bluuebunny/crossref_metadata_2025 huggingface dataset:
La tension de vapeur et la chaleur de sublimation du carbone IV
Authors: Goldfinger P. , Waelbroeck F.
Published: September 2010

All 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

Chemiluminescence 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

L'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

Current 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

Carmin 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.
Contribution à l'étude de la transformation allotropique du cobalt
Authors: Lanners A. , Breckpot R.
Published: September 2010

The allotropic transformation of cobalt has been followed with a direct reading X‐ray spectrometer. The α→β transition occurs stepwise between 400° and 500° C, each increase in temperature in the given interval giving rise to the practically instantaneous formation of a new amount of β. The reverse transition occurs similarly but over a much wider temperature range and is not complete even far below 0° C.

The proportion of β remaining at room temperature is dependent on the density of lattice defects as measured by the broadening of definite α lines. This proportion can be increased to 90% by severe deformation followed by heat treatment, below 500°. Deformation after heat treatment suppresses totally the β phase. Heat treatment of short duration in the 500° ‐ 1480° C region tends to restore the lattice order, decreasing at the same time the proportion of β, retained in the cold, to some 35%.
Analyses inorganiques avec emploi conjugué du polarographe et de la colonne d'échange
Authors: Gierst L. , Dubru L.
Published: September 2010

I. Analytical potentialities of the simultaneous use of exchange and polarographic techniques are briefly discussed.

II. Isolation of traces of zinc from cadmium may be performed successfully by use of Dowex 50 exchanger and ammonium citrate buffer as eluting agent, under described conditions. The limiting sensitivity of the method is about 0.002 % Zn in Cd. 0.1% of Zn is determined with an accuracy of 2%.
Etude Expérimentale de l'Oxydation Lente III. Influence de l'hydrogène et de l'oxyde d'azote dans l'oxydation de l'ammoniac
Authors: Volders A. , van Tiggelen A.
Published: September 2010

On a étudié la réaction lente dans les mélanges NH3 + O2 + H2 et NH3 + NO. L'énergie d'activation ainsi que l'ordre de ces réactions par rapport aux pressions partielles des constituants ont été déterminés.

L'hydrogène accélère fortement la réaction dans les mélanges NH3 + O2 + H2 et on n'a plus observé les deux domaines (réaction lente et rapide) mis en évidence antérieurement pour les mélanges binaires NH3 + O2.

Ces deux domaines subsistent par contre dans le cas des mélanges NH3 + NO, mais la cinétique (énergie d'activation et ordre) est complètement modifiée dès qu'on passe d'un domaine à l'autre.

Des schéma réactionnels sont proposés.
Méthodes et appareils utilisés au Bureau des Etalons Physico‐Chimiques XIV. Mesure de la constante diélectrique des composés organiques à 20°C.
Authors: Timmermans J. , Piette A. M. , Philippe R.
Published: September 2010

Le présent travail a pour but de montrer qu'il est possible à l'aide d'un appareil courant, d'exécuter des mesures relatives de constante diélectrique avec une reproductibilité et une précision suffisantes. Nous décrivons en détail et sur de nombreux exemples, l'appareil, la méthode de mesure et de calcul utilisés et nous discutons les résultats obtenus en les comparant avec ceux de la littérature.
Le comportement diélectrique des solutions diluées de polyélectrolytes
Authors: De Brouckere Lugia , Vos Gilbert
Published: September 2010

Dielectric constants of aqueous solutions of polyacrylic acid, partially or totally neutralised by sodium hydroxide, and of sodium, lithium and baryum polymethacrylates, were measured at various frequencies, ranging from 10 to 500 kilocycles. Polymer concentration was varied from 0.1 to 10 millimoles of monomer per liter. The degree of polymerisation was varied from circa 300 to 3,500.

All dispersion curves had an inflexion point for frequencies of approximately 100 kilocycles, so that the relaxation times were of the order of one microsecond. It was hardly influenced by the degree of neutralisation, by the polymer concentration or by the molecular weight.

The dielectric increment, for a given frequency, increased with the degree of neutralisation, rising sharply until α reached 0.5, rather slowly for higher degrees of neutralisation.

The dielectric increment was not proportional to the polymer concentration. It was considerably lower for the salt of a divalent cation, baryum, than for the lithium and sodium salts. The increment was slightly larger for the more mobile sodium than for the lithium polymethacrylate. The degree of polymerisation was practically without influence on the dielectric increment.

All the observed facts point to an interpretation attributing the dielectric properties of dilute solutions of polyelectrolytes to relaxation phenomenon in the ionic atmospheres surrounding the charges localised along the polyion.
Comportement du cycle benzénique halogéno‐substitué, sous l'impact électronique (II) Influence de l'énergie des électrons ionisants sur les spectres de masse
Authors: Momigny J.
Published: September 2010

The influence of the energy of ionising electrons on the behaviour of monohalogeno‐substituted benzenes, has been studied.

In proportion as this energy is decreasing, the stability of the molecular ions is increasing, but the stability still decreases from fluorobenzene to iodobenzene, as in the case of high energy electrons (see article I).

The scope of the diagrams representing the abundance of the principal groups of ions is not affected.

