bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxydation Du Cyclohexane: Activation Par Les Aldéhydes
Authors: Rouchaud J.
Published: September 2010

The oxidation of cyclohexane in liquid phase at 150°C by a mixture of oxygen and nitrogen in the ratio of 1:1 under an initial partial pressure of 11 kg. cm−2 by oxygen, and catalyzed by cobalt naphtenate ([Co] = 50 ppm by weight), gives principally cyclohexanol, cyclohexanone and adipic acid. The transformation of cyclohexane carried out in a stainless steel autoclave, is powerfully accelerated when concentrations of about 0 to 0.5 mol.l−1 of aldehydes are added to the cyclohexane at the start. Thus the rate of oxidation of cyclohexane in the presence of 0.150 mol.l−1 of benzaldehyde, is ten times greater in the mixture than the rate at which pure cyclohexane is oxidized under the same conditions. The activities of aldehydes, in the oxidation of cyclohexane, are in the order of: m‐methoxybenzaldehyde, 2, 3‐dimethoxybenzaldehyde > benzaldehyde, acrolein > p‐methoxybenzaldehyde > acetaldehyde > 3, 4‐dimethoxybenzaldehyde > phtalaldehyde. The dragging effect varies following the power one of the concentration of additive. Nevertheless, whenever this concentration exceeds a certain value, the acceleration diminishes. Therefore the optimum conditions for the use of these additives are situated in feeble concentrations of aldehyde. In addition, the induction time of reaction is reduced in their presence (t> 4 min, when [benzaldehyde] = 0.150 mol.l−1). The dragging effect is attributed to the increase in the concentration of radicals, produced by the oxydation of the additives. A comparison of the rate of oxidation of pure cyclohexane and of the same in the mixture form, permits an approximate evaluation of the rate constants specific to the oxidation of cyclohexane and relative to the different stages of the reaction mechanism:

k3 = 1.8.102 (mol.l−1−1 (RO2.+RH → ROOH+R);k5 = 2.2. 10−3 sec−1 (ROOH → RO.+.OH); k8 = 3.6. 10−2 (mol.l−1)−1. sec−1 (ROOH+RH → 2 ROH); k9 = 2.2. 10−1 sec−1 (ROOH → R1 CO R2+H2O).
Acylcyclopentanones VII (1): Synthesis of 2, 5‐diacetyl‐1‐cyclopentanone and 2, 5‐dibenzoyl‐1‐cyclopentanone
Authors: Vandewalle M. , Dewaele S.
Published: September 2010

2, 5‐Diacetyl‐1‐cyclopentanone and 2, 5‐dibenzoyl‐1‐cyclopentanone are obtained by base induced cyclisations of ethyl 2‐acetyl‐6‐oxo‐heptanoate and ethyl 2, 5‐dibenzoyl‐pentanoate. Competing with this condensation aldol type cyclisations occur.
Étude, Par Spectrométrie Raman, De La Complexation Du ZnCl2 En Solution Aqueuse
Authors: Gilbert B.
Published: September 2010

We have examined by Raman spectroscopy the autocomplexation of ZnCl2 solutions. Our experiments are in good agreement with previous results. A detailed investigation of the intensity of the band located at about 284 cm−1 has allowed us to confirm the presence of the species ZnCl4− and ZnCl2 at concentrations respectively above 1 M and 4 M.

The dissociation constants of the following reactions have been determined:

magnified image
N. M. R. Experiments on Ketals. XI (1): Shifts of acyclic and cyclic ketals
Authors: Anteunis M. , Borremans F. , Gelan J. , Heyndrickx L. , Vandenbroucke W.
Published: September 2010

Shift values of the methyl and methylene protons of dimethylketals and dioxolanes of cyclic and acyclic carbonyl compounds are affected by substitution, f.i. the ring size in 1, 3 dioxaspiranes. No simple relation could be obtained, and the influence of ring strain (bond hydridization) is not important. The difference in the general trend between dioxolanes and dithiolanes is observed. No simple theory concerning shift dependence on fairly remoted magnetic anisotropy seems possible.
Isolation and Identification of the Amines Resulting From Chemical and Catalytic Reduction of 20‐Hydroxyimino‐Steroids (Restatement)
Authors: Van Woude G. De , van Hove L.
Published: September 2010

Sodium‐propanol reduction of 3β‐hydroxy‐5‐pregnen‐20‐one oxime affords the two 20‐amino epimers in a ratio 20 α to 20 β equal to 1.3, while hydrogenation with platinum in acetic acid gives a mixture of the two corresponding saturated amines in the ratio of 2:1.

Quantitative separation of 20‐amino epimers is conveniently achieved by chromatography on silica gel.

Thin layer chromatography, optical rotatory dispersion, infrared absorption, nuclear magnetic resonance data are joined.
The Surface Shear Viscosity of Mixed Monolayers Interaction Between Cholesterol and Digitonin
Authors: Joos P. , Vochten R. , Ruyssen R.
Published: September 2010

A theory is developed to calculate the surface shear viscosity of a mixed film if the flow parameters of each single component are given. This theory starts from the model of Eyring, assuming that the free energy of viscous flow for the mixture is proportional to the mole fractions of the component in the surface and to the free energy of viscous flow of the single components. To test this equation the surface viscosity of mixed adsorbed films of two saponins, digitonin and senegin is considered. Large deviation from this behaviour, as in the case of dilute cholesterol monolayers penetrated by digitonin, points to an interaction.
Magneto‐Chemical Studies on Some Aromatic Carbonyl Compounds
Authors: Gupta R. R. , Mital R. L.
Published: September 2010

A survey of the literature reveals that the magnetic data on the substituted aromatic aldehydes and ketones is very meagre and no systematic magneto‐chemical investigation appears to have been made on them. Therefore these aromatic carbonyl compounds form an interesting series for magneto‐chemical studies.

These studies may throw some light on the effect of delocalisation of the electrons, the mesomerism of the carbonyl group, the positional isomerism and the interactions introduced by the substitution in the benzene ring.

