bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comportement anodique du cuivre et de ses alliages III.‐Structure superficielle d'un alliage hétérogène cuivre‐beryllium poli anodiquement
Authors: Hubrecht L. 
Published: September 2010

AbstractElectrolytically polished samples of a heterogeneous copper‐beryllium alloy have been examined by electron diffraction. Patterns of the γ phase were always obtained although this is the minor constituent of the alloy. It has been shown by electron diffraction, by optical and by electron microscopy that this γ phase forms minute asperities on the surface of the alloy.
Synthèse et caractérisation de l'o‐Amino‐Thiophénol
Authors: Nys J. , van Dormael A. 
Published: September 2010

AbstractThe authors describe an improved method of preparation of o‐amino‐thiophenol, as well as the characterization of this substance by means of an alcoholic solution of 2‐4‐dinitro‐chloro‐benzene in alkaline medium. The structure of the product resulting from the latter reaction is ascertained with the help of an infrared spectrophotometric investigation, by transformation into the corresponding sulfone and by diazotization followed by condensation with β‐phenol, whereby an azo‐dyestuff is obtained.
La Congélation des Solutions comme méthode d'investigation de quelques problèmes de Chimie pure XIV: Étude de quelques systèmes contenant les antipodes des acides monochlorsuccinique, α‐oxybutyrique et chlormaliques I et II
Authors: Timmermans J. , Machtelinckx P. , Mokry † J. 
Published: September 2010

AbstractL'étude des mélanges, des eutectiques des acides chlormaliques I et II avec acides tartriques et dichlorsucciniques, racémiques et méso, a confirmé l'attribution de l'acide I à la série racémique, et de l'acide II à la série méso, telle que Kuhn l'avait proposée. Le comportement des antipodes des acides chlormaliques, chlorbutyriques et chlorsucciniques a permis de classer les antipodesldans la même série que l'acide tartrique‐d, complétant ainsi les résultats obtenus dans les recherches antérieures.
Méthodes et appareils en usage au Bureau International des Étalons Physico‐chimiques XIII. – Un appareil simple pour la production d'eau de conductivité ultra‐pure
Authors: Beckers Marcel , Mathieu Marcel 
Published: September 2010

AbstractIl nous a paru utile de donner une brève description de l'appareil simple qui nous a permis d'obtenir, à partir d'une eau distillée ordinaire, en un seul tour de distillation et avee un rendement de 50 à 80%, une eau dont la conductivité atteint 6.10−8 ± 0,5.10−8 mbos.
XVI. Recherches sur les solutions concentrées Contribution à l'étude thermodynamique de mélanges d'hydrocarbures formés de molécules de dimensions différentes
Authors: Marechal J. 
Published: September 2010

AbstractRésumé. ‐ Les tensions superficielles et les volumes de mélange de quelques solutions d'hydrocarbures formées par des molécules de dimensions différentes ont été déterminés. Ont été étudiées les solutions dans le benzène du diphényle, du dibenzyle, du tolane et du 1‐8 diphényloctane. Les tensions superficielles ont été discutées en liaison avec la théorie statistique de I. Prigogine et ses collaborateurs.Les pressions de vapeur saturante de solutions de tolane dans le benzène ont été déterminés à 40,50 et 60°C. On observe de faibles écarts positifs à la loi de Raoult.Les coefficients d'activité observés ont été comparés à l'équation théorique de Guggenheim et l'énergie de mélange Nω (où ω se rapporte à z premiers voisins et où N est le nombre d'Avogadro) a été calculée. Nous avons trouvé Nω=119 ± 1 calories/mole.
VII. ‐ Distribution de la ribonucléase dans les extraits de granules cellulaires du foie
Authors: Pirotte M. , Desreux V. 
Published: September 2010

