hrs. The system adheres to Beer's law in the range of 0.3–10 ppm of nickel, and the optimum range for measurement (1 cm cell) is 3–10 ppm of the metal. The color reaction is highly sensitive (spectrophotometric: 0.014 g Ni cm^–2 at 575 nm identification limit: 0.5 g Ni ml^–1; 12 · 10⁶).All the common anions are without any effect excepting CN^– and EDTA which interfere seriously. Interference of Pb²⁺, Bi³⁺, Al³⁺, Ti⁴⁺, Zr⁴⁺ and Th⁴⁺ can be masked by excess tartrate; while in the presence of Cu²⁺, Co²⁺, Zn²⁺, Mn²⁺ and Fe³⁺, the Ni²⁺ is first separated by the anion exchange method of Kraus and Moore ³ and then determined as usual.From the results of polarographic investigations it has been concluded that in alkaline medium nicotinamidoxime is first oxidized possibly to an azo type of compound which interacts with nickel(II) forming the deep blue color.Part II: K. K. Tripathi and D. Banarjea: Z. analyt. Chem. 168, 407 (1959).     

Bismuthiol II as an analytical reagent

Summary Lead was estimated as Bismuthiol II complex of composition (C₈H₅N₂S₃)₂Pb by precipitating it from its chloride or nitrate solution in presence of a mineral acid, acetic acid, tartrate or cyanide. The estimation is quantitative up to a maximumph of about 6.5. The lead-Bismuthiol II complex is stable up to about 311° C and the conversion factor is 0.315. The method affords a complete separation of lead from alkalis and alkaline earths, Be²⁺, Mg²⁺, Zn²⁺, Mn²⁺, Co²⁺, Ni²⁺, Fe²⁺, Fe³⁺, Cr³⁺, Al³⁺, rare earths, Ti⁴⁺, Zr⁴⁺, Th⁴⁺, UO₂ ²⁺, Pd²⁺, As³⁺, Sb³⁺, Cl^–, SO₄ ^2–, PO₄ ^3–, AsO₄ ^3–, MoO₄ ^2– and WO₄ ^2–. Among the sulphide group members Ag⁺, Au³⁺, Hg⁺, Hg²⁺, Tl⁺, Tl³⁺, Cd²⁺ and platinum metals, except Pd²⁺, interfere while oxidising agents decompose the excess reagent. Bi³⁺, Cu²⁺ and Sn²⁺, do not interfere up to a maximum limit of 30 mg, 50 mg, and 250 mg respectively.Part I: see Z. analyt. Chem. 154, 262 (1957).     

2-Mercapto-benzimidazole as an analytical reagent

Summary Palladium is quantitatively precipitated at aPH 5.0 to 10.1 by 2-mercapto-benzimidazole and the complex, Pd(C₇H₅N₂S)₂, which is found to be diamagnetic, is stable up to a temperature of 447 C. In presence of EDTA and tartrate or citrate and at aPH between 6 and 8, it is separated from alkalis, alkaline earths, Mg, Fe³⁺, Cr, Th, Zr, Ti, UO₂ ²⁺, Be, Ce³⁺, Ce⁴⁺, rare earths, Zn, Mn, Ni, Co, Pb, Bi, As, Sb³⁺, Sn⁴⁺, Tl⁺, Cu²⁺, Cd, Ir⁴⁺, Rh³⁺, Ru³⁺, Os⁴⁺, CrO₄ ^2–, MoO₄ ^2–, WO₄ ^2–, VO₃ ^–, PO₄ ^3– and AsO₄ ^3–. Pb, Ag and Hg²⁺ are kept in solution by potassium iodide while a small amount of Au³⁺ by thiosulphate. The palladium complex is either weighed after drying at 110 C or dissolved in a cyanide solution and determined volumetrically by back titrating the excess cyanide with a standard silver nitrate solution.     