Finally the rates of the abundances of certain groups of ions for a given substance passes by a minimum as the accelerating potential of the electrons varies; so that there are generally two different values of this potential for which this ratio takes the same value.
Une application de Calcul Statistique à la Cinétique Chimique
Authors: Huyberechts Melle S. , Halleux A. , Kruys P.
Published: September 2010

The statistical method of least squares has been applied to the estimation of energy and entropy of activation when there is available a variable number of experimental values of the kinetic constant, at several temperatures.

Furthermore, the method is described, by which the variances of the estimates can be calculated, and significance tests applied to them.
Etude cinétique des réactions de solvolyse II. Solvolyses des chlorures d'α‐méthylallyle et d'α‐phényléthyle
Authors: Wilputte‐Steinert Mme L. , Fierens P. J. C.
Published: September 2010

Arrhenius parameters have been measured, conductometrically, in the case of several solvolysis reactions of α‐methylallyl‐ and α‐phenylethyl chlorides.

The conductometric method has been extended to kinetic measurements in pure water or in dioxane‐water mixtures, rich in water, and relevant modifications are described.
Contribution à l'étude de l'hydratation des silicates de calcium purs
Authors: van Bemst A.
Published: September 2010

Recent experimental results relative to the system CaO‐SiO2‐H2O at ordinary temperature have been applied to the study of the reactions occuring during the hydration of tricalcium and dicalcium silicate.

The first part of this work deals with the study of the pure calcium silicate hydrates I and II, i.e. 0,8‐1,5 CaO.SiO2.aq and 1,7‐2,0 CaO.SiO2.aq. They were synthetized by two different new ways and studied by chemical, differential thermal and thermogravimetric analyses, X ray diffraction, electron microscopy and infrared spectrometry.

The second part of the work describes the results, based on the same experimental methods, of the study of the reaction between Ca3SiO5, ß and γ Ca2SiO4and various amounts of pure water or lime‐water, at temperatures between 4° and 60°C, after different periods of hydration.

The method of determining the composition of the ternary CaO‐SiO2‐H2O phase in samples of partially hydrated silicate is indicated.

The rate of hydrolysis of Ca3SiO5increases with decreasing amount of water used for its hydration. The hydraulic properties of tricalcium silicate are enhanced in the conditions of hydrating cement; calcium silicate hydrate II and Ca(OH)2are formed. The mechanism of formation of calcium silicate hydrates I and II from Ca3SiO5is different. Hydrate I is the only one which forms through the liquid phase.
Sédimentation et viscosité de l'acide désoxyribonucléique
Authors: Oth A.
Published: September 2010

On présente une série de mesures de viscosité et de sédimentation faites sur un échantillon d'A.D.N. très polymérisé ainsi que les dimensions et les poids moléculaires que l'on peut en déduire suivant les modèles classiques.
Dosage de l'hydrogène radioactif
Authors: Verly W. G. , Bricteux‐Grégoire S. , Koch G. , Espreux G.
Published: September 2010

Tritiated hydrogen generated from tritium labelled compounds is introduced into a 100 cm3 ionisation chamber and the filling is completed to atmospheric pressure with ordinary hydrogen; a 300 volts potential difference is established between the electrodes and the ionisation current is determined with a vibrating reed electrometer by the rate of drift method.

This set up is able to detect 1 desintegration per second and reduces the background to a value equivalent to the current generated by 2 desintegrations per second, When the activity is above 15 desintegrations per second, the standard deviation on its measurement does not exceed 2 %.
A Theory of Chromatography Based on the Theory of Counter‐Current Distribution
Authors: Verzele M. , Alderweireldt F.
Published: September 2010

En se basant sur la séparation par chromatographie de partage du “complexe des humulones” (sur gel de silice tamponné à pH 9,0 avec l'isooctane comme éluant) les auteurs montrent qu'il est possible d'appliquer la théorie de la “counter‐current distribution” à la chromatographie. La hauteur équivalente à un plateau théorique d'une colonne chromatographique (HETP), notion introduite par Martin et Synge, est équivalente è une cellule d'un train extracteur. Des méthodes pour trouver le coefficient de partage chromatographique (K) et le nombre de HETP's d'une colonne (n) sont données. Les valeurs de K et n étant connues, il est possible, tout comme en C.C.D. de calculer d'avance la courbe chromatographique. Les résultats pratiques de la chromatographie du “complexe des humulones” concordent avec les prévisions théoriques.
Viscosimétrie à gradient variable
Authors: Oth A.
Published: September 2010

On décrit un viscosimètre à gradient variable ainsi que la méthode de calcul et d'extrapolation des résultats.

Un exemple de mesures est également donné.
Interactions de protéines et d'ions en solution II.‐Energie d'association de la sérumalbumine et d'anions organiques
Authors: Fredericq EugÉNe
Published: September 2010

The binding of picrate, tropeolin, flavianate, naphthol orange, indigo di‐, tri‐and tetrasulphonate anions by serum albumin at pH 4.7 and 3.5 was determined by dialysis at 25°. It is shown that the experimental curves cannot be interpreted by the Scatchard equation and the Debye‐Hückel theory. The charge effect is always much lower than that predicted by the theory. It is proposed to include in the binding equation a term for the Van der Waals energy of interaction. By a consideration of experimental affinities of association, it is possible to estimate the contributions of different energies: electrostatic interactions of charged groups (3,500‐4,500 cal.) and Van der Waals energy increment provided by —CH2—(350 cal.), benzene (1000 cal.) and naphthalene (2,500 cal.) rings. The effect of substituents in the aromatic nuclei is also explained by the consideration of Van der Waals energy and hydrogen bonds.