In the present studies the diamagnetic susceptibility of a number of the aromatic aldehydes and ketones has been measured with a sensitive Gouy balance. The magnetic susceptibilities of these compounds were calculated with the help of diamagnetic constants of atoms and multiple bonds as given in Ingold's book (1) also. A comparison between the experimentally determined and calculated χM values shows a poor agreement which may be attributed to the effects of the delocalisation of electrons, the mesomerism, the positional isomerism and the interactions of the substituent groups.

In these compounds m‐isomer is comparatively more diamagnetic than ortho and para isomers although Bhatnagar and coworkers (2) have considered ortho isomer more diamagnetic than meta and para isomers, but in these aromatic carbonyl compounds m‐isomer may be regarded more diamagnetic on account of the electron with‐drawing‐nature of the carbonyl group. This is an analogous case to aryl β‐chlorovinylketones as studied by us (3).

Yang's method (4) has been applied to evaluate the contribution towards molecular diamagnetism of the carbonyl group.
Organometallic compounds. V. Mass spectra of some aryltrimethyltins
Authors: Gielen M. , Nasielski J.
Published: September 2010

The mass spectra of a series of aryltrimethyltins are described and analysed. The main features are: a relatively weak molecular ion, a very important ArSnMe2+ ion (base peak), a low intensity ArSnMe+ fragment and a non negligible ArSn+ peak. These findings may be related to the well known stable valence states of tin (IVSn and IISn) and the unfavourable IIISn and ISn states. Whereas a methyl group is easier to cleave from the ArSnMe3+ ion than the phenyl radical, n‐butyl seems to be more strongly bound to the metal than the aryl moiety in ArSnnBu3+.

The spectra of three aryltrimethylsilicons, recorded in the same conditions, show stronger molecular ions and weaker divalent fragments than in the corresponding tin derivatives.

An interpretation of these various findings is attempted in terms of bond energies and electron delocalization.
Synthèse de pyrimidines et de thiazolo[5,4‐d]pyrimidines. II. Analogues de la succinoadénine
Authors: Brocas‐Neuwels Mme H. , Promel R.
Published: September 2010

Two new analogs (III and VII) of succinoadenine have been synthesized. Starting from 7‐chlorothiazolo[5,4‐d]pyrimidine (I), the first one has been prepared by reaction with diethyl D,L‐aspartate, followed by alkaline hydrolysis. On the other hand, direct amination of 7‐methylthiothiazolo[5,4‐d]pyrimidine (IV) with D,L‐aspartic acid has given a product formulated as 5‐formamido‐4‐mercapto‐6‐methylthiopyrimidine (V). An authentic specimen has been prepared for comparison by formylation of 5‐amino‐4‐chloro‐6‐methylthiopyrimidine (VIII) and replacement of the chlorine atom with sodium hydrosulfide.

The second analog has been obtained either by reaction of 7‐chlorothiazolo[5,4‐d] pyrimidine (I) with D,L‐mercaptosuccinic acid or by alkylation of 7‐mercapto‐thiazolo[5,4‐d]pyrimidine (VI) with D,L‐bromosuccinic acid.
Nmr Experiments on Ketals XIII [1]. Pmr Features and Relative Sign of Coupling Constants of 4‐Phenyl‐6‐Methyl‐1,3‐Dioxane
Authors: Feeney J. , Anteunis M. , Swaelens G.
Published: September 2010

In accordance with expectation, it is found that 2J5 is of opposite sign to the vicinal coupling constants 3J4,5 and 3J6,5 in trans‐4‐phenyl‐6‐methyl‐l,3‐dioxane From the coupling values it is found that the conformational energy term for 4‐phenyl is roughly the same as that for a methyl group. Some previously mentioned [5, 6] long range couplings through four and five bonds are also found in this substance.
Catalyseurs D'Oxydation I. Influence De La Coordinence Sur L'Activité Des Chélates D'Éléments De Transition
Authors: Rouchaud J.
Published: September 2010

Different chelates of the transition elements, resembling to the metallic enzymes, were investigated for their catalytic activities in the oxidation, by molecular oxygen (1 atm) at 100°C., of liquid cumene. Cumylhydroperoxide is the main product. Catalytic activity was measured from the increase of the rate of reaction, and the decrease of the yield in hydroperoxide (relatively to the amount of cumene transformed) following the use of the catalyst. The ligands of Co (II), Ni (II.), Mn (II,), Cu (II), Fe (II) and Cr (III) were (successively: the ligand, the ratio ligand: cation, and the coordinence of the chelate: 1) salicylaldehyde ethylenediimine, 1:1, 4; 2) diazoic pigments, 2:1, 6; 3) formazylic complexes, 1:1, 4. Comparison has been made between the activities of these chelates, and that of the corresponding naphtenate and stearate. The chelates of the same cation bound to different ligands have equal activities when the coordinence is the same. The relative catalytic activities of the complexes—of the same cation—of coordinence 2, 4, and 6 are respectively about 4, 5, 3, and 1.
Étude Théorique Des Dérivés Azotés Des Hydrocarbures Conjugués Alternants IV. L'évaluation Des Paramètres α Et β De Hückel Dans Les Dérivés Azotés Des Hydrocarbures Conjugués
Authors: Leroy G. , Aussems C. , van Remoortere F.
Published: September 2010

The matrix elements HSCFpq obtained by the method described in the previous papers are analysed and classified in order to establish rules for the determination of the Hückel parameters α et β of any aza‐derivatives of the conjugated hydrocarbons.
Spectrophotometric Determination of the Dissociation Constant of N, N′‐Bis(2‐Sulphoethyl) Monothiooxamide and N, N′ ‐Bis(Parasulphobenzyl) Monothiooxamide
Authors: Goeminne A. M. , Herman M. A.
Published: September 2010

The dissociation constant of N, N′‐bis(2‐sulphoethyl) monothiooxamide and N, N′‐bis (p.sulphobenzyl) monothiooxamide was determined by a spectrophotometric method, using a weighted least squares technique for the calculations. The values of the thermodynamic dissociation constant are respectively pKT = 11.97 and pKT = 11.67.
Catalyseurs D'Oxydation II. Activité Et Configuration Électronique
Authors: Rouchaud J.
Published: September 2010