Electrometric end points in the oxidation of thiocyanate by permanganate. Determination of cerium

Summary Oxidation of thiocyanate by standard permanganate using electrometric end points is shown to be quantitative in 1.5–2.5N HCl medium and in the presence of ICl as catalyst. A method of estimating cerium(IV), based upon its reduction to cerium(III) by excess KSCN and potentiometric titration of the excess against KMnO₄, is also described.Sincere thanks of the author are due to Prof. S. S. Joshi for research facilities.     

Bis-salicylaldehyde-ethylenediamine as an analytical reagent

Summary Copper has been determined gravimetrically as its bis-salicylaldehyde-ethylenediamine complex of the composition C₁₆H₁₄O₂N₂ · Cu, dried at 100–120° C. The complex is completely precipitated in theph range of 10.5–13.5, adjusted with ammonia or caustic alkali. It is stable in presence of excess ammonia, 0.1 N alkali, ammonium salts and complexing agents as tartrate, citrate, sodium-thiosulphate, fluoride, thiourea, triethanolamine and EDTA. In presence of tartrate and ammonia the ions of alkali metals, alkaline earths, Ag⁺, Tl⁺, Tl³⁺, Pb²⁺, Cd²⁺, Co²⁺, Mn²⁺, Pd²⁺, Al³⁺, Cr³⁺, La³⁺, Ce³⁺, Au³⁺, Pt⁴⁺, Ti⁴⁺, Zr⁴⁺, Th⁴⁺, UO₂ ²⁺ and anions as VO₃ ^–, MoO₄ ^2–, WO₄ ^2–, CrO₄ ^2–, PO₄ ^3–, AsO₄ ^3– do not interfere. Ni²⁺ and Hg²⁺ are masked by tartrate, EDTA and ammonia; As³⁺, Sb³⁺ and Sn²⁺ are separated using fluoride as the complexing agent; at an alkalinity of 0.1 N caustic alkali in presence of tartrate As³⁺, Sb³⁺, Sn²⁺, Bi³⁺, Zn²⁺ and Fe³⁺ are separated. Fe³⁺ can also be separated using triethanolamine as the masking agent at aph of about 13.0. Copper can be separated from almost all the ions, thus affording a highly selective method for the determination of copper.

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Zusammenfassung Es wird eine gravimetrische Methode zur Bestimmung von Kupfer beschrieben, die auf der Bildung des Bis-salicylaldehyd-äthylendiaminkomplexes beruht. Dieser hat die Zusammensetzung C₁₆H₁₄O₂N₂ · Cu. Die Fällung wird imph-Bereich 10,5–13,5 (mit Ammoniak oder Alkalilauge eingestellt) vorgenommen und der Niederschlag bei 100°–120° C getrocknet. Der Komplex ist beständig in Gegenwart von überschüssigem Ammoniak, 0,1 n Alkali, Ammoniumsalzen sowie Tartrat, Citrat, Natriumthiosulfat, Fluorid, Thioharnstoff, Triäthanolamin und ÄDTA. In Gegenwart von Tartrat und Ammoniak stören nicht: Alkalien, Erdalkalien, Ag⁺, Tl⁺, Tl³⁺, Pb²⁺, Cd²⁺, Co²⁺, Mn²⁺, Pd²⁺, Al³⁺, Cr³⁺, La³⁺, Ce³⁺, Au³⁺, Pt⁴⁺, Ti⁴⁺, Zr⁴⁺, Th⁴⁺, UO₂ ²⁺ sowie VO₃ ^–, MoO₄ ^2–, WO₄ ^2–, CrO₄ ^2–, PO₄ ^3– und AsO₄ ³⁺. Ni²⁺ und Hg²⁺ können mit Tartrat, ÄDTA und Ammoniak maskiert werden, As³⁺, Sb³⁺ und Sn²⁺ mit Fluorid. In 0,1 n ätzalkalischer Lösung in Gegenwart von Tartrat können As³⁺, Sb³⁺, Sn²⁺, Bi³⁺, Zn²⁺ und Fe³⁺ abgetrennt werden. Fe³⁺ kann ebenfalls mit Triäthanolamin beiph 13,0 maskiert werden. Das beschriebene Verfahren erlaubt somit eine Abtrennung des Kupfers von fast allen anderen Ionen.