Association constants of anions and serumalbumin or insulin are determined in mixed solvents at pH 3.5 and 6.6. In all cases the association constants strongly weaken in 20% dioxane and practically vanish in 40% dioxane. These facts are in agreement with the hypothesis that electrostatic interactions are greatly exceeded by Van der Waals forces arising between proteins, large anions and solvent molecules.
Synthèse d'acides oxy‐2, isophtaliques substitués
Authors: Hanson G. A.
Published: September 2010

L'auteur décrit 1°) la préparation du phényl‐4, anisyl‐6, oxy‐2, isophtalate d'éthyle à partir a) de la benzal p.méthoxyacétophénone, b) de l'anisalacétophénone, par condensation avec l'acétone dicarboxylate d'éthyle; 2°) la préparation de l'acide phényl‐4, o.méthoxyphényl‐6, oxy‐2, isophtalique à partir de l'o.méthoxy benzalacétophénone et de l'acétone dicarboxylate d'éthyle.
Etude expérimentale de l'oxydation lente IV. —Réaction entre l'ammoniac et l'oxyde nitreux
Authors: Volders A. , van Tiggelen A.
Published: September 2010

Les réactions NH3 + N2O (avec ou sans NO), N2O + H2 et NO + H2 ont été étudiées.

Dans chaque cas on a déterminé l'énergie d'activation ainsi que l'ordre des réactions par rapport à chacun des constituants et par rapport à la pression totale.

Les résultats ont été comparés à ceux obtenus antérieurement pour les systémes NH3 + O2, NH3 + O2 + H2 et NH3 + NO.
Effet stérique dans la réaction de l'iodure de potassium sur les α‐chlorocétones
Authors: Fierens P. J. G.
Published: September 2010

The Arrhenius parameters for the reaction of potassium iodide on the α‐chloroketones CH3—CO—CHCl—R (R=Me, Et, iso‐Pr or t.Bu), in anhydrous acetone, have been measured.

The differences of reactivity are explained by a steric effect the order of magnitude of which is shown to be analogous to that already observed in SN2 reactions on aliphatic halides R—CH2X.
Echange hétérogène entre le CH3Br et le Br80 (18 mn) issu de Transition Isomérique
Authors: Coekelbergs R. , Gosselain P. A. , Van Venne M. J. Der
Published: September 2010

Experiments conducted in Pyrex bulbs and with aluminium and gold coatings have shown that Br80 (18 mn) generated from gaseous CH3Br80 (4,5 h) by isomeric transition, undergoes an heterogeneous exchange reaction with methyl bromide, the importance of which depends on temperature and nature of the wall, and resulting in the appearance of gaseous CH3Br80 (18 mn).

A reaction scheme, involving a chemisorbed Br80 (18 mn) and a physically adsorbed CH3Br gives a rate ν = γ p / 1 + α p · nBp is the Br80 (18 mn) adsorbed at the wall, which agrees with the experimental facts between 22°5 and 111°C. In that case, the heat of adsorption of CH3Br on Pyrex would be 5 Kcal, and the activation energy of the exchange process 16 Kcal.
Species differences in Ribonucleases
Authors: Craddock Valda M. , Dalgliesh C. E.
Published: September 2010

Species differences are shown to exist between various mammalian pancreatic ribonucleases. Rat and beef ribonucleases are readily separable on partition chromatography in a cellosolve‐ammonium sulphate system. This separation is not affected by prior treatment with reducing agents. Rat and beef ribonucleases also behave differently on ion‐exchange chromatography, and on paper electrophoresis under certain conditions of pH.
Untersuchungen über ein blutzuckersenkendes pflanzliches Peptid
Authors: Holt C. V. , Leppla W.
Published: September 2010

Aqueous extracts from unripe fruits of Blighia sapida contain two ninhydrinpositive substances strongly active in lowering the blood sugar.

The active substances are absorbed on columns of Dowex 50 together with inactive ninhydrinpositive material. By repeated extraction of the eluate with a n‐BuOH‐acetic acid mixture an active fraction is obtained. Counter current distribution of this material leads to the isolation of the two active compounds. One of them crystallizes to give a peptide Hypoglycin A. The second substance, Hypoglycin B, isolated in a smaller quantity, was not yet obtained in crystalline form.

After acid hydrolysis of Hypoglycin A two‐dimensional paper chromatograms show a number of ninhydrinpositive spots which have not yet been identified with known amino acids. A yellow spot not identical with proline or hydroxyproline is observed.

Hypoglycin A is letal in a dose of 4‐5 mg/100 g rat. The animals exhibit a deep hypoglycemia, loss of liver glycogen and a contraction of the left ventricle of the heart. The blood sugar lowering activity of Hypoglycin A is also shown in adrenalectomized and alloxandiabetic rats. The glycosuria of alloxandiabetic rats is markedly reduced under repeated oral administration of one tenth of the letal dose. Neither the glycogen content of the rat diaphragm is significantly influenced by Hypoglycin A in vitro nor an activation of the glycogenolysis of rat liver slices is effected by Hypoglycin A in vitro.

The alpha‐cells of the islets of Langerhans show no signs of destruction in animals which died from letal doses of Hypoglycin A.

