bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Relation Between the Interaction Energy and the Surface Potential of Some Films (1) (2)
Authors: Mignolet J. C. P. 
Published: September 2010

AbstractUn examen critique des données expérimentales relatives à I'énergie différentielle d'interaction (Δq) à I'énergie intégrale d'interaction (ΔQ) et au potentiel de surface (ν) de quelques films d'hydrogène, conduit à trois relations empiriques entre ces grandeurs:Δq=eν (a)ΔQ=eν/2 (b)Δq=2ΔQ (c)où e représente la charge de l'électron.La relation (a) diffère de la relation de Boudart par un facteur 2. Un essai d'interprétation des relations (a) et (b) sur la base de considérations électrostatiques montre que l'interaction entre adatomes n'est pas exclusivement électrostatique, mais que des forces de nature quantique jouent un rôe prépondérant.La relation (a) conduit à penser que l'adsorption covalente d'un atome d'hydrogène nécessite le transfert d'un électron de la bande de conductibilité du métal à une orbitale superficielle vacante. La relation (a) exprime simplement que, lors de l'adsorption d'un film, le niveau occupé le plus élevé de la bande de conductibilité, le travail d'extraction électronique et l' énergie différentielle d'adsorption varient de quantités équivalentes.Les relations (b) et (c) découlent de la relation (a) dans l'hypothèse o&&ugrave; le potentiel de surface varie proportionellement à la fraction de surface couverte.En examinant la signification de la relation (c), on arrive à la conclusion que les forces d'interaction ont une longue portée.L'interprétation de la relation (a) conduit à formuler la règle suivant laquelle tous les films atomiques covalents doivent être de signe négatif.
Comportement du cycle benzénique halogéno‐substitué, sous l'impact électronique (I)
Authors: Momigny J. 
Published: September 2010

AbstractBy means of mass spectrometry, the behaviour of monohalogeno‐substituted benzenes, under the electronic impact, has been studied.On the basis of the obtained data, we compared the stabilities of the various molecular ions, measured by the percentage of these ions in the whole ionic current; similarly, the abundances of various kinds of fragmentary ions.Noticeable regularities have been observed. The graphic representation of the abundance of certain groups of ions reveals a cognate behaviour, on one side between the benzene and the fluorobenzene, on the other side, between the other three halogenated derivatives.
La méthode conductométrique en cinétique chimique
Authors: Fierens P. J. G. , Halleux A. , Hannaert H. 
Published: September 2010

AbstractA conductimetric method for the study of homogeneous reaction rates in organic solvents is described. In particular, the method has been used for the determination of kinetic constants pertaining to SN2 exchanges and solvolysis of organic halides. In general, results show an accidental error of less than 3%.
Synthèses dans le domaine des hydrocarbures cancérigènes XIII 3,4‐diméthyl‐et 2,3,4‐triméthylpyrènes
Authors: Martin R. H. , Senders J. 
Published: September 2010

AbstractThe syntheses of 3,4‐dimethyl‐and 2,3,4‐trimethylpyrenes are described. These new alkyl derivatives of pyrene have both been obtained from 2‐oxo‐3,4‐dimethyl‐1,2,8,9,10,11‐hexahydropyrene (VII).An improved method of preparation of this ketone, involving the following steps, has been worked out: reduction of 4‐oxo‐6‐7‐dimethyl‐1,2,3,4‐tetrahydrophenanthrene (V) with LiAlH4; treatment of the resulting alcohol with HCl, malonic ester condensation, hydrolysis, decarboxylation and finally cyclisation with anhydrous HF.Reduction of the tetracyclic ketone (VII) with LiAlH4 followed by catalytic dehydration and dehydrogenation with Pd on charcoal, affords the expected 3,4‐dimethylpyrene (IV) (m. p.: 103‐104°). Treatment of VII with CH3MgI, followed by dehydration and dehydrogenation (Pd on charcoal), gives a poor yield of 2,3,4‐trimethylpyrene (IX) (m. p.: 123‐124°).The U. V. spectra of these hydrocarbons were determined.
Préparation de Thorium‐234 (UX1) de haute pureté radioactive
Authors: Deutsch S. , Nikolic M. 
Published: September 2010

AbstractA solution of Th‐234 from Uranyle nitrate was prepared for the use as tracer of its α emitting isotopes Th‐230, 228, 232.The aim of the work was to obtain Th‐234 containing as little as possible α emitting elements.U was separated from Th by ether extraction.The impurities present in the solution of Th‐234 are:

— U due to incomplete separation.

