bluuebunny/crossref_metadata_2025_split huggingface dataset:
The bromination of naphthalene IV.): A theoretical treatment of the influence of the temperature on the proportions of α‐ and β‐bromonaphthalene formed below 300°
Authors: Sixma F. L. J. 
Published: September 2010

AbstractA theoretical treatment is given of the non‐catalytic bromination of naphthalene. In the bromination of liquid naphthalene in the temperature range from 85° to 215° and in the bromination of gaseous naphthalene in the presence of a non‐specific contact material (pumice or glass wool) below 300° the ratio of β‐bromonaphthalene to α‐bromonaphthalene is determined by the difference in activation energies of the simultaneous reactions. This difference in activation energies is calculated by means of approximate methods elaborated in wave mechanics.
A new synthesis of ω‐amino‐p‐hydroxyacetophenones and their reduction to the corresponding aminoethanols
Authors: Asscher M. 
Published: September 2010

AbstractA new synthesis is described of compounds of the typemagnified imageby the condensation of phenol or its derivatives with aminoacetonitriles according to the method of Hoesch and Houben. The corresponding alcohols are prepared by catalytic reduction of the ketones obtained.
Étude Cinétique de la Polycondensation de L'acide Amino‐II Undécanoïque
Authors: Champetier G. , Vergoz R. 
Published: September 2010

AbstractL'étude cinétique de la polycondensation à l'état fondu d'un aminoacide particulier, l'acide amino‐II undécanoique, conduit à admettre que la réaction est du second ordre, mais que la constante de vitesse est fonction du temps et représentée convenablement par l'expression k = k0 exp (‐ αt).Si t est exprimé en secondes, k0 = 5.2 et α = 1.775 × 10−4.
On the range of existence of the liquid state
Authors: Zernike J. 
Published: September 2010

AbstractThe contention sometimes met with that the ratio of critical and triple point temperature is about constant for different substances, is shown to be erroneous. It actually may have values from 1.07 to 12.3. Though some compounds, usually classed as one group, show about the same value for this ratio, other related compounds have largely different values. As a first approximation a linear relation is found between this ratio and the logarithm of the triple point pressure. On the strength of this relation it is suggested that when the vapour pressure of a solid has been measured to about 120 at no reversible melting is to be expected. Reasons are advanced that mercuric sulphide and paracyanogen may be cases in point.
The preparation of some amino‐1,4‐Benzodioxanes and AZO dyes derived therefrom
Authors: Heertjes P. M. , Revallier L. J. 
Published: September 2010

AbstractIn this paper an improved method for the preparation of 6‐nitro‐1,4‐benzodioxane, the preparation of 6‐amino‐7‐nitro‐1,4‐benzodioxane and of 6‐amino‐1,4‐benzodioxane‐sulphonic acid is described.Some azo dyes derived from the last two substances, showing moderate to good properties, are given.
The degradation of lupeol derivatives to C27‐ketones
Authors: Davy G. S. , Jones E. R. H. , Halsall T. G. 
Published: September 2010

AbstractThe degradation of α‐lupene to trisnorlupanone has been re‐examined and analogous reactions with lupenyl acetate have yielded the corresponding C27 keto‐acetate. Conclusive evidence of the presence of a carbonyl group in these compounds has been obtained by spectrographic methods and by lithium aluminium hydride reduction.
Spectres D'absorption Infrarouges de Trichloracrylates Métalliques
Authors: Duval Cl. , Gerding H. , Lecomte J. 
Published: September 2010

AbstractNous avons examiné, pour la première fois, entre 1600 et 700 cm−1 environ, les spectres d'absorption de six sels métalliques de l'acide trichloracrylique, ainsi que cet acide lui‐même. La technique habituelle, correspondant à l'étude des substances en poudre, s'est appliquée sans aucune difficultéSur la technique générale: J. Lecomte et P. Lambert, Ann. office natl. combustibles liquides 6, p. 1001 (1932); Ann. phys. [X] 18, 329 (1932); ibid. [XI] 10, 503 (1938); Publs, sci. et tech. ministère air France No. 34, 1933 et 142, 1939. Sur la méthode des poudres, en général: J. Lecomte, Cahiers de physique, 1943, No. 17, p. 1.
). II faut noter cependant que la dispersion du spectrographe étant faible entre 1200 et 1600 cm−1, les positions des bandes situées dans cette région ne sont données qu'à titre indicatif.
Recherches sur les Composés à Deux Cycles Pyridiques: Bis‐pyridiniums, bis‐pyridones‐2, bis‐piperidones‐2 et leur dérivés
Authors: Gautier J. A. , Renault J. 
Published: September 2010