AbstractSummary. ‐ The distribution of ribonuclease in the different extracts of liver granules has been studied. The authors show that this enzyme is bound with inactivation to some constituents of these granules and that salts and sulfuric acid are able to dissociate the complex formed. On the other hand, the action of water and of the mixer, also the inhibitory power of the supernatant are indications that the inactive complex can be dispersed in solution. In order to explain the facts which have been observed, it was neccessary to suppose that sucrose has a stabilizing effect on the fractions of small particular dimensions. The authors call the attention on the danger of establishing a distribution of an enzyme in the granules if these granules have not undergone a deep desaggregation before the enzymatic test.
Les nitriles et les amides bromcrotoniques III action de la N∼Bromsuccinimide sur les butènes‐nitriles
Authors: Couvreur P. , Bruylants A. 
Published: September 2010

AbstractLes auteurs ont étudié la réaction de la N‐bromsuccinimide sur les trois butènes‐nitriles, à savoir: les nitriles crotoniques cis et trans et le nitrile vinylacétique.Ils démontrent que la réaction avec les nitriles crotoniques est une substitution classique qui permet d'obtenir, avec des rendements de l'ordre de 70 à 80%, les nitriles bromcrotoniques cis et trans. La substitution envisagée est accompagnée d'une stéréomutation.La réaction avec le nitrile vinylacétique est plus complexe; c'est une addition concurrencée par une substitution. Cette dernière est accompagnée d'une transposition allylique et d'une stéréomutation, elle donne en effet naissance également au nitrile bromcrotonique γ.
Absorption spectra and structure of 2‐thiouracil derivatives as a function of pH
Authors: Shugar David , Fox Jack J. 
Published: September 2010

AbstractSummary ‐ The ultraviolet absorption spectra of several 2‐thiouracil derivatives were measured at various pH values and apparent dissociation constants determined from these spectra. General comparisons were made with corresponding uracil analogues. The structure of 2‐thiouracil is shown to be in the diketo form in acid and near‐neutral aqueous solutions. With further increase in pH two equilibria are demonstrated spectrophotometrically, referring to tautomerism and concomitant ionization at the 2 and 4 positions respectively. The spectra and structure of other 2‐thiouracil derivatives are discussed.A comparison of the degrees of dissociation of 2‐thiouracil and its 6‐methyl analogue at blood pH values as determined from their spectra places in question the necessity of assuming appreciable dissociation of these compounds for iodine absorption in anti‐thyroid activity.
Synthèses dans le domaine des hydrocarbures cancérigènes VII Le 5,8‐diméthyl‐1,2,6,7‐dibenzophénanthrène
Authors: Descamps Cl. , Martin R. H. 
Published: September 2010

AbstractSummary. ‐ 5,8‐dimethyl‐1,2,6,7‐dibenzphenanthrene has been synthesised, starting from 9,10‐dihydrophenanthrene, by the following steps: Friedel‐Crafts reaction with phthalic anhydride [2‐(9,10‐dihydrophenanthroyl)‐o‐benzoic acid (VIIa)], cyclisation with benzoyl chloride containing a small amount of conc. sulfuric acid [1,2‐(2′,1′‐naphto) [anthraquinone (IX)], treatment of the quinone with CH3MgI followed by HI and SnCl2+HCl [5,8‐dimethyl‐1,2,6,7‐dibenzphenanthrene, (Xb)].2‐(9,10‐dihydrophenanthroyl)‐o.benzoic acid (VIIa) and 2‐phenanthroyl‐o.benzoic acid (VIIIb) both gave 2‐phenanthroic acid when submitted to potash fusion.Attempts to prepare 1‐anthrylacetic acid have so far failed.
Mécanisme de l'alcoolyse des esters‐I Alcoolyse des propionates et acrylates de méthyle et de butyle normal, en milieu acide
Authors: Buess‐Thiernagand M. D. , Fierens P. J. C. 
Published: September 2010

