Étude de réactions à l'état solide entre l'arbre de Saturne et des sels contenant le groupement XO3

Résumé Le plomb utilisé sous forme d'arbre de Saturne possède une grande réactivité et permet de réduire les nitrates en nitrites. Il s'agit d'une réaction à l'état solide, débutant dès la température ordinaire. On a pu caractériser ainsi la présence de nitrites en mélangeant le plomb avec les nitrates de lithium, sodium, potassium, césium, cuivre, argent, magnésium, calcium, strontium, baryum, zinc, thallium, plomb, cobalt et nickel.

---

Summary Lead used in the form of the lead tree has great reactivity and is able to reduce nitrates to nitrites. This involves a solid state reaction and starts at room temperature. In this way it is possible to detect the presence of nitrites after mixing the lead with the following nitrates — Li, Na, K, Cs, Cu, Ag, Mg, Ca, Sr, Ba, Zn, Tl, Pb, Co, Ni.

---

Zusammenfassung In der Form des Bleibaumes ist Pb sehr reaktionsfähig und reduziert Nitrat zu Nitrit. Dabei handelt es sich um eine Festkörperreaktion, die bei gewöhnlicher Temperatur einsetzt. Nach Vermengen von Blei mit den Nitraten von Li, Na, K, Cs, Cu, Ag, Mg, Ca, Sr, Ba, Zn, Th, Pb, Co und Ni konnte die Anwesenheit von Nitrit festgestellt werden.

---

---

En l'honneur du ProfesseurA. A. Benedetti-Pichler, pour son 70^e anniversaire.     

Emploi de la thermogravimétrie et de la spectrophotométrie infrarouge pour suivre les réactions à l'état solide

Résumé L'auteur indique sur des exemples variés comment on peut combiner les indications de la thermobalance et du spectromètre infrarouge pour suivre les réactions à l'état solide, qu'il se dégage ou non un produit gazeux: action de la strontiane sur les pyrophosphates, polymérisation spontanée des métaborates, adsorption du permanganate par le sulfate de baryum, combinaison supposée SiO₂ + 12 MoO₃, action de l'iode sur la magnésie. Ensuite, il étudie plus longuement la synthèse des chromites et la mise en solution par l'oxylithe des oxydes métalliques; cette dernière réaction s'effectue suivant quatre mécanismes différents illustrés par des exemples concrets.

---

Summary The writer shows by means of varied examples how the information furnished by the thermobalance may be combined with that derived from the infra red spectrometer in following solid state reactions, which may or may not produce gaseous products. Examples are: action of strontium oxide on the pyrophosphates, spontaneous polymerization of metaborates, adsorption of permanganate by barium sulfate, alleged compound SiO₂ + 12 MoO₃, action of iodine on magnesia. The investigation also included a lengthy study of the synthesis of chromites and the solution of metal oxides by sodium peroxide. The latter reaction, effected by four different mechanisms, is illustrated by concrete examples.

---

Zusammenfassung An Hand verschiedener Beispiele wird gezeigt, wie man mit Hilfe der Thermowaage und des IR-Spektrophotometers Festkörperreaktionen mit oder ohne Gasentwicklung verfolgen kann. Als solche Beispiele werden angeführt: die Einwirkung von Strontiumoxyd auf Pyrophosphat, die Spontanpolymerisation von Metaboraten, die Absorption von Permanganat durch Bariunisulfat, die Bildung des Gemisches SiO₂ + 12 MoO₃ durch Erhitzen von Oxin-Silicomolybdat, Einwirkung von Jod auf Magnesiumoxydhydrat. Weiters wird die Synthese von Chromiten und die Auflösung von Metalloxyden mit Natriumperoxyd ausfuhrlich erörtert. Der letztgenannte Vorgang verläuft nach vier verschiedenen Reaktionsmechanismen, die an konkreten Beispielen erklärt werden.

---

---

Conférence prononcée le 25 avril 1961, au Congrès de chimie analytique de Budapest.     

Influence des réactions chimiques préalables sur la forme des courbes de polarisation

Equations have been established for polarographic waves observed while a chemical reaction slowly takes place before the exchange of electrons.The method of calculation is analogous to that already used by one of the authors in the case of polarisation curves relative to the reversible or irreversible systems.The variation of the two half-wave potentials and the limiting densities of current have been deduced. The results have been verified by means of the experimental results of R. brdicka concerning pyruvic and phenylglyoxylic acids.     

