Solvent extraction of halogens

Summary The solubility formula previously proposed was applied to the partition of halogens between water and some typical organic solvents, and the character of parameter in the formula was examined. The formula reproduces the experimental data of the solvent extraction of halogens reasonably. The ratio is controlled by the solute independently of the solvent. The ratio is unity for all solutes in the water-hydrocarbon system, and is 3 ^n–1 (n is periodic number) depending on the solute in the water-non-hydrocarbon system.

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Lösungsmittelextraktion von Halogenen

Zusammenfassung Die früher vorgeschlagene Löslichkeitsformel wurde auf die Verteilung von Halogenen zwischen Wasser und einigen typischen organischen Lösungsmitteln angewendet und der Charakter des Parameters in der Formel untersucht. Die Formel gibt die experimentellen Werte der Halogenextraktion zufriedenstellend wieder. Das Verhältnis der -Werte wird vom Gelösten unabhängig vom Lösungsmittel bestimmt. Dieses Verhältnis ist im Wasser-Kohlenwasserstoff-System in allen Fällen gleich 1. Im System aus Wasser und Nicht-Kohlenwasserstoff hängt es vom Gelösten ab und beträgt 3 ^n–1 (n = Periodenzahl des Halogens).

     

Gas chromatography of halogens

Summary The semi-empirical theory on the retention volume in gas chromatography recently developed by some experiments, was found to require partial correction. It was newly refined and summarized. Overall experimental checking was performed by the use of Cl₂, Br₂, and I₂.

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Gas-Chromatographie von Halogenen

Zusammenfassung Die halbempirische Theorie über das Retentionsvolumen in der Gas-Chromatographie, die kürzlich an Hand einiger Versuche entwickelt wurde, erforderte eine teilweise Korrektur. Sie wurde verbessert und zusammenfassend dargestellt. Kontrollversuche wurden mit Hilfe von Chlor, Brom und Jod durchgeführt.

     

Regio- and Z-Selective Alkyne Hydroamination and Hydrophenoxylation using Tetrafluoro-λ6-Sulfanyl Alkynes under Superbasic,Naked Anion Conditions

Alkyne hydroamination is an effective approach for the production of enamines and enamine-containing N-heterocycles. However, stereoselectivity control is a considerable challenge in this reaction because of the electronic repulsion between an incoming nitrogen lone pair and the alkyne π-system. Herein, we propose a methodology involving β-regio- and Z-selective alkyne hydroamination by using tetrafluoro-λ⁶-sulfanyl (SF₄) alkynes under superbasic, naked anion conditions. The reaction is compatible with a wide variety of N-heterocycles, including indoles, carbazoles, pyrazoles, and imidazoles, and selectively furnishes SF₄-linked Z-vinyl enamines with β-regioselectively. Moreover, the method can be extended to the β- and Z-controlled, base-mediated alkyne hydrophenoxylation with phenols to provide SF₄-linked Z-vinyl ethers in high yields. As the SF₄ unit has attracted attention as a bioisostere for alkynes, p-benzenes, bicyclo[1.1.1]pentyl (BCP) groups, and cubanes in medicinal chemistry, this chemistry represents an effective approach to creating novel drug candidates incorporating SF₄-containing molecules.     

The mechanism of the reaction of elementary astatine with organic solvents

The mechanism of the reaction of elementary astatine with benzene, toluene and monochlorobenzene were studied by means of radiogaschromatography. The reaction proceeds in two steps with benzene and toluene. In Step 1 the chemical bond of At₂ is cleaved by the disintegration of either astatine and the remained astatine reacts immediately with solvent. At Step 2 the compound produced at Step 1 is started to decompose by the decay of astatine. But this mechanism could not be applied to the astatine-monochlorobenzene system.     

Mechanism of halide conversion process of colloidal AgCl microcrystals by Br ions : I. Observation of the dynamic changes in shape, structure, and composition

The mechanism of the halide conversion process in suspension of AgCl microcrystals by bromide ions was studied by electron microscopy, X-ray diffractometry, and electron-beam diffractometry. The typical conversion process after the introduction of Br⁻ was found to consist of more than three distinctive steps. The first step was an almost instantaneous reaction within a few seconds for a surface conversion without apparent morphological change of the original particles. The second step was a very rapid epitaxial growth process of virtually pure AgBr crystals on every corner and partly on the edges of the AgCl cubic microcrystals with dissolution of their own {100} faces, which was finished in about 1 min at 25°C. The third step was a much slower process of about 2 h at 25°C (ca. 5 min at 45°C) for the formation of an AgCl_0.5Br_0.5 solid solution developing from the joints of AgBr guest and AgCl host by simultaneous dissolution of the guests and the hosts. After the complete dissolution of the AgBr guests, a further recrystallization process that formed a solid solution richer in chloride content followed. Finally, the conversion virtually stopped midway to yield double-structured particles of Ag(Cl, Br) shell/AgCl core. However, when the initial molar ratio of [Br⁻]₀/[AgCl]₀ was so high as to exceed unity, the original AgCl particles were totally decomposed into about eightfold AgBr particles in number. In this case the steps later than the second one were missing. Also, it was suggested from the subsidiary study on open systems, where bromide ions were added continuously, that the kinetics was basically controlled by the deposition rate of the solute of the AgBr component of the growing parts, though it was switched to being limited by the dissolution rate of the host AgCl crystals when their open surface area for dissolution was extremely diminished.     

High-temperature gas-chromatography of some inorganic chlorides

Summary Electric-conductivity detector is used successfully for the detection of inorganic chlorides in high temperature gas chromatography (450–1000°C). Following mixtures can be separated by the carrier gas He (60 ml/min) on a 250 mm Pt-column with the packing constructed of a fused salt and Chromosorb WAW: BeCl₂/AlCl₃at 560°C; PbCl₂/SnCl₂at 780°C; BiCl₃/SbCl₃at 660°C; BiCl₃/PbCl₂ at 560°C; TlCl/FeCl₃, TlCl/BeCl₂, TlCl/AlCl₃, ThCl₄/AlCl₃ at 640°C; InCl₃/(AlCl₃+FeCl₃) at 660°C; ZnCl₂/PbCl₂ at 780°C; SnCl₂/(NaCl+KCl) at 830°C; and TlCl/PbCl₂ at 830°C.

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Hochtemperatur-Gas-Chromatographie einiger anorganischer Chloride

Zusammenfassung Zum Nachweis anorganischer Chloride bei der Hochtemperatur-Gas-Chromatographie (450–1000°C) wird mit gutem Erfolg ein Leitfähigkeitsdetektor verwendet. Es wird eine 250 mm-Pt-Säule benutzt, gefüllt mit einem geschmolzenen Salz (Alkaki oder Erd-alkalichloride) auf Chromosorb WAW. Als Trägergas dient Helium (60 ml/min). Folgende Gemische können getrennt werden: BeCl₂/AlCl₃ bei 560°C; PbCl₂/SnCl₂ bei 780°C; BiCl₃/SbCl₃ bei 660°C; BiCl₃/PbCl₂ bei 560°C; TlCl/FeCl₃, TlCl/BeCl₂, TlCl/AlCl₃, ThCl₄/AlCl₃ bei 640°C; InCl₃/(AlCl₃ + FeCl₃) bei 660°C; ZnCl₂/PbCl₂ bei 780°C; SnCl₂/(NaCl+KCl) bei 830°C; TlCl/PbCl₂ bei 830°C.