The results and a hypothesis of a possible mechanism of the biological action of Hypoglycin A are discussed.
Some Chemical and Physical Properties of Antidiabetic, an Oral Insulin
Authors: Roberts Richard G.
Published: September 2010

The preparation of a hemin‐insulin‐choline chloride complex has been described. Some of the physical and chemical properties of this preparation are given. This complex was found to have prolonged insulin activity over that of crystalline insulin and also to have activity when administered orally. The hypoglycemic activity of both insulin and Antidiabetic was completely destroyed after treatment in liquid ammonia under pressure at room temperature.
Recent Studies on Sialic Acids
Authors: Werner I. , Blix G.
Published: September 2010

Four types of sialic acids have so far been isolated, from cattle, sheep, pig and horse material respectively. They are chemically very closely related and seem to differ in respect of substitutional groups only.

The constitution of the substances is still unknown. Some characteristic properties and reactions of the acids are described and the constitutional possibilities are discussed.

The relationship of the sialic acids to the neuraminic acid described by Klenk is discussed. It seems highly probable that the methoxy‐neuraminic acid and the different sialic acids are all derivatives of the same basic substance.
Étude radiocristallographique de l'hétérocycle γ‐pyrone I. Structure moléculaire et cristalline de la diméthyl‐2‐6 γ‐thiopyrone
Authors: Toussaint J.
Published: September 2010

The crystal structure of dimethyl‐2‐6 γ‐thiopyrone has been determined by means of electron density projections on the (001) and (100) planes.

Bond lengths of the pyrone ring are interpreted in terms of a resonance structure and hence values are deduced for the weights of the forms contributing to the electronic structure of the molecule.
Les spectres Raman de quelques dérivés organiques de l'aluminium et de l'indium
Authors: van Der Kelen G. P. , Herman M. A.
Published: September 2010

The dimethylaluminiumhalogenides [(CH3)2AlX]2 (X = Cl, Br, I) and the monomethylaluminiumhalogenides [CH3AlX2]2 (X = Cl, Br) have been studied in the liquid state by Ramanspectrography. For [(CH3)2AlCl]2 and [CH3AlCl2]2 depolarization factor measurements are reported. For both series of compounds the results agree best with a dimeric structure of symmetry C2v and D2h. Dimerization occurs by formation of a ring comprising two aluminium atoms and two methylgroups.

The valence distribution around the aluminium atom with coordination number four is supposed to be tetraedric.

These results do not agree with previous measurements of electron‐diffraction on the vapors of dimethylaluminiumchloride and bromide. They agree best with the Ramanspectroscopic studies of aluminiumtrimethyl and of the aluminiumhalogenides.

Indiumtrimethyl has also been studied in the liquid and the solid state by Ramanspectrography. The results show, as was expected, that In(CH3)3, is monomeric in both phases and possesses a pyramidal structure of the NH3 type.
The chemistry of the Δ2‐Dihydro‐azoles Part. II. A new method for the preparation of Δ2‐thiazolines
Authors: Nys J. , Libeer J.
Published: September 2010

On décrit une nouvelle méthode de synthèse de Δ2‐thiazolines, basée sur l'ouverture du noyau des Δ2‐oxazolines correspondantes sous l'action de l'acide thiobenzoïque.

Plusieurs bases 2‐méthyl‐thiazoliniques non encore décrites dans la littérature et portant en position 4 un ou deux groupements hydroxy‐ ou acétoxyméthyle furent obtenues de cette manière. Après quaternation, elles furent utilisées dans la synthèse de diverses cyanines triméthiniques dont les caractéristiques optiques sont mentionnées et discutées.
Synthèse d'acides 2‐Oxyisophtaliques substitués
Authors: Hanson G. A.
Published: September 2010

L'auteur décrit 1°) la préparation de l'acide 4‐phényl, 6‐anisyl, 2‐oxyisophtalique à partir de l'ester éthylique correspondant, 2°) la préparation de l'acide 4,6‐dianisyl, 2‐oxyisophtalique, à partir de l'anisal p.méthoxyacétophénone et de l'acétone dicarboxylate d'éthyle.
The influence of hydrogen on carbon monoxide Oxygen flames
Authors: Slootmaekers P. J. , van Tiggelen A.
Published: September 2010

La vitesse de propagation de la flamme dans les mélanges d'oxyde de carbone et d'oxygène augmente très rapidement lorsqu'on remplace progressivement CO par H2.

Par l'étude systématique de cette vitesse à dilution croissante par l'azote de séries de mélanges à rapport H2/CO fixe, on montre que la réaction de ramification des chaînes dans le CO pur est remplacée en présence d'hydrogène par celle qui vaut pour H2 pur. l'énergie d'activation apparente de la ramification varie ainsi de 22 kcal (CO pur) à 18 kcal (H2 pur) tandis que l'ordre apparent de la réaction de ramification passe de 2 à 3.
Contribution à l'étude des éthers monoalcoylés des (poly) éthylène glycols I. Synthéses, constantes physiques et spectres infra‐rouges
Authors: Chakhovskoy N. , Martin R. H. , van Nechel R.
Published: September 2010

The following eighteen (poly)ethylene glycol monoethers have been prepared according to one or the other of the schemes II, IV, V, VI outlined in table I :

RO(CH2CH2O)nH R = normal butyl: n = 1;

R = normal amyl: n = X and 2; R = normal hexyl:

n = 1, 2, 3 and 4; R = normal octyl: n = 1, 2, 3, 4, 5 and 6; R = normal dodecyl: n = 1, 2, 3, 4 and 5.

