A volumetric determination of arsenic and antimony in mixed manganese arsenide,antimonide and phosphide compounds

A procedure is described for the titrimetric determination, of arsenic and antimony without separation. Total combined arsenic and antimony were determined by reduction with tin(II) chloride and titration with permanganate; antimony is found by selective reduction with mercury(I) chloride and titration with permanganate. A precision of 0.1–0.2% was obtained for total combined arsenic and antimony, and approximately 1% for antimony alone (small amounts in the presence of large amounts of arsenic). The procedure was developed for and applied to the analysis of synthesized compounds of the type MnAs_1-xP_x and MnAs_1-ySb_y.     

Alkylierung ambidenter Heterocyclen-Anionen, 2.Mitt.: Zur Alkylierung von 4-Hydroxy-carbostyrilen

Zusammenfassung Der Lösungsmitteleinfluß bei der Alkylierung von 4-Hydroxy-carbostyrilen (1–3) mit Äthyl- bzw. Methyljodid und Allylbromid wird untersucht. Während inDMF und Äthanol fast ausschließlich O-Alkylierung zu den 4-Alkoxy-carbostyrilen (4–7) eintritt, beobachtet man in wäßr. Alkalien auch die Bildung von C,C-dialkylierten Verbindungen (8–10). 3-Äthyl-4-hydroxy-carbostyril (2) reagiert leichter mit C₂H₅J zum 3,3-Diäthyl-2,4-dioxo-tetrahydrochinolin (8) als das unsubstit. 4-Hydroxy-carbostyril (1). Einige in der Literatur als 3,3-disubstit. 2,4-Dioxo-tetrahydrochinoline formulierte Verbindungen werden als Carbostyril-4-äther erkannt.

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The influence of the solvent in the alkylation reaction of 4-hydroxyquinol-2-ones (1–3) with various alkyl halogenides has been studied.DMF and ethanol favor high yields of O-alkylated products (4–7), in aqueous alkali, however, carbon alkylation successfully competes with O-alkylation, affording a substantial amount of 3.3-disubstituted 2.4-dioxo-tetrahydro-quinolines (8–10). The reexamination of a patent showed that some compounds previously described as 2.4-dioxo-tetrahydro-quinolines actually are carbostyril-4-ethers.

     

Flammenphotometrische Bestimmung geringer Kaliummengen in Natrium und seinen Verbindungen nach Anreicherung mittels Tetraphenylborammonium

Zusammenfassung Das hier beschriebene Verfahren gestattet, in metallischem Natrium oder in Natriumsalzen bei einer Einwaage von 1 g Kaliumgehalte bis herunter zu 10^–4% mit einem mittleren Fehler von ± 5% zu bestimmen. Der flammenphotometrischen Messung geht eine Anreicherung des Kaliums durch Konzentrationsfällung mit Ttraphenylborammonium voraus.Herrn Dr. Spang, Forschungslaboratorium der Siemens-Schuckertwerke, danken wir für seine Mithilfe bei der Durchführung der radiochemischen Untersuchungen, Herrn Dr. Iwantscheff für das der Arbeit entgegengebrachte fördernde Interesse.     

Thermogravimetric analysis of polycarbonates and polythiocarbonates from diphenols with methyl groups

The thermal behaviour of polycarbonates and polythiocarbonates derived from biphenols with methyl groups in the aromatic rings was studied by dynamic thermogravimetry. The thermal degradation temperatures (TDT) were determined, showing that polythiocarbonates are more stable than the corresponding polycarbonates. The kinetic parameters of the thermal decomposition were determined by using the Arrhenius relationship, and showed two steps for the degradation of the polycarbonates, the first being a zero-order process and the second having first-order kinetics; the steps were associated with two different reaction mechanisms. Polythiocarbonates degraded according to first-order kinetics.     

Thermosonimetry of the phase II/III transition of hexachloroethane

A thermosonimetric study has shown that the Phase II/III polymorphic transition of hexachloroethane emits acoustic signals. This solid-solid phase transition is known to occur by a nucleation-growth process during which a nucleus of the new phase, once formed, grows at the expense of the mother phase to form a complete crystal without fracture. Acoustic emissions from a conditioned multi-crystal sample have been used to study the transition. Acoustic activity correlated well with dilatometric measurements. Frequency analysis on waveforms of many hundreds of individual acoustic emissions revealed marked differences between individual signals. Principal-components analysis on 24 signal features revealed a single dispersed cluster with a highly non-uniform distribution of signals. These experiments provided highly reproducible average power spectra. Time-resolved acoustic power spectra were also generated. These additional types of information cannot be obtained by other techniques.     

Calorimetric investigation of the adsorption of binary vapour mixtures of tetrahydropyrrol with methanol and cyclopentane on the homogeneous surface

Adsorption isotherms and differential heats of adsorption of tetrahydropyrrol (THP) and cyclopentane CP), as well as THP and methanol mixtures (mole ratio 1∶1, 1∶2 and 1∶4) on the graphitized carbon black Sterling MT surface were determined. The influence of dilution of [THP] on its ability to undergo homomolecular association was tested. Even 1∶4 dilution of THP does not prevent is association. Methanol strongly interacts with THP in the mixed adsorbed layer forming heteromolecular associates.     

Matériaux composites à base de graves et de liants polymères—III. Caractéristiques et propriétés rhélogiques d'un nouveau liant à base de polyéthylène de récupération et de cires de polyéthylène

Recovered polyethylene is used with polyethylene waxes as a new binder for mineral granules. This binder is characterized and optimized mainly on a rheological basis. Its fluid index (I.F.), molecular distribution and crystallinity are especially studied. Its rheograms and tensile properties are compared with those of industrial polyethylene (I.F. = 250). The dimensional shrinkages of such binders during cooling from 190° to ambient temperature are measured.