AbstractLes composés à double fonction pyridinium quaternaire (bis‐pyridiniums) conduisent, au moyen de l'oxydation ferri‐cyanhydrique, aux bis‐pyridones‐2 correspondantes qui sont elles‐mêmes aisément hydrogénables (nickel de Raney) en bis‐pipéridones‐2. Ces dernières présentent la constitution de bis‐lactames d'acides δ‐amino‐valériques N‐substitués, et sont, comme telles, transformables en bis‐amino‐acides. Ceux‐ci ont pu être isolés et fournissent des dérivés bien définis tels qu'esters et amides.
The determination of the position of the double bond in mono‐ethenoid fatty acids
Authors: Begemann P. Haverkamp , Keppler J. G. , Boekenoogen H. A. 
Published: September 2010

AbstractMethods hitherto used for determining the position of the double bond in the fatty acid molecules are somewhat crude and unreliable when applied to fatty acid mixtures. Applying partition chromatography to the analysis of fatty acid oxidation products more reliable results were obtained. Experiments have shown that ozonisation and permanganate oxidation in glacial acetic acid cause only a slight secondary disintegration of the dibasic acids formed, but that permanganate oxidation in acetone is less suitable.The improved method as described does not yield fully quantitative results, but it is sufficiently good to permit valuable conclusions to be drawn. The method is checked by the analysis of pure samples of various fatty esters. “Vaccenic acid” obtained by partial hydrogenation of tang oil has been proved to be a mixture of isomeric oleic acids.
Pyridine‐N‐oxide as an intermediate for the preparation of 2‐ and 4‐substituted pyridines
Authors: den Hertog H. J. , Overhoff J. 
Published: September 2010

AbstractA description is given of methods for the preparation of 4‐, 2,4‐ and 3,4‐substituted pyridines, e.g. 4‐aminopyridine. the N‐oxide of pyridine or derivatives of pyridine is used as an intermediate to make e pyridine nucleus accessible for substitution in positions 2 and 4.
The energy of localization
Authors: Ketelaar J. A. A. , van Dranen J. 
Published: September 2010

AbstractThe energy of localization (KooymanandKetelaar) of one pair of π‐electrons is calculated for benzene and for naphthalene, in the latter case for the 12 bond and for the 23 bond. The usual L.C.A.O. approximation of the molecular orbital method is applied in zero approximation with neglect of overlapping integrals and in first approximation with these integrals equal to 0.25.The values found in the zero approximation are 27.4 (benzene), 22.7 (12 bond naphth.) and 31.2 kcal (23 bond naphth.): in a first approximation 30.2, 21.8 and 36.3 kcal, respectively. The observed difference in the rate of the reaction of ozone with benzene and naphthalene is in accordance with these results.
Oxidation of alkyl groups attached to the naphthalene nucleus
Authors: Pickering G. B. , Smith J. C. 
Published: September 2010

AbstractBy the action of N‐bromosuccinimide the side‐chain of an alkyl‐naphthalene is brominated on the α‐carbon atom (allyl system). Removal of hydrogen bromide gives an olefin which is easily oxidised to the naphthoic acid.
N‐Methylated menthylamines and piperitylamines
Authors: Read John , Cuthbertson William Wilson 
Published: September 2010

AbstractThe N‐methyl‐ and N‐dimethyl‐derivatives of l‐ and d‐neomenthyla nines, as well as the corresponding trimethylammonium iodides and hydroxides, have been described by Read and HendryJ. Read and J. A. Hendry, Ber. 71,2544.
). Corresponding derivatives of d‐iso‐ and d‐neoisomenthylamine have now been prepared and characterised, together with those of the closely related l‐piperitylamine. d‐neoisoMenthylamine has been obtained in a new way, starting from l‐piperitone.
La réaction du tétrahydrure de lithiumaluminium sur quelques composés organiques soufrés
Authors: Strating J. , Backer H. J. 
Published: September 2010

