Reduction of ammonium nitrate with titanium(III) chloride in acid media

Investigation of acid ammonium nitrate solutions in the presence of titanous chloride has led to a new mechanism of nitrate reduction. It is proposed that the reduction proceeds through two electron changes and terminates as nitrous oxide in solutions whose acid content is greater than 0.1 N. The stronger reducing power of the titanous buffer method previously reported arising from a direct pH affect on the titanous -titanyl couple has been discerned rather as an effect arising from different reduction products in that media. The affects of prolonged reaction at 100° and use of osmium tetroxide catalyst were examined. A pH of 4.5 and 100% excess of titanous was insufficient to reduce nitrate to ammonia quantitatively.     

Studies in bivalent chromium salts

Summary It has been shown in these investigations that the titrations of methylene blue, indigo, crystal violet, eosin, malachite green, magenta and orange G can be carried out successfully with chromous sulphate solution. Comparative results with titanous chloride and chromous sulphate indicate a fair degree of agreement. However, the reduction is found to be more facile with chromous sulphate.Part I: See Z. analyt. Chem. 158, 20 (1957).The authors' thanks are due to Dr. R. N. Singh, Professor of Chemistry, B. R. College, Agra, for providing laboratory facility and encouragement.     

A rapid titrimetric determination of iron in copper concentrates and copper-bearing leach solutions

A titrimetric method for the determination of iron(III) in the presence of copper is presented. This method involves the reduction of iron(III) with titanous sulphate followed by titration with dichromate. It has been successfully used for the determination of iron in both leach solutions and copper concentrates with a relative error of 1%.     

The analysis of combustion products : Some improvements in the methods of analysis of peroxides

The conditions for the estimation of peroxides by three established, methods have been re-examined in detail. 1. It is shown that the reduction of organic hydroperoxides by stannous chloride (barnard and hargrave method) can be carried out quantitatively and rapidly in alkaline solution. The advantages of this modification are discussed. 2. The exact conditions are described for accurately measuring the concentrations of hydrogen peroxide and of the lower organic peroxides by the thiocyanate method. Amyl alcohol is recommended as a decolourizer for the reagent since the red colour produced by the action of the peroxides is stabilized, permitting accurate spectrophotometric measurements, Using this reagent, 0.03 micrograms of peroxide per ml can be estimated. 3. The limits of the titanous sulphate method of estimating hydrogen peroxide have been determined and a method suitable for the determination of 0.3 micrograms of hydrogen peroxide per ml is described.     

Copper hydrometallugry and extraction from chloride media

The development of copper hydrometallurgy is presented and various processes proposed for copper recovery from sulphide concentrates are discussed. Leaching, extraction and stripping are considered, including reagents and processes. The extraction of copper from chloride solutions is discussed. Various extractants are presented and their use for copper transfer from chloride solutions to the organic phase and back to chloride and to sulphate solutions is discussed.     

Semimicro determination of nitro groups by reduction with titanous sulphate

Summary A simple and rapid procedure for the determination of nitro groups in organic compounds, based on the usual macro method of reduction with titanous sulphate, has been described. 20–25 mg sample, dissolved in glacial acetic or in aldehyde free ethanol (if the sample was steam volatile), was heated for 15 to 30 minutes with an excess of titanous sulphate, after reduction the excess reducing agent being estimated by back titration against standard solution of ferric ammonium sulphate. The entire operation was carried out in an atmosphere of nitrogen.

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Zusammenfassung Ein Verfahren zur einfachen und schnellen Bestimmung von Nitrogruppen in organischen Verbindungen in Probemengen von 20–25 mg ist auf Grund der Reduktion mit Titan(III)-sulfat ausgearbeitet worden. Die Probe wird in Eisessig (wasserdampfflüchtige Substanzen in aldehydfreiem Äthanol) gelöst; mit einem Überschuß an Titan(III)-sulfat 15 bis 30 min erhitzt, und nach erfolgter Reduktion wird der Überschuß des Reduktionsmittels mit Eisen(III)-ammoniumsulfatlösung zurücktitriert. Es wird in Stickstoffatmosphäre gearbeitet.

     

The reaction of ammonium salts in molten alkali metal nitrites

The thermal decomposition of ammonium chloride and sulphate in molten alkali metal nitrite eutectics cannot be represented by a simple stoichiometry. Nitrous oxide and nitric oxide are produced as well as nitrogen and water.Thermogravimetry is complicated by loss of solid material when the extremely rapid reaction commences at temperatures just below the melting points of the nitrite eutectics and by volatilisation of unreacted ammonium compounds, largely chloride and nitrite/nitrate from reactant solutions of ammonium chloride and ammonium sulphate, respectively.     