The synthesis of tetraethylene glycol monohexyl ether was achieved by condensing the paratoluene sulfonate of diethylene glycol monohexyl ether with the monosodio derivative of diethylene glycol. As far as we are aware, this type of reaction has never been used before to prepare compounds of this class.

The ethers have been purified, as well as possible, by fractional distillation under reduced pressure. The following properties of these compounds were determined: b.p. (°C), m.p. (°C), density (d), refractive index (n29: Hα, D, Hβ, H, Hg'), dispersion of the refractive indices as a function of 1/λ2, molecular refraction, static superficial tension (T. S. 20°C), parachor, elementary analysis (C and H), functional analysis (OH) and infra‐red spectra.

The results are summarised in tables II to V.
Hybridation et réactivité V. Solvolyse, par l'acide formique aqueux des chlorures d'allyle et de propargyle
Authors: Fierens P. J. C. , Verschelden P.
Published: September 2010

The solvolysis of allyl and propargyl chlorides have been carried out in the mixture: formic acid (93,6%) ‐ water (6,4%).

The relative rates are interpreted in terms of a previously published qualitative general treatment (P. J. C. Fierens, J. Jaminet et P. Kruys, Bull. Soc. Chim. Belges 64, 557 (1955)) based on the competition between two main factors: inductive and mesomeric effects.
Étude cinétique des réactions de solvolyse V. Solvolyses des para‐chlorométhylanisole et para‐chlorométhyltoluène
Authors: Adam‐Briers Mme M. , Bivort P. , Fierens P. J. C.
Published: September 2010

The solvolysis of parachloromethylanisol and parachloromethyltoluene has been studied in several solvents. The Arrhenius parameters have been determined.

The results, which are discussed in the light of the Winstein‐Grunwald linear relationship, seem to indicate that these solvolysis are if not, at least not far from the SNI limit.
La sélénosemicarbazide et ses dérivés I. Isomérisation du sélénocyanate d'hydrazine en présence de dérivés carbonylés
Authors: Huls R. , Renson M.
Published: September 2010

Nous étudions la préparation de la sélénosemicarbazide et des sélénosemicarbazones à partir de l'isomérisation du sélénocyanate d'hydrazine. Nous montrons que la présence d'un dérivé carbonylé est essentielle à cette transformation et nous proposons un mécanisme de réaction.
La spécificité des halogénations atomiques I. La réaction de la N‐chlorosuccinimide avec le toluène
Authors: Adam J. , Gosselain P. A. , Goldfinger P.
Published: September 2010

The thermal reaction of N‐chlorosuccinimide with toluene has been investigated and an atomic and free radical mechanism for the reactions of N‐haloimides in non‐polar media proposed. Because of the small steric factors of reactions between polyatomic particles, these reagents do not react directly, but act as a source of molecular halogen, which by an atomic mechanism leads to the observed reactions. This explains the long induction period, followed by a rapid reaction, the accelerating effect of HCl and H2O and the inhibition by O2. It accounts also for the well‐known specificity of compounds of this type to substitute in α to a double bond.
La spécificité des halogénations atomiques II. Les règles générales qui déterminent le mécanisme et la spécificité des halogénations atomiques
Authors: Gosselain P. A. , Adam J. , Goldfinger P.
Published: September 2010

A general mechanism for atomic halogenation reactions is considered, which is supposed to comprise all possible reactions steps in a great variety of cases. The kinetic analysis of this mechanism leads to the well‐known equations showing that the rate of these reactions may depend on the power 1/2, 1 or 3/2 of the halogen concentration. Rough estimates of activation energies and entropies of the elementary steps permit one to foresee the rate equation which must be expected in most specific cases and what changes may be caused by varying the experimental conditions (temperature, partial pressure). Similarity, the rules governing the competition of addition and substitution are given. Further it is shown that in many cases a halogen substitution reaction may undergo a fundamental change in mechanism, a sensitized dehydrohalogenation replacing the substitution reaction at a higher temperature and a lower halogen concentration.
Dérivés N‐vinyliques II. Copolymérisation de l'isocyanate d'isopropényle
Authors: Hart R. , van Dormael A.
Published: September 2010

Isopropenyl isocyanate was copolymerised with methyl acrylate and styrene. The reactivity ratios r1 and r2 are calculated: methyl acrylate — isopropenyl isocyanate r1 = 0.8r2 = 0.08. styrene — isopropenyl isocyanate r1 — 7r2 — 0.14.

These results are discussed according to the theory of Alfrey and Price. The isocyanate group acts as an electron donor. This is in agreement with the mesomeric structures usually assigned to the aliphatic isocyanates.
Interactions de protéines et d'ions en solution III. Associations de l'ovalbumine et d'anions organiques
Authors: Fredericq Eugène
Published: September 2010

The binding of aromatic anions by ovalbumin at pH 4.7 and 3.5 was determined by equilibrium‐dialysis at 25°. In some cases the binding curves affect a sigmoid shape; this is interpreted by the existence of Van der Waals interactions between the successively bound ions. The association constants and the affinities of the first anion are calculated from the binding curves. In decreasing order of affinity, the anions are: amaranth, metanil yellow, orange II, thymol blue, flavianate, picrate, dihydroxyazobenzenesulphonate, indigotrisulphonate, hydroxyazobenzenesulphonate, phenol red, anthraquinone‐β‐sulphonate.