The catalytic activities of the enzyme‐like chelates of transition elements, towards the oxidation by molecular oxygen of liquid hydrocarbons (cumene, 100 °C, 1 atm) has been related to the electronic configuration of the complexes. The ligands were salicylaldehyde‐ethylenediimine (C), azoïc pigments (A), formazanic compounds (F), and the salts of naphtenic (N) and stearic acids (S). The theory of catalysis developed by Dowden was applied to the oxidations. The catalytic activity, which results from electron transfer from the hydroperoxide or peroxidic radicals to the catalyst, depends on the energy and entropy of the exchange. From the measurement of magnetic susceptibilities, the number of unpaired electrons (n), and the electronic configuration of the complexes were deduced. A and C induce a high ligand field, which is measured by the high splitting energy of the 3d orbitals of the cation. With these ligands, n is minimum (successively: ligand, cation+2 — but Cr+3, n): C Co, 1; A Co, 1; N Co, 3; C Ni, O; S Ni, 2; C Mn, 1; S Mn, 5; C Cu, l; F Cu, 1; A Cr, 3. The intensity (∫ϵdγ) of absorption of light (14 – 29.103 cm−−1) by the ligands is increased through metallization: by a coefficient of 3.4 to 5.2 for C, and 1.7 for A. This is to be ascribed to charge transfer, i.e. electron transfer from the ligand to the central cation. All these properties explain, in accordance with the theory of catalysis in oxidation, the decrease of the catalytic activity of the transition elements through chelation (energy and entropy factors: vacancy of low energy orbitals and number of them). Results suggest however that means of activation (such as actinic light) can confer high activity to these chelates.
The Friedel‐Crafts Acylation Reaction IV. Multiple Substituent Effect in the Friedel‐Crafts Acylation of Toluene With Disubstituted Benzoyl Chlorides
Authors: Slootmaekers P. J. , Verbeerst R.
Published: September 2010

Nous avons étudié L'effet de substituants dans la réaction d'acylation de Friedel‐Crafts dans le cas du toluène en solution dans L'ortho‐dichlorobenzène. Nous avons utilisé des chlorures de benzoyle substitués en position 3, 4 et 3, 5 ainsi que le chlorure d'aluminium comme catalyseur.

La relation de corrélation de Hammett n'est pas vérifiée même pour des termes de la série réactionnelle portant des substituants en position 3, 5. De plus, dans cette série de réactions, L'effet des substituants est caractérisé par une dispersion prononcée méta‐para. Lors de L'étude d'une relation linéaire fonction de L'énergie libre, on observe des écarts importants au principe d'additivité des effets de substituants comparé à L'effet de substituant du chlorure de benzoyle. L'analyse des résultats révèle que aussi bien L'écart par rapport à la relation de Hammett que L'écart par rapport au principe d'additivité sont plus importants pour les termes de la série de réaction où le groupe fonctionnel est le plus déficient en électrons. Ces termes semblent répondre en première approximation à une réaction de second ordre. Tous ces faits peuvent être interprétés en admettant L'existence de plusieurs agents d'acylation effectifs, dont L'un est de structure ionique, par exemple une paire d'ions, et dont L'importance relative dans la réaction globale d'acylation est déterminée par les substituants présents dans le chlorure de benzoyle.
Determination of Diethylamine‐Hci With Hypobromite
Authors: Velghe N. , Claeys A.
Published: September 2010

La détermination de diéthylamine‐HCl par titrage ampérométrique avec de L'hypobromite a été étudiée. L'influence du pH, de la vitesse de titrage et du prétraitement de la micro‐électrode tournante en platine a été contrôlée.

La méthode, appliquée pour des concentrations variant de 5.10−−2 à 5.10−−4 M en amine, et contrôlée par deux méthodes classiques, donne des résultats d‚une précision excellente.
Aromatic Electrophilic Substitution VIII [1]. Ortho Effects in the Iododestannylation of Phenyltrialkyltins
Authors: Nasielski J. , Buchman O. , Grosjean M. , Schurter J‐J. , Vandendunghen G.
Published: September 2010

It is shown that one ortho methyl group has a weaker accelerating effect than a para methyl group in the iododestannylation of phenyltrialkyltins, whatever the size of the alkyl chains bound to the tin atom. Two ortho methyl groups lead to a rate which is exactly that calculated assuming additivity of the effects, when the leaving group is Sn(CH3)3. If Sn(nPr)3 is the leaving group, 2, 6‐disubstitution leads to a small but significant increase in rate. The results are interpreted in terms of overcrowding in the reactant, and of relief of strain in the transition state; the observed effects are however smaller here than in the case of similar silicon derivatives, and the difference is attributed to the difference in carbon‐metal bond lengths.
Long Range Phenomena VI [1] CIS‐ and Trans‐Isomers of Ethylheptenoates
Authors: Anteunis M. , De Bruyn A. , De Pooter H. , Verhegge G.
Published: September 2010

Use of the NOE (Nuclear Overhauser Effect) made a choice possible between the cis‐trans isomers A and B of the ethylesters of 3‐ethyl‐3‐pentenoic acid.

It was found that for both isomers 5Jtransh.all. (homoallylic coupling) is more important than 5Jcish.all. while to the contrary 4Jtransall. (allylic c.) <4Jcisall.. Some other possible criteria for cis‐trans assignations are discussed. The conclusions are corroborated by the spectrum of the isomeric 3‐ethyl‐2‐pentenoate (C).
Burning Velocity in Mixtures of Cyanogen or Hydrogen Cyanide With Oxygen
Authors: Ailliet M. , van Tiggelen A.
Published: September 2010

Burning velocity, flame temperature and thickness of the reaction zone have been measured in different cyanogen/oxygen/nitrogen and hydrogen cyanide/oxygen/ nitrogen mixtures.