Étude de la résonance du mode géostrophique dans un tore

We show that when (ΩR/c₀) ≪ 1, and (a/R) ≪ 1, the air motion in a torus is governed by the problem of inertial oscillations in this torus excited by a perturbation on its surface, which moves with constant angular velocity Ω and gets recurrently at the same place with period 2π/Ω. This excitation makes one of the inertial oscillation modes enter in resonance, the geostrophic mode, which increases proportionally to time when t → ∞.     

Étude par spectroscopie i.r. de la protonation de l'ácétone

The i.r. spectra of protonated acetone, and its deuterated analogs, by super-acids HF, SbF₅ and HF, BF₃ have been recorded for the first time by using low temperature spectroscopic techniques.The protonation has been characterized by the appearance of three new vibrations due to the O⁺H group. It provokes also small changes in the spectrum of the acetone skeleton, in particular a lowering of the carbonyl stretching by one hundred and thirty waves-numbers. The new frequencies, at 1590 cm⁻¹, still far from the stretching frequency of a single CO bond, confirms that in the protonated acetone, the CO group keeps a strong double-bond-character, thus the (CH₃)₂ COH⁺ is an oxonium ion and not a carbonium ion.When operating with an excess of acetone in its mixture with HClSbCl₅ or HFSbF₅, we are able to obtain the homocon jugated salts [(CH₃)₂COHOC(CH₃)₂] ⁺SbX₆⁻. Their i.r. and Raman spectra indicate that the cation contains a very strong and quasi-symmetrical OHO hydrogen bond.     

Étude des propriétés mécaniques des géomateriaux argileux associant la décoction de Parkia Biglobosa (néré)

Researches for non-energy intensive construction products, that are durable and cheaper is today of global concern because of the limited resources (energy, financial, etc.). To address this issue, the present work presents the combination of the decoction of pods of Parkia Biglobosa (néré) that is rich in tannins compounds including gallic acid, epicatechin gallate and epigallocatechin, with a clay-sand mixture. The clay used is referenced KORO and contains montmorillonite, illite, quartz, albite, orthoclase, kaolinite and goethite. The study of the mechanical properties of geomaterials formulated from the mixture shows that they have values of mechanical resistance higher and that their behavior becomes viscoplastic. This is due to the formation of chemical complexes from carboxylic groups of tannins macromolecules with the iron oxy-hydroxide in the interlayer spacing of clay minerals. This process is enhanced by the sorption of tannins on the surface of clay minerals.     

Étude de la rétention des sels monovalents et bivalents par nanofiltration

Study of the retention of monovalent and bivalent salts by nanofiltration. The objective of this work was to study the influence of applied pressure, solution concentration and conversion rate on the salts retention by nanofiltration. Our study showed that the bivalent ions SO₄^2– are better retained than the monovalent ions F^–, Cl^– and I^– by nanofiltration. We also observed that the small ions F^– and Mg²⁺ are better retained than the big ions Cl^–, Ca²⁺, and I^– by effect of solvation. In spite of the bigger size of ion Ba²⁺ compared to Ca²⁺, Ba²⁺ is better retained than Ca²⁺; this is due to the effect of pressure. We also noticed that the increase of the (NH₄)₂SO₄ concentration and of the conversion rate leads to a decrease in the retention of SO₄^2–. To cite this article: A. Abouzaid et al., C. R. Chimie 6 (2003).     

Étude des propriétés des mélanges pebd régénéré / pebd vierge

This study is a contribution to the valorization of recycled low-density polyéthyléne (LDPE). First the characterization of five recycled LDPE produced from wastes coming from different sources was performed. The physical properties (density, melt flow index), chemical structure (Fourier transform infra-red spectroscopy) and mechanical properties (tensile strength and hardness) were investigated. The effect of the ratio of virgin LDPE on these physical and mechanical properties was studied in the case of the blends of recycled LDPE / virgin LDPE.     

Réactions non classiques au cours de l'alkylation de dérivés d'éléments de la colonne IVB par des réactifs de grignard : IV. étude du mécanisme pour des dérivés de la forme RnSiΣ4-n

At a temperature > 100° the transformation of triorganosilanes of the type R₃SiΣ (ΣCl or OCH₃) into hydrogenosilanes R₃SiH by tert-butylmagnesium chloride proceeds by two simultaneous processes: the direct reduction by the organomagnesium compound and the indirect reduction by the magnesium hydride coming from the thermic decomposition of the Grignard reagent. These results can be generalised to the reductive action of various sterically hindered Grignard reagents: R=C₆H₁₁, C₅H₉, i-C₃H₇.     

