bluuebunny/crossref_metadata_2025_split huggingface dataset:
Préparation de Nouveaux bis (Thiazolyl‐4)‐Benzènes
Authors: De Roocker A. , De Radzitzky P. 
Published: September 2010

AbstractEight new bis‐(4‐thiazolyl) benzenes substituted on the 2‐position of both thiazole rings by the groups –CH3, –C6H5, –NH2 or –NHC6H5 have been prepared in high yield by reacting a bis‐x‐halogeno‐acetyl‐benzene with a thioamide. These compounds are models for some heat stable polymers containing the thiazole ring in the chain.
Enthalpy, free energy, entropy and heat capacity of cyclohexane and acetaldehyde
Authors: Lippincott E. R. , Nagarajan G. , Katon J. E. 
Published: September 2010

AbstractOn the basis of the recent vibrational and structural data, enthalpy, free energy, entropy and heat capacity of cyclohexane and acetaldehyde have been computed for the temperature range 200‐2000°K by the statistical‐mechanical treatment. The calculated values of heat capacities are in good agreement with the experimental ones. This agreement provides confirmatory evidence for the validity of the vibrational assignments of these two molecules, especially in low frequency regions.
Etude du Comportement Électrochimique des Organomagnésiens dans les Éthers Anhydres
Authors: Martinot L. 
Published: September 2010

AbstractNous avons étudié la cinétique électrochimique de l'oxydation et de la réduction d'une série d'organomagnésiens aliphatiques dans l'éther éthylique et le tétrahydrofuranne.La réaction anodique donne naissance aux hydrocarbures éthyléniques et paraffiniques correspondant au radical organique du magnésien et à l'hydrocarbure paraffinique de doublement. Un dépôt de magnésium constitue la réaction cathodique.L'étape cinétiquement déterminante est le transfert électronique à l'anode et l'électrocristallisation du dépôt métallique à la cathode.
Triterpènes VI. L'Oxydation de la Coriacéolide par le Dioxyde de Sélénium
Authors: Tursch B. , Daloze D. , Chiurdoglu G. 
Published: September 2010

AbstractSelenium dioxide oxidation of acetoxycoriaceolide (Stryphnodendron coriaceum sapogenin B) leads to compounds exhibiting abnormal ultraviolet absorption. These have been identified as acetoxy‐12, 19‐seleno‐Δ coriaceolide (XIV) and acetoxy‐12, 19‐dioxo‐Δcoriaceolide (XII).
Oxydation Entraînée des Hydrocarbures. I. Influence de la Stabilité des Radicaux Péroxydiques
Authors: Rouchaud J. 
Published: September 2010

AbstractThe reactivity of cyclohexane in the catalyzed autoinitiated oxidation by cobalt naphtenate under an initial partial pressure of oxygene of 11 kg/cm2, in the presence of cumene was studied. The addition of about 5% in volume by cumene in the total volume of the mixture resulted in an increase in the rate of oxidation. In the oxidation of cyclohexane with cumene, the rate was doubled, while in the presence of cumene and a salt of cobalt, the rate of oxydation was 5 times as great. This increase in the rate of oxidation of cyclohexane by the presence of cumene corresponds to the increase in the rate at which this oxidation was initiated. This increase in the rate of initiation results from the increase in concentration of peroxydic radicals which corresponds to the disparition constant of cumyl peroxydic radicals which is about 600 times below the disparition constant of the cyclohexyl peroxydic radicals. The apparent energy of activation in the mixture is 28,5 kcal mol−1 in the temperature range of 130‐60°C.
Oxydation Entraînée des Hydrocarbures. III. Influence des Alcools
Authors: Rouchaud J. 
Published: September 2010

AbstractIn the oxidation of cyclohexane in the liquid phase by molecular oxygen, under the pressure of 11 kg. cm−2, at about a temperature of 150°C and in the presence of 50 ppm by weight in cobalt, the influence of the products of reaction on the rate of oxydation of cyclohexane was studied at different concentrations. The cyclohexanol and cyclohexanone have an accelerating effect while on the other hand, adipic acid reduces the rate of transformation.In using certain aliphatic alcohols such as ethanol, n‐ propanol and the isomers of butyl alcohol under different initial concentrations, an accelerating effect was observed, and more particularly with the t‐butanol.In their presence, the rate of reaction is ten times increased for concentrations of alcohol being less than 0.4 mol. l−1. From the schematized, in the liquid phase, competitive oxidation reactions of two substances, by autoinitiated catalysis, an expression of the rate of oxidation of cyclohexane in the mixture was derived. The rate of oxidation of cyclohexane observed when additives are present, is in general twice as higher, than the calculated maximum rate. This divergence is interpreted as an increase in the degree of branching of chains of reactions, following the addition of the additive.
Essais de Chloration Dirigée. VIII. Photochloration des Composés Aliphatiques en Présence D'Additifs
Authors: Rouchaud J. , Bruylants A. 
Published: September 2010

AbstractLes auteurs ont étudié la photochloration, en phase liquide, de l'isovaléronitrile en présence d'additifs, principalement des amines aliphatiques, aromatiques et hétérocycliques. Ils ont observé des effets de sélectivité. Ainsi la triéhylamine à la concentration 0,5 ml.l−1 conduit à 76% de β‐chloro‐isovaléronitrile et la pyridine à 2 m.l−1 en donne 77%, résultat pratiquement identique à celui obtenu en présence de benzène à 8 m.l−1, c'est‐à‐dire jouant le rôle de solvant.
Étude par Diffraction de Rayons X de Complexes D'Halogénures Alcalins et de Molécules Organiques. VII. Structure de LiCl.C5H5N
Authors: Durant F. , Verbist J. , van Meerssche M. 
Published: September 2010

AbstractLiCl.C5H5N crystallizes in the orthorhombic system, space group P212121; a = 8.61, b = 17.92, c = 4.02 Å, Z = 4.The structure has been determined by heavy atom method using 579 reflections of the (hk0), (hk1) and (hk1) planes, refined by Fourier synthesis and least squares method to an R index of 0.161. Each lithium ion is tetraedrically surrounded by three chloride ions and one nitrogen atom. The structure consists of molecular chains (Li+.Cl−.C5H5N)n, parallel to the [001] axis and held together by means of C–H … Cl− bonds.Distances LiCl: 2.38, 2.39 and 2.38 Å. LiN: 2.01 Å. Mean distances in pyridine: NC: 1.36, CC: 1.39, CC′: 1.40Å. Distance between C5H5N superposed cycles: 3.54Å.
Étude par Spectrométrie Infrarouge de la Complexation de Phénols Substitués par la Triéthylamine
Authors: Lutgen P. , van Damme M. P. , Zeegers‐Huyskens Th. 
Published: September 2010

AbstractBy infrared spectrometric measurements, we have determined the complexation constants (K12) of several complexes formed by substituted phenols with triethylamine in carbontetrachloride solution, at 27°C.Plot of log K12 in function of the a substitution constant of Hammett show two straigth lines with different slopes. The first line, containing the substituents of group I (3–4 di‐CH3, p.CH3, p.I, p.Br, p.F), obeys the relation magnified image.The second line, containing the substituents of group II (3–5 di‐Cl, p.CN, p.NO2) follows the relation magnified image.For the complexes of group I, one may admit the predominance of normal hydrogen bonded complexes of the type magnified image.Compared with the values of ρ obtained previously for complexes formed by phenols with aniline or pyridine, the value of ρ found in this work is greater owing to the greater enthalpy of complexation.For the complexes of type II; our results suggest the predominance of an ion‐pair complexe of the type magnified image.This view is supported by experimental facts such as the variation of colour of the solutions, the diminution of solubility of the complexes and the apparition, in the infrared spectra, of a large band lying between 2900 and 2200 cm−1. This result agrees also with our earlier infrared spectrometric determinations.
Cyclopentanones I. The Synthesis of 2‐Alkyl‐4‐hydroxy‐1‐Cyclopentanones and Derivatives
Authors: Vandewalle M. , Compernolle F. 
Published: September 2010

AbstractThe metal‐ammonia reduction of 2‐alkyl‐4‐hydroxy‐3‐methoxy‐2‐cyclo‐pentene‐1‐ones, (III) gives 2‐alkyl‐4‐hydroxy‐1‐cyclopentanones (IV) and 4‐alkyl‐1, 3‐cyclopentanediols (V).The former products can easily be dehydrated to 5‐alkyl‐2‐cyclopenten‐1‐ones (VI).
I. Oxydation Du Cumène I. Activité catalytique des composés du cobalt
Authors: Rouchaud J. 
Published: September 2010

AbstractThe oxydation of cumene in liquid phase, at a temperature of about 100°C, by oxygen under a pressure of 730 mm Hg, gives principally the corresponding hydroperoxyde. The oxydation was carried out in the presence of various cobaltic compounds which are completely soluble in cumene at the used concentrations. The chelate of cobalt (II)‐ bis (2,2' hydroxybenzylidene) ethylene diamine, C. Co, catalyses vigorously this oxydation. The rate of reaction is initially high (16 mol.% of cumene transformed an hour for [C.Co] = 10−4 ion g l−1, and falls to 20% of the original value after an hour's reaction, showing thus the intervention of inhibition. The maximum rate of reaction varied following 0.5 power of the concentration in C.Co. The yield in hydroperoxyde as compared to the transformed cumene is above 90% for [C.Co] = 10−4 ion g l−1. The same yield falls to 20% for a metal concentration 50 times greater. For [C.Co] = 1,05. 10−4 ion g l−1, the apparent energy of activation in this oxydation is about 12 kcal mol−1 between 80 and 120°C. The optimum conditions—the best compromise between the rate of reaction and the yield of hydroperoxyde—is using C. Co as compared to the cobalt naphtenate, N.Co, corresponds at 100°C, to a concentration of 2, 1. 10−4 ion g l−4 of cobalt, for which the yields in hydroperoxyde are the same (85%), and the rate of oxydation of cumene 1, 6 times faster in presence of C.Co. The different catalysts used fall under the following sequence in activity: C.Co.>N.Co>Acetate (II) 4 aq.>Sulfate (II) 7 aq. The differences in activity are interpreted by electronic effects and by the solvatation of the catalysts.
II. Oxydation Du Cumène II. Action catalytique des métaux lourds chelatés par une Même base de Schiff
Authors: Rouchaud J. 
Published: September 2010

AbstractThe oxidation of cumene in liquid phase by molecular oxygen at 100°C and under a pressure of 730 mm Hg was carried out in the presence of the chelates of bis (2,2' hydroxybenzylidene) ethylenediamine with cobalt (C.Co), nickel (C.Ni), manganese (C.Mn), iron (C.Fe), copper (C.Cu), and zinc (C.Zn). The hydroperoxide of cumene was formed with a yield on the cumene transformed, decreasing as the concentration of the catalyst increased. With C.Co and C.Mn, the initial rate of reaction corresponds to the maximum rate observed. With the other chelates, a period of induction followed by a period of autoacceleration and slowing down was noted. For every catalyst, the maximum rate of oxidation is of 0.5 order in respect to the catalyst concentration, except for C.Mn for which the order is 0.27. At concentrations greater than those which correspond to the limits of solubility of C.Cu or C.Zn in the cumene, these two last chelates inhibit the oxidation. The results are significant of the intervention of inhibition, which agrees with V = k(a — x)X(1+by)−1 and Vi = ki x, where V and Vi are respectively the rate of formation of the hydroperoxide and of the inhibitor y. a is the initial concentration of hydrocarbon. The rate of oxidation becomes V = k(a — x)1+K−1 × a−K−1 with K = kki−1b−1. The results show (Catalyst, [M]. 105 ion g l−1, K. 102, k.104(mol l−1)−1sec−1, kib. 103 (mol l−1)−1 sec−1, kd.102(mol l−1)−1, 5sec−1): C.Co, 21/5.25/6.3/12. 0/27.4; C.Ni, 21/6.6/2.0/3.01/2.75; C.Mn, 21/2.86/17.3/61.0/207.0; C.Cu, 13.2/14.2/0.357/0.25/0.11; C.Fe, 22/2.86/2.92/10.2/5.75. The kinetic constants indicate that the value of the rate of oxidation depends on the inhibition and on the activity of the catalysts in the decomposition of the hydroperoxide. These kinetic constants explain this observed sequence: Vmax C.Co>C.Mn>C.Ni>C.Cu>C.Fe and for the yield of hydroperoxide: C.Co<C.Mn<C.Cu, C.Ni, C.Fe.
Dielectric Constant of Carbon Tetrachloride and 1,1,1‐Trichloro‐Ethane Mixtures
Authors: van Loon R. , Fuks S. , Bellemans A. 
Published: September 2010

AbstractThe static dielectric constant of CCl4, CH3CCl3 and their mixtures has been measured in the liquid region between −20 and +20°C. Applying the Onsager‐Kirkwood theory and extrapolating to infinite dilution we found 1.73 ± 0.03 debye for the permanent dipole moment of the CH3CCl3 molecule. A weak tendency for parallel alignment of the dipolar molecules was observed for concentrated mixtures in CH3CCl3.
Contribution to the Knowledge of the Electrochemistry of Uranium in Molten LiCl‐KCl Eutectic (): IV. The potential of the couple U(III)/U(0)
Authors: Caligara F. , Martinot L. , Duyckaerts G. 
Published: September 2010

AbstractWe have measured the standard potentials of the system U(III)/U(0), in the molten LiCl‐KCl eutectic, within the temperature range from 400 to 550°C. The cell used has been the following:magnified imageThe work has been carried out in glove‐boxes, under inert atmosphere, and special care has been taken in preventing even the slightest oxidation of U(III).A comparison has been made with previous results, obtained by different Authors.
L'étude Des Décompositions Thermiques Par Spectrométrie De Masse
Authors: L'Acétone IV. , Collin Jacques E. 
Published: September 2010

AbstractA mass spectrometric investigation of the thermal decomposition of acetone in a quartz reactor has been undertaken, in the 40–200 microns pressure range, in the absence of a carrier gas. The analysis of the results shows that below 400°C acetone undergoes a dehydration by loss of a water molecule and formation of an allene molecule, in a heterogeneous reaction. The activation energy is found to be of the order of 15 kcal/m. Above 400 °C, the reaction becomes more and more homogeneous and may be explained by a free radical mechanism, although no free radicals could be detected directly. The overall activation energy is of the order of 60 to 70 kcal/m. No secondary reaction leading to methane formation is found to occur in significant amounts.
Extension of the Average Potential Model of Solutions to Systems Submitted to a Moderate Pressure
Authors: Vilcu R. , Bellemans A. 
Published: September 2010

AbstractFormulas required for using the Average Potential Model of Solutions at finite pressures are deduced from the experimental molar volumes of compressed liquid argon and methane, by applying the theorem of corresponding states. As an illustration the theoretical excess volumes of the simple mixtures argon‐methane and carbon monoxide‐methane are discussed.
PMR Shift Values in β‐Diketone Enol Ethers
Authors: Anteunis M. , Schamp N. 
Published: September 2010

AbstractPMR spectral shift data make it possible to distinguish the two possible mono enol ethers of β‐diketones i.e.magnified imageProtons located in α position of the “ene” side resonate at lower field than the same protons in the other isomer where they are in α of the “ one” side.
Structure Du Difer‐Sulfonyle‐Octacarbonyle Fe2(CO)8SO2
Authors: Meunier‐Piret J. , Piret P. , van Meerssche M. 
Published: September 2010

AbstractThe crystal structure of Fe2(CO)8SO2 has been determined from three dimensional X‐ray data. The complex crystallizes in space group P21/c of the monoclinic system, with four formula weights in a cell of dimensions a = 8,75, b = 13,19, c = 12,74 Å, β = 113,4°. The SO2 ligand bridges the two groups Fe(CO)4. The iron‐iron distance is 2,717 Å. The average bond lengths are Fe‐C 1,80, C‐O 1,15, Fe‐S 2,22 and S‐O 1,45 Å. The O‐S‐O angle is 114°. The complex possesses approximately the ponctual symmetry 2 mm.
Molecular Orbital Study of Hydrated Titatium Ion
Authors: De Brouckere Guy 
Published: September 2010

AbstractThe electronic structure of the ion Ti(H2O)6+++ has been studied by a self‐consistent Wolfsberg‐Helmholz method. The effect of the Coulomb repulsion between net charges of each atom has been included in the effective hamiltonian. The formal positive charge +3 is shared between the central atom and the ligands in such a way that the charge of Ti becomes of the order of one. The unpaired electron is in a molecular orbital Tg, whose main components are the 3d orbitals of Ti; in agreement with the crystal field theory.
Enolization and Hydrogen Bridge Formation in Cyclopentane β‐Tricarbonyl Systems
Authors: Anteunis M. , Dewaele S. , De Pooter H. , Compernolle F. 
Published: September 2010

AbstractProtons situated next to the “ene”‐side of enolized β‐diketone systems are less deshielded than when they are situated next to the “one” side in the isomeric enol system. As published before (1) the ethers and esters of the same system show the opposite behaviour. This allows discussion regarding the structure of several cyclopentane β‐tricarbonyl derivatives, in which the different enol forms can be differentiated by I.R. and P.M.R. spectroscopy.
The Thermodynamics of p‐Toluidine and of the p‐Toluidinium Ion: A Mass Transfer Study
Authors: Aboul‐Seoud A. 
Published: September 2010

AbstractThe activity coefficients of p‐toluidine were determined using a modified distribution method. The results were found to conform with the Setchenow relationship, and with the Debye theory of salt effects.The dissociation constant of the p‐toluidinium ion was determined under different conditions of temperature and salt concentration. The thermodynamic dissociation constant was obtained by extrapolation. The activity coefficient quotient fH+/fp‐toluidinium, (Kb)o and (Kb)m were calculated, and the results were discussed. ΔH, ΔG and ΔS, for the dissociation of the p‐toluidinium ion, were determined.
Studies in Organic Mass Spectrometry. V (1): Keto‐enol tautomerism in mass spectrometry
Authors: Schamp N. , Vandewalle M. , Francque M. 
Published: September 2010

AbstractExamination of isomeric 3‐propyl‐ and 3‐butyl‐2, 4‐pentanediones demonstrates that the electron impact induced degradation of a β‐diketone molecule is different when it is enolised or not.
Composés Organométalliques IV. Spectres de résonance magnétique nucléaire protonique de dérivés organostanniques (CH3)3SnR′ ()
Authors: Boué S. , Gielen M. , Nasielski J. 
Published: September 2010

AbstractThe P.M.R. spectra of 29 compounds containing a Sn(CH3)3 group have been recorded. The chemical shifts and the coupling constants are related to Tafťs and Hammetťs σ sequences. For polycyclic aromatic tin derivatives, the shift is influenced by the ring current.
Thermodynamics of Mixed Monolayers
Authors: Joos P. 
Published: September 2010

AbstractFrom the identity of the chemical potential of each component, including the solvent, in the bulk and the surface phase, the Gibbs equation is deduced. Relations are obtained between surface pressure, adsorptions and molar fractions in the bulk phase. The equations hold both for adsorbed and for spread films. A penetrated film is also considered. The relation between molar fraction and surface pressure was tested for the system Na‐laurate and sapoalbin, having very different saturation adsorption values. Agreement between theory and experiment is satisfactory.
L'Étude Théorique Des Systèmes Périodiques III. L'orthonormalisation des orbitales atomiques
Authors: André J. M. 
Published: September 2010

AbstractThe independence of the core terms on the dimensions of the periodic system is proved in a basis of orthonormalized orbitals, and it is shown that the infinite system can be caracterized by these integrals. The formalism for the orthogonalization of the orbitals and for the calculation of the different integrals in the new basis is described.
Studies in organic mass spectrometry. VI [1]. Influence of alkylsubstituents on the fragmentation of 1,3‐dioxane
Authors: Vandewalle M. , Schamp N. , van Cauwenberghe K. 
Published: September 2010

AbstractThe mass spectra of 1,3‐dioxane and its 2,4,5‐ and 6‐alkyl substituted derivatives are discussed. Two main degradation patterns result respectively from initial elimination of a 2‐hydrogen atom or alkyl substituent and from the expulsion of a formaldehyde molecule. Subsequent fragmentations are highly influenced by the presence of substituents.4,6‐Disubstituted 1,3‐dioxanes exhibit a distinct and typical fragmentation, starting with the expulsion of a substituent.Some of the mechanisms proposed are sustained by deuterium labeling.
Organometallic compounds. VI . Electron impact fragmentation of some mixed and symmetrical tetraalkyltins
Authors: Boué S. , Gielen M. , Nasielski J. 
Published: September 2010

AbstractThe mass spectra of mixed tetraalkyltins are described and analysed. The fragmentation pattern is in agreement with the hypothesis of prefered Sn(IV) and Sn(II) valence states in the tin‐containing fragments. These states are reached by losing an alkyl radical from the next higher unfavourable valence state, or by losing an alkene or alkane molecule from a favourable valence state. The ease of cleavage of a carbon‐tin bond in the molecular ion parallels the stabilization of the leaving alkyl radical by hyperconjugation. The findings are tentatively extrapolated to the general behaviour of tetraalkyl derivatives of group IV organometallics.
Enthalpy and entropy changes associated with the ionization of hydroxyethylenediaminetriacetic acid
Authors: Fuger J. , Merciny E. 
Published: September 2010

AbstractEnthalpy changes associated with the three ionizations of hydroxyethylenediaminetriacetic acid have been measured calorimetrically. The values reported for 25°C and μ = 0.1 (KCl) are ΔH1 = −1.12±0.12, ΔH2 = + 3.09±0.05 and ΔH3 = + 6.65±0.08 kcal.mole−1, respectively. From these data and from the acid dissociation constants, entropy changes are calculated.The results are compared with literature data obtained by the determination as a function of temperature of the acid dissociation constants.
Mesure du potentiel standard du couple Np(IV)/Np(III) dans l'eutectique LiCl‐KCl entre 400 et 550°C
Authors: Martinot L. , Duyckaerts G. , Caligara F. 
Published: September 2010

AbstractWe have measured the standard potential of the couple Np(IV)/Np(III) in the molten LiCl‐KCl eutectic, within the temperature range from 400 to 55O°C.The cell used has been the followingmagnified imageThe work has been carried out in glove‐boxes under inert atmosphere and special care has been taken in preventing even the slightest oxidation of Np(III).
Mechanisms for the cleavage of carbon‐tin bonds. IV [1]. Electrophilic substitution at an olefinic carbon atom
Authors: Baekelmans P. , Gielen M. , Malfroid P. , Nasielski J. 
Published: September 2010

AbstractThe stereochemistry and the rate of the reaction of nine vinylic organotin compounds with iodine has been studied. A highly polar transition state A is suggested in order to interpret the reactivity sequences (1) and (2), the observed salt effect and the retention of configuration of the vinyl group.magnified image
Dosage de traces de plomb par «cocristallisation» avec NaCl et spectrophotométrie
Authors: Gillet A. C. 
Published: September 2010

AbstractThe procedure consists, briefly, in crystallizing a small amount of NaCl out a saturated brine containing the test sample. Lead in solution cocrystallizes quantitatively. After filtration, it is determined by spectrophotometry with 4 (2 pyridylazo) resorcinol.Among heavy metals, only cadmium interferes. The total sensitivity can reach a few parts per billion.The results obtained are in good accordance with those given by polarographic and atomic absorption spectrophotometric methods.The procedure has the advantage of selectivity without needing cyanide. It can be substituted to the classical dithizone method in most cases.