Über die Hydrolyse von Eisen(III)-Salz-Lösungen. II Die Alterung der Hydrolyseprodukte

On the Hydrolysis of Iron (III) Salt Solutions. II. Ageing of Hydrolysis Products The long time ageing up to 15 years of the products obtained by alkalifying iron(III) chloride solutions to different neutralisation degrees has been studied. The concentration of the Fe³⁺ and the Cl- ions, the strength of the alkali, and the rate of its addition influence the results. Slow alkalifying produced up to 90% neutralisation β-FeOOH. The transformation of the amorphous iron(III) oxidehydroxide to β-FeOOH was promoted by a high concentration of the Cl- ions. When a large amount of amorphous iron(III) oxidehydroxide was formed, intimately intergrown crystals of α- and β-FeOOH resulted. On further ageing β-FeOOH transformed into α-FeOOH. At a degree of neutralisation of 95 and 100% transformation of the amorphous iron(III) oxidehydroxide into α-Fe₂O₃ occurred. The 100% neutralized precipitate, however, remained partly amorphous. Authors discuss the factors that determine very slow reactions leading to these results.     

Über basische Aluminiumsalze und ihre Lösungen. VII. Zum Einfluß der Herstellungsbedingungen,der Konzentration und der Alterungszeit auf die Zusammensetzung von Lösungen basischer Aluminiumsalze

Basic Aluminium Salts and their Solutions. VII. Influence of Preparation, Concentration, and Aging on the Constitution of Solutions of Basic Aluminium Salts 0.1 to 4 molar basic aluminium chloride solutions – prepared by dissolving aluminium metal in substoichiometric quantities of hydrochloric acid and 10^?4 to 0.2 molar basic solutions of aluminium chloride and perchlorate – prepared by adding alkali to the solutions of the neutral salts were investigated for the kinetics of their reactions with ferrone and by ²⁷Al NMR spectroscopy. In all solutions the contents of polymeric species decreases at equal basicity with increasing aluminium concentration. On the other hand the Al₁₃O₄₀ complex is only formed in solutions prepared by addition of alkali. The differences of composition are confirmed by the aging behaviour of the solutions.     

Über die Bildung von röntgenamorphem Eisen(III)-hydroxid durch Luftoxydation von Eisen(II)-hydroxid und Eisen(II)-carbonat

In the presence of certain foreign cations (Ca²⁺, Mg²⁺), amorphous iron(III) hydroxide may be obtained from Fe^II hydroxide or carbonate by air oxidation.     

Untersuchungen über die Hydrolysenfällung von Eisenlösungen. I. Modell für Hydrolyse und Fällung von Eisen(III)-Nitratlösungen

Ohne Zusammenfassung     

Der Mechanismus der Hydrolyse von Chlortriazinen in protischen Lösungsmitteln. II. Mitteilung Über nukleophile uromatische Substitutionen

The complex kinetics found for the hydrolysis of 1, 3, 5-trichloro-s-triazine in 9/91% (v) acetone/water at 10.0°C have been evaluated as a function of the hydroxyl ion and the acetate ion concentration using an analogue computer. The kinetics are consistent with a nonsteady state mechanism in which the primary intermediate anion is protonated giving a neutral species whose concentration goes through a maximum during the course of the reaction. This secondary intermediate forms the final product by deprotonation and release of a chloride ion. The product itself can undergo a second (reversible) deprotonation. In dimethylsulfoxide the analogous intermediate of the hydrolysis of 1, 3-dimethoxy-5-chloro-s-triazine can be identified by analysis of the NMR. and UV. spectra.     

Untersuchungen über die Löslichkeit von Molybdatophosphaten. I. Löslichkeit von Chinoliniummolybdatophosphat

Studies on the Solubility of Molybdatophosphates. I. Solubility of Quinolinium Molybdatophosphate The solubility of quinolinium molybdatophosphate was determined radiochemically under conditions of the gravimetric determination of phosphate in hydrochloric acid as well as in nitric acid media. The residue concentration of phosphate variies in the range of 10^?8 to 10^?9 mol/I. The dependence of the solubility on the reagent concentration and on the concentration of solution components was investigated and discussed variing the pore width of the filters used for separating the precipitate. The accuracy and the precision of the determination of phosphate was not influenced in practice by the solubility.     