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Part I: Singh, B. R., and S. Kumar: Z. analyt. Chem. 185, 211 (1962).     

Chelataustauscher auf Maleinhydroxams?ure-Basis zur Abtrennung von Fe(III)-Spuren aus konzentrierten Salzl?sungen

Zusammenfassung Mit Hilfe des neu hergestellten Maleinhydroxamsäureaustauschers lassen sich Fe(III)-Spuren aus relativ konzentrierten Salzlösungen entfernen.In Batch-Versuchen wird die Fe(III)-Konzentration in einer 1M MgCl₂-Lösung bei einem pH-Wert von 4 und der Anwendung von 2 g Harz in 50 ml Lösung nach 24 h von 10^–6 M auf ca. 10^–8 M herabgesetzt und bei einer NH₄Cl-Lösung gleicher Konzentration auf 5 · 10^–9 Mol/l.Bei den Säulenversuchen ist für die gleiche Lösungsmenge die entsprechende Erniedrigung der Fe(III)-Konzentration in wesentlich kürzerer Zeit zu erreichen, und zwar bei einer Austauschermenge von 20 ml und einer Durchflußgeschwindigkeit von 0,25–0,30 ml/min in etwa 3 h.Eine noch weitergehende Fe(III) -Entfernung ist bei nochmaliger Übergabe der Lösungen oder größerem Harzeinsatz möglich.

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Summary A new maleichydroxamic acid ion-exchanger has been prepared and is recommended for removing traces of iron(III) from relatively concentrated salt solutions. When employing the batch technique and using 2 g of the exchanger per 50 ml of solution the Fe(III) concentration in a 1 M MgCl₂ solution of pH 4 could be reduced from 10^–6 M to about 10^–8 M after 24 hrs, and to 5×10^–9 M in a 1 M NH₄Cl solution. With the column technique a considerably shorter time is required for obtaining corresponding results, i.e. 3 hrs. with 20 ml of exchanger and a flow rate of 0.25–0.30 ml/min. Further removal of iron can be achieved by repeated passage of the solution through the column or by applying larger quantities of the exchanger.

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Herrn Prof. Dr. B. Eistert zur Vollendung des 65. Lebensjahres gewidmet.     

2-Mercapto-benzothiazole as an analytical reagent

Summary The reagent 2-mercapto-benzothiazole quantitatively precipitates palladium at a PH 5.6 to 10.2. The red coloured compound, Pd(C₇H₄NS₂)₂, is diamagnetic and is stable up to a temperature of 388 C. Palladium is separated from alkalis, alkaline earths, Mg, Fe³⁺, Cr, Th, Zr, Ti, UO₂ ²⁺, Be, rare earths, Ce³⁺, Ce⁴⁺, Zn, Mn, Co, Ni, Pb, Bi, Sb³⁺, As³⁺, Sn⁴⁺, Tl+, Cu²⁺, Cd, Ir⁴⁺, Rh³⁺, Ru³⁺, Os⁴⁺, CrO₄ ^2–, MoO₄ ^2–, WO₄ ^2–, VO₃ ^–, PO₄ ^3– and AsO₄ ^3– at apH 6–8 in presence of EDTA and tartaric or citric acid. Besides Pb, Ag and Hg²⁺ are kept in solution with potassium iodide and Au in a limited quantity forms a soluble complex with thiosulphate. The palladium complex is either weighed after drying and determined gravimetrically or dissolved in an excess of cyanide and determined volumetrically by back titrating the latter with silver nitrate.     