It is shown that the Debye‐Hückel electrostatic theory gives better account of the charge effect in ovalbumin than in serumalbumin. This point is discussed in relation with charge distribution and permeability of protein molecules to ions.

The affinities of serumalbumin, insulin and ovalbumin for several classes of anions are compared. The relative order of affinity is similar in the three cases. The theories interpreting the differences in binding power of proteins are discussed. It is concluded that the exceptionally high affinity of serumalbumin for anions is probably related to an uneven distribution of polar groups and lipophilic residues at the surface of the molecule.
Interactions de protéines et d'ions en solution IV. Étude spectrale des associations de protéines et d'anions organiques
Authors: Fredericq Eugène
Published: September 2010

The influence of serum albumin, ovalbumin and insulin on the absorption spectra of organic anions in solution is investigated in the visible range. The spectra of azo‐dyes, phthaleins, indigosulphonates and anthraquinone dyes are affected in the same way by the three proteins: there is a general depression of the intensity of absorption and slight shifts of the maximum. Moreover the modifications are similar to those produced by 90% aqueous dioxane. These facts are interpreted by Van der Waals interactions between hydrophobic parts of dyes and proteins.

On the contrary the spectra of picrate and flavianate ions are differently affected by 90% dioxane and by serumalbumin. In the latter case there is a marked shift towards shorter wave lengths indicating a diminution of the resonance. This is interpreted by the formation of hydrogen bonds between proteins and nitro‐groups. The spectral study confirms the deductions previously made on the nature of interactions between proteins and anions.
Estimation du diamètre des micelles d'une suspension colloïdale de sélénium par spectrophotométrie
Authors: Watillon A. , van Grunderbeeck F.
Published: September 2010

In a preceding paper, we proposed a counting method permitting the precise determination of particle sizes in lyophobic colloids. Results obtained by this method in the case of Selenium hydrosols were controlled by electron‐microscopy. The latter technique was also used in verifying isodispersity of the suspensions.

In the present paper, we propose a simple spectrophotometric method — calibrated by above mentioned absolute techniques — for discriminating between isodispersed and polydispersed Selenium Sols and for rapid estimation of the average size of the Seleninium particles.
Composés alicycliques à carbone quaternaire V. Synthèse et spectres infra‐rouges de quelques 2‐éthoxycarbonyl‐1‐oxacyclopropane‐spiro‐cyclanes
Authors: Chiurdoglu G. , Mathieu M. , Baudet R. , Delsemme A. , Planchon M. , Tullen P.
Published: September 2010

Les 2‐éthoxycarbonyl‐1‐oxacyclopropane‐spiro‐cyclobutane (I), ‐cyclo‐pentane (II), ‐cyclohexane (IV), les dérivés 2, 4, 5, 6, ‐méthylés (V à VIII) de ce dernier et le 2‐méthyl‐2‐éthoxycarbonyl‐l‐oxacyclopropane‐spiro‐cyclopentane (III) sont décrits par l'intermédiaire de leurs constantes et de leurs spectres infra‐rouges et, pour certains, Raman.

Le fait essentiel, révélé par les spectres est l'existence, chez ces esters glycidiques, d'un net dédoublement de la bande carbonyle : 1730 cm−1 et 1750 cm−1. Ce dédoublement s'observe, en outre, chez le 2‐méthyl‐2‐éthoxycarbonyl‐1‐oxacyclopropane (X) et pas chez le 2‐éthoxycarbonyl‐1‐oxacyclopropane (IX) ou encore chez le 2‐carbo‐carboxy‐1‐oxacyclopropane‐spiro‐cyclohexane (XI) et pas chez le sel de sodium correspondant.
Bepaling van Mo door de isotopen dilutie methode
Authors: Geldhof M. L. , Eeckhaut J. , Cornand P.
Published: September 2010

The determination of Mo by the isotopic dilution method has been examined, using Mo99 as tracer. Reliable results have been obtained for quantities of 1 to 20 mg Mo, either by β‐counting or by γ‐counting.

The method has been applied to the determination of Mo in steel. When Cu is present, a correction should be made for the Cu content of the Mo precipitate.
Étude cinétique des réactions de solvolyse VII. Note sur l'hydrolyse, par l'cau, du chlorure d'allyle
Authors: Fierens P. J. C. , Kruys P.
Published: September 2010

The kinetics of the hydrolysis of allyl chloride in water has been studied.

The results and other data related to solvolysis of allyl chloride are expounded on the basis of an already published interpretation (L. Wilputte‐Steinert and P. J. C. Fierens, Bull. Soc. Chim. Belges, 65, 719 (1956)).
Étude comparée de la dénaturation de la pepsine en solution et en surface II. Dénaturation de la pepsine en surface
Authors: Dieu Hector A.
Published: September 2010

In this paper we have estimated the surface molecular values of pepsin dissolved at pH 5,5 and spread on HCl substrate at pH 2.