Some measurements have been made also on C2N2/O2/N2 mixtures with addition of hydrogen. Kinetical parameters have been derived: activation energy and reaction order. A kinetical mechanism has been proposed which is based on observations made by others in some studies using the technique of flash photolysis.
Oxydation En Phase Liquide Du 2,3‐Diméthylbutane
Authors: Rouchaud J. , Lutète B.
Published: September 2010

High yield in acetic acid were obtained in the by oxygen liquid‐phase oxidation of 2,3‐dimethylbutane at 160°C., under 25 atm, and catalyzed by 0.64 wt% manganese. The kinetic behaviour of the products formed clears up the mechanism of oxidation. The high reactivity of the tertiary hydrogen atoms relatively to the primary explains the distribution of products. Acetone is highly reactive toward peroxidic radicals. However, its transformation into acetic acid is easily performed only when its oxidation is coupled with that of an hydrocarbon. The initiating effect is interpreted by the theory of the degenerately banched chain reactions.
The Mixed Complexes of Ni(II) in Aqueous Solutions Containing Ethylenediamine and β‐Alanine
Authors: van Poucke L. C. , Herman M. A.
Published: September 2010

The mixed complexes between Ni(II), ethylenediamine (A) and the β‐alaninate ion (B) are studied in 0.5 M K.NO3 at 25 °C. The existence of NiAB+ and NiA2B+ is proved and the stability constants of these complexes are given. The visible and near‐infrared spectrum of each species is reported and briefly discussed.
Base‐Catalysed Prototropic Isomerization IV. Isomerization of Conjugated Diynes on a Basic Catalyst. The Mechanism of the Base‐Catalysed Isomerization of Triple‐Bonds.
Authors: Hubert A. J. , Anciaux A. J.
Published: September 2010

The base‐catalysed isomerization of substituted 1,8‐diphenylocta‐3,5‐diynes has been studied. The reaction is strongly influenced by steric effects. These results help to understand the mechanism of the base‐catalysed isomerization of acetylenes which is discussed in connection with these novel observations.
Configuration Électronique Du Cation Molybdyle Chélaté Par Des Azoïques
Authors: Rouchaud J. , De Pauw M.
Published: September 2010

Several chelates of the MoO2++ cation with azoic compounds have been synthesized. The corresponding peroxo compounds were obtained by reaction with H2O2. The visible absorption spectra show that the metalisation of the azoics reduces their molar extinction coefficients but does not alter significantly the wavelengths corresponding to the maximum of the absorption bands. The chelates have magnetic susceptibilities corresponding from 0 to 3 unpaired electrons. The physical properties of the chelates show the strong influence of the ligand field on the electronic configuration of the cation.
Catalyse De L'oxydation Du Propylène En Phase Liquide
Authors: Rouchaud J. , De Pauw M.
Published: September 2010

Propylene dissolved in benzene (propylene/benzene = 0.63 g/g) has been oxidised in the liquid phase by molecular oxygen at 150 °C., under a total pressure of 45 atm. Conversion was limited to 7.5%. Several azoic chelates of the MoO2++ cation were used as catalyst. They catalyse the oxidation toward the formation of high yield in epoxypropane. One of them leads to a selectivity of 70% in epoxypropane, when the concentration of molybdenum is 3.10−4 cation g/kg of the mixture benzene‐propylene. There is a nonaccidental relationship between the magnetic susceptibilities of the molybdyl chelates and of their peroxo derivatives, and the selectivities in epoxypropane. That relationship is interpreted by the molecular orbital theory of metal‐ligand bonding.
Un Disaccharide Nouveau Extrait De La Farine De Manioc I. Établissement De La Formule De Structure
Authors: Jadot J. , Maghuin‐Rogister G.
Published: September 2010

Ce disaccharide nouveau, extrait du résidu de fermentation alcoolique d'un hydrolysat de farine de manioc, est constitue de deux molécules de D‐glucose unies par une liaison 1‐5 α. La structure a été déterminée par oxydation à L'acide periodique et par comparaison des propriétés de ses dérivés avec les propriétés des dérivés correspondants de disaccharides connus.
The Influence of Certain Nuclear p‐Substituents on the Kinetics of N‐Nitrosation and Diazotisation of Aniline
Authors: Aboul‐Seoud A. , Ahmad Moustafa
Published: September 2010

The specific reaction rates for the chloride‐catalysed diazotisation of aniline and p‐toluidine were combined with equilibrium data on the proton ionisation of the anilinium and p‐toluidinium ions, and on the hydrolysis of nitrosyl chloride. The specific reaction rates were calculated for the N‐nitrosation of the free amines, which is the rate‐determining stage in the diazotisation of the amines, under the present conditions. ΔG≠, ΔH≠, ΔS≠, and E were determined for this rate‐determining stage. These values were compared with the corresponding values for p‐chloroaniline. The influence of the substituents on the rates of the N‐nitrosation of these amines was discussed.
Sélectivité Catalytique Dans L'oxydation du P‐xylène
Authors: Rouchaud J. , Sondengam L.
Published: September 2010

P‐Xylene (1.9 moles/liter, initially) dissolved in acetic acid has been oxidised by oxygen at 165deg;C (total pressure: 32 atm; partial pressure of oxygen: 25 atm). The oxidation was catalysed by bromine or by the cobalt naphthenate, or by a mixture of the two catalysts. The conversion of p‐xylene was 50%. The distribution of the main products (p‐toluic and terephthalic acids) during oxidation corresponds to the consecutive mechanism: p‐xylene →(1) p‐toluic acid →(2) terephthalic acid. Bromine and cobalt, used separately as catalysts, activate the two steps with the same intensity. The catalytic mixture of bromine with cobalt accelerates the second step much more intensively than the first one.
Physico‐Chemical Properties of Acid Saponins Surface Adsorption of Sapoalbin
Authors: Vochten R. , Joos P. , Ruyssen R.
Published: September 2010

Het minimum in de oppervlaktespanningskoncentratiekurve werd met de betrekking van Gibbs kwantitatief geïnterpreteerd. Berekeningen werden uitgevoerd waarbij gepoogd werd de adsorptie in funktie van de pH te beschrijven. Bij de genine vrije sapoalbine ligt de adsorptie ongeveer 40% hoger dan bij de genine bevattende saponine. In funktie van de pH werd eveneens de adsorptie nagegaan enerzijds door toepassing van de betrekking van Gibbs en anderzijds door de rechtstreekse en dynamische methode. De berekende adsorptiewaarden volgens Gibbs stemmen niet volledig overeen met deze van de rechtstreekse metingen. Wegens de grote tijdfunkties blijft het nochtans een open vraag of door extrapolatie van deze rechtstreekse metingen de evenwichtsadsorptie kan gevonden worden. Door de aanwezigheid van zouten in een relatief hoge koncentratie (KNO3 0.1 M) werd een verhoging in de adsorptie waargenomen. Een eventuele verklaring zou men kunnen zoeken in de afschermende werking van de ionen op de elektrostatische repulsie.
Influence de la Température sur l'oxydation du Propylène Liquide
Authors: Rouchaud J. , Karangua A.
Published: September 2010