Synthese und Konfigurationszuordnung eines potentiell antimikrobiellen 5,6-Dihydroxyisobenzofuranons

Summary Isobenzofuranone3 was prepared by KMnO₄-oxidation of2. 3 was reacted to give acetals4–10, which adopt the boat-conformation.3 and its acylated derivatives11–13 on the other hand prefer the chair-conformation. The relative configurations of3–13 at the chiral centres 3a, 5, 6, and 7a were determined by¹H-NMR-spectroscopy.

     

1, 2-Dithiolium salts

4-(p-Tolyl)-1,2-dithiolium hydrogen sulfate (I) is not a specific analytical reagent for the majority of anions, and it is not very selective, only in a few cases attaining pD=5 (MoO₄ ^2–, [Hg(CNS)₄]^2–, and [PtCl₆]^2–). All strongly colored anions give colored salts with I. Among the weakly colored anions, the [Fe(CN)₆]^4– anion is worthy of special note, since it forms a deeply colored salt with I. This anion can be detected with I in the presence of Cl^–, Br^–, I^–, CNS^–, ClO₄ ^–, IO₄ ^–, and ReO₄ ^–, which form fairly readily soluble salts with I. Compound I is also a fairly selective reagent for Pd²⁺ in acid solution (pD=5).For part II, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 5, pp. 595–597, May, 1970.     

Titration of AsO43? ions with 0.1 M magnesium sulphate solution in the presence of Ca2+, Mg2+, Fe3+, Cu2+ ions and some other foreign substances

Summary For the convenient and sufficiently accurate determination of AsO₄ ^3– ions in technical products containing different filling, suspending and colouring materials, as well as impurities—e.g. for the assay of arsenate containing plant protecting materials—the following procedure is recommended.About 5 g of the sample is dissolved, resp. extracted with 4 N hydrochloric acid, and aliquots of the clear filtrate are titrated after elimination of the interfering metal ions by combining them with complexing agents (potassium cyanide and disodium ethylenediamin tetraacetic acid) in a properly buffered medium. The titration with 0.1 M MgSO₄ solution is conducted in the presence of eriochrome black T solution as indicator, first time for eliminating the excess of EDTA added, and afterwards to determine the AsO₄ ^3– ions, after adding about 40% of ethanol.The procedure may be useful chiefly for serial routine analyses.The authors are indebted to engineer L. Fokássy, department leader at the State Institute for Agricultural Quality Control, as well as to engineeress P. Fodor and Mr. Gy. Josepovits, scientific collaborators of the Research Institute for Plant Protection, for kindly supplying some of the samples for the experiments.     

Dimericd- anddl-dysprosium(iii) tartrates: paramagnetic birefringence,molecular mechanics,stereoselectivity

The molar constants of paramagnetic birefringence (PBR) for the dimeric dysprosium(iii)d- anddl-tartrates, Dy₂(d-Tart)(l-Tart)^2– (1) and Dy₂(d-Tart)₂ ^2– (2) have been determined by means of pH-metric and PBR measurements. The simulation of the structure of the ligand and solvate environment has been carried out using the method of molecular mechanics (Dashevsky-Plyamovaty model, the MIND program). In addition to the four oxygen atoms from the ligand, each Dy^III ion coordinates four molecules of water and a Na⁺ ion.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1029–1032, June, 1994.     

Insect pheromones and their analogues. XVI. Practical synthesis of hexadec-9Z-enal — A component of the sex pheromone of the cotton bollwormHeliothis armigera