— Th‐230 growing from U‐234 and chemically inseparable frm U‐234

— U‐234 formed by desintegration of Th‐230

The most favourable conditions for obtaining a solution of Th‐234 with high radioactive purity are discussed.The preparation of a Th‐234 solution with a ratio αβ < 1,8 10−6 is described in detail. This solution can be used as radiotracer in measuring quantities of Th‐230 (Ionium) as low as 10−11 g.
Etude cinétique des réactions de solvolyse III. Solvolyses des chlorures d'α, α diméthylnéopentyle et d'α phénylnéopentyle
Authors: Wilputte‐Steinert Mme L. , Fierens P. J. C. 
Published: September 2010

AbstractThe kinetic study of the solvolysis of α,α dimethylneopentyl‐and α‐phenylneopentyl chlorides has been made in several media.
Synthéses dans le domaine des hydrocarbures cancérigènes — XIV Dérivés méthylés du pyréne
Authors: De Clercq Monique , Martin R. H. 
Published: September 2010

AbstractSeveral new polymethylpyrenes have been synthesised in order to test them for possible carcinogenic activity. Formylation of 3‐methylpyrene (german nomenclature) gives a complex mixture of aldehydes from which 3‐methyl‐5‐formylpyrene (m.p.: 102‐103°) has been isolated.It has been shown that 3‐methyl‐10‐formylpyrene is also present in the reaction mixture.Reduction (Huang‐Minlon) of the formyl derivatives affords 3,5‐dimethylpyrene (m.p.: 98‐99°) and 3,10‐dimethylpyrene (m.p.: 129‐130°) respectively.Treatment of 3,8‐dibromopyrene with butyl‐lithium followed by methyl sulfate gives the isomeric 3,8‐dimethylpyrene (m.p.: 165‐166°).3,5‐Dimethyl‐8‐formylpyrene (m.p.: 171‐172°), 3,8‐dimethyl‐5‐formylpyrene (m.p.: 187°) and 3,10‐dimethyl‐5‐formylpyrene (m.p.: 175‐176°) are obtained by formylation of the above corresponding dimethylpyrenes.These isomeric aldehydes all give 3,5,8‐trimethylpyrene (m.p.: 178‐179°) on reduction. Further formylation and reduction affords 3,5,8‐trimethyl‐10‐formylpyrene (m.p.: 275‐276°) and 3,5,8,10‐tetramethylpyrene (m.p.: 269‐270°).Formylation of 4‐methylpyrene (new preparation given) followed by reduction gives a dimethylpyrene (m.p.: 62°) different from 3,4‐dimethylpyrene (m.p.: 104‐105°) and which, therefore, probably is the 4,8‐dimethylpyrene. The intermediate 4‐methyl‐8‐formylpyrene (m.p.: 93‐94°) was isolated.U. V. Spectra of the new polymethylpyrenes are given.
Contribution à l'étude des réactions à l'état solide entre OCa, O3Fe2, O3Al2
Authors: De Keyser W. L. 
Published: September 2010