三氯化钛存在下碘酸钾滴定法测定锡

提出了采用铝加铁混合还原剂还原,三氯化钛存在下碘酸钾滴定法测定锡的绝对测量方法,研究了三氯化钛抑制氧的作用效果及作用机理。应用于巴氏合金中锡含量的测定,方法简便、快速,结果准确可靠。     

Simultaneous determination of dichromate and cupric ions

Summary The stage-wise reaction of titanous chloride with a mixture of dichromate and cupric copper is used as the basis of a rapid method for the determination of the individual components of the mixture cited. Diphenylamine is used as indicator for the first reaction while a few drops of ferrous solution in the presence of excess thiocyanate serve as indicator for the second reaction.     

Rapid estimation of chlorate in presence of perchlorate

Summary A rapid and simple method is described for the determination of chlorate in the presence of a large amount of perchlorate. The solution containing the mixture is acidified with either sulphuric acid or hydrochloric acid and titrated in the presence of sodium bromide directly against titanous chloride using quinoline yellow as indicator near the end point. The limit of uncertainty of the method is 0.361 mg for a sample analysing 52.48 mg of sodium chlorate.     

Determination of uranium and plutonium in plutonium based fuels by sequential amperometric titration

A method is described for the sequential determination of uranium and plutonium in plutonium bearing fuel materials. Uranium and plutonium are reduced to U(IV) and Pu(III) with titanous chloride and then titrated with dichromate to two end points which are detected amperometrically using two polarized platinum electrodes. Uranium-plutonium solutions of known concentrations containing plutonium in the proportions of 4, 30, 50, and 70% were analyzed with precisions better than 0.3%, maintaining the amounts of plutonium per aliquot in the range of 2–10 mg. No significant bias could be detected. Several samples of (U, Pu)O₂ and (U, Pu)C were analyzed by this procedure. The effects of iron, fluoride, oxalic acid and mellitic acid on the method were also studied.     

Titanous chloride as a reagent for quantitative organic microanalysis. III. Microdetermination of quinones

Summary The preparation of stabilized 0.02N titanous chloride solution is described. Benzoquinones and naphthoquinones are reacted with excess 0.02N titanous chloride at room temperature and back-titrated with 0.02N ferric ammonium sulfate. Anthraquinone and its derivatives, except aminoanthraquinone, require boiling temperatures for complete reduction. Polycyclic quinones are resistant to titanous chloride under these conditions.

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Zusammenfassung Die Herstellung stabiler 0,02-n Titan(III)-chloridlösung wird beschrieben. Benzo- und Naphthochinone reagieren bei Zimmertemperatur mit dieser Maßlösung, die dann mit 0,02-n Eisen(III)-chloridlösung zurücktitriert wird. Anthrachinon und dessen Derivate mit Ausnahme von Aminoanthrachinon werden nur bei Siedehitze vollständig reduziert. Polyoyklische Chinone werden von Titan(III)-chlorid unter diesen Bedingungen nicht angegriffen.

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Résumé On décrit la préparation d'une solution de chlorure titaneux 0,02N stabilisée. On fait réagir les benzoquinones et les naphtoquinones avec un excès de chlorure titaneux 0,02N à température ambiante et l'on titre en retour par le sulfate de fer-III et d'ammonium 0,02N. Les anthraquinones et leurs dérivés, sauf l'amino-anthraquinone, exigent la température de l'ébullition pour la réduction complète. Dans ces conditions, les quinones polycycliques résistent au chlorure titaneux.

     

Studies in bivalent chromium salts

Summary A comparative study of reduction of triphenylmethane (rhodamine, rosaniline, methyl violet and aniline blue), indigoid (isatine) and quinoneimine (safranine) dyes with chromous sulphate and titanous chloride has been made and it has been shown that all these dye-stuffs can be successfully titrated against chromous sulphate. It thus provides an alternative method for the estimation of the dyes belonging to the various groups.

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Zusammenfassung Es wurde eine vergleichende Untersuchung über die Reduktion von Triphenylmethan-, Indigoid- und Chinoniminfarbstoffen mit Chrom(II)sulfat sowie Titan(III)-chlorid vorgenommen. Zur volumetrischen Bestimmung wird die Titration mit Chrom(II)-sulfatlösung empfohlen. Folgende Farbstoffe der einzelnen Gruppen wurden untersucht: Rhodamin, Rosanilin, Methylviolett, Anilinblau, Isatin, Safranin.