Propylene dissolved in benzene has been oxidised by oxygen under a partial pressure of 12 atm, between 130 and 180 deg;C and with or without catalytic amounts of a soluble salt of MoO2++. The products result from the two competitive oxidation steps: magnified image

The difference between the energies of activation relative to the addition and substitution, EA–S, is constant for the uncatalysed oxidation and amounts to + 6,3 kcal/mole. There is no constant EA–S for the catalysed oxidation. The results show that, in this case, the products arise from two simultaneous mechanisms: that corresponding to the uncatalysed oxidation and the one issuing from the catalytic cycle in which the peroxidic organic intermediates transform the catalyst in a peroxo compound; the last is a selective epoxidising agent of the olefinic bond.
Indole Alkaloids. XVII. Five Dihydroindole Alkaloids from Aspidosperma Verbascifolium
Authors: Braekman J. C. , Hootele C. , van Moorleghem C. , Kaisin M. , Pecher J. , Antonaccio L. D. , Gilbert B.
Published: September 2010

A study of Aspidosperma verbascifolium has led to the isolation of four known dihydroindole alkaloids: kopsanone [I], kopsanol [II], 3'‐epikopsanol [III], 10‐oxo‐3'‐epikopsanol [IV] and a new natural product: Nα‐formylkopsanol [VII].
Fluorescence Solvent Shifts and Singlet Excited State pK's of Indole Derivatives
Authors: Donckt E. Vander
Published: September 2010

Fluorescence shifts of indole derivatives in aprotic solvents can be understood on the basis of a general dielectric effect. In protic media as water and ethanol, hydrogen bonds are formed between indole acting as a base and the solvent as an acid. It is shown that the basicity increase in the S1 state of indole derivatives is consistent with this view.
Communication to the Editor. A New Synthetic Route to Vic‐Triazoles
Authors: L'Abbé G. , Ykman P. , Smets G.
Published: September 2010

We wish to report our discovery and mechanistic characterization of a reaction in which an ester phoshorus ylid I is transformed by acyl azides II into 1‐acyl‐vic‐triazoles IV.
Essais de Chloration Dirigée. X. Photochloration Directe D'acétates D'Alcoyles [1]
Authors: Ph. Soumillion J. , Bruylants A.
Published: September 2010

A series of alkylacetates, R–COOCH3, with R‐ = n‐propyl, isopropyl, n‐butyl, isobutyl and amyl, was chlorinated photochemically in order to obtain mono‐substituted products. Analysis of reaction samples was made by gas‐liquid chromatography and identification of monochlorinated derivatives was performed by reference synthesis and N.M.R. spectroscopy.

Experimental results showed an important activation for positions of the molecules substituted by electrodonor groups like methyl. On the contrary, positions substituted by electron withdrawing functions, like the acetoxy group, were desactivated. These results were correlated by a reactivity‐structure relationship, showing the separation between inductive and resonance effects. The equation used was: magnified image with p* = ‐0.843 and h = +0.034.

In view of the fact that the polar effect constants (σ*) for acetoxy and acetoxy‐methylene groups were not known, these constants were determined: magnified image.

The acetoxy sigma constant was considered as the sum of two terms: inductive (σ*−1) and mesomeric (σ*+M).
Organophosphorus Chemistry. Part I. On The Synthesis of Arylphosphines and Arylphosphine Halides
Authors: De Ketelaere R. , Muylle E. , Vanermen W. , Claeys E. , Van Kelen G. P. Der
Published: September 2010

Detailed and improved procedures for the preparation of (4‐FC6H4)nPCl3‐n and (3‐FC6H4)nPCl3‐n are presented. The identity and the purity of the substances were checked by I.R., n.m.r. (1H, 19F, and 31P) and mass spectrometry.
Solvent Shift Criteria in NMR. The Assignment of Cis‐Trans Isomers of Glycidic Esters
Authors: Vandenbroucke W. , Anteunis M. , De Bruyn A.
Published: September 2010

Solvent shift criteria can be used for the cis‐trans structural assignment in glycidic esters. Protons of substituents which are trans to the alkoxycarbonylgroup are shifted towards higher field in benzene than in carbon tetrachloride. Definitive proof of the structures were obtained by Nuclear Overhauser Effect experiments.
The Friedel‐Crafts Acylation Reaction. VII. Kinetic Analysis of the Aluminum Chloride Catalysed Reaction of Various Substituted Benzoyl Chlorides with Some Benzene Derivatives the Behaviour of the Benzoylating Complex
Authors: Hoornaert G. , Slootmaekers P. J.
Published: September 2010

Ce travail traite de l'acylation de quelques hydrocarbures aromatiques, présents en excès, par des chlorures de benzoyle substitués. Surtout le comportement du complexe benzoylant en ce qui concerne son ordre courant et initial est étudié.

II est vérifié que l'augmentation de k1 app. en fonction de la concentration initiale du complexe est due à l'action compétitive d'une, sinon deux, réactions d'ordre formel égal à deux par rapport au complexe réactionnel. En nous basant sur les valeurs du poids moléculaire de tels complexes dans plusieurs solvants, nous avons proposé l'intervention partielle d'une forme dimère du complexe. Une voie de réaction, par laquelle un intermédiaire, constitué d'une molécule de l'hydro‐carbure actif et d'une molécule du complexe benzoylant, réagit avec une deuxième molécule du complexe benzoylant dans l'étape limitative, peut également être admise.
Synthèse et Étude de la Structure Moléculaire de la 2‐(3'‐Pyridyl)‐Pyrido[2,3d]Pyrimidine
Authors: Osselaere J. P. , Dejardin J. V. , Dejardin‐Duchêne M.
Published: September 2010

