Simple and catalyst-free method for the synthesis of diaryl selenides by reactions of arylselenols and arenediazonium salts

We describe here a simple and catalyst-free method to synthesize diaryl selenides by reaction of arenediazonium tetrafluoroborate salts with arylselenols, generated in situ by using diaryl diselenides and hypophosphorous acid (H₃PO₂), using THF as solvent. This is a direct nucleophilic aromatic substitution (SNAr) reaction performed with diaryl diselenides and arenediazonium salts bearing electron-withdrawing and electron-donating groups affording the corresponding diaryl selenides in moderated to good yields.     

Nachweis von Zinn in Mineralien,Legierungen sowie in mit Zinnsalzen beschwerter Seide

Zusammenfassung Die Überführung von Zinn in benzollösliches Zinn(IV)jodid und die daran angeschlossene Fluoreszenzreaktion von Zinn(IV)hydroxyd und Morin gestatten den schnellen und eindeutigen Nachweis von Zinn in Minerahen, Legierungen und Seide.Die Durchführung des Nachweises in der Arbeitsweise der Tüpfelanalyse wird beschrieben.

---

Summary The conversion of tin into the benzene soluble tin(IV)iodide and the subsequent fluorescence reaction of tin(IV)hydroxyde with morin permit the rapid and reliable detection of tin in minerals, alloys and silk.The procedure of the test in spot technique is described.

---

Résumé La transformation de l'étain en iodure d'étain-IV soluble dans le benzène et la réaction de fluorescence que l'on peut en dériver entre l'hydroxyde d'étain-IV et le morin, permettent la recherche rapide et spécifique de l'étain dans les minéraux, les alliages et la soie. On décrit l'introduction de la recherche dans le mode opératoire de l'analyse à la touche.

---

---

Herrn Univ.-Prof. Dr.Adolf Franke zum 80. Geburtstag gewidmet!

---

Wit danken an dieser Stelle dem Conselho Nacional de Pesquisas für die Unterstfitzung bei Durehfiihrung dieser Untersuchungen.     

<Emphasis Type="Italic">L</Emphasis><Superscript><Emphasis Type="Italic">q</Emphasis></Superscript>-Functional Inequalities and Weighted Porous Media Equations

Using measure-capacity inequalities we study new functional inequalities, namely L ^q -Poincaré inequalities

Spot test detection of N-Cyano compounds

Summary A specific spot test for N-cyano compounds can be based on the fact that when they are treated with zinc and a mineral acid, hydrocyanic acid is split off. This volatile acid gives a blue color with filter paper moistened with copper acetate and benzidineacetate. The limits of identification are within the bounds of spot test analysis.

---

Zusammenfassung Ein spezifischer Nachweis von N-Cyanverbindungen kann darauf begründet werden, daß beim Erwärmen mit Zink und Mineralsäure flüchtiger Cyanwasserstoff abgespalten wird, der ein mit Kupferacetat oder Benzidinacetat befeuchtetes Filterpapier blau färbt. Der Nachweis führt in der Arbeitsweise der Tüpfelanalyse zu mikroanalytischen Erfassungsgrenzen.

---

Résumé Il est possible de fonder un essai à la touche spécifique pour les composés N-cyanés sur le fait que lorsqu'ils sont traités par le zinc et un acide minéral ils libèrent de l'acide cyanhydrique. Cet acide volatil développe une couleur bleue sur un papier-filtre mouillé avec une solution d'acétate de cuivre et d'acétate de benzidine. Les limites d'identification sont dans le domaine de l'analyse par essais à la touche.

---

---

Translated byRalph E. Oesper, University of Cincinnati     

A discrete model for the study of a lake

An original discrete lake model is presented. Its state variables are phytoplankton, zooplankton, dead organic material and minerals. It takes into account the carrying capacity of the environment for biological variables and the mineralization process. Simulations which study the influence of some parameters or some modifications of pollution inputs are presented to increase the usefulness of such a discrete model.     

Das thermische Verhalten von Na5[Fe(CN)5SO3]·2H2O

The thermal behaviour of Na₅[Fe(CN)₅SO₃]·2H₂O has been investigated by thermogravimetric and differential thermal analysis. Detailed studies of the decomposition residues using various physicochemical methods show that decomposition occurs in a manner similar to that previously postulated for related compounds.     

Coincidence measurement of residues and light particles in the reaction 56Fe+p at 1 GeV per nucleon with the spallation reactions setup SPALADIN

The spallation of 56Fe in collisions with hydrogen at 1A GeV has been studied in inverse kinematics with the large-aperture setup SPALADIN at GSI. Coincidences of residues with low-center-of-mass kinetic energy light particles and fragments have been measured allowing the decomposition of the total reaction cross section into the different possible deexcitation channels. Detailed information on the evolution of these deexcitation channels with excitation energy has also been obtained. The comparison of the data with predictions of several deexcitation models coupled to the INCL4 intranuclear cascade model shows that only GEMINI can reasonably account for the bulk of collected results, indicating that in a light system with no compression and little angular momentum, multifragmentation might not be necessary to explain the data.