At low pressure (0,0005‐0,02 dyne/cm) the film molecular weight is 34.800 and the gaseous area is 1,91 sq. m/mgr. At higher pressure (0,02‐0,6 dyne/cm) the film molecular weight is 38.000 and the gaseous area 0,71 sq. m/mgr.

We have also compared these values as a function of the pH of the pepsin solution spread on both HCl and (NH4)2SO4 substrates in the range of pressure 0,02‐0,6 dyne/cm. The increase of the film molecular weight and the decrease of the gaseous area, depending upon the pH of the solution and the nature of the substrate, are due to a swelling of the pepsin molecules.

Finally we have measured the sedimentation and viscosity constants of collected films which exhibit no more proteolytic activity when spread at pressure below 0,6 dyne/cm.
Dérivés β‐anilinovinyliques de bases hétérocycliques IV (1). Comparaison de leurs spectres d'absorption avee ceux des anils maloniques correspondants
Authors: Nys J. , van Dormael A.
Published: September 2010

It has been observed that a convenient route to pure β‐anilinoacroleineanil‐bases, bearing nucleophilic as well as electrophilic substituents in the p.‐position of their phenyl groups, lies through the acid‐catalysed condensation of propiolaldehyde acetal with the appropriately para‐substituted aniline‐compounds, followed by the filtration of the resulting crude anil‐salts through a chromatographic column filled with alumina.

The absorption data of the new dyestuffs were recorded in neutral and in acid medium. Their knowledge induced a thorough investigation of the peculiar optical properties of substituted anilinovinyl salts of heterocyclic. nuclei (which may be considered as the structural hybrids between the monomethinic cyanines and the β‐anilinoacrolein anil‐salts).

The aberrant behavior of anilinovinyl‐salts towards the “deviation” concept is discussed and a tentative interpretation of their abnormal optical comportment is proposed.
Sur une relation empirique entre le potentiel de surface de certains films chimiques et l'electronégativité de leurs constituants
Authors: Mignolet J. C. P.
Published: September 2010

The empirical relationship magnified image between the surface potential of a complete film (∀1) the work function of the bare surface (ϕ0) and the electronegativity of the adsorbate (xa), is derived from the experimental data concerning the WO, WI, WH, NiH, FeH and PtH films. Deviations up to 30% are found for surface potentials varying within a factor of 9. Correcting the ∀1 values for the incompleteness of the films used brings the deviations within the limits set by the uncertainty on the xa values. Some possible applications are pointed out.
Sur l'évaluation cle la masse moléculaire des protéines et des polymères par la technique des couches monomoléculaires I. ‐ Étude des films de protéine
Authors: Dieu Hector A.
Published: September 2010

A study of the film molecular weight of various proteins is made.

Two ranges of surface pressure are examined using in the 0,001‐0,02 dynes/cm range a modified Guastalla balance, and, in the 0,02‐0,6 dynes/cm range a Wilhelmy plate method or a Marcelin balance.

Usually the molecular weights found in both ranges of pressure are in agreement although in some cases those found in the 0,02‐0,6 dynes/cm range are not correct due to the shape of the isotherm.

The influences of several variables: pH, ionic strength, surface active agent, temperature are investigated. Special mention is to be made of the influence of the substrate temperature on the isotherm of eggalbumin.

On the basis of our results, proteins can be classified in two groups: firstly, we find all the proteins giving, when spread at pH 2, a film molecular weight of the same order of magnitude of the osmotic or ultracentrifugation‐diffusion molecular weight; secondly, we have the proteins which give a film molecular weight lower than that found in solution.

A discussion of the influence of the electrostatic factor and of the flexibility of the protein pattern is made.

Finally attention should be paid to the necessity of considering an enthalpy factor in any theory of protein monolayer.
The Synthesis of Diglyceromonophosphoric Acids by the Reaction of 2‐glycerophosphate with 1‐epichlorohydrin or 1‐ and 2‐monochlorohydrin
Authors: Stockx J. , Vandendriessche L.
Published: September 2010

Une étude a été faite de la synthèse de l'acide 1‐2′ diglycérophosphorique, par condensation de la 1‐épichlorhydrine ou de la 1‐monochlorhydrine avec le 2‐glycérophosphate disodique. Il apparaît que l'isomère 1‐1 se forme simultanément en quantités variables et que probablement aussi l'isomère 2‐2 se forme en quantités réduites. La condensation de la 2‐monochlorhydrine avec le 2‐glycérophosphate disodique conduit en ordre principal à l'obtention de l'acide 1‐2 diglycérophosphorique.

L'hydrolyse acide de l'acide glycolaldéhyde 2‐glycérophosphorique, formé à partir de l'acide 1‐2 diglycérophosphorique par oxidation au moyen de periodate, s'effectue avec une libération pratiquement quantitative d'acide glycérophosphorique.
Interactions de protéines et d'ions en solution. V.— Associations de protéines et d'anions minéraux Discussion générale
Authors: Fredericq Eugène
Published: September 2010

The binding of chloride, bromide, nitrate and thiocyanate ions by insulin was determined by potentiometry or by equilibrium dialysis. Mineral anions are bound by insulin in acid solutions; the order of the affinities conforms to the Hofmeister series.

The binding curves are adsorption isotherms. The influence of the net charge of the protein is weak. Free energy changes for the binding of the first anion were estimated. They vary from ‐3,000 to ‐3,600 calories for chloride and thiocyanate respectively. The binding of chloride ions by serumalbumin was interpreted by the Debye‐Hückel theory of electrostatic interactions. It was found necessary to use the Tanford's theory of protein swelling to fit the experimental data.