Nicotinamide was treated by ammonium sulphamate, and 2‐(3'‐pyridyl)‐pyrido‐[2,3d]pyrimidine was isolated as unexpected product with a good yield. The molecular structure of this compound was investigated by means of Infrared, NMR and Mass spectrometry. The results obtained from this study allowed to establish the given formula.
Établissement de la Formule de Structure d'un Nouvel Acide Aminé Soufré de Xerocomus Subtomentosus
Authors: Jadot J. , Casimir J. , Warin R.
Published: September 2010

Le nouvel acide aminé soufré isolé du champignon Xerocomus Subtomentosus est caractérisé par la formule brute C8H10N2O4S. Des études analytiques et des réactions de dégradations ont montré qu'il s'agissait d'un acide α‐aminé bibasique dérivant du thiazole. II s'agit de l'acide α‐amino γ‐(carboxy‐4 thiazolyl‐2) butyrique. La synthèse de cette, substance corrobore la structure chimique proposée du composé naturel.
NMR‐Experiments on Acetals. XVI. Low Temperature Experiments and Conformational Data on 4‐Substituted CIS‐1,3‐Dioxadecalanes
Authors: Swaelens G. , Anteunis M.
Published: September 2010

In contrast to 4,6‐disubstituted‐1,3‐dioxanes it is possible to obtain at low temperature for 4‐Ra ⇌ e‐cis‐1,3‐dioxadecalanes(†) (I ⇌ I0) the NMR spectra of the individual conformers. Direct integration of suitable regions in the spectrum gave the composition of conformers. An attempt was made to estimate the ΔH° values of R‐groups in 1,3‐dioxanes by means of à priori calculations, based on assumed interactions. The ΔH° between O‐inside and O‐outside‐1,3‐dioxadecalane (I ⇌ I0 R = H) is evaluated to be 2.62 kcal/mole.
On the Calculation of Polycenter Integrals
Authors: André J. M. , Leroy G.
Published: September 2010

A justification of the Mulliken approximation is given. It is shown that this approximation gives correct results for π‐type polycenter integrals. Corrective terms are also deduce d for σ‐type polycenter integrals.
Méthode générale de synthèse de thio‐1 et séléno‐1 coumarines par cyclisation d'acides O‐méthylthio et O‐méthylsélénocinnamiques
Authors: Ruwet A. , Renson M.
Published: September 2010

We synthetize for the first time the seleno‐1 coumarin, a new heterocyclic compound [1]. The chemistry of the thiocoumarins is not very satisfactory. It is possible now to accede easily to thio‐1 coumarins as well as seleno‐1 coumarins by a general method giving good yields: the cyclization of o‐methylthio and o‐methylseleno‐cinnamic acids. About fifty examples are given. The coumarins are also available from o‐methoxycinnamic acids in similar conditions. We show how we arrive to this way and we discuss the mechanism of the cyclization.
Propriétés physico‐chimiques de composés caractère aromatique. potentiels de demi‐onde de réduction polarographique d'aldéhydes polycycliques aromatiques
Authors: Anthoine G. , Nasielski J. , Wilmet‐Devos B.
Published: September 2010

A series of ten aromatic aldehydes have been reduced at the dropping mercury electrode in dry D.M.F. Oscillopolarography has shown (table III) that the first wave is reversible at 20 Hz. The half‐wave potentials correlate reasonably well (table IV) with the energy of the lowest vacant M.O.
Étude théorique des systèmes hétéroatomiques conjugués. III. les composés carbonylés
Authors: Aussems C. , Jaspers S. , Leroy G. , van Remoortere F.
Published: September 2010

The semi‐empirical LCAO—SCF—MO method described in previous papers is further applied to some conjugated compounds containing the carbonyl group.

The theoretical results are discussed in the light of available experimental data, especially the electronic spectra and the ionization potentials.

The overall agreement between calculated values and measurements is satisfactory.
Mesure du potentiel standard du couple Np(III)/Np(o) dans l'eutectique LiCl‐KCl entre 400 et 550°c
Authors: Martjnot L. , Duyckaerts G.
Published: September 2010

We have measured the standard potential of the system Np(III)/Np(o) in the molten LiCl—KCl eutectic.

The cell used has been the following:magnified imageThe work was carried out in glove‐boxes under a pure argon atmosphere.

A comparison has been made with previous standard potentials determinations of uranium and neptunium in the same eutectic.
Indole Alkaloids. XX. Isolation and Structural Elucidation of Four Minor Alkaloids from Voacanga Chalotiana Pierre Ex Stapf
Authors: Braekman J‐C. , Tirions‐Lampe M. , Pecher J.
Published: September 2010

A further study of Voacanga chalotiana Pierre ex Stapf has led to the isolation of two known indole alkaloids: polyneuridine [2] and akuammidine [3], and of two new oxygenated derivatives of voachalotine [1]: voachalotine oxindole [4] and 21(?)‐hydroxyvoachalotine [5].
Microbiologie analytique. étude du dosage de la thymine à l'aide de streptococcus faecalis()
Authors: Rappe André
Published: September 2010

Dans le cadre de l'étude que nous avons entreprise sur le dosage microbiologique des bases puriques et pyrimidiques, nous présentons dans ce travail l'adaptation au milieu liquide du dosage de la thymine dont la réalisation en milieu solide a été précédemment décrite [4].

Nous examinerons successivement la technique de l'essai, l'étude du dosage de la thymine et dérives et l'étude de la spécificité.
Détermination empirique de l'effet d'anisotropie diamagnétique exercé sur les protons aliphatiques en résonance magnétique nucléaire
Authors: Nagy O. B. , Ph. Soumillion J. , Bruylants A.
Published: September 2010

An empirical correlation method relating proton chemical shift to Taft σ* parameters is extended to a series of halogenated compounds. The results obtained make it possible to determine new diamagnetic anisotropy corrections for various substituents. The scope and limitation of the method are discussed.
N.M.R. Experiments on Acetals: XX [I]. Conformational Equilibrium in 5,5‐Disubstituted 1,3‐Dioxanes
Authors: Coene E. , Anteunis M.
Published: September 2010