Über basische Aluminiumsalze und ihre Lösungen. (XIII). Kristalline basische Aluminiumchloride als Produkte der Rehydratisierung und Hydrochlorierung von Übergangstonerden

Basic Aluminum Salts and their Solutions. XIII. Crystalline Basic Aluminum Chlorides Formed as Products of Rehydration and Hydrochlorination of Transition Aluminas By reaction of transition aluminas with hydrochloric acid in sealed tubes at temperatures above 100°C crystalline basic aluminum chlorides were prepared. From the aluminum oxides used (χ-Al₂O₃, χ-Al₂O₃, and χ-Al₂O₃) χ-Al₂O₃ was most suitable for preparation. The homogeneous basic salts are characterized by a certain variability in composition as phases. After a treatment with water vapor there is a remarkable change in the X-ray diagrams of the compounds. It is shown, that at this alteration the lattice was only changed unessentially. Therefore the existence of intercalation compounds with a 3D host lattice is assumed; the water molecules are located at defined positions in the voids.     

Über die Silicatanionenkonstitution in Tetraethylammoniumsilicaten und ihren wäßrigen Lösungen

On the Constitution of Silicate Anions in Tetraethylammonium Silicates and their Aqueous Solutions Investigations by paperchromatography, ²⁹Si-NMR spectroscopy and trimethylsilylation method show that concentrated solutions of tetraethylammonium (TEA) silicates with molar TEA:Si ratios from 2.8 to 1 contain mainly double three-ring silicate anions. Besides of these small amount of mono-, di-, tri-, tetra-, cyclotri-, cyclotetra-, double four-ring- and other polycyclic silicate anions are present. From these solutions a crystalline double three-ring silicate of the formula [N(C₂H₅)₄]₆[Si₆O₁₅] · 57 H₂O could be obtained by crystallization at low temperature. Concentrated solutions with TEA:Si ratios of 0.8 to 0.6 contain mainly double three-, double four-, double five- an probably double six-ring silicate anions. From such solutions always the solid TEA-double four-ring silicate is obtained by crystallization. The reasons for the prefered formation of double ring silicate anions in TEA-silicate solutions and their crystallization are discussed.     

Über basische Aluminiumsalze und ihre Lösungen. XIX. Zur Art der Al-Kationen in hochbasischen,hochkonzentrierten Aluminiumchloridlösungen

Basic Aluminium Salts and their Solutions. XIX. Nature of Aluminium Cations in Highly Basic Highly Concentrated Aluminium Chloride Solutions It is shown that in highly concentrated basic aluminium chloride solutions (c_Al ≈ 7.7 mol · l^?1; r = OH/Al = 2.48), prepared by dissolving aluminium metal in substoichiometric quantities of hydrochloric acid, polymeric aluminium cations (Al_poly) dominate. By dilution of these solutions also increasing amounts of monomeric cations (Al_mono) occur. On aging Al_mono reacts with Al_poly forming small portions of tridecameric Al₁₃O₄₀ cations (Al₁₃). On the basis of these results literature data, after which corresponding commercial basic aluminium chloride solutions contain essentially Al₁₃ cations, are critically discussed.     

Über basische Aluminiumsalze und ihre Lösungen. XVI. Kinetische Untersuchungen an niederbasischen Aluminiumchloridlösungen

Basic Aluminum Salts and their Solutions. XVI. Kinetic Studies on Low Basic Aluminum Chloride Solutions Basic aluminum chloride solutions of low basicity were prepared by different methods and investigated by means of the ferrone kinetics. In solutions prepared by expulsion of hydrogen chloride or addition of solid sodium carbonate preferably dimeric cations are formed. In solutions prepared by addition of sodium hydroxide solution or sodium carbonate solution only at very low basicity small quantities of dimeric ions are formed, at increasing basicity tridecameric ions arise. An explanation of this behaviour is given, involving the action of hydroxide ions and a possible formation of the dihydroxy-aluminum complex. The rate constant for the reaction of the dimeric ions with the ferrone reagent was determined to be k = 0.97 ± 0.06 min^?1.     

Über die Stereochemie der Hydrogenolyse von N-Benzyl-Bindungen I. Die Hydrogenolyse von Derivaten der 2-Amino-2-phenyl-propionsäure.

The stereochemistry of the hydrogenolysis of benzyl-N bonds was studied using S(+)-2-dimethylamino-2-phenyl-propionic acid (I) and its derivatives, and R(?)-2-anilino-2-phenyl-propionic acid (II). The configuration of I was confirmed, that of II established by ORD. measurements, after transformation of the phenyl into cyclohexyl groups. On a palladium catalyst the hydrogenolysis of I, its methyl and ethyl esters and its amide proceeded with 72 to 99% inversion of configuration, that of II with at least 66% inversion. The ester of the quaternary ammonium derivative of I gave as much inversion as retention (= racemisation).     