AbstractThis work has been carried on with the same methods as those used in our earlier work on reactions in the solid state of the system (Al2O3, SiO2, CaO) (Bull. Soc. Chim. Belg. 1951 n° 60, 1953 n° 62, 1954 n° 63).Samples were prepared by mixing pure oxides of Ca, Fe, Al in the following proportions: 2 CaO+Fe2O3; 6 CaO+Al2O3+2 Fe2O3; 4 CaO+Al2O3+Fe2O3; 6 CaO+Al2O3+Fe2O3.After heating to temperatures ranging from 500°C, to 1300°C, the samples were examined by XR.For the interpretation of the results, differential thermal analysis and differential thermogravimetry were used.The following conclusions were reached:1°—For all the mixtures the first compound formed by heating is C2F (from about 800°C).The compound CF is formed at a higher temperature and its percentage is at its maximum at 1000°. At an even higher temperature CF disappears by reaction with C and formation of C2F.For the mixtures containing Al2O3, A3C5 is formed between 1000° and 1250°C. At a higher temperature a solid solution appears.2°—By D. T. A., it was found that the speed of formation of C2F is at its maximum at about 1200°C.3°—D. G. A. showed that in mixtures of CO3Ca and Fe2O3, the reaction of CaO with Fe2O3 begins at a temperature lower than that corresponding to the decomposition of CO3Ca.
Etude des propriétés diélectriques de solutions aqueuses diluées d'électrolytes forts I. La constante diélectrique
Authors: Mandel M. 
Published: September 2010

AbstractA new bridge method has been used for measuring dielectric constants of dilute aqueous electrolytic solutions. Sodium, potassium and barium chloride, and potassium iodide have been used at molalities ranging from 10−4 to 5.10−3 mole per 1000 gr water. Measurements have been carried out at frequencies varying between 10 and 400 kilocycles per second.Electrode effects were observed in all cases, and corrections according to Oncley's formula were applied. Final results are claimed to be accurate to 0,5%.Dielectric constants for extremely dilute solutions were very close to that of pure water. For molalities lower than one millimole per 1000 grs water, dielectric increments were compatible with the theory of Debye and Falkenhagen. At higher concentrations dielectric constants showed a sharp decrease. This may be due to a saturation effect, but this hypothesis should be confirmed by measurements at still higher concentrations.
Hybridation et réactivité I.‐Introduction à une série d'articles‐Hydrolyse alcaline de l'acrylate et du propiolate de méthyle
Authors: Fierens P. J. C. , Jaminet J. , Kruys P. 
Published: September 2010

AbstractThe kinetic study of the alcaline hydrolysis of methyl acrylate and propiolate, in acetone 70% — water 30%, have been made.The rate of hydrolysis of methyl propiolate is to fast to be measured: at‐12° the reaction is finished in less than 4 minutes.In the case of methyl acrylate the Arrhenius parameters are: E=12,9 Kcal./mole log PZ=8,27.
Hybridation et réactivité II.‐Hydrolyse, par l'eau, des bromures de propyle normal, d'allyle et propargyle
Authors: Fierens P. J. C. , Kruys P. 
Published: September 2010

AbstractArrhenius parameters are determined for the hydrolysis of n‐propyl, allyl‐and propargyl bromides, in water and in the mixture: water (59,1%)— dioxane (40,9%).CH3—CH2—CH2—Br	water: E: 24,4 log PZ: 11,4water‐dioxane: E: 21,48 log PZ: 8,75CH2=CH—CH2—Br	water: E: 22,61 log PZ: 11,80water‐dioxane: E: 19,35 log PZ: 8,76CH≡CH—CH2—Br	water: E: 25,0 log PZ: 11,54water‐dioxane: E: 20,7 log PZ: 8,24
Composés alicycliques à carbone quaternaire III.‐Oxydation de quelques dérivés gem cyclohexaniques par l'oxygéne, sous U‐V
Authors: Chiurdoglu G. , Maquestiau A. 
Published: September 2010

AbstractLes cyclanes dépourvus de carbone tertiaire: le cyclohexane (I), le 1,1‐diméthylcyclohexane (II), le 1,1,3,3‐tétraméthylcylohexane (III), le 1,1,3‐triméthyl‐3‐éthylcyclohexane (IV) et le 1,1,3‐triméthyl‐3‐isopropylcyclohexane (V) ont été oxydés, les dérivés gem pour la première fois, par l'oxygène moléculaire et sous U‐V, respectivement à 70° (I), 110° (II) et 120° (III, IV et V). Tous fournissent du méthanal (polyoxyméthylénes) à cǒté d'un mélange complexe d'acides. Ceux‐ci, ont pu être déterminés, en partie, au départ des cyclanes I et II; I: acides formique, glutarique, valérique et adipique; II: acides formique, diméthyl‐malonique et ß‐ß‐diméthyladipique.La nature de ces dernières substances est en accord avec le mécanisme d'oxydation faisant intervenir, entre autres, une décomposition monomoléculaire de l'hydroperoxyde au niveau du chaînon –O–O–.
La substitution nucléophile activée en série aromatique II.—Effet polaire des groupements alcoyle‐Réaction d'échange bromo‐iode dans une série de 1‐alcoyl‐4‐bromo‐3,5‐dinitro‐benzènes
Authors: Pinguair Mlle A. , Fierens P. J.C , Frennet A. , Halleux A. 
Published: September 2010