A number of 5, 5‐disubstituted 1,3‐dioxanes (mostly methyl, alkyl) were prepared and their PMR spectra studied at various temperatures. Conformational equilibria and thermodynamic parameters were obtained (table I), using correct [7] shift data. The results obtained with data for H‐2 hydrogens are more accurate then those for H‐4,6 hydrogens. Some ambiguity however exists concerning equilibria for 5‐Me‐5‐nalkyl‐mdioxanes and different sets of values remain possible (table III). In general however it seems that the method of calculation as previously introduced [7] gives more then satisfactory results. Accuracy seems to be very high and without correction of the shift parameters for their temperature dependance, the linearity of the total free energy differences with temperature is often very bad. Even after correction it remains bad however for 5‐Me‐5‐rBu‐1, 3‐dioxane. Some spectral features of the latter compound are discussed and it is shown that H‐4a (H‐6a) resonates at lower field then H‐4e (H‐6e).
N.M.R. Experiments on Acetals: XXI [1]. Barriers for Ring inversion in Some Geminal Substituted 1,3‐Dioxanes
Authors: Coene E. , Anteunis M.
Published: September 2010

Barriers for ring inversion in some 5,5‐gem. substituted m. dioxanes (dialkyl‐ and spiro derivatives) were measured and compared with some 2,2‐gem. substituted derivatives. The results are compatible with a lowering of ΔG≠ when steric compression is higher in the ground state (table I). An exceptional low value is found in 5,5‐di isopropyl‐m‐dioxane (ca. 8 kcal/mole), whereas normally the geminal 5‐substitution raises the inversion barrier. Some spectral features of 5,5‐pentamethylene‐ and 5,5‐dimethyl‐2,2‐pentamethylene‐m‐dioxane are commented.
A Kinetic Study of the Diazotisation and N‐Nitrosation of The Toluidines
Authors: Aboul‐Seoud A. , Ahmad Moustafa
Published: September 2010

The kinetics of the chloride‐catalysed diazotisation of the toluidines were investigated. For the rate‐determining stage, which is, under the present conditions, the N‐nitrosation of the unprotonated amine by NOCl, the values of the specific reaction rate, the free energy of activation, ΔG≠, the enthalpy of activation, ΔH≠, the entropy of activation, ΔS≠, and the energy of activation, E, were determined and compared. The influence of the nuclear methyl substituent, in the different positions of the benzene ring in the aniline molecule, was interpreted in terms of electrical effects.
The Reaction of Sodium Bisulfite with Propylene Oxide
Authors: Bombeke J. , Goethals E. J.
Published: September 2010

It is shown by spectroscopic and chemical methods that the ring opening reaction of sodium bisulfite with propylene oxide exclusively yields sodium 2‐hydroxypropane‐1‐sulfonate.
Spectrophotometric Study of N,N′‐bis(m‐Sulphobenzyl) Dithio‐Oxamide as a Reagent for Palladium (II)
Authors: Janssens A. A. , Herman M. A.
Published: September 2010

The complex formed between N, N′‐bis(m‐sulphobenzyl)dithio‐oxamide and palladium (II) can be used for the spectrophotometric determination of this metal in aqueous solution.

In 6 M hydrochloric acid solution, the absorbance measurements are carried out at 432 mμ. Beer's law is obeyed over the range 0,4 to 12 μg Pd per ml and the sensitivity is 0,0076 μg per sq. cm.

In buffered weak acid solution (pH 6,8) the absorbance measurements are made at 390 mμ. Beer's law is obeyed ove. the range 0,4 to 12 μg Pd per ml and the sensitivity is 0,0090 μg per sq. cm. Foreign ions interfere less in 6 M hydrochloric acid than in buffered weak acid solution.
Étude de Complexes Moléculaires I. Cinétique et Équilibre de la Réaction de la Phénothiazine Avec le p‐Chloranile dans L'acétonitrile
Authors: Barigand M. , Orszagh J. , Tondeur J. J.
Published: September 2010

The kinetics of the reaction phenothiazine + ρ‐chloranil is followed by spectrophotometry, in the solvent acetonitrile. The molar absorption coefficient of the green product of this reaction is calculated.

As shown by the experimental results, this second order reaction leads very slowly to an equilibrium.

The values of kinetic constants, equilibrium constant, activation energy and enthalpy of reaction are given.
Étude des Spectres de masse D'Une Série de Méthylalkyl Mercure
Authors: Spielmann R. , Delaunois C.
Published: September 2010

We have realized the synthesis of a serie of dialkylmercury compounds, where a group alkyl is always the same. The mass spectra are described and analysed. The main fragmentation observed is the lost of an alkylradical.

However, we have also observed secondaries fragmentations coming from intramolecular mecanism. We have mentioned the differents states of oxydations and the probable rupture's sequences of the differents substituants fixed on the mercury. We do not observe metastable ion for this series of derivatives.
The Oxidation of N‐Substituted V‐triazole: (A Meisenheimer‐Rearrangement)
Authors: Hubert A. J.
Published: September 2010

The oxidation of I‐substituted v‐triazoles R‐CH2‐(N3C2HR') gives oxy derivatives R‐CH2‐O‐(N3C2HR'). They are probably formed by a Meisenheimer‐rearrangement of an N‐oxide which cannot be isolated under the conditions used for the reaction.
Essais de Chloration Dirigée: XIV. Effets de Solvant sur la Photochloration D'Hydrocarbures Arylaliphatiques(1)
Authors: Corbiau J. L. , Bruylants A.
Published: September 2010

In the photochlorination of arylaliphatic hydrocarbons (C6H5R; R = C2H5; n. C3H7; i. C3H7; n. C4H9; sec. C4H9; n. C5H11) substitution only takes place in the side chain, and preferentially in the α position, as was showed in the previous paper. Now, in order to make clear which effect is operative‐ either the polar effect of the substituent or a complexation effect of the aromatic nucleus of the reagent, photochlorination of the title compounds was examinated in various solvents (CCl4, aromatics and CS2). Firstly, diluting by CCl4, it was observed that relative reactivity, r. r. (a/b), of an hydrogen a versus another b, varies with the concentration and can be expressed as a linear function:

Including complexation constant K1, specific rate ka1 and relative reactivity kao/kbo at infinite dilution (whose numerical values can be calculated by means of the former formula), if R is C2H5; n. C3H7; i. C3H7; sec. C4H9, and with a more sophisticated one:

for the other terms, R = n. C4H9, n. C5H11. With benzene, selectivity is enhanced but with chlorobenzene it is depressed. Finally, the best results concerning the selectivity are obtained by photochlorination in the presence of CS2. We mention here the most interesting result of cumene (R = i. C3H7), giving up to 98% of α‐chloroisomer in the presence instead of 86% of the same in the absence of CS2.
The Thermodynamics of Ionization of Anilinium Ions in Ethanol‐Water Mixtures
Authors: van de Poel W. , Slootmaekers P. J.
Published: September 2010

Thermodynamic parameters of ionization of a number of substituted anilinium ions were measured in water and in ethanol–water mixtures at 25°C. Both the enthalpy and entropy of ionization show extreme values in a solvent mixture containing 0,90 mole fraction of water. Free energy values decrease smoothly and monotonically with increasing ethanol content of the solvent.

It is shown that the solvent effect is dependent on the nature of the substituent on the anilinium ion.

The results are treated in terms of the structural theory of water and of ethanol–water mixtures. Furthermore, an attempt is made to determine the value of β, the proportionality constant between ΔHext and ΔSext, which was introduced by Hepler.
L'Étude Théorique des Systèmes Périodiques: V. Les Expressions Analytiques des Intégrales Électroniques et des Bandes D'Énergie
Authors: André J. M. , Delhalle J. , Leroy G.
Published: September 2010

On déduit la forme explicite des intégrales électroniques dans les systèmes périodiques tridimensionnels. Dans la dernière partie, on décrit un procédé général pour obtenir une expression analytique simple des bandes d'énergie dans les cristaux.
Couches de Diffusion D'Aluminium Formées par Électrolyse sur le Nickel dans les Chlorures Fondus
Authors: de Haan A. , Vander Poorten H. , Legrelle A.
Published: September 2010

The formation of aluminium diffusion coatings on nickel is considered in molten chloride bath.

The coatings obtained by immersion of nickel samples in molten chloride baths containing a pyrosol or a sub‐compound of aluminium are not adherent.

By electrolysis of NaCl‐KCl eutectic (+ 10% weight AlCl3) at 750°C and under a current density of 50 mA/cm2, homogeneous layers of Al3Ni2 are coated on nickel.

A process of depolarisation appears in the mecanism of electrodeposition of aluminium on nickel.

The layers of about 150 μ are adherent, well crystallised and present a very high hardness of about 800 kg/cm2.

The resistance to the corrosion in atmospheric air at high temperature is enhanced.
Sodium‐Ammonia Reductions in N‐Heteroaromatic Chemistry. Protodehalogenation and Protodealkylation of Sulphur Containing Pyrimidines, Pyridazines and S‐Triazines
Authors: de Lannoy J. , Gysen A. , Nasielski‐Hinkens R.
Published: September 2010

The Birch reduction of chloro‐pyrimidine, ‐pyridazine and ‐s‐triazine derivatives bearing a prototropic substituent gives the corresponding dehalogenated compounds in good yields. Methylthio‐ and ethylthio‐substituents undergo a reductive cleavage: 4‐amino‐6‐methylthiopyrimidine (II) and 2,4‐bis‐diethylamino‐6‐ethylthio‐s‐triazine (III) are converted to the corresponding mercapto compounds. Moreover, the sodium‐ammonia reagent is able to remove a chlorine atom from a molecule containing a mercapto or alkylthio substituent; the efficiency of this reaction is shown by the one step reduction of 4‐amino‐6‐chloro‐2‐methylthiopyrimidine (VI) and 3‐chloro‐6‐mercaptopyridazine (VII) to the corresponding dehalogenated mercaptans in 66 and 58% yield, respectively.
Note on “the Stereochemical Requirements for Long Range Coupling in α‐Halogenocyclohexanones”
Authors: Anteunis M. , Schamp N.
Published: September 2010

In reply to the paper of Jefford and Waegell [1] it is shown that non‐classical long‐range coupling does exist in 3,3,5,5‐tetrasubstituted‐2‐halo‐cyclohexanones. Following the reasoning of those authors, an even larger abnormal coupling than originally proposed by us [2] would exist. It is illustrated however that in our original assignation of peaks to axial resp. equatorial H‐4 and H‐6 hydrogens, we have not used false premises. Therefore our original statements [2] are maintained.
Essais de Chloration Dirigée: XV. Corrélation Structure‐Réactivité Dans la Photochloration des Alkylbenzènes [1,2]
Authors: Corbiau J. L. , Soumillion J. Ph. , Bruylants A.
Published: September 2010

A quantitative discussion of the experimental results previously obtained in the photochlorination of the alkylbenzenes (C6H5‐R: R = C2H5‐,n.C3H7‐,i.C3H7‐,n.C4H9‐,n.C5H11) is presented.

The correlation used is as following: logr.r.(a/b) = ρ*(Σσa*– Σσb*) + Ψa– Ψband accounts for the inductive (σ*) and mesomeric effects (Ψ) of the substituents upon the relative reactivity [r.r. (a/b)] of the ≥ C‐H bond; the last one is only acting upon the α position. The absolute value of both parameters (ρ and Ψ) increases with the concentration of the aromatic substrate. The relative magnitude of their actions is commented.
Purification and Single Crystal Growth of V2O5
Authors: Haemers J.
Published: September 2010

A means of obtaining single crystals of V2O5 of reasonable perfection is described. Starting from p. a. material preliminary purification as described is needed.
Étude de Complexes Accepteur‐Donneur par Spectrométrie Infrarouge: I. Influence de la Nature du Donneur Carbonylé
Authors: Lecl Nedden G. Ère‐Zur , Duyckaerts G.
Published: September 2010

Infrared intensity measurements of the free C = O band have been used to investigate the complex formation between ketones or other carbonylated donorsand antimony trichloride in CCl4solutions using Job's continuous variation method. The dissociation constants of the acceptor‐donor complexes with a 1:1 and 1:2 stoichiometry have been calculated. The sequence of donor basicity based on the 1:1 equilibrium constant is discussed in terms of electronic effects of the substituents R and R.