Zur Anreicherung der stabilen Isotope des Schwefels durch Fest-Flüissig-Austausch unter Verwendung von Ionenaustauschern

An verschiedenen Systemen chemischer Verbindungen wurden Versuche zur Anreicherung des stabilen Isotopes ³⁴S unter Verwendung der Ionenaustauscher Wofatit L 150, SBW und SBK nach den Methoden der Frontalchromatographie und der Bandenverdrāngungschromatographie ausgeführt. Beim Isotopenaustauschsystem Hydrogensulfit (am Ionenaustauscher)/Schwefeldioxid (in wäβriger Lösung) wurden Verfahrensweise und Betriebsparameter hinsichtlich des Anreicherungsgrades optimiert. Mit Hilfe einer einfachen Methode gelang es, aus den Versuchsergebnissen Werle für den elementaren Trennfaktor und die Trennstufenhöhe zu berechnen.     

Die Untersuchung einer Laboratoriumsanlage nach dem Heiß-Kalt-System mit einfachem Durchfluß der Fluide

Es wird ein Heiβ-Kalt-System mit einfachem Durchfluβ der Fluide untersucht. Dabei wird gezeigt, daβ zwischen den Isotopenkonzentrationen des Gases und der Flüssigkeit lineare Beziehungen bestehen. Eine Möglichkeit zur experimentellen Bestimmung der realen Werte der Parameter der Kolonne wird angegeben.     

Füllstandsmessung mit Streustrahlungssonden

Es wird die Abhängigkeit der Impulsdichte vom Füllstand bei Meßanordnungen mit γ-Streustrahlungssonden verschiedener Länge untersucht. Verwendet werden die Nuklide ⁶⁰Co und ¹³⁷Cs. Ein nahezu linearer Anstieg der Impulsdichte mit dem Füllstand wird bei Füllgütern kleiner Ordnungszahl nur bei Sondenlängen L ≥ μ₀ ^?1.erzielt. Der Einfluß des Schüttwinkels und der Dichte des Füllgutes wird diskutiert.     

Poly(phenylene oxide) copolymer anion exchange membranes

Poly(phenylene oxide) block and random copolymers are synthesized by oxidative polymerization of 2,6-dimethylphenol and 2,6-diphenylphenol for potential alkaline exchange membrane application. The copolymers are functionalized on the methyl substituted repeat units through a two-step process to produce pendent quaternary ammonium cationic groups. The amount of quaternary ammonium cations and the ion exchange capacity are quantified through titration measurements. Ionic conductivity of the copolymer membranes is measured by electrochemical impedance spectroscopy. Block copolymers show increased bromide conductivity at higher ion exchange capacities compared with the random copolymer analogs. The bromide conductivity for a block copolymer film with an ion exchange capacity of 1.27 mequiv/g reaches 26 mS/cm at 90 °C and 95% relative humidity. The hydroxide conductivity for the same film was measured to be 84 mS/cm at 80 °C and 95% relative humidity. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1770–1778, 2013     

The solubility of bosentan in aqueous-2-propanol mixtures at several temperatures,measurement and data correlation

ABSTRACT

The solubilities of bosentan (BST) in binary aqueous mixtures of 2-propanol at temperatures ranging from 293.15 to 313.15 K were determined using a shake-flask method. The produced data were modelled with the Jouyban-Acree-van’t Hoff model and difference between the predicted data and experimental ones were illustrated by percent average relative deviations (%ARD). Moreover, the thermodynamic functions of dissolution for BST in the aqueous 2-propanol solutions were computed which suggest that the dissolution process is endothermic and not spontaneous.     

Solvatochromic Solvent Polarity Measurements In Analytical Chemistry: Synthesiss And Applications Of Et-30

Abstract

The E_T(30) scale of solvent polarity has been shown to be useful in examining many diverse analytical processes. It is based on the charge transfer absorption of 2,6-diphenyl-4-(2,4,6-triphenyl-N-pyridinio)phenolate (referred to as ET-30 in this paper). Unfortunately, use of the E_T(30) scale has been hindered by (a) the lack of a commercial source of the ET-30 dye and (b) the lack of an English language synthetic procedure. Here we discuss recent applications of the E_T(30) scale to analytical techniques, as well as a simplified procedure for the synthesis of ET-30.     

Novel non-aggregated soluble metallophthalocyanines bearing carboxylic acid groups

Synthesis and characterization of zinc and cobalt phthalocyanines substituted with biphenylmethylpropionic acids, methyl-o-tolylpropionic acids, and methyl-p-tolylpropionic acids are described in this study. The new compounds have been characterized by elemental analyses, FT-IR, UV-Vis, MALDI-TOF, and ¹H NMR spectroscopy. All new compounds are soluble in THF, DMF, DMSO, and dilute sodium hydroxide solution. The influence of the carboxylic acid and bulky biphenyl, ortho-methylbenzyl and para-methylbenzyl groups on the spectroscopic properties has been investigated. UV-Vis experiments suggest that the tendency of phthalocyanines to aggregate in polar solvents is significantly reduced owing to the carboxylic acid groups and bulky peripheral substituents.     

Coordination Chemistry of Gold Catalysts in Solution: A Detailed NMR Study

Coordination chemistry of gold catalysts bearing eight different ligands [L=PPh₃, JohnPhos (L2), Xphos (L3), DTBP, IMes, IPr, dppf, S‐tolBINAP (L8)] has been studied by NMR spectroscopy in solution at room temperature. Cationic or neutral mononuclear complexes LAuX (L=L2, L3, IMes, IPr; X=charged or neutral ligand) underwent simple ligand exchange without giving any higher coordinate complexes. For L2AuX the following ligand strength series was determined: MeOH?hex‐3‐yne <MeCN≈OTf^??Me₂S<2,6‐lutidine<4‐picoline<CF₃CO₂^?≈DMAP<TMTU<PPh₃<OH^?≈Cl^?. Some heteroligand complexes DTBPAuX exist in solution in equilibrium with the corresponding symmetrical species. Binuclear complexes dppf(AuOTf)₂ and S‐tolBINAP(AuOTf)₂ showed different behavior in exchange reactions with ligands depending on the ligand strength. Thus, PPh₃ causes abstraction of one gold atom to give mononuclear complexes LLAuPPh₃⁺ and (Ph₃P)_nAu⁺, but other N and S ligands give ordinary dicationic species LL(AuNu)₂²⁺. In reactions with different bases, LAu⁺ provided new oxonium ions whose chemistry was also studied: (DTBPAu)₃O⁺, (L2Au)₂OH⁺, (L2Au)₃O⁺, (L3Au)₂OH⁺, and (IMesAu)₂OH⁺. Ultimately, formation of gold hydroxide LAuOH (L=L2, L3, IMes) was studied. Ligand‐ or base‐assisted interconversions between (L2Au)₂OH⁺, (L2Au)₃O⁺, and L2AuOH are described. Reactions of dppf(AuOTf)₂ and S‐tolBINAP(AuOTf)₂ with bases provided more interesting oxonium ions, whose molecular composition was found to be [dppf(Au)₂]₃O₂²⁺, L8(Au)₂OH⁺, and [L8(Au)₂]₃O₂²⁺, but their exact structure was not established. Several reactions between different oxonium species were conducted to observe mixed heteroligand oxonium species. Reaction of L2AuNCMe⁺ with S^2? was studied; several new complexes with sulfide are described. For many reversible reactions the corresponding equilibrium constants were determined.