AbstractRate constants and Arrhenius parameters pertaining to the bimolecular exchange between 1‐alkyl‐4‐bromo‐3,5‐dinitro‐benzenes and potassium iodide, in dry acetone, have been determined. The alkyl radical is sucessively: H, CH3, (CH3)3C. The experimental data give a measure of the polar effect of these alkyl groups located para to the seat of substitution.
La substitution nucléophile activée en série aromatique III.—Ordre de mobilité des halogènes dans la réaction de 1‐halogéno‐2,4‐dinitro‐benzènes et 1‐méthyl‐2‐halogéno‐3,5‐dinitro‐benzènes avec l'iodure de potassium dans l'acétone
Authors: Cortier J. , Fierens P. J. C. , Gilon M. , Halleux A. 
Published: September 2010

AbstractThe order of mobility of the halogens in the reaction of 1‐halo‐2,4‐dinitro‐benzenes and 1‐methyl‐2‐halo‐3,5‐dinitro‐benzenes with potassium iodide in dry acetone is shown to be F < Cl < Br. The ratio of reactivities evaluated from kinetic constants is approximately F : Cl : Br = 0,06: 1: 120 (cf Part I, this bull. 64, 700 (1955), for kinetic data concerning the bromo‐compounds).Arrhenius parameters have been determined for the reaction, in the case of 1‐chloro‐2,4‐dinitro‐benzene and 1‐methyl‐2‐chloro‐3,5‐dinitrobenzene.The synthesis of 1‐methyl‐2‐fluoro‐3,5‐dinitro‐benzene is described.
Flame Propagation in Gaseous Mixtures Containing Nitrous‐Oxide as Oxidant
Authors: van Wonterghem J. , van Tiggelen A. 
Published: September 2010

AbstractOn a mesuré la vitesse de propagation, la température et la distance entre le cône lumineux et le cône révélé par strioscopie pour toute une série de flammes laminaires entretenues par des mélanges contenant de l'oxyde nitreux et l'un des combustibles suivants: NH3, CO, H2 ou C2H2.On en déduit l'énergie d'activation apparente du processus de ramification des chaînes.Une comparaison est faite avec les mêmes flammes contenant O2 au lieu de N2O.
Species differences in Heparin
Authors: Bell Helen J. , Jaques L. B. 
Published: September 2010

AbstractDog, beef, pork and sheep α‐heparin, β‐heparin, and a crude sample of human heparin were assayed for metachromatic, antithrombin and anticoagulant activity, carbohydrate (anthrone reagent) and glucuronic acid (naphthoresorcinol reagent). Metachromatic activity was about the same for the purified samples. Great differences were found in anticoagulant activity and antithrombin activity. Dog heparin had the highest activity, followed by beef, pork and sheep, while β‐heparin, and the crude human heparin had very low activity. All contained anthrone‐reacting carbohydrate. A value of 40% glucuronic acid was obtained for β‐heparin while only 2‐4% was obtained for the α‐heparins, using the naphthoresorcinol reagent. The variation in values reported for antithrombin assays was examined and it was concluded that if matches between unknown and standard are rejected when they do not lie in the middle of the series of heparin dilutions used in the test, satisfactory replicate assays agreeing to within ± 4% can be obtained. This favours the use of a titration type of assay. Two new methods of extraction of heparin from tissue are briefly described. They appear to extract heparin from human tissue in greater amount than the Charles and Scott method. Pork heparin has been separated by paper chromatography. While glucosamine, glucuronic acid, sulphate, glucose and an unidentified sugar were found associated with the antithrombin‐metachromatic fraction, some sulphate and considerable amounts of glucosamine, glucuronic acid and glucose were found in the fractions representing polysaccharide impurities.
Sur la structure chimique des acétates de cellulose. I
Authors: Gerbaux R. 
Published: September 2010

AbstractLa mesure des viscosités de solutions diluées d'acétates de cellulose dans des mélanges de chlorure de méthylène et d'alcool éthylique permet, entre certaines teneurs limites en groupes acétyles, dé définir la place des substituants tout au long de la chaîne macromoléculaire.La connaissance de la structure réelle de la molécule associée à la connaissance des différentes espèces de fonctions hydroxyles restées libres jette quelque lumière sur le déroulement de la réaction d'acétylation de la cellulose.
Dérivés N‐vinyliques I. Synthèse des isocyanates de vinyle et d'isopropényle
Authors: Hart R. 
Published: September 2010

AbstractVinyl and isopropenyl isocyanates are obtained in good yield by reacting a toluene solution of acrylic or methacrylic acid with an aqueous solution of sodium azide (Curtius reaction). Some properties of these vinyl monomers are described.
Hydrolyse des dérivés α chloracyles d'acides aminés
Authors: Hanson G. A. 
Published: September 2010

AbstractSoumettant à l'hydrolyse, de nombreux dérivés α‐chloracylés d'acides aminés, l'auteur s'est efforcé de déterminer quelle était l'influence, due à la constitution de ces dérivés, sur la stabilité des liaisons peptidiques.
Contribution à l'étude des éthers monoalcoylés des (poly) éthylène glycols II. Températures critiques de démixtion des systèmes éther monoalcoylé de (poly)éthylène glycol‐eau et influence d'un troisième constituant
Authors: Chakhovskoy N. 
Published: September 2010

AbstractThe critical saturation temperatures (CST) of the following binary systems have been determined (the observed critical temperatures and the corresponding critical weight concentrations in ethers are given in brackets):magnified imageThe saturation temperatures of the binary mixturesC12H25O(C2H4O)4H — H2O and C12H25O(C2H4O)4H —H2O and C12H25O(C2H4O)5H — H2Ocould not be measured accurately in view of their great viscosity, particularly when the concentrations in ethers exceeded 40% and 10% respectively.2) The influence of a third constituent, added in increasing quantities to some of the above binary mixtures at their critical concentrations, on the saturation temperatures of the ternary systems formed, has been studied.The following ternary systems have been examined:chemical structure imageAmong the five compounds tested[C6H13O(C2H4O)3H,para.ClC6H4SO3Na, C4H9OSO2Na and C12H25OSO3Na] the last two have proved particularly effective in raising the saturation temperatures when added in very small quantities.
La spécificité des halogénations atomiques IV. La déshydrochloruration photosensibilisée du pentachlorétane
Authors: Adam J. , Goldfinger P. 
Published: September 2010

AbstractFrom 130°C, the photochlorination of gaseous C2HCl5 results in the formation of C2Cl4 according to the equationmagnified imageThe kinetic study of the transition between the low temperature substitution reaction and the high temperature dehydrochlorination reaction permits one to confirm the values found previously for D and for the steric factor of the stepmagnified image
Sur quelques réactions dans le grillage de sulfures précipités
Authors: Lefevre Melle M. , Lemmerling J. , van Tiggelen A. 
Published: September 2010

AbstractLors du grillage du sulfure de Cuivre, la sulfatation directe (Cu S + 2O2→ Cu SO4) au delà de 250° C est contrariée par la destruction du Cu SO4par Cu S (5 Cu SO4+ 3Cu S → 4 Cu2O + 8 SO2) réaction suivie de 2 Cu2O + O2→ 4 Cu O.Au delà d'une température voisine de 450° C la totalité du sulfate obtenu lors du grillage résulte de la réaction globale:magnified imagePour chacune des réactions élémentaires impliquées dans ces processus on a déterminé l'énergie d'activation ainsi que l'ordre par rapport au composé gazeux engagé dans la réaction. On a obtenu ainsi:magnified imageLe comportement du CoS dans les mêmes conditions a été comparé à celui du Cu S.
Préparation de quelques dihydroxy‐3‐5 acylophénones au moyen de dérivés organocadmiques
Authors: Huls R. , Hubert A. 
Published: September 2010

AbstractNous décrivons une méthode de préparation des dihydroxy‐3‐5 acylophénones, à partir du chlorure de diacétoxy‐3‐5 benzoyle. Par condensation de ce dernier avec divers dialcoylcadmiums, nous obtenons, avec de bons rendements, différentes dihydroxy‐3‐5 acylophénones correspondantes.
La sélénosemicarbazide et ses dérivés III. Mise an point d'une méthode rapide de dosage du sélénium dans les sélénosemicarbazones
Authors: Huls R. , Renson M. 
Published: September 2010

AbstractNous décrivons une méthode rapide de dosage du sélénium, dans les sélénosemicarbazones. Cette méthode, basée sur la formation quantitative de Ag2Se par le nitrate d'argent, permet des déterminations à moins de 1 % prés; elle est applicable en principe à toutes les substances renfermant l'angle fonctionnel NH2‐CSe‐.
Synthèse d'acides 2‐oxyisophtaliques substitués
Authors: Hanson G. A. 
Published: September 2010

AbstractL'auteur décrit la préparation de l'acide 4‐phényl, 6‐(2′, 3′‐diméthoxy) phényl, 2‐oxyisophtalique à partir de la 2,3‐diméthoxychalcone.II décrit également la préparation de deux chalcones substituées et des produits de condensation de celles‐ci avec l'acétone dicarboxylate d'éthyle.
Étude cinétique des réactions de solvolyse VI. Solvolyses du chlorure de benzyle
Authors: Wilputte‐Steinert L. , Fierens P. J. C. 
Published: September 2010

AbstractThe Arrhenius parameters of several solvolysis of benzyl chloride have been measured.As expected, the experimental data do not verify the SN1 Winstein‐Grunwald linear relationship. The deviations are expounded on the basis of a new concept “nucleophilic action” δN, which is related to the rate (k;) of the actual process (SN2) and to the rate (η) which should be observed if the solvolysis did follow a SN1 mechanism:δN = log k — logk′The discussion is extended to linear relationships of the Winstein‐Grunwald type, corresponding to SN2 solvolysis occuring in solvents which differ only in respect to the proportions of the components.
Étude de la sélectivité dans la chloration photochimique
Authors: Benoy G. , Jungers J. C. 
Published: September 2010

AbstractDans ce travail relatif a la chloration photochimique du toluène, des xylènes, de l'éthylbenzène, du cyclohexane et de leurs dérivés chlorés on a d'abord déterminé les conditions dans lesquelles on pouvait réaliser sélectivement la réaction envisagée à l'exclusion des réactions parasites, substitution catalytique et addition photochimique, qui sont parfois extrêmement rapides. II a été possible ainsi de préciser la cinétique de la substitution photochimique qui se réalise par une suite de réactions successives et de déterminer la constante de vitesse relative des différentes étapes. Cette recherche permet en conséquence de fixer les conditions optimum pour la préparation de tel terme dans la série des dérives chlorés.
Mesures de tensions superficielles dynamiques par lame plongeante sur entonnoir débordant
Authors: De Rycker M. , Defay R. 
Published: September 2010

AbstractDuring the measurement of the surface tension of solutions by the ring method, on a moving surface, the part of the surface enclosed in the ring reaches a steady state corresponding to an aging different from the aging of the outside part. One can avoid this difficulty by the method of the dipping plate. The errors due to the Archimede's force and to the lift force of the liquid flow are eliminated by using a very thin plate of mica.The horizontal parts of the curves, surface tension versus rate of flow, are similar to those observed by the ring method but are higher. This confirms that the new method eliminates the error due to the aging of the surface enclosed in the ring.This method is applied to aqueous solutions of adipic acid, azelaic acid and sebacic acid. The adipic acid reaches its static value of surface tension too quickly and the dynamic values cannot be measured by this method. The time evolution of the two others acids is easily observed.