All associations between proteins and anions are discussed according to a common scheme, based on a summation of electrostatic attractions, Van der Waals attractions between particles and solvation interactions.
Note sur les mélanges d'alcool méthylique et de sébacate de butyle
Authors: Courtoy C.
Published: September 2010

Nous avons étudié les spectres infrarouges d'une série de mélanges de méthanol et de sébacate de dibutyle. Nous en déduisons quelques renseignements sur l'association des molécules de méthanol entre elles ou avec le sébacate.
Etude cinétique des réactions de solvolyse VIII. — Solvolyse des chlorures de benzyle substitués
Authors: Bivort P. , Fierens P. J. C.
Published: September 2010

The Arrhenius parameters of solvolysis reactions of some substituted benzyl chlorides have been measured.

The results are expounded on the basis of the concept of nucleophilic action.

A qualitative relationship is found between the nucleophilic action and the Hammett's substituent constant.
Réaction SN2 de l'iodure de Potassium Sur Divers Chlorures de Benzyle Monosubstitués
Authors: Bivort P. , Pierens P. J. C.
Published: September 2010

The action of potassium iodide on some substituted benzyl chlorides has been studied kinetically.

The results are expounded by means of the scale of nucleophilic substitution mechanisms.
Etude cinétique de l'action du nitrile acétique sur le bromure d'éthylmagnésium
Authors: Moris J. , Bruylants A.
Published: September 2010

En soumettant le nitrile acétique à l'action du bromure d'éthylmagnèsium, on déclenche une série de réactions consécutives compétitives: la première d'entre elles fournit le sel magnésien du nitrile, la seconde conduit au sel magnésien du dimère, tandis que la troisième donne le sel dimagnésien du dimère. Par hydrolyse ultérieure, on obtient le diacétonitrile comme tel ou sous forme d'un de ses produits de condensation.

La stoechiométrie de ces réactions a été étudiée antérieurement dans ce laboratoire. Nous avons cherché, quant à nous, à établir les constantes cinétiques qui régissent ces phénomènes.

En étudiant la formation du sel magnésien du nitrile, qu'on peut suivre en mesurant le volume d'éthane dégagé par suite de la décomposition du réactif de Grignard, nous avons pu déterminer l'ordre en fonction de la concentration initiale, les constantes de vitesse à trois températures et, par conséquent, l'énergie d'activation ainsi que le facteur stérique.

La réaction est d'ordre deux global: d'ordre un par rapport au nitrile acétique et d'ordre un par rapport au composé magnésien. Les constantes de vitesse prennent les valeurs suivantes aux différentes températures:

L'énergie d'activation s'éléve à 16.000 calories. Le facteur stérique log PZ vaut 9,28, ce qui donne pour P une valeur de 0,6.10−2 (Z a une valeur moyenne de 3.1011).

Cette cinétique est en accord avec un mécanisme d'après lequel l'étape déterminants de vitesse consiste en un échange acide‐base entre le nitrile et le magnésien.
Interpretation of Some Flame Spectra in Terms of Reaction Kinetics
Authors: Nenquin G. , Thomas P. , van Tiggelen A.
Published: September 2010

L'intensité des spectres émis par différents radicaux dans quelques flammes entretenues par des combustibles et des comburants assez divers (NH3, H2, C2H4et C2H3Cl chlorure de vinyle) d'une part et N2O, O2d'autre part a été mesurée.

L'énergie d'activation des réactions de production des radicaux peut être calculée à partir des intensités mesurées à divers degrés de dilution, à condition de connaître les températures dans le front de flamme.

On a constaté que, pour certains radicaux tout au moins, la variation d'intensité à dilution croissante par un gaz inerte est étroitement liée à la variation de vitesse de propagation de la flamme.

Pour ces radicaux les énergies d'activation sont vraisemblablement proches de celles des réactions de ramification des chaînes.
Mesure de Potentiels d'Excitation Moléculaires au Moyen d'Une Source d'Ions
Authors: Momigny Jacques
Published: September 2010

An analysis of the molecular processes in conventional ion source has lead to the conclusion that the appearance of molecular ions for values of the electron energy by far inferior to the ionisation potential, is due to successive excitation and ionisation of the molecule, by means of two electronic impacts.

The existence of this phenomenon enabled us to measure molecular excitation potentials by means of an usual ion source.

The study of neon, helium and carbon monoxide has shown good agreement between our results and those obtained by optical spectroscopy.
La Sélénosemicarbazide et Ses Dérivés IV. –Spectres U‐V des sélénosemicarbazones et phényl‐4 sélénosemicarbazones
Authors: Huls R. , Renson M.
Published: September 2010

Les spectres U‐V des sélénosemicarbazones et phényl‐4 sélénosemicarbazones sont généralement semblables à ceux de leurs homologues oxygénés et sulfurés, mais présentent par rapport à ceux‐ci un déplacement bathochrome de l'ordre de 90 et 16 mμ respectivement. L'étude des relations spectrales entre les sélénosemicarbazones d'aldéhydes variés a mis en évidence l'influence de la conjugaison et de diverses substitutions sur la position et l'intensité des maxima d'absorption.