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Part IX: Tandon, J. P., and R. C. Mehrotra: Z. analyt. Chem. 187, 410 (1962).

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Thanks are due to Dr. R. C. Mehrotra, Professor and Head of the Department of Chemistry, for his keen interest in the work.     

Pollution-free method for the determination of iron in iron ore

A method for the determination of total iron in iron ores and concentrates is described which avoids the use of mercuric chloride. The sample is decomposed either by an acid attack or by fusion with sodium peroxide. The hot sample solution in about 6M hydrochloric acid is treated with hot 10% stannous chloride solution till pale yellow, followed by addition of a slight excess of 2% titanous chloride solution; the excess is then oxidized with perchloric acid (1 + 1). The solution is rapidly cooled in ice-water, and the iron (II) is titrated with potassium dichromate (sodium diphenylsulphonate as indicator). The results show the same degree of precision, accuracy, and degree of interference as those obtained by the standard stannous chloride-mercuric chloride method.     

Homolytic reductive alkylation of methylvinyl ketone with ethers by Ti(III) decomposition of t-butyl hydroperoxide

Reductive alkylatin of methylvinylketone has been accomplished by hydrogen abstraction from cyclic ethers with the redox couple: t-butyl hydroperoxide-titanous chloride. A redox radical mechanism is proposed and the selectivity of the hydrogen abstraction by t-butoxy radicals and reduction of α-ketoalkyl radical by titanous ions is discussed.     

Radiation effects on polymers—XIII. The application of cellulose acetate-g-polyacrylamide membranes in the process of water desalination by reverse osmosis

Using computerized programs, the water flux and salt rejection properties in reverse osmosis of cellulose acetate-g-acrylamide membranes are determined. Comparisons are made with ungrafted commercial cellulose acetate membranes, using 0.1 and 1.0 M sodium chloride, sodium sulphate and ammonium sulphate solutions. The grafted cellulose acetates show improved water flux but reduced NaCl rejection. However, they show promising prospects in bigger ion separation as for Na₂SO₄ and (NH₄)₂SO₄ solutions.     

Photometric determination of gallium with rhodamine b

Gallium is extractable as rhodamine B chlorogallate with benzene from 6M hydrochloric acid, and can be determined absorptiometrically or fluorimetrically in the extract. The interference of iron(III) is avoided by first separating gallium by extraction with isopropyl ether from hydrochloric acid solution containing titanous chloride. Traces of gallium can be determined in the presence of aluminium, indium, zinc, antimony, thallium, tungsten and other elements.     

Electrophoretic Behaviour of 34 Organic Acids on Impregnated Strips

Abstract

Electrophoretic behaviour of 34 organic acids on calcium sulphate impregnated papers has been studied. The 19 binary separations in aqueous sodium chloride and sodium sulphate solutions and distilled water have been achieved.     

Water transference through nickel hydroxide precipitate membrane

The transference of water that results from ion migration through the nickel hydroxide precipitate membrane was studied in chloride, perchlorate, nitrate, and sulphate solutions to estimate the transference number of water and the co-ion transport. In the systems of univalent anions, the moles of water transported per mole of electrons in 0.1 N solutions is almost identical to the hydration number of each anion. This water flow decreases gradually as the concentration of external solution increases, because of increase in the co-ion (cation) transport with increasing concentration of the solution. In the system of sulphate solutions the co-ion transport is remarkable, the transport number of Na⁺ ions being 0.03 in 0.01 N, 0.27 in 0.10 N, and 0.50 in 0.5 N Na₂SO₄ solution. This large co-ion transport in Na₂SO₄ solution is attributed to the partical replacement of hydroxyl groups on the membrane by SO^2?₄ ions, which then acts as a negative fixed charge. The order of the selectivity for co-ion transport is K⁺ > Na⁺ > Li⁺ > Ni²⁺ ? Mg²⁺ in sulphate solutions and also in chloride solutions, although the transport number of the cations is much smaller in chloride solution than in sulphate solution.     

Chemistry of thorium : Volumetric determination of thorium

Thorium has been determined volumetrically. It has been precipitated with m-nitrobenzoic acid according to the method of Neish. Thorium m-nitrobenzoate has been then dissolved in sulphuric acid and titrated with titanous chloride to determine the NO₂-group which gives the amount of thorium directly.