AbstractSummary. ‐ It is shown that the acid‐catalysed esterification of propionic and acrylic acids, by absolute methanol, has a frequency factor which is approximately the same in both cases, and for a given temperature, the rate constants depend on the activation energies only, propionic acid: Ea=10,0 Kcal/mole log PZ=6,1 (16) acrylic acid: Ea=12,4 Kcal/mole log PZ=6,2 The same observation is true for another bimolecular reaction i.e. the acid‐catalysed hydrolysis of ethyl propionate and acrylate. ethyl propionate: Ea=16,2 Kcal/mole log PZ=7,5(17) ethyl acrylate: Ea=18,1 Kcal/mole log PZ=7,4.An analogous result is obtained for the acid‐catalysed methanolysis of n‐butyl propionate and acrylate, on the one hand and the acid‐catalysed butanolysis of methyl propionate and acrylate, on the other hand.Methanolysis: n‐butyl propionate: Ea=12,7 Kcal/mole log PZ=4,4 n‐butyl acrylate: Ea=14,4 Kcal/mole log PZ=4,7.Butanolysis: methyl propionate: Ea=12,6 Kcal/mole log PZ=4,3 methyl acrylate: Ea=14,2 Kcal/mole log PZ=4,5.The interpretation of the relative values obtained for the activation energies in these alcoholysis reactions is only possible on the basis of a bimolecular mechanism.
Les propriétés diélectriques des hauts polymères en solution II. Etude de solutions de chlorure de polyvinyle dans le système tétrahydrofurane‐heptane
Authors: De Brouckere Lucia , van Nechel Roger 
Published: September 2010

AbstractSummary. ‐ In this paper, dielectric constants and dielectric losses have been measured at various frequencies for solutions of Polyvinyl Chloride in mixtures of Tetrahydrofurane and normal Heptane. Previous conclusions have been confirmed. Moreover it has been shown that the precipitant has practically no influence on dipole moment, critical frequency, activation energy or entropy.
Recherches sur la Thermodiffusion en Phase Liquide IV Influence de la Longueur de Chaîne sur la Thermodiffusion
Authors: Buess R. 
Published: September 2010

AbstractSummary ‐The author studied by the thermogravitational method the variation of the Soret coefficient with the chain length of polyethylenglycols derivatives in benzenic solution.It is seen that the Soret coefficient tends towards a constant value as soon as the number of carbon atoms exceeds 16.An extension of the kinetic theory of thermodiffusion in the liquid phase enables the interpretation of this experimental result in connecting the Soret coefficient with the difference of density of cohesion of both constituents.
Synthèses dans le domaine des hydrocarbures cancérigènes X Le 9,10‐diméthyl‐1,2,3,4,5,6‐tribenzanthracène
Authors: Lambert P. , Martin R. H. 
Published: September 2010

AbstractSummary9,10‐dimethyl‐1,2,3,4,5,6‐tribenzanthracene (VII) has been prepared from the corresponding quinone by the method of Sandin and Fieser.A new synthesis of 1,2,3,4,5,6‐tribenzanthraquinone (VI) involving the following steps is described: condensation of phenanthrene‐9,10‐dicarboxylic anhydride (IV) (preparation improved) with 1‐naphthyl‐magnesium bromide [9‐(α‐naphthoyl)‐10‐phenanthroic acid (V)], cyclisation with H3PO4+P2O5 [1,2,3,4,5,6‐tribenzanthraquinone; small yield]. The acetoxy‐lactone (VIII) was isolated after treatment of the crude reaction mixture with acetic anhydride.Other cyclising agents such as C6H5COCl+H2SO4, phthalic anhydride+C6H5COCl, H3BO3+H2SO4 and ClSO3H failed to give the desired quinone.Attempts to cyclise 9‐(β‐naphthoyl)‐10‐phenanthroic acid (IX), an isomere of the above keto‐acid, gave no better results.The oxydation of 1,2,3,4,5,6‐tribenzanthracene with sodium bichromate in acetic acid has been shown to give a mixture of three quinones: 1,2,3,4,5,6‐tribenzanthraquinone (m.p. 250–251°; yield: 52%), an ortho‐quinone (only detected by isolation of the corresponding phenazine) and an ortho‐para‐bisquinone (m.p. 318–320°).
Structures peptidiques.‐I Microdétermination de la Séquence des Acides Aminés dans les Petits Peptides
Authors: Leonis Jose 
Published: September 2010