AbstractLiAlH4 réduit les rhodanures et les sulfochlorures en mercaptanes. Par contre, on obtient les disulfures, en réduisant les chlorures sulféniques, les acides sulfiniques, les chlorures sulfiniques et les 1,2‐disulfones. La plupart des disulfures peuvent être réduits par LiAlH4 en mercaptanes, mais cette réaction s'accomplit très lentement.La formation aisée de mercaptanes aux dépens des rhodanures et des sulfochlorures ne s'accomplit donc pas par l'intermédiaire des disulfures.Le comportement des esters sulfoniques d'alcools aliphatiques primaires et secondaires est très remarquable. Soumis à l'action de LiAlH4, ils donnent naissance à l'acide sulfonique et à l'hydrocarbure dont l'alcool se dérive.
Kinetic analysis of organic halides. II. Analysis of macromolecules built up of monohalide units
Authors: Salomon G. , Koningsberger C. 
Published: September 2010

AbstractA number of hydrochlorides of natural and synthetic rubbers and allied polymers have been prepared and subjected to kinetic analysis with organic bases. The hydrochlorides of natural rubber react at 100° C with a rate identical with that of low molecular tertiary chlorides. At 50° C the reactivity of the polymer is, however, reduced by physical factors.The hydrochloride of GR‐S (a synthetic rubber made from butadiene and styrene) has been prepared for the first time by heating the swollen polymer with HCl under pressure. Kinetic analysis of this product revealed two fractions; the expected secondary chloride and a small fraction of a very reactive (tertiary?) chloride.After elimination of experimental difficulties, we succeeded in the preparation and kinetic identification of the pure tertiary hydrobromide of natural rubber. Attempts to prepare the secondary bromide under peroxide conditions failed.Kinetic analysis of two types of Neoprene revealed the presence of a small quantity of allylic groups in the polymer, while 95% of the chlorine in Neoprene has the expected stability of a vinyl chloride. This stability can be used for the identification of Neoprene.
A rapid determination of the average molecular weight of rubber in hevea latex
Authors: van Essen W. J. 
Published: September 2010

AbstractA method is described for determining viscometrically the molecular weight of rubber in freshly tapped latex. For this purpose the latex is dissolved in a toluene‐pyridine mixture. From the intrinsic viscosity of this solution the molecular weight of the rubber can be determined, using the Staudinger equation and a known viscosity constant. Molecular weights have been found, varying between 238000 and 480000, depending on the kind of clone. Rubber in fresh latex does not have a lower molecular weight than in old preserved latex.
Synthèse de Stérols à Chaînes Latérales Variées
Authors: de Vries Harmen , Backer H. J. 
Published: September 2010

AbstractAfin de synthétiser les stérols ayant des chaînes latérales différentes, les auteurs ont préparé quelques céto‐stéroïdes dont la fonction cétone se trouve dans la queue, soit en position 22 soit en 24.On transforme le groupe carbonyle en groupe méthylène par l'intermédiaire des mercaptals cycliques de dithioglycol, que l'on soumet à une décomposition réduisante au moyen de nickel Raney.Après avoir vérifié l'applicabilité de cette méthode en synthétisant le cholestérol, les auteurs s'en sont servis pour la synthèse du 25,25‐bis‐desméthyl‐cholestérol et du 25‐desméthylcholestérol (le dernier produit selon deux voies).
Nouveaux Dérivés du Dibenzofuran et de Ses Isologues
Authors: Buu‐Hoï Ng. Ph. , Royer René 
Published: September 2010

AbstractDans ce travail, on continue l'étude des dérivés du dibenzofuran, notamment par la description de nouveaux 3‐acyldibenzofurans, et d'une série de 3‐alkyldibenzofurans préparés par réduction de Clemmensen des cétones correspondantes. On montre que ces homologues du dibenzofuran peuvent être acylés à leur tour au moyen de la réaction de Friedel‐Crafts. Une étude parallèle a été faite dans les séries isologues du dibenzothiophène et du fluorène, et de nombreux 2‐alkylfluorènes et 3‐alkyldibenzothiophènes ont été synthétisés et leur réactivité étudiée sur la réaction de Friedel‐Crafts. Plusieurs composés indoliques ou quinoléiniques se rapportant aux cétones précédentes sont décrits également ici:
Compounds related to provitamin D3 (II). The sulphur analogue of provitamin D3
Authors: Strating J. , Backer H. J. 
Published: September 2010

AbstractThe preparation of the sulphur analogue of provitamin D3 is described. Bromination of S‐acetyl‐cholestene‐5‐thiol‐3, followed by elimination of hydrogen bromide, did not give good results.The synthesis has been realised by applying these reactions to cholesteryl rhodanide; 7‐dehydrocholesteryl rhodanide so obtained submitted to selective reduction by means of LiAlH4 afforded cholestadiene‐5,7‐thiol‐3.Bis‐(7‐dehydrocholesteryl‐3)‐disulphide, