bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Oxidation‐Reduction Systems. III. The Reversible System Ti+4‐Ti+3
Authors: Verbeek F. , Eeckhaut Z.
Published: September 2010

Oxidation‐reduction potentials of solutions of Ti+4 and Ti+3 have been determined as a function of time and dilution. It follows from this study that the equation of Nernst can be applied and that deviations which occur for more dilute solutions are due to the influence of the cathodic reduction current of the solvent, as is shown from the polarization curves.

As the anodic oxidation of the reductant (Ti+3) occurs at more negative potentials than the cathodic reduction of the solvent, oxidation of Ti+3 cannot be avoided even in a nitrogen atmosphere. In solution all Ti+3 is eventually oxidized to Ti+4.
The Olefin‐Forming Elimination Reaction. The Preparation Of 2,3‐ Dimethyl‐1‐Butene
Authors: Anteunis M. , Schamp N. , Thierie R.
Published: September 2010

A new explanation for the apparant contradiction in the Hofmann and Saytzeff‐rules in elimination reactions is advanced. Evidence is given to show that Hofmann elimination occurs as the consequence of an irreversible reaction. Eliminations following the Saytzeff rule then are reversible reactions, giving the most stable products.
Contribution a la Spectrométrie Raman – III Etude de la fréquence de vibration de la raie raman du Carbonyle
Authors: Michel Gilbert
Published: September 2010

The author shows that, if the inter‐ or intramolecular associations and the particular case of ring strain are excluded, the vibration frequency of the carbonyl band is especially influenced by the electronic effects of neighbouring groups.

He attempts to explain by the inductive and mesomeric effects of the X groups, the sequence of the carbonyl frequency characteristic of esters, aldehydes and ketones.

He points out that, in the case of α‐substituted compounds, the splitting of the carbonyl band is easily interpreted by rotational isomerism introducing a discrimination between normal and field inductive effects.

While the carbonyl frequency seems to be a complex function of inductive and mesomeric effects, the intensity of carbonyl band appears to be chiefly dependent on mesomerism and so, promises to be a powerful tool for the study of conjugation and steric effects.
Affinement de la Structure de SP(C2H5)3
Authors: van Meerssche Léonard M. A. , Stoffyn P. J.
Published: September 2010

The structure of SP(C2H5)3 has been refined by adding 0kl, hk1, and hk2 data to the hk0 zone previously studied. By random distribution, enantiomorphous molecules acquire a statistical symmetry not inherent in the individual molecule.

The space group appears to be P6amc with Z = 2. Cell dimensions are
a = 8.98, c = 6.32 Å.

Bond lengths (PS = 1.86; PC = 1.87 Å) are compared with bonds reported for similar compounds.
Spectre de Vibration, Structure et Stabilité du Dioxolane 1.3
Authors: Tarte Pierre , Laurent Pierre A.
Published: September 2010

The I. R. and Raman spectra of pure 1.3 dioxolan have been investigated, and the results compared with recent published work. Some slight discrepancies are explained by a fairly rapid decomposition of dioxolan in the presence of air. The bands assigned to the skeletal vibrations are broad in the liquid, and diffuse in the gas. Bands due to CH2 vibrations however preserve their rotational structure. This is tentatively explained by a flattened shape of the curve of potential energy in relation with the geometry of the molecule.

The behaviour of some characteristic frequencies of dioxolan and related molecules is briefly discussed.
Études Conformationnelles IV – Equilibre Conformationnel Équatorial‐Axial du Cyclohexanol
Authors: Chiurdoglu G. , Masschelein W.
Published: September 2010

Solvent effects on conformational equilibrium of cyclohexanol have been studied by infra‐red spectroscopy. Relative absorption intensities of ν(C–O) stretching vibrations of equatorial and axial hydroxyl groups of cyclohexanol have been determined for a series of 10 solvents. The intensity of the absorption of cyclohexanol at 1069 cm−1 has been compared with that of the ν(C–O) absorption of trans‐4‐tertiobutylcyclohexanol. No appreciable change of conformational equilibrium in different media was apparent. Values for the free energy difference between equatorial and axial conformation of the hydroxyl group in cyclohexane are reported.

Solvent effects on ν(C–O) frequencies may provide a new experimental method for the localisation of ν(C–O) bands.
Le Spectre de Masse du Cyclopentanol et du 2d2, 5d2‐Cyclopentanol
Authors: Natalis P.
Published: September 2010

By the study of 2d2, 5d2‐cyclopentanol mass spectra recorded with variable energy electrons from 12 to 70 volts, it is possible to explain the behaviour of non‐labelled cyclopentanol under electron impact.

An interpretation of the ring opening and breaking processes for ionized molecules can be given by determining the composition and to some extent the structure of fragment ions and by studying the metastable transitions. The molecular ions have mainly the structure (CHOH–CH2–CH2–CH2–CH2)+. The rearrangement ions OH2+, OH3+, CHOH2+ common to alcohols have been found. Some conclusions are in agreement with previous results obtained with cyclopentanone, methylcyclopentane and cyclopentyl bromide, in particular the fragility of the α(C–C) bond.
Spectrophotométrie Infra‐Rouge des Produits de Réaction de L'Isocyanate de Vinyle Avec Les Amines
Authors: Moelants L. J. , Hart R.
Published: September 2010

Pax réaction de l'isocyanate de vinyle avec les dérivés aminés, on obtient des produits pour lesquels deux structures tautomères sont possibles: soit du type N‐vinylurée (I), soit du type N‐éthylidène‐urée (II).

L'étude spectrophotométrique infra‐rouge permet d'attribuer à ces produits la structure I.
Studies on halogenated aliphatic compounds. V. The halogenated acetonitriles under electron impact
Authors: van Der Kelen G. P. , De Bièvre P. J.
Published: September 2010

Les spectres de masse de CH3CN, CH2FCN et CH2ClCN ont été étudiés à des potentiels d'accélération des électrons décroissants de 70 V jusqu'au potentiel d'ionisation des molécules. Les spectres de masse de CHCl2CN, CHF2CN, CCl3CN et CF3CN ont été examinés à 70 V et à 25 V. L'allure des courbes d'abondance des différents fragments ioniques en fonction de l'énergie des électrons et l'étude de l'abondance relative de ces fragments, conduisent à l'établissement d'un schéma de décomposition de ces molécules sous l'impact électronique. Pour les trois composés CH3CN, CH2FCN, CH2ClCN on observe que le nombre d'ions formés par des processus indirects augmente linéairement en fonction de la valeur de l'électronégativité suivant Pauling des atomes H, Cl et F.
Stéroïdes et Terpénoïdes de Différentes Espèces D'Irésine
Authors: Crabbé Pierre , Azpeitia E. A. , Djerassi Carl
Published: September 2010

Investigation of Iresine pringlei led to the identification of the pentacyclic triterpene friedelin (III) (in the stem), ceryl alcohol (IV), as well as the steroids stigmastanol (VIII), stigmasterol (XI), β‐sitosterol (V) and α‐spinasterol (XII).

From Iresine calea were isolated ceryl alcohol and β‐sitosterol.
Considérations Théoriques sur L'Emploi D'Hypobromite de Soude en Milieu Alcalin
Authors: Claeys A.
Published: September 2010

Les erreurs mentionnées dans différentes méthodes employant de l'hypobromite, et attribuées à la présence de divers composés dans la solution oxydante, nous a amené à une étude théorique générale concernant l'emploi d'une solution oxydante composée.

A l'aide de données graphiques en se basant sur l'inclinaison des droites obtenues, il est possible de calculer le nombre d'électrons échangés dans l'oxydation en milieu alcalin et en milieu acide. En plus, la composition de la solution oxydante peut être déterminée à l'aide du point d'intersection des droites.

Les mêmes données indiquent que la détermination à l'aide d'un excès d'hypobromite est indépendante de la composition de la solution oxydante et élimine ainsi les erreurs dues à l'instabilité ou le changement interne de la solution oxydante employée.
Steroïdes CLXXIV Synthèse de Bis — Steroïdes Diacétyléniques
Authors: Crabbé Pierre , Zderic John A.
Published: September 2010

The diacetylenic steroids (VI), (VII) and (X) have been prepared by the cupric acetate — pyridine method. The “bis‐norlutine” (VI) has been partially hydrogenated to the corresponding “diene” (VIII) and the “bis‐acetate” (X a) has been converted to “bis‐ethisterone” (VII).
Higasi's Method for the Determination of Electric Dipole Moments
Authors: Claeys E. G. , van Der Kelen G. P. , Eeckhaut Z.
Published: September 2010

Dans l'intention de vérifier la généralité de l'équation de Higasi pour la détermination rapide du moment dipolaire de molécules en solution, une série de composés organométalliques et aliphatiques, dissous dans différents solvants apolaires, a été étudiée. De la bonne concordance entre les moments dipolaires obtenus par calcul classique selon Debye (μ.c) et ceux obtenus par l'application de l'équation simplifiée (μH), il résulte que la méthode de Higasi constitue une aide de valeur pour l'étude de substances sensibles à l'air ou à l'humidité.
Contribution A L'étude de L'Anneau Butanique par Spectroscopie Infra‐Rouge
Authors: Chiurdoglu G. , Doehaerd Th. , Duts M.
Published: September 2010

The examination of ∼90 cyclobutanic substances, in the I.R. region of 900‐950 cm−1, indicates that all the components possessing at least one cyclic CH2‐group, free of substitution, presents 1 to 3 absorption bands; one of them at least belonging likely to the vibration γr (CH2). It would thus be easy to recognize the existence of a C4‐ring in such components if there was not the fact, that a great number of non cyclobutanic derivatives also absorb in this region.

This work, together with the one of C.H.F. Allen and Coll. permits to close the series of works concerning the direct correlations: I.R., reactions of the alicyclic ring. Except for definite cyclanones, spectroscopy admits only suppositions with regard to the size of the ring.
A New Method for the Preparation of 4,5‐Substituted Δ4‐Oxazoline‐2‐Thiones
Authors: Willems J. F. , Vandenberghe A.
Published: September 2010

Een nieuwe methode voor de bereiding van 4,5‐gesubstitueerde Δ4‐oxazoline‐2‐thionen wordt beschreven. Uitgaande van benzoïnen of acyloïnen en thiocyaanzuur (of de zouten hiervan en een zuur) worden met goede opbrengsten Δ4‐oxazoline‐2‐thionen bekomen. In sommige gevallen vormen zich de isomere Δ4‐thiazolin‐2‐onen als nevenprodukten. Enkele gegevens over I.R. spectra en vormingsmechanisme worden eveneens vermeld.
Etudes Spectroscopiques des Molecules Hydroxylees III. Localisation des bandes d'absorbtion v(C–O)H du cyclopentanol, du cycloheptanol et du cyclooctanol
Authors: Chiurdoglu G. , Masschelein W.
Published: September 2010

The ν(C–O) absorption bands of cyclopentanol, cycloheptanol and cyclooctanol are determined by the effects of solvent on the infrared spectrum of these compounds.

The possibilities of conformational analysis by this method are discussed.
Étude Infrarouge de Phosphates de Calcium de la Famille de L'Hydroxylapatite
Authors: Winand L. , Duyckaerts G.
Published: September 2010

This article deals with infrared spectroscopic studies, in the range 400‐4000 cm−1, of some calcium phosphates having an apatitic structure. The bands are assigned and small differences between some spectra are explained.

Occurrence of free OH− groups in the apatitic cell is confirmed; acidic phosphate groups, linked together by hydrogen bonds, have been detected in the spectra of compounds having a Ca/P value lower than the hydroxylapatite one.

Heat effect upon the constitution of these compounds has also been studied; these infrared data get information which could not be obtained by X rays spectrography; i.e. the occurrence of pyrophosphate groups in solid solution in the apatitic cell.

The experimental data are satisfactorily explained by the assumption that H+ ions are able to «substitute» progressively Ca++ ions in the apatitic structure.

An original formula is proposed for the α tricalcium phosphate.
Structure du Chlorure de Benzoylsalicyloyle et Préparation de Benzodioxanne‐1,3 Ones‐4 Par Action des Dérivés Organocadmiques
Authors: Renson M. , D'Harcour J‐C.
Published: September 2010

Bien que le chlorure de benzoylsalicyloyle posséde une structure normale déterminée avec certitude par spectrographie infra‐rouge, il donne par action des organocadmiques un dérivé cyclique de la classe des benzodioxanne‐1,3 ones‐4. Par contre, les dérivés obtenus par action des alcools ou des amines possèdent comme lui la structure normale.

Sur la base de ces données, ainsi que sur celles fournies par l'identification et la détermination de l'origine des produits secondaires obtenus, nous discutons en détail le mécanisme de la réaction.
Mean Amplitudes of Vibration of some Tetrahedral XY4 Type Molecules‐Part II
Authors: Nagarajan G.
Published: September 2010

As a second paper of this study, the computed values of (1) mean‐square amplitude quantities, (2) generalised mean‐square amplitudes (mean‐square parallel amplitudes, mean‐square perpendicular amplitudes and mean cross products) and (3) mean amplitudes of vibration at the temperatures T=0 and T=298°K have been reported for the molecules GeH4, GeD4, SiH4, SiD4, GeF4 and TiCl4 respectively.
The Friedel‐Crafts Acylation Reaction I. Substituent Effect in the Friedel‐Crafts Benzoylation of Toluene
Authors: Slootmaekers P. J. , Roosen R. , Verhulst J.
Published: September 2010

On a mesuré les constantes de vitesse de la réaction de Friedel et Crafts de chlorures de benzoyle, substitués en para, sur le toluène et dans le chloro‐benzène comme solvant. Des valeurs obtenues à différentes températures on a déduit les paramètres cinétiques des réactions: p.X‐; k2.104 1.mole−1 sec−1 à 20°C; ΔH* kcal/mole; Δs* u.e.: t.Bu‐: 0,63; 14,7; −27,3; Me‐; 0,83; 14,1; −29,0; H‐; 3,51; 13,7; −27,0; F‐; 3,39; 13,8; −27,0; Cl‐; 6,17; 13,1; −28,0; Br‐; 6,77; 13,3; −27,2.

Les réactivités globales n'obéissent pas à l'équation de Hammett. On prouve que cela ne peut être attribué à un changement dans la distribution des isomères ou dans le mécanisme de la réaction pour les difféents membres de la série. It est possible qu'une relation linéaire relie l'enthalpie à l'entropie d'activation de la réaction, mais les résultats ne sont pas convaincants. La constante de vitesse dépend de la concentration initiale en complexe réactionnel. Les valeurs de la constante de vitesse obtenues par extrapolation vers une dilution infinie n'obéissent non plus à l'équation de Hammett. Ceci est probablement dû à l'emploi de la concentration du réactif comme paramètre d'extrapolation au lieu d'une propriété physique du mélange réactionnel. Les réactions sont suivies par titration de l'acide chlorhydrique formé dans la réaction et entraîné dans un courant de gaz inerte. Cette méthode expérimentale est discutée et décrite en détail.
The Humulinic Acids Part 1. Isolation and preparation of humulinic acid isomers
Authors: Anteunis M. , Bracke M. , Verzele M. , Alderweireldt F.
Published: September 2010

The isolation and preparation of several humulinic acid isomers named humulinic acid A, B, C and D is reported. They can be obtained by isomerization of the known degradation product of humulone which is the humulinic acid A of the above series.
Contribution a L'Étude De Dérivés De La Carnitine Et De La Bétaine Crotonique
Authors: Binon F. , Bruckner P. , Deltour G.
Published: September 2010

New method for the synthesis of alkyl esters of carnitine chloride and crotonobetaïne are described.
Essais de Chloration Dirigée VI. Corrélation Structure‐Réactivité Dans la Photochloration des Composés Aliphatiques. Données Expérimentales et Théoriques
Authors: Wautier J. , Bruylants A.
Published: September 2010

The photochemical chlorination of isobutyric acid and its functional derivatives has been undertaken with the aim of completing the data previously collected in this Laboratory on the relative distribution of monochloro‐isomers obtained. The studies bear on the acid, its methyl ester, on acyl chloride and the nitrile. The analysis of the products of chlorination has been effected by gas‐phase chromatography.

Samplings taken during the course of the reaction have shown that the concentration of mono‐chlorinated products remain in a constant proportion as long as a certain moleper cent is not exceeded.

This conclusion has permitted the integration of the observed orientation effects in free‐radical chlorination into the general problem of structure and reactivity, in establishing a relation between relative ratio of substitution on the one hand and polar and hyperconjugative effects of substituents on the other, of the form:

The application of this equation to the experimental results leads to a negative value for the reaction constant (p = –0,212) and a positive value for the parameter of hyperconjugation (h = +0,114).

This relation permits the calculation of the distribution of monochloroisomers for an aliphatic compound at a temperature of about 100°C.
Potential Field and Force Constants of Some Octahedral XY6 Type Molecules
Authors: Nagarajan G.
Published: September 2010

A short account of the vibrational analyses for the octahedral XY6 type molecules possessing the symmetry point group On has been reported. The construction and orientation of symmetry coordinates, F and G matrices following the methods outlined by Wilson have been clearly deduced. By making use of the redundant symmetry coordinates a unique set of force constants have been obtained for the molecules SF6, SeF6, TeF6, MoF6, WF6, UF6, NpF6, PuF6, ReF6, OsF6, IrF6 and PtF6 respectively.
A Potentiometric Study of The Silver Complexes of N,N'‐Bis (2‐Hydroxyethyl) Dithio‐Oxamide
Authors: Herman M. , van Poucke L. , Eeckhaut Z.
Published: September 2010

It has been proved that N,N'‐Bis (2‐hydroxyethyl) dithio‐oxamide forms with silver different complexes, dependent from the pH of the solutions and the excess of the metal ion.

With an excess of ligand an insoluble yellow complex Ag3H5X4 is formed in the pH range 2,5 to 3,5. The solubility product in strong buffered solution was found to be Ks=10–61,31

In the pH range 4 to 6 a more stable yellow complex AgHX is formed with a solubility product Ks=10–19,27.

With an excess of silver ion a very unstable white complex Ag2X is formed.
Synthèse de Dérivés Fonctionnels Des Acides Aminés
Authors: Hannart J. , Bruylants A.
Published: September 2010

The authors describe a new synthetic procedure for the preparation of aminocyanoesters, by which they have obtained ethyl‐α‐amino‐γ‐cyanobutyrate (m. 105 °C) and ethyl‐α‐amino‐δ‐cyanovalerate (m. 132 °C). The value of the aminocyanoesters as intermediates in the synthesis of natural or synthetic aminoacids has been demonstrated. Indeed the first one gives on hydrolysis glutamic acid and on reduction dl‐ornithine whereas the second one gives respectively α‐aminoadipic acid and dl‐lysine in moderate yield (ca. 50%).

The authors have also studied the nitrosation of aliphatic dinitriles as a means of preparing α‐aminodinitriles. The glutaro‐and adiponitriles can be transformed into their isonitrosoderivatives which are then converted by hydrogenation into the corresponding α‐aminodinitriles. They have thus obtained dl‐glutamonitrile for the first time as its hydrochloride (m. 93 °C).
Détermination du Magnésium Dans Les Fontes Nodulaires Par Analyse Par Activation au Moyen de Deutons Énergétiques
Authors: De Bruyne P. , Hoste J.
Published: September 2010

Small amounts of magnesium confer valuable properties on nodular cast iron. Ordinary chemical and spectrographic methods for determining magnesium in iron are not satisfactory for concentrations below 0,1%, which is the range of interest in the case of cast iron.

It is the object of the present work to study the possible application of activation analysis techniques to this problem.

It appears that a short bombardment with deuterons of 12 MeV will produce an easily detectable amount of Na22 which will be a measure of the magnesium content of the sample. The iron of the sample itself may be used as an internal monitor through the Fe(d, α)Mn reaction.

After correction for the decay of the 6‐day Manganese‐52, the ratio of the Na22 activity to the Mn54 activity is directly proportional to the magnesium content of the iron.

In order to measure the sodium and manganese activities, a method for separating them from iron, cobalt and other elements was developed. The procedure studied was based on the use of an anion‐exchange resin.
Studies on the Grignard Reaction‐V polar substituent effects in the grignard addition reaction on substituted acetophenones
Authors: Anteunis M. , van Schoote J.
Published: September 2010

Relative reaction rates of fifteen meta and para substituted acetophenones were measured using gas chromatography. With the normal Hammett σ‐values, a linear free energy relationship is found (ρ=+ 0.415), from which strongly conjugative substituents (p. EtO‐, p. MeO‐, p. NMe2‐) deviate. No deviation is found for weak and moderately strong+M substituents. These results are interpreted in the light of a previously proposed (8) reaction mechanism. Resonance contribution can displace the rate‐determining step of the multistep process of the Grignard addition reaction.
The Practical pH‐Calculation of Mixtures of Acids
Authors: Claeys A.
Published: September 2010

An application of formerly proposed formulas is made in calculating the hydrogen‐ion concentration of mixtures of acids in aqueous solution.
Potential Energy Constants, Rotation Distortion Constants and Thermodynamical Properties of GeH3CN and GeD3CN
Authors: Pillai M. G. Krishna , Perumal A.
Published: September 2010

The force constants, obtained from a normal coordinate analysis of the molecules GeH3CN and GeD3CN using Wilson's F.G. matrix method, have been made use in the evaluation of rotational distortion constants for these molecules. Molar thermodynamic properties of these molecules for the ideal gaseous state at one atmospheric pressure, with rigid rotor harmonic oscillator approximation have also been obtained.
1,2‐Cyclohexanedione
Authors: De Borger L. , Anteunis M. , Lammens H. , Verzele M.
Published: September 2010

1,2‐Cyclohexanedione (I) is an interesting substances for which adequate synthesis methods are lacking. Its preparation and some chemical and physical properties are the subject matter of this paper.
Étude des Propriétés du Chlorure D'O‐Chlorosélénobenzoyle Application À la Synthèse D'O‐Alcoylsélénoacylophénones
Authors: Renson M. , Piette J‐L.
Published: September 2010

Contrairement à son isologue sulfuré, l'acide o‐méthylsélénobenzoïque ne se transforme pas en son chlorure sous l'action du chlorure de thionyle mais bien en chlorure d'o‐chlorosélénobenzoyle. La rupture de la liaison Se‐C aliphatique d'un sélénoéther arylaliphatique sous l'effet de ce réactif semble générale à la lumière des différents cas étudiés.

Le chlorure d'o‐chlorosélénobenzoyle a cependant pu être utilisé avec succès pour la préparation des o‐alcoylsélénoacylophénones à partir des dérivés organocadmiques.

En vue d'une étude infra‐rouge à publier très prochainement un certain nombre de dérivés nouveaux de ce chlorure, ainsi que plusieurs dérivés sulfurés semblables également inconnus ont été préparés dans ce travail.
Isomérie de Position et Spectres de Masse II‐Triméthylcycloalcanes et méthyléthylcycloalcanes à cycle en C3, C5 et C6
Authors: Natalis P.
Published: September 2010

Mass spectra of position isomers have been examined in three series of cyclic hydrocarbons, (a) trimethylcycloalkanes with C3, C5 or C6 ring, (b) methylethylcyclopentanes and (c) gem derivatives of methylethylcycloalkanes with C3, C5 or C6 ring. Correlation rules of some features of mass spectra with molecular structure are attempted i.e. abundances of molecular ions P+ and fragment ions corresponding to the loss of C1 or C2 groups, (P‐CH3)+, (P‐C2H5)+ and (P‐C2H4)+.

As a result it is shown that correlation rules of branched hydrocarbons can generally be applied to the bi‐and trialkylcycloalkanes investigated. In addition new correlation rules for cyclic hydrocarbons can be deduced from the present work and specific correlations for C5 and C6 rings are suggested.
Potential Energy Constants, Rotational Distortion Constants and Mean Square Amplitudes of Vibration of Some XY3Z Type Monohalogermanes
Authors: Pillai M. G. Krishna , Perumal A.
Published: September 2010

Potential energy constants for the molecules GeH3F and GeH3Br have been calculated using the observed fundamental frequencies and potential function consisting of all significant valence potential constants. Also included in this paper are the calculated values of rotational distortion constants and mean square amplitudes of fundamental vibrations for these molecules as well as for the molecules GeH3Cl and GeD3Cl.
Modification de la Fonction Carboxy de la Pénicilline
Authors: Claesen M. , Vanderhaeghe H.
Published: September 2010

La fonction carboxy de la pénicilline V (I, R=C6H5OCH2−, X=OH) a été transformée en fonction alcool, par réduction de l'azide avec du LiBH4. L'azide a permis aussi la synthése du benzylcarbamate. Lors de la réduction de l'ester de la pénicilline V, la fonction ester et le carbonyle du β‐lactam sont réduits par le LiBH4.
Grignard Reaction VIII. On the Bimolecular Nature of the Grignard Reagents
Authors: Anteunis M.
Published: September 2010

It is the purpose of this paper to show that in contrast with the now widely accepted view (see f.i. ref. 1) the bimolecular form of the Grignard reagent (I) is not necessarily the unique active species. In most cases the activity can just as well be attributed to the monomolecular form. Undoubtedly several forms including the monomeric are actually present in the solutions, but the question is which species is responsible for the Grignard reactions?
Préparation de Styrènes α, β Disubstitués
Authors: Barbieux M. , Martin R. H.
Published: September 2010

Several mixtures of unsaturated esters were obtained by dehydration of hydroxyesters (Ia→Ih) (from a Reformatsky reaction) and each constituent, after separation by gas liquid chromatography, was assigned either the α, β‐ or the β, γ‐unsaturated ester structure following the observed νc‐0 frequency and the cis or trans configuration. The less rigid non‐conjugated ester is formed predominantly or exclusively when steric strain prevents conjugation in the “conjugated” isomer. α, β dialkylstyrenes were obtained after hydrolysis and decarboxylation and this last reaction proceeds with concomitant shift of the double bond, α β dialkylstyrenes were obtained also through dehydration of appropriate tertiary alcohols (from a Grignard reaction). Attribution of geometric configuration for the α, β dialkylstyrenes and the β, γ unsaturated esters was realised on the basis of volatility and U.V. spectrum according to Cram's method.
Structure Moléculaire de Trois Complexes du Fer‐Carbonyle Avec L'Acétylène et Ses Dérivés
Authors: van Meerssche M. , Piret P. , Meunier‐Piret J. , Degrève Y.
Published: September 2010

Détermination par diffraction des R.X. de l'architecture moléculaire de trois complexes du fer‐carbonyle: 2 isomères de Fe2(CO)6 (C2H2)3 et Fe2(CO)6 (C6H5.C6H5). Dans les trois molécules les ligands organiques subissent un remaniement important de manière á permettre la formation d'édifices diamagnétiques obéissant à la règle du gaz rare pour les atomes de fer.
A Thermodynamic Study of the Dissociation of Aniline Hydrochloride
Authors: Aboul‐Seoud A.
Published: September 2010

The distribution of aniline between benzene and aqueous sodium chloride solutions was studied at 10, 25 and 35°C. The data obtained was used to calculate the activity of the amine under the different conditions.

The dissociation of aniline hydrochloride was studied at different temperatures, different concentrations and in presence of different concentrations of sodium chloride, by the distribution method.5 The ratio of the activity coefficients of hydrogen and anilinium ions was calculated for the different conditions. The relationship between the activity of the free amine in water, and salt concentration, was studied.
Mean Amplitudes of Vibration, Bastiansen‐Morino Shrinkage Effect and Thermodynamic Functions in some Intergroup IVA Molecules
Authors: Nagarajan G.
Published: September 2010

Mean amplitudes of vibration for the GeC2, Ge2, Ge2Si and GeSiC molecules possessing a linear asymmetrical structure with the point group C∞ ν have been calculated on the basis of the principle postulated by Cyvin. A brief description of the Bastiansen‐Morino shrinkage effect has been narrated with an analytical expression for this molecular system. The calculated values of the shrinkages at the temperatures T=0, T=298°K and T=500°K are reported. The molar thermodynamic functions have also been computed for the temperature range 100‐2000°K with an assumption of a rigid rotator, harmonic oscillator model.
N.M.R. Experiments on Ketals IV. P.M.R. Spectra and Conformations of the Dioxolanes of 2,3‐Butanediol and Acetophenone
Authors: Anteunis M. , Alderweireldt F.
Published: September 2010

The dioxolanes of acetophenone and 2,3‐butanediol were prepared and the three possible isomers were separated by GLC. Structural assignment was based on physical and spectral behaviour. The magnetic anisotropy effect between cis‐1,2‐ and 1,3‐located methylgroups and/or protons is found to be in accordance with previously found values (1,6). The cis‐β‐phenyl interaction seems to cause a ca 0.20 ppm downfield shift of the ring proton, while this effect is about 0.06‐0.10 ppm downfield for a methyl group. A cis‐1,2‐dimethyl interaction on the contrary causes an upfield shift of about 0.12 ppm. The entire X3AA'X'3 patterns were solved using literature data (2,3). In the erythro compound no AX' coupling was found, while the previously proposed 2 correlation between JAA' and JAX' seems not to be fulfilled.
Étude du Comportement D'Isomères Géométriques Sous L'Impact Électronique V. Comparaison des données obtenues, par différentes méthodes, pour les 1,2‐diméthylcyclohexanes cis et trans
Authors: Natalis P.
Published: September 2010

Ionization potentials of cis and trans 1,2‐dimethylcyclohexanes have been determined by electron impact as well as appearance potentials of fragment ions first produced by breakdown of these molecules. Ionization efficiency curves treated by Warren's extrapolated difference method yield values in good agreement with those obtained by Lossing's semilogarithmic method.

Identical ionization potentials and different appearance potentials of main fragment ions measured for both isomers can be related to the extra energy stored in the cis compound because of its steric conformation.

Comparison is attempted between present electron impact data and photoionization data for the compounds investigated and qualitative agreement is found.
Étude Spectroscopique de Molécules Halogénées. III. Analyse conformationnelle en série cycloheptanique
Authors: Reisse J. , Ottinger R. , Chiurdoglu G.
Published: September 2010

The conformational analysis of halogenocycloheptanes was approached by infra‐red measurements in the ν (C‐Hal) region. For each derivative, the ν (C‐Hal) bands are attributed by solvent effect. It seems possible to describe halogenocycloheptanes as a mixture of three conformers in thermodynamic equilibrium.
The distribution ofm‐chloroaniline and the dissociation ofm‐chloroaniline hydrochloride
Authors: Aboul‐Seoud A. , Abou‐Egla B. , Bezirdjian K.
Published: September 2010

For the interpretation of kinetic measurements involvingm‐chloroaniline hydrochloride, the dissociation constant of the latter was determined at 5, 15, 25 and 35 °C, in sodium chloride solutions of 0 to 3 mole/1, using a modified distribution method (1). The distribution ofm‐chloroaniline between petroleum ether and aqueous sodium chloride solutions, was studied under the same conditions. The activity coefficients of the amine in aqueous solution, were determined at these conditions. The thermodynamic dissociation constant of the amine hydrochloride, at zero molality, was estimated at the different temperatures. ΔH, ΔF and ΔS were calculated.
Kinetics of laminar premixed methane — oxygen — nitrogen flames
Authors: Burke R. , van Tiggelen A.
Published: September 2010

La vitesse de propagation de la flamme, la température des gaz de combustion, et l'épaisseur de la zone de réaction ont été mesurées dans plus de trois cent mélanges de composition différente de méthane‐oxygéne‐azote.

Cette étude expérimentale confirme le résultat d'investigations, faites par d'autres auteurs, sur la structure de la zone de réaction de la flamme se propageant dans quelques mélanges particuliers. On peut en dériver une énergie d'activation apparente ainsi que des ordres partiels par rapport au combustible et à l'oxygène.
N. M. R. Experiments on ketals. V1 the conformation of 2‐substituted 1,3‐dioxolanes
Authors: Weireldt F. Alder , Anteunis M.
Published: September 2010

The A2B2 system of the ring methylene protons in seventeen 2‐mono‐ and di‐substituted 1,3‐dioxolanes is analysed. The gem, cis and trans spin coupling constants and the shift values are reported. The results confirm the existence of a pseudo‐rotation (I to X) with favoured (pseudo) equatorial substitution.
An IR study of the 2‐(=NCOX)‐thiazoline group
Authors: Seth Paul Willem A.
Published: September 2010

Infrared examination of compounds containing a 2‐(=NCOX)‐thiazoline group has revealed that the imino‐N atom bears proton accepting properties. The spectra of the bases exhibit bands at 1570 and 1477 cm−1. The first band is probably derived from the CO group while the low frequency band finds its origin most likely in the C…N group. The spectra of the corresponding hydrochloride salts show the CO band around 1740 cm−1 which represents a shift of 140 cm−1 to shorter wavelengths as compared with the corresponding bases. Furthermore, these spectra show a close resemblance in the 1750‐1500 cm−1 region to the spectrum of 2‐(acetylamino)‐4‐methyl‐thiazole‐HCl. We are therefore of the opinion that protonation has occurred at the imino‐N atom.
Synthèses et Propriétés des Bases de Schiff. II. — Propriétés acidobasiques et vitesses d'hydrolyse acide des α(p, N‐diméthyl‐aminophényl) iminobenzoylacétanilides (PIBA)
Authors: De Hoffmann E. , Bruylants A.
Published: September 2010

Ce travail est consacré à l'étude cinétique de l'hydrolyse de l'α(p,N‐diméthyl‐amino‐phényl) iminobenzoylacétanilide (PIBA), en milieu acide, ainsi qu'à celle des dérivés de substitution PIBAX et PIBAY; X est le substituant du noyau benzoyle et Y celui du groupe anilide: magnified image.

Les constantes d'acidité de l'ion anilinium conjugué ont été déterminées par spectrophotométrie; les résultats suivants sont obtenus: log KaxKao = pxσ et log Kay/Kao = pvσ Kao = 2,206, px = 0,288 et py = 0,137 (25,5°C).

Les constantes de vitesse ont été mesurées à diverses concentrations en acide, révélant un ordre unitaire par rapport à l'azométhine neutre et fractionnaire vis‐à‐vis de l'acide.

Il n'a pas été possible de lier les constantes d'acidité et les constantes de vitesse d'hydrolyse par une relation simple.
L'Étude des Décompositions Thermiques par Spectrométrie de Masse. III. Acétaldéhyde
Authors: Collin J. E. , Delplace A.
Published: September 2010

The thermal behavior of acetaldehyde, at pressures of the order of 100 microns, has been investigated, up to 750°C, in a quartz reactor connected to a TOF Bendix mass spectrometer. In those conditions, no methane formation has been observed. Two important processes are the formation of acetylene and water, possibly by unimolecular decomposition of acetaldehyde, and the formation of ethylene and water, probably by decomposition of ethanol, a secundary product. The primary step of acetaldehyde decomposition is discussed, as well as the overall order of the reaction. At the low pressures used in this work, data are consistent with a first order reaction, rather than 3/2 or 2, and an activation energy of 57 kcal/m is proposed.
Chaleurs D'Interaction de Complexes par Liaison Hydrogène. 1. — Complexes Alcool ou Phénol — Pyridine
Authors: Neerinck D. , Lamberts L.
Published: September 2010

Heats of formation of Hydrogen bond complexes between pyridine and alcohols or substituted phenols are measured in carbon tetrachloride solution by calorimetry. The obtained energies are compared with the acid ionization constants in water and the a values of the phenol substituents. Steric hindrance lowers the bond energy. However the heats of complex formation are linearly related to the frequency shift of the hydroxyl absorption brought about by the Hydrogen bond interaction.
The polarographic determination of bromite at the rotating pt‐electrode
Authors: Velghe N. , Claeys A.
Published: September 2010

The polarographic determination of bromite is studied using a clean as well as a preanodised rotating Pt‐electrode. Although both methods give good results the use of the preanodised electrode is preferred due to better precision and higher sensitivity.
Contribution A L'Étude des Composés Sesquiterpéniques. VII. Guaioxyde et bulnesoxyde. Détermination de leur structure
Authors: Ledoux P. , Vaterlaus B. P. , Chiurdoglu G.
Published: September 2010

Guaioxide (III) and bulnesoxide (IV) were obtained from guaiol (I) and bulnesol (II), and their structures have been determined.
Acetylation of anthracene by the Friedel‐crafts reaction using nitrobenzene as the solvent
Authors: Bassilios H. F. , Salem A. Y. , Anous M. T.
Published: September 2010

The acetylation of anthracene by the Friedel‐Crafts reaction using nitrobenzene as the solvent leads, under certain conditions to pronounced 2‐substitution. It is liable to the effect of different factors. No diacetylation occurs. 2‐Acetylanthracene is also formed by the isomerisation of 9‐acetylanthracene. The effect of the solvent and the different factors are discussed. The preparation of 2‐acetylanthracene, 2‐acetylanthraquinone and anthraquinone‐2‐carboxylic acid are described.
Oxydation Entraînée des Hydrocarbures. II. Influence des sels de Cobalt
Authors: Rouchaud J.
Published: September 2010

In the autoinitiated oxidation of pure cyclohexane in the liquid phase at 150°C and under an initial partial pressure of oxygen ot 11kg/cm2, the salt of cobalt reduces the time of induction, but does not increase the rate of transformation. On the other hand, in the oxidation of the mixture cyclohexanecumene, the rate of transformation of cyclohexane is increased, and this increase is more pronounced by the addition of cobalt naphtenate. The induction period decreases with higher cumene or cobalt concentration. The differences between the observed and calculated effects, on the base of deduced kinetical relations, are interpreted as an increase in the chain branching degree when cumene is present. The stability of the cumylperoxydic radicals is related to the effect.
Borohydride Reduction of Isohumulones
Authors: Khokher A. , Anteunis M. , Verzele M.
Published: September 2010

Following chart 1 the borohydride reduction of isohumulones A and B gives four diastereoisomeric reaction products, (ρ‐isohumulones A1, A2, B1 and B2).
Détermination De La Structure Du 3‐OXO‐3,3a‐Dihydroguaiazulène, Produit De La Réaction De Dakin Sur Le 3‐Formylguaiazulène. Un Exemple Inhabituel De Tautomérie Cétoénolique
Authors: Fuks R. , Chiurdoglu G.
Published: September 2010

The Dakin reaction on 3‐formylguaiazulene (I) did not lead to the expected 3‐hydroxyguaiazulene (II). The structural study of the pale‐yellow crystalline compound, isolated in 60% yield, proves it to be 3‐oxo‐3,3a‐dihydroguaiazulene (IIIa), the ketonic tautomer of 3‐hydroxyguaiazulene. Chemical (reduction, Grignard reaction and hydrogenation) and spectroscopic investigations (IR, UV and NMR) are confirmatory to this conclusion. The NMR spectra have shown two structures to be present in solution. These are probably the two ketonic tautomers (IIIa and IIIb) possible for 3‐hydroxyguaiazulene. Preponderance of a ketonic non azulenic structure over its hydroxyazulenic tautomer is the first example of such a tautomery.
Excess Free Energies and Volumes of two Simple Binary Liquid Mixtures: Methane‐Krypton and Nitrogen‐Methane
Authors: Fuks S. , Bellemans A.
Published: September 2010

The excess free energies and volumes of the liquid systems: Methane‐Krypton and Nitrogen‐Methane, are obtained from total vapor pressure and density measurements respectively. The experimental results are compared to those available from other authors and briefly discussed in relation to the Average Potential Model of Solutions developed by Prigogine and coworkers.
Triterpènes X (): Spectroscopie de résonance magnétique nucléaire de composés triterpéniques. Influence de la substitution sur les fréquences de résonance des groupes méthyles en série Δ12‐oléanénique
Authors: Savoir R. , Ottinger R. , Tursch B. , Chiurdoglu G.
Published: September 2010

A complete assignment of the NMR methyl frequencies of Δ12‐oleanene triterpenes has been achieved. A list of additive chemical shifts permitting a priori calculation of the methyl frequencies for various substituents has been established. The synthesis of some new oleanenic derivatives is described.
Cyclopentanones II. The Synthesis of 4‐alkyl‐5‐hydroxy‐1, 3‐cyclopentanediones
Authors: Compernolle F. , Vandewalle M.
Published: September 2010

Specific reduction methods for the 2‐carbonyl function of 3‐alkyl‐1, 2, 4‐cyclopentanetriones are described. On reduction with zinc‐hydrogen chloride in acetic acid the enol acetates of these triones yield a mixture of cis and trans isomers of 4‐alkyl‐5‐hydroxy‐1, 3‐cyclopentanediones. Sodium borohydride reduction of 3‐alkyl‐3, 5‐dibromo‐1, 2, 4‐cyclopentanetriones leads exclusively to the trans isomers. The obtained 4‐alkyl‐5‐hydroxy‐1, 3‐cyclopentanediones can be acylated at the 2‐position, as demonstrated by the synthesis of dihydrohumulinic acid A.
N. M. R. Experiments on Ketals. X: Temperature‐Dependent Chemical Shifts of Methoxyprotons in Alkyl‐Cem‐Dimethoxycyclohexanes
Authors: Tavernier D. , Anteunis M.
Published: September 2010

The chemical shift difference Δν of methoxyprotons of alkyl‐gem‐di‐methoxycyclohexanes is dependent on temperature. This dependence cannot be solely explained in terms of a chair‐chair equilibrium. Other effects must play a role. An earlier proposition for a half‐chair form in 4‐t. Bu‐1, 1‐dimethoxy‐cyclohexane (1) is retracted.
Long Range Phenomena I Long Range Coupling in Cyclopentane Compounds Through Chains Containing sp2 Carbon Atoms
Authors: Anteunis M. , Compernolle F.
Published: September 2010

Apart from the more frequently occurring long range coupling in homoallylic and allylic systems (i.e. H‐C‐C‐C=C‐H systems), an analogous but much smaller effect can be found when the double bond is partial. The magnitude in “pseudo‐homoallylic” systems
equation image
however can be as high as 1 cps, especially with substituents on the olefinic bond, containing p‐orbitals.

The newly discussed long range mechanisms are illustrated by several examples (table).
Catalyse Homogène De L'Oxydation Des Hydrocarbures Liquides
Authors: Rouchaud J. , Mulkay P.
Published: September 2010

Liquid cyclohexane has been oxidized by molecular oxygen under a partial pressure of 15–18 atm., between 140 and 160°C. Cyclic products are formed: cyclohexanone, cyclohexanol and dicyclohexyladipate. The non‐cyclic products are: adipic, glutaric and monocarboxylic acids. Higher yield in non cyclic products is obtained when soluble cobalt catalyzes the reaction (10−4 ion g Co, as naphtenate/1 cyclohexane). When supported Co2O3 is used as catalyst, 102 times higher concentration in cobalt is necessary to obtain the same results as with the soluble salt. This difference of activity is interpreted as the result of steric and electronic‐magnetic effects. With cobalt naphtenate, about 85% of the initial cobalt is precipitated before 10% of the cyclohexane has been oxidized. Results indicate that only the remaining dissolved catalyst influences the reaction. The comparison of the rates of oxidation to the yield in non cyclic products shows that the compounds of transition elements catalyze the isomerization of the peroxidic radicals. This mechanism applies as well to the homogeneous as to the heterogeneous catalysis.
L'Étude Théorique Des Propriétés Conductrices Des Semi‐Conducteurs Organiques
Authors: André J. M. , Gouverneur L. , Leroy G.
Published: September 2010

The LCAO method is used to calculate the electrical conductivity in a series of conjugated systems. The results, though qualitative, lead to an understanding of several factors responsible for the presence of an energy gap in the band structure.
Étude Théorique Des Dérivés Azotés Des Hydrocarbures Conjugués Alternants II. Les Dérivés Monoazotés Des Hydrocarbures Alternants
Authors: Leroy G. , Aussems C. , van Remoortere F.
Published: September 2010

Using parameters fitted to the pyridine spectrum, SCF calculations have been carried through for seven monoaza cyclic compounds. The results obtained are discussed in the light of available experimental data and attention is particularly drawn to the electronic spectra and the ionization potentials.
Étude De La Chloration De La 2‐Méthylcyclohexanone
Authors: Peters P. A. , Ottinger R. , Reisse J. , Chiurdoglu G.
Published: September 2010

Synthesys of 2‐chloro‐2‐methylcyclohexanone, cis‐ et trans‐2‐chloro‐6‐methyl‐cyclohexanone, trans‐2,6‐dichloro‐2‐methylcyclohexanone, 2,6,6‐trichloro‐2‐methylcyclohexanone, and related deuterated compounds, are reported. Structural and stereochemical determinations are established on the basis of IR, UV. and NMR spectra.
Triterpénes XV [1]. Réductions De Diène‐Diones Oléanèniques Par L‚Hydrure De Lithium‐Aluminium
Authors: Tursch B. , Bartholomé C. , Daloze D. , Chiurdoglu G.
Published: September 2010

Lithium‐aluminium hydride reduction of diacetoxy‐12,19‐dioxo‐Δ9 (11),13 (18)‐21‐epi‐methylmachaerinate yields 3β, 19ξ, 21α‐trihydroxy‐28‐noroleana‐9(11),12,17‐triene. LAH reduction of acetoxy‐H.‐dioxo‐Δ9(11), 13(18)‐methyloleanolate affords a 3:1 mixture of 3β, 28‐dihydroxy‐12,19‐oxido‐Δ9(11), 13(18) ‐oleananeand 3β,19ξ‐dihydroxy‐28‐noroleana‐9(ll),12,17‐triene.
Calorimetric Determination of the Enthalpy of Formation of the 1:1 Chelates of the Tripositive Lanthanide Ions With N‐Hydroxyethylethylenediaminetriacetic Acid
Authors: Fuger J. , Merciny E. , Duyckaerts G.
Published: September 2010

Enthalpy changes associated with the formation of the 1:1 chelates of the lanthanide ions with N‐hydroxyethylethylenediaminetriacetic acid have been determined by a calorimetric method at 25°C and μ = 0.1 (K.Cl). The various thermodynamic functions corresponding to the formation of the chelates are discussed in terms of the structure of these species and compared with literature data on the corresponding chelates of ethylenediaminetetraacetic acid.
Preparation of the Enantiomers of 2‐Carbobenzyloxyaminoadipic Acid and Their 1‐Benzylesters
Authors: Claesen M. , Vlietinck A. , Vanderhaeghe H.
Published: September 2010

Different methods of synthesis of 2‐aminoadipic acid were examined. The enantiomers of this acid, obtained by enzymatic resolution of the chloroacetylderivative, were transformed into L‐ and D‐2‐carbobenzyloxyaminoadipic acids. The two isomers were also prepared by fractional crystallization of the D‐ and L‐threo‐1‐p‐nitrophenyI‐2‐amino‐1,3‐propanediol salts.

The 1‐monobenzylesters of L‐, D‐, and DL‐2‐carbobenzyloxyaminoadipic acid were prepared by esterification with phenyldiazomethane. The corresponding ester could also be obtained by reaction of the triethylammonium salt of the acid with benzylbromide in dimethylformamide solution. The structure of the mono‐benzylester was proved by transformation into the 1‐benzyl‐6‐ethylester, from which 2‐aminoadipic 6‐ethylester was obtained by hydrogenolysis.