Zur Ermittlung und rechnerischen Überprüfung thermodynamischer Daten aus experimentell gefundenen Werten, 7. Mitt.: Dampfdruckmessungen an binären,azeotropen Systemen und ihre Auswertung mit Hilfe des Matrizenkalküls

Zusammenfassung An Hand zweier binärer Systeme (Äthylamin/n-Butan und Benzol/Äthanol) wird die Anwendbarkeit verschiedener Ansätze zur Berechnung der Aktivitätskoeffizienten und zur Zerlegung der Totaldrucke in die Partialdrucke diskutiert. Die Koeffizienten desMargules-Ansatzes werden mit Hilfe des Matrizenkalküls hergeleitet. Für stark assoziierende Systeme wird die parktische Anwendbarkeit von Ansätzen mit logarithmischen Zusatzgliedern und ihre Auswertbarkeit nach der Methode der kleinsten Quadrate besprochen. DerMargules-Ansatz mit wenigstens vier Parametern vermag die Verhältnisse im stark verdünnten Bereich richtig wiederzugeben und ist zufolge seiner thermodynamischen Konsistenz jedem Ansatz mit logarithmischen Gliedern vorzuziehen. Voraussetzung für seine uneingeschränkte Anwendbarkeit ist allerdings die Benützung einer modernen elektronischen Rechenanlage.

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Various statements for the calculation of activity coefficients are discussed for the two binary systems ethylamin/n-butane and benzene/ethanol. The statement ofMargules is deduced under application of the matrix calculation. Statements with logarithmic terms are used for systems with considerable association. The methode ofGauss of the smallest squares is shown to be applied in first and second approximation. The statement ofMargules with at least four parameters is able to describe correctly the thermodynamic conditions in very diluted concentrations. This statement must therefore be preferred to all these ones with logarithmic terms. In making use of the statement ofMargules a modern electronic computer has to be employed, if the number of the parameters increases.

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Mit 4 Abbildungen     

Ein Dreikomponenten-Zweiphasensystem für die schnelle Flüssigkeits-Chromatographie

Zusammenfassung Für die Hochdruck-Flüssigkeits-Chromatographie wird ein Dreikomponenten-Zweiphasensystem beschrieben. Die Mischungslücke besteht zwischen dem wenig polaren Methylenchlorid und dem stark polaren Wasser und kann durch Zugabe von Äthanol als Lösungsvermittler geschlossen werden. Durch den Anteil der stark polaren Komponente in den jeweils koexistenten Phasen ist die Polarität von stationärer und mobiler Phase als stationäre gebunden und aus der mobilen immer wieder regeneriert. Durch Verteilungs-Chromatographie in der Mischungslücke ist eine Vielzahl von Stoffklassen der Trennung zugänglich, so z.B. Corticosteroide, Östrogene, Phenole, Phenolcarbonsäuren usw.

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A three-component two-phase system for high speed liquid chromatography

Summary High pressure liquid chromatography with a three-component two-phase system is described. For the less polar methylenechloride and the highly polar water a wide range of incomplete miscibility exists which can be decreased with ethanol. The water content of the coexistent phases determines the polarity of the stationary and the mobile phases. The more polar phase is adsorbed on silicagel as the column support material and serves as the stationary phase. Numerous compounds can be separated by partition chromatography between the coexistent phases, for instance; corticosteroids, estrogens, phenols, phenol-carboxylic acids and so on

     

Heavy metals in human urinary calculi

Summary Heavy metals are incorporated in human urinary calculi during a complex pathological process. The trace metals cadmium, lead, chromium, nickel and mercury are determined with regard to significance in pathogenesis and therapy. The amounts of cadmium, lead and chromium were determined as well directly in the solid sample as after chemical digestion by Zeeman-GFAAS. Both analyzing techniques show corresponding results. Nickel could be determined after chemical digestion only, while mercury was determined by a solid sampling technique. The evaluation of the results of trace metal analysis in the pilot study of 11 urinary calculi showed increased amounts of lead and cadmium compared to the results of tartar and salivary calculi.     

Strukturaufklärung gemischter Komplexe von Eisen(II), Kobalt(II) und Nickel

Iron(II), cobalt(II) and nickel form complexes of the formula [Me(TTA)₂B¹] with 1-(2′-thenoyl)-3,3,3-trifluoroacetone (HTTA) and 2-pyridinalphenylimines (B¹) or bis-(2-pyridinal-R-diimines) (B²) and — in dependence of the -R group in the B² compounds — complexes of the formula [Me₂(TTA)₄B₂] and [Me₂(TTA)₂B²]. The octahedral geometry of the complexes can be unequivocally proven by means of electron spectra, IR spectra and from magnetic measurements. The labelling of solid [Ni(TTA)₂B¹] complexes with the nickel isotopes⁵⁸Ni or⁶²Ni permits an allocation of the Me-O- and Me-N-valency oscillations in the FIR.     

Theory of chirality functions,generalized for molecules with chiral ligands

The theory of chirality functions described in a previous publication is generalized to allow for chiral ligands. In the earlier theory, all symmetry operations of the molecular frame could be thought of as permutations of the ligands among the sites; in the present work, improper rotations not only permute the ligands, but convert them into mirror images. The group that generates all isomers from a given ordered molecule belonging to a frame with n sites is now the hyperoctahedral group of order 2ⁿ n! consisting of all possible combinations of permutations and site reflections. The representation theory of these groups is described, and applied to the problem of constructing qualitatively complete chirality functions, and of deciding which ligand partitions, and which isomer mixtures, are chiral. It is found useful to classify chiral representations of the covering group as ligand specific and class specific. The ligand specific representations describe chiral properties which are common to all frames and arise purely from the chirality of the ligands, while the class specific representations describe the chiral properties of the frame. A number of examples are explicitly worked out.     

Über die Cyclisierung von Histidinderivaten

Cyclisierung vonl-Histidin-methylester und Histamin über die (nicht isolierten) N-Phenylthiocarbonyl-derivate (Ia) führt durch intramolekulare Harnstoffbildung zu Derivaten des neuartigen bicyclischen Ringsystems Imidazo(1,5-c)tetrahydrooxopyrimidin (II, III).Dieses ist relativ beständig gegen saure Hydrolyse; Einwirkung von basischen Reagenzien (Alkali und Amine) und von Lithiumaluminiumhydrid führt unter Öffnung des Pyrimidinringes (zwischen 4 und 5) zur Bildung von 4(5)-substituierten Imidazolderivaten, wobei mit Aminen N-Carbonsäure-amide (V bis IX) und mit LAH in der Seitenkette N-methylierte Produkte (X, XI) entstehen.Untersuchungen an offenkettigen Modellsubstanzen mit ähnlicher Struktur (XVI, XVII) führten zu ähnlichen Ergebnissen — Abspaltung von Imidazol und entsprechender Substitution der zweiten Komponente, die in manchen Fällen primär als Isocyanat abgespalten wird. Für diese Reaktionen wird ein möglicher Mechanismus diskutiert.DieR _F-Werte einiger Imidazolderivate wurden bestimmt.     

Determination of isotopic composition of lithium by neutron activation analysis; comparison with mass spectrometry

An activation analysis method is described for routine determination of⁶Li-abundances in various lithium compounds on the basis of the reaction sequence⁶Li(n,α)T and¹⁶O(t, n)¹⁸F and the measurement of¹⁸F. Irradiations of diluted equeous solutions of samples containing CrO₃ as internal flux monitor were carried out at a thermal neutron flux density of ϕ≤10¹¹ n·cm⁻²·sec⁻¹. Interferences from variations in neutron self-shielding oxygen concentration and triton range do not exceed 0.5% when using the dilution technique. The results for⁶Li abundances from 3.52 to 7.60% with standard deviations of 1 to 2.5% were confirmed by mass spectrometric measurements.     

Schnelle Trennung von Rückstoßprodukten in der Gasphase

Experiments are described in which recoil products are separated fast and selectively. The aim of these investigations is an identification of short-lived nuclides, either for the study of nuclear reactions or for the study of decay properties of new products. The recoil products were provided by a Cf-252 source. The transportation zone and the identification zone could be heated to different temperatures. Using N₂ as carrier gas it was possible to separate Te selectively under certain experimental conditions. When Cl₂ was added, Sb, Tc, Nb, Mo, Zr, Ru and Sn were transported. Transport output was determined in dependence of temperature and composition of the gas.     

The catalytic hydrogenolysis of 1-phenylbicyclo[4.1.0]heptane and the corresponding azidirine and epoxide

The hydrogenolysisof 1-phenylbicyclo[4.1.0]heptane (1a), cis-1-phenyl-2-methylbicyclo[4.1.0]heptane (1b), 1-phenyl-7-azabicyclo[4.1.0]heptane (2) and 1-phenyl-7-oxabicyclo[4.1.0]heptane (3) was studied using Ni, Pd, Rh and Pt as catalysts. The hydrogenolysis of the C₁C₇ bond of 1a and 1b led to the selective formation of trans-1-phenyl-2-methylcyclohexane (4a) with retention of configuration. Compound 1a gave not only 4a but also phenylcycloheptane (6a), which is the product of C₁C₆ bond fission, and the ratio of 6a to 4a increased in the sequence: Ni ? Pd, Rh < Pt. No C₁C₆ bond fission was observed in the hydrogenolysis of 1b. These results can be explained by a mechanism involving the formation of the π-benzyl complex.trans-2-Phenylcyclohexylamine (8) was obtained stereoselectively in the hydrogenolysis of 2 over Raney Ni. This selective formation can be ascribed to the competition of “SN i” and “radical” processes. The Pd catalysed hydrogenolysis gave cis-2-phenylcyclohexylamine (9) as the main product, while the presence of sodium hydroxide promoted the formation of 8.Raney Ni catalysed hydrogenolysis of 3 yielded a mixture of phenylcyclohexane (13) and 2-phenylcyclohexanols (10 and 11). trans-2-Phenylcyclohexanol (10) was the dominant isomer; the hydrogenolysis resulted in the predominant configurational retention. Compound 13 was confirmed to be produced via 1-phenylcyclohexene (12). This deoxygenation may be explained by a mechanism involving the radical cleavage reaction of 3. The presence of sodium hydroxide led to the formation of cis-2-phenylcyclohexanol (11). The Pd catalysed hydrogenolysis also gave mainly 11.The difference in behaviour of cyclopropane, azidirine and epoxide we ascribe to the differences in the affinity for the catalyst and differences in the electronegativity between C, N and O atoms.     

Synthesis,spectroscopic characterization and redox reactivity of the copper(II) salicylaldiminates containing sterically hindered 2,6-diphenylphenol

New bidentate N-(2,6-di-phenyl-1-hydroxyphenyl) salicylaldimines bearing X = H and 3,5-di-t-butyl substituents on the salicylaldehyde ring, L ^x H, and their copper(II) complexes, Cu(L ^x )₂, have been synthesized and characterized by i.r., u.v./vis., ¹H-n.m.r., ¹³C-n.m.r., e.s.r. spectroscopy and magnetic susceptibility measurements. E.s.r. study has shown that chemical oxidation of Cu(L ^x )₂ with PbO₂ produces ligand-centered Cu^II-phenoxyl radical species. The complexes are easily reduced with PPh₃ via intramolecular electron transfer from ligand to copper(II) to give unstable radical intermediates, which in time are converted to another stable secondary radical species. The analysis of e.s.r. spectra of Cu(L ^x )₂ and generated radical intermediates are presented.