A synthesis of hexadec-9Z-enal — a component of the sex pheromone of the cotton boll-wormHeliothis armigera (Hübner) — based on cyclooctene (I) is proposed. Through a solution of 22 g of (I), 250 ml of cyclohexane, and 40 ml of MeOH is passed (at 5°C) 0.2 M O₃/O₂, the solution is decanted off, and the precipitated ozonide is dissolved in 200 ml of MeOH and is reduced with 19 g of NaBH₄ (40°C) with the isolation, after the usual working up, of 23.4 g of octane-1,8-diol (II). From 0.5 mole of (II) and 0.6 mole of 45% HBr 8-bromooctan-1-ol (III) is obtained and this is converted into 1-(2-THPL)oxy)-8-bromooctane (IV). The condensation of (IV) with oct-1-yne (Ar, LiNH₂, HMPTA, 10°C, 1 h, and then 55°C, 10 h) leads to 1-(2-THPL-oxy)hexadec-9-yne (V) the hydrolysis of which (MeOH, H₂O, p-TsOH, 20°C for 20 h) yields hexadec-9-yn-ol (VI). The reduction of (VI) (Et₂O, iso-BuMgBr, Cp₂TiCl₂, 0°C, 15 min, then 20°C, 1 h) yieldshexadec-9Z-en-l-ol (VII). The oxidation of (VII) (PyHCrO ₃ ⁺ Cl^–, CH₂Cl₂, 20°C, 2 h) gives hexadex-9Z-enal (VIII). Characteristics of the compounds (yield (%), n _D ^{20 (25)}: (II) – 80, mp 61–62°C; (III) – 75, 1.4807; (IV) – 99, —; (V) – 52, 1,4650; (VI) – 85, 1.4657; (VII) – 99, 1.4650; (VIII) – 98, 1.4600. Characteristics of the IR and PMR spectra of compounds (V–VII) are given.Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 286–289, March–April, 1987.     

KMnO4-OP Chemiluminescence system for FIA determination of hydrogen peroxide

A fast and simple KMnO₄-OP chemiluminescence system for flow-injection analysis of hydrogen peroxide is described. When a mixture of sample and OP is injected into acidic KMnO₄, solution in a flow-cell, strong chemiluminescence occurs. The response is linear to the concentration of hydrogen peroxide in the range of 1.0 × 10^–8 to 6.0 × 10^–5 mol/l with 0.1 mol/l permanganate, and the upper limit of linear response could be extended to 6 × 10^–3 mol/l by increasing the permanganate concentration. The relative standard deviation of the method is between 1.6 and 2.3%. The detection limit is 6.0 × 10^–9 mol/l. This method is suitable for automatic and continuous analysis and has been successfully tested for determination of hydrogen peroxide in rain water. The chemiluminescence intensity was found to be remarkably enhanced in the presence of the OP micellar system.     

New cobalt and iron pivalate complexes with 2,2′:6′,2″-terpyridine: synthesis, structure, and magnetic properties

The mononuclear complexes (η³-terpy)M(Piv)²·MeCN (M = Fe ⁱⁱ (3) and Co ⁱⁱ (4), and Piv is the pivalate anion) were synthesized by the reactions of polymeric iron(ii) and cobalt(ii) pivalates with 2,2′:6′,2″-terpyridine (terpy). The oxidation of compound 3 affords the pentanuclear heterospin iron(ii,iii) complex (η³-terpy)Fe₅(μ₄-O)(μ₃-OH)(μ-OH)₂(μ-Piv)₇(η¹-Piv)₂ (5). All compounds were characterized by X-ray diffraction. Dedicated to the 90th anniversary of the L. Ya. Karpov Institute of Physical Chemistry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1186–1190, June, 2008.     

The substitution kinetics of the aqua ligand by cyanide ions in [Ru(TPPS)(CO)(H2O)]4−

Summary The reaction between the title compound, ,,,-tetra(p-sulphonatophenyl)porphynatoaquacarbonylruthenate(II), [Ru(TPPS)(CO)(H₂O)]^4–, and CN^- revealed that only the aqua ligand is substituted even in the presence of a large excess of the nucleophile. The pK _a1 was spectrophotometrically determined as 13.4(5) (at 33.2 °C) and kinetically as 13.44(5) (at 33.6 °C). The rate of aqua substitution was determined as 89(4)m ^–1 s ^–1 at 35.1 °C and the activation enthalpy and entropy as 55.44(1) kJ mol^–1 and-27.90(4) J K^–1 mol^–1, respectively.