AbstractThe sequence of amino acids in short peptides can be unequivocally solved on a “chromatographic” scale, using as little as .015‐ .1 mg. of the compound. This is performed by an adaptation of a set of previously described reactions, handling the small volumes of solutions mainly on filter paper.
De inwerking van Alkaliën en Alkalimetalen op Rotenon en Toxicarol
Authors: Jennen A. 
Published: September 2010

AbstractRésumé ‐La réaction des alcalis et des métaux alcalins sur les solutions benzéniques de roténone donne le déhydroroténolate de sodium. La formation du déhydroroténol, de l'acétate de déhydroroténol, de l'iso‐phénylhydrazone de roténone et du diacétyltoxicarol à chaîne ouverte est décrite.Il a été fourni une explication du mécanisme des réactions qui aboutissent aussi bien à l'ouverture et la racémisation de l'anneau C de la dihydro‐γ‐pyrone sous l'influence des alcalis qu'à la formation et l'hydrolyse acide de l'acétylroténone ou il n'y a pas d'ouverture de l'anneau C.
Sur la mesure de la Constante Diélectrique des Liquides Conducteurs
Authors: Mandel M. , Jung P. 
Published: September 2010

AbstractSummary ‐ The aim of the present paper is to describe a method of measuring capacities of highly conducting media, using a Schering type bridge.The equations of the bridge are discussed, and it is shown how the method set up can be altered to give satisfactory results for frequencies up to 500 kc/s. Using the substitution method capacities can be measured with a reasonable accuracy for frequencies ranging from 10 to 500 kC/s and ohmic resistances not lower than 100 ohms.The bridge was calibrated by means of resistances constructed in such a manner that the reactance could be calculated from its geometrical form.Particular stress is tend on the determination of the maximum error inherent to the method.
Synthèses dans le domaine des Hydrocarbures Cancérigènes. XI Le 11,14‐Diméthylpicène Essai de synthèse du 1,8‐diméthyl‐2,3,6,7‐dibenzophénanthrène
Authors: Hebbelynck M. F. , Martin R. H. 
Published: September 2010

Abstract1,2‐di‐(1′‐méthyl‐naphthyl‐2′)ethane (IX) has been prepared, starting from 1‐bromo‐2‐methylnaphthalene, by the following steps: bromination with N‐bromsuccinimide [1‐bromo‐2‐bromomethylnaphthalene (VII)] condensation (Fe) [1,2‐di‐(1′‐bromo‐naphthyl‐2′) ethane (VIII)] and treatment of the dibromo derivative with BuLi and (CH3)2SO4.Attempt cyclodehydrogenation of 1,2‐di(1′‐methyl‐naphthyl‐2′)‐ethane with AlCl3 in CS2 did not give the expected 1,8‐dimethyl‐2,3,6,7‐dibenzphenanthrene (I d). The constitution of the reaction product (m.p.: 173‐174°) has not yet been elucidated.1,2‐di‐(2′‐methyl‐naphthyl‐1′)ethane (XVI) and 1,2‐di(4′‐methylnaphthyl‐1′)ethane (XVIII) have been obtained from 2‐methyl‐1‐chloromethylnaphthalene and 4‐methyl‐1‐chloromethylnaphthalene respectively.Treatment of 1,2‐di(4′‐methyl‐naphthyl‐1′)ethane (XVIII) with AlCl3 in CS2 afforded 11,14‐dimethylpicene (XIX) in approximately 30% yield.The U.V. spectra of 1,2‐di(1′‐methyl‐naphthyl‐2′)ethane, 1,2‐di(2′‐methyl‐naphthyl‐1′)ethane, 1,2‐di(4′‐methyl‐naphthyl‐1′)ethane and 11,14‐dimethylpicene are given.
Note sur la mesure directe du coefficient dT/dP de variation de la température de fusion avec la pression, entre 0 et 1 atmosphère
Authors: Mathieu Marcel‐P. 
Published: September 2010