Contribution à l'étude Électrochimique de Dérivés de l'Acide Mercapto-2 Pyridinecarboxylique-5. II

Abstract

Electrochemical caracteristics of 2-mercaptopyridine-5-carboxylic acid and its methylic ester have been determined using recent polarographic techniques. Measurements have been carried out as a function of parameters such as frequency, others surimposed signals and as a function of concentration and pH. Results are compared to those obtained for selectively methylated on sulfur or nitrogen atoms derivatives. Interpretations of the data are given. The optimal conditions for a quantitative determination by D.C. and differential pulse polarography are fixed.     

Évolution des populations lympho-réticulaires spléniques au cours de la réaction immunitaire in vitro chez le poulet

The different types of cell population in organotypic cultures of spleen from chicken immunized with Salmonella paratyphi B were enumerated.The kinetics of immunoglobulin and of antiflagellar antibody synthesis followed the cellular variations observed. Two phases were generally observed: one was characterized by a considerable decrease in small and medium-sized lymphocytes by a lytic process and the appearance, by transformation and/or multiplication, of a large population of hyperactive macrophages. The IgM and IgG synthesized between the 2nd and 9th days only partially consisted of antiflagellar antibodies; some were synthesized probably by large basophilic cells and others by the few plasma cells which were observed, generally isolated on the prints. The second phase, from the 11th to the 21st day, manifested a narrower antibody specificity in that all the IgG, the only immunoglobulin synthesized during this period, might be entirely absorbed by the antigen and corresponded to the proliferation of a new lymphoreticular population. A close cellular cooperation seemed to occur at this stage between these two types of population, the macrophages appearing to stimulate lymphopoiesis. Colonies of plasma cells, characteristics of this phase, appeared from the 13th day.These two phases were separated around the 9th day by a brief period of cellular depression. Although the transformations, the contacts and the islets observed among the lympho-reticular populations indicated their     

Etude par spectroscopie Raman de la liaison hydrogène dans l'éthylènediamine à l'état solide sous ses deux formes allotropiques

The Raman spectra of partially deuterated ethylenediamine (5 and 95% on NH₂ groups) have been recorded between − 46 and − 196°C in the region of the NH and ND stretching vibrations. The vibrational frequencies of the isotopically diluted NH and ND bonds enabled us to demonstrate the importance of the hydrogen bonds in the cohesion of the crystals and during the allotropic transformation, and also to show the influence of the asymmetric effect on the form of the normal modes of vibration of the NH₂ groups.     

Virémie printanière de la carpe: Étude expérimentale de l'infection évoluant à différentes températures

The mode of spring viraemia of carp virus (SVCV) temperature-dependence was investigated using water route infection trials in 50 g fish held for 2 h in the Autumn at 11°C (5 × 10³ p.f.u./ml water) followed by carefully controled temperature variations. Above 18°C, infection occurred but immunity arose before any mortality appeared. Between 18 and 11°C, clinical disease supervened, but some fish became immune and survived the infection. Under 10°C there was no immunity and the disease was always fatal. Thus the further the temperature is removed from the physiological thermal optimum for the fish, the more serious the prognosis becomes, even if viral replication is itself is slowed by the cold (e. 5°C). It is concluded that the water temperature elevation which naturally occurs in spring is not a necessary factor in SVCV pathogenicity.     

Application de la fluorimétrie de phase à l'étude des interactions soluté-solvant de quatre amino-9 acridines substituées

The apparent lifetimes of 9-aminoacridine, of atebrin and of two of its derivatives (9-amino-2-methoxy-6-chloroacridine and 9-n-butylamino-2-methoxy-6-chloroacridine) have been measured by phase modulation fluorometry in a glycerol-water mixture (high viscosity) and an ethanol-water mixture (low viscosity). Results are easily interpreted in terms of a relaxation of the first singlet excited state involving a rearrangement of solvent molecules before excitation.In the glycerol-water mixture, the stationary fluorescence spectra of atebrin and its two derivatives can be resolved into fluorescence spectra emitted by the relaxed state and fluorescence spectra emitted by the unrelaxed state. For each compound the lifetimes of these two states have been calculated.In the same solvent mixture the origin of 9-aminoacridine fluorescence is the relaxed state alone. However, the relaxation process is slow enough to be detected by phase modulation fluorometry. The lifetimes of the relaxed and unrelaxed states are still accessible.In the ethanol-water mixture this is no longer true. For each compound under study the origin of the fluorescence is still the relaxed state but the relaxation process is so rapid, compared with the deactivation processes, that it can no longer be detected by phase modulation techniques. In this case, only the lifetime characteristic of the relaxed state is accessible.     

Identification spécifique des acides aminés et des vitamines par l'indice de réfraction et la température eutectique: Application a la chromatographie sur papier et au contrôle

Refractive index and eutectic melting temperature of binary systems, together lead to specific identification of organic individuals and isomers. A number of vitamins and amino acids have been experimented with to that purpose. The result is that analysis of an entire spot of amino acids on paper becomes easy owing to these properties. An example using glumatic acids shows that better results on the composition of an entire spot on paper can be obtained by this analysis than by Chromatographie R_F values.     

Courbes de Bézier pour le calcul des indices de rétention en chromatographie gaz–liquide à température programmée

Bezier curves for the calculation of retention indices in temperature-programmed gas–liquid chromatography. Retention indices of eleven organochlorine species, separated by temperature-programmed gas chromatography, computed by smoothing reference data with Bezier curves of orders 7 and 10 are more consistent with the scheme of this retention parameter, and present standard deviations systematically smaller than those associated with classical retention indices. These results are reproduced when solutes are referred to even alternate n-alkanes. © 2000 Académie des sciences / Éditions scientifiques et médicales Elsevier SASgas chromatography / temperature programming / smoothing of reference data / independent of local properties function     

Étude par chromatographie en phase gazeuse de nouveaux composés cristaux liquides nématiques à chaîne latérale

The analytic performances of three stationary phases ‘liquid crystal’ to side chain have been presented. Mesogenic compounds studied in this work are:– 3-CH₃: 2-(3-methylbenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene;– 4-CH₃: 2-(4-methylbenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene;– 3-Cl : 2-(3-chlorobenzyloxy)-3-n-hexyloxy-4-(4-chlorobenzoyloxy)-4’-(4-methyl benzoyloxy)-azobenzene.The originality of these three compounds is essentially due to the presence of a substituted benzyloxy group, more voluminous, which is close to the n-hexyloxy flexible chain. Retention properties of these new liquid crystals have been characterised by the capillary column treated and impregnated according to the dynamic method. The position, ortho or para, of the methyl group on benzyloxy does not interfere significantly on the retention mechanism. In the case of the replacement of the methyl group by a halogen atom (chlorine), we noticed a radical change of the retention properties.     

Influence de la cinétique des réactions chimiques sur les courbes de polarisation : Application à l'étude des complexes thiocyanés du titane(iv) et du titane(III)

The electrochemical oxidation-reduction of the system titanium(IV) — titanium(III) is slow at dropping mercury electrode in perchloric acid or hydrochloric acid, but becomes rapid in the presence of thiocyanate ions.On the basis of polarization curves, interpreted according to a preliminary theoretical study, the authors conclude that the rapid electrochemical reaction is the following: TiOH.SCN⁺² + H⁺ + e ? TiSCN⁺² + H₂OAn application of the findings to the polarographic determination of titanium is given.     

Étude des états excités de chroménes-2H représentant la partie benzopyrannique de spiropyrannes photochromiques

The absorption and emission (fluorescence, phosphorescence) characteristics of three 2H-chromenes, with structures similar to those of good photochromic spiropyrans have been studied at room temperature and at low temperature. Theoretical results have also been used to propose a relative order of the lowest π π^* and nπ^* singlet and triplet energy levels. The order of the energy levels plays an important role in the photocoloration of spiropyrans.     

Étude théorique de la structure électronique et des énergies de formation de quelques composés magnésiens typiques

The electronic structure of typical organomagnesium compounds is calculated by the SCF molecular orbital method, using a set of gaussian atomic orbitals. The most stable conformation of MgX₂ compounds is found to be linear for all the basic orbitals. A comparaison is made for the energy and structure of MgF, MgCl and MgC bonds; the analysis of the electronic density curves suggests a pronounced ionic character for those bonds.