Über die Umsetzung von Phosphor (III)-fluoriden mit Phenylazid

On the Reaction of Phosphorus(III) Fluorides with Phenyl Azide The reaction of phenyl azide with phosphorus(III) fluorine compounds was found to proceed according to the principle of a Staudinger reaction producing, normally, fluorine-containing N-phenylphosphine imides. From diethylamino difluorophosphine and phenyldifluorophosphine the dimers, [(Et₂N)F₂PNPh]₂ and [PhF₂PNPh]₂, were obtained with phenyl azide. These compounds have previously been prepared by a different route. The compounds were characterized by elemental analysis, determination of the molecular weight, either cryoscopically or by mass spectrometry as well as through their n.m.r. spectra (¹H, ¹⁹F and ³¹P).     

Über basische Aluminiumsalze und ihre Lösungen. (XII). Vergleichende Untersuchungen an unterschiedlich dargestellten Basischen Aluminiumchloridlösungen

Basic Aluminium Salts and their Solutions. XII. Comparative Studies of Basic Aluminium Chloride Solutions Prepared in Different Ways Basic aluminum chloride solutions were prepared from solutions of the neutral salt by adding alkali or by dissolution of metallic aluminum. The solutions prepared by both methods contain monomeric, tridecameric, and polymeric aluminum cations, as was shown by the ferrone method and by ²⁷Al NMR spectroscopy. The formation of tridecameric ions is favoured by low temperature, low basicity, and in diluted solution; at higher temperatures and basicities they are transformed to polymeric and monomeric forms.     

Die photometrische Bestimmung von Eisen(III) und die papierchromatographische Abtrennung

Ohne Zusammenfassung     

Über basische Aluminiumsalze und ihre Lösungen. X. NMR-Untersuchungen am tridekameren Al-oxo-hydroxo-Kation

Basic Aluminum Salts and their Solutions. X. NMR-Investigations on the Tridecameric Al-Oxo-Hydroxo Cation Using solid-state high resolution ²⁷Al-NMR it is shown that in the basic aluminum chloride with a degree of alkalinity r = OH/Al = 2.5 cations of the [Al₁₃O₄(OH)₂₅(H₂O)₁₁]⁶⁺ type exist. The ¹H-NMR detects besides the constitutional water still an amount of mobile, enclosed H₂O molecules which can be removed by thermal treatment at 104°C. The ²⁷Al spectrum of the aqueous solutions of the chloride shows only one peak at 62.5 ppm which is characteristic for the tridecameric cation. Adding HCl to the solution causes a decomposition to low-molecular species (peak at 0 ppm). Adding NaOH to the aqueous solution of the chloride effects a rearrangement of the tridecameric cations to higher molecular particles which are no more accessible by ²⁷Al-NMR.     

Ionenaustausch Bei Hohen Konzentrationen der Lösung VI. Einfluss des Vernetzungsgrades Auf die Sorpton Anionischer Komplexe von Thallium(III) und Eisen(III) Durch Sulfonsaure Kationaustrauscher

Ion exchange at high concentrations of the mobile phase. VI. The influence of the degree of crosslinking on the sorption of anionic complexes of Tl(III) and Fe(III) by sulphonic cation exchangers The sorption of TI(III) and Fe(III) on sulphonic cation exchangers with 2-16% divinylbenzene has been investigated. In the range of concentration 4-8 mol/1 HBr and 4-10 mol/l HC1 the distribution coefficients decrease with the degree of crosslinking of the matrix. The same dependence has been observed for the selectivity of sorption, i.e. the quotient of the volume distribution coefficient of the trace component and the Donnan coefficient of the electrolyte.     

Über die Stereochemie von Zwischenprodukten (Aldolbasen) der Doebner-von Miller-Chinolin-Synthese

In the Doebner-von Miller quinoline synthesis with acetaldehyde or crotonaldehyde two stereoisomeric 4-hydroxy-1, 2, 3, 4-tetrahydroquinaldines are formed as intermediates. The stereochemistry of these compounds differing in the relative positions of the hydroxygroups to the methyl-group can be ascertained by NMR.-spectroscopy. The pK_a-values of stereoisomers are not identical due to the different spacial positions of the HO-groups.     

Beiträge zur Chemie der Alkyverbindungen von Übergangsmetallen. XVII. Leitfähigkeits- und ÜberführungsMessungen an Lösungen von Lithiumalkylotitanaten(IV)

On the Chemistry of Transition Metal Alkyl Compounds. XVII. Measurements of Conductivity and Transference on Solutions of Lithium Alkylo Titanates (IV) Conductivity measurements and transference experiments on solutions of lithium alkylo titanates(IV) are described. On account of the experimental results these compounds may be considered to be ionic complexes.