AbstractEn vue de déterminer avec précision, à 0° 001 C, la différence existant entre le point triple et la température de cristallisation à pression atmosphérique, du benzène et du nitrobenzène, nous avons mesuré directement, à ± 0° 000.2 C, la variation de la température de cristallisation de ces substances, en faisant passer brusquement la pression de quelques mmHg à 1 atmosphère.Ceci nous a permis de vérifier l'équation de Clapeyron‐Clausius avec plus de précision qu'il n'avait été possible jusqu'ici.
The Volume Change on Mixing Two Gases at Constant Pressure
Authors: Michels A. , Boerboom A. J. H. 
Published: September 2010

AbstractAn apparatus is described for the measurement of the volume change occuring when two different gases are mixed. Results are given for hydrogen, helium, nitrogen, argon, carbon monoxide, carbon dioxide, methylfluoride, ethene and propene. Some theoretical discussion is given.
Forces intermoléculaires et volume d'excès des solutions
Authors: Prigogine I. 
Published: September 2010

AbstractLe lien entre les forces intermoléculaires et le volume d'excès des solutions binaires est étudié, d'abord sur la base du modèle des solutions régulières puis sur celle de la théorie des solutions conformes, enfin en utilisant le modèle cellulaire de l'état liquide. Différentes règles qui résultent des travaux de l'auteur et de ses collaborateurs (MM. Garikian; Mathot; Trappeniers; Bellemans) et qui permettent de préciser le signe du volume d'excès sont énoncées et discutées.
Une méthode calorimétrique pour la mesure des vitesses de réaction en phase gazeuse
Authors: Vanpee M. 
Published: September 2010

AbstractOn décrit une méthode calorimétrique qui permet de mesurer la vitesse instantanée des réactions gazeuses. Celle‐ci a été testée sur 17 réactions différentes parmi lesquelles figurent 15 combustions, la synthèse de l'acide chlorhydrique et la recombinaison des atomes de chlorure (effet Budde).La méthode est particulièrement avantageuse pour l'étude des corps instables dont la vie moyenne est comprise entre la seconde et quelques minutes.
La tension de vapeur et la chaleur de sublimation du carbone III
Authors: Doehaerd Th. , Goldfinger P. , Waelbroeck F. 
Published: September 2010

AbstractThe rate of effusion of carbon vapor from a graphite Knudsen cell was studied between 2400 and 2760°K. The resulting molecular (atomic) beam, defined by a collimator, was collected on glass plates. The amount and distribution of the deposit was determined by measuring its optical density.Measurable deposits have been obtained in 53 out of 65 experiments. In 10 experiments for known and in two for unknown reasons no measurable deposit could be detected.The aperture/total area ratio (ω) of the cell was varied between 1/100 and 1/23400. The establishment of the equilibrium vapor pressure of carbon has been thus observed, yielding for the condensation (or evaporation) coefficient f of carbon on hot graphite surfaces log f = −3,0 ± 0,5 The equilibrium vapor pressure was practically obtained in 33 experiments with ω = 1/3750 and 1/23400; the heat of sublimation of carbon Lc, calculated from these is : Lc = 141,7 kcal. A detailed discussion of the fortuitous and systematic errors is given. It is believed that the fortuitous errors are smaller than ± 4 kcal. which is the maximum deviation from the mean in 42 experiments. On the other hand the systematic errors could be as great as ± 6 kcal.The excellent agreement of our result with the value Lc = 141,26 kcal, resulting from the analysis of the CO spectrum and a well known thermochemical cycle, indicates that the systematic errors have probably been overestimated. However the possibility of Lc=135,74 keal which is also in agreement with the data on the CO spectrum, cannot be excluded.
La tension de vapeur et la chaleur de sublimation du carbone IV
Authors: Goldfinger P. , Waelbroeck F. 
Published: September 2010

AbstractAll significant direct and indirect evidence on the heat of sublimation of carbon, Lc, agrees with the authors recent result Lc =141.26 kcal.Only electron collision experiments in carbon monoxyde on the one hand, in methane and its derivatives on the other, seem to lead unambiguously to the same value within the limits of experimental error (about ± 5 to 10 kcal) of this method.Spectroscopic data on CO could yield an unambiguous and much more exact result if a second dissociation (or predissociation) limit were ascertained; e. g. the convergence limit and the nature of the excited state of the Birge Hopfield bands near 1000 A.Vapour pressure measurements with the carbon are and the counter pressure method give Lc ± 140 kcal, although the interpretation of these measurements is involved and by no means free of ambiguity, except perhaps in the case of Ribaud and Bégué's experiments.Rate of evaporation measurements and earlier rate of effusion measurements, although their interpretation had been partly erroneous, lead to the same result if the low value of the evaporation (condensation) coefficient, measured by the authors, is taken into account.
Le mécanisme de la Chimiluminescence en solution ‐ II (1) Oxydation du 3‐Aminophtalhydrazide
Authors: Bremer Thérèse 
Published: September 2010

AbstractChemiluminescence is considered as the inverse of an elementary photochemical reaction. Nine elementary processes which could lead to luminescence are distinguished on this basis, and illustrated by examples.It is shown that the energy of the emitted quanta can only result from four combinations of bond dissociation energies; the most frequent are association and exchange processes. Moreover, in solution, a blue, violet, or ultra‐violet chemiluminescence can only be due to a reaction involving two free radicals. The quantum yield of such a reaction is necessarily small.The particular case of luminol (3‐aminophtalhydrazide) is considered.The luminescence of alcaline solutions of this substance, even in absence of H2O2, is enhanced by substances known to produce OH and O2H radicals in H2O2; for example, oxidizing and reducing agents and diazo‐compounds. This effect practically disappears on thorough outgassing, and the same treatment suppresses completely the spontaneous faint emission of the alcaline solutions (visual observation of estimated sensitivity less than 105 quanta per sec); the presence of O2 is thus essential for the reaction to take place.The quantum yield of the luminescence, Φ, induced by Fe(CN)6K3 and by NaOCl has been determined in the absence and in presence of H2O2. The light intensities were measured by a photographic method, yielding a mean value Φ = 2,5.10−3 quanta per molecule of luminol.A mechanism of the oxidation of luminol by monovalent steps is suggested in which the luminescent reaction consists in an association of two different radicals; a dismutation is less probable. One of these radicals, derived from luminol, must be stable and should have semi‐quinonic structure, the other radical must have hydroperoxidic character (HO2). The analogy with autoxydation reactions is pointed out.Previous data on the chemiluminescence of luminol are in agreement with this mechanism.
Influence de divers facteurs sur la polymérisation radiochimique isobare, du chlorure de vinyle
Authors: Mund W. , van Meerssche M. , Momigny J. 
Published: September 2010

AbstractL'effet des variations de la pression du gaz et celui du rayon de la chambre de réaction ont été séparés. Le coefficient de température négatif de la réaction a été établi quantitativement pour différentes pressions. L'effet de l'addition d'un gaz inerte au gaz irradié, de même que l'effet d'un petit pourcentage d'oxygène, a été observé et interprété.
Irrégularités observées à la microélectrode de platine tournante
Authors: Heyndrickx A. 
Published: September 2010

AbstractCurrent voltage curves on the platinum microelectrode were registered from positive to negative and negative to positive potentials. In different supporting electrolites a cathodic dissolution pattern was observed at − 0,30 V in the presence of 0,1 M NaOH.Lead yields two well defined anodic patterns in 0,1 M NaOH running from negative to positive potentials.It was impossible by means of the known thermodynamics of the systems to give any explanation about these phenomena.
Dosage colorimétrique de traces de Bore par le Carmin
Authors: Cypres R. , Leherte P. 
Published: September 2010

AbstractCarmin makes possible a rapid and precise colorimetric determination of Boron from 0.05 γ up to 50 γ.A method has been worked out successfully for the determination of B in Ca, Carbons and U, used in the construction of nuclear reactors, without preliminary separation of the B as volatile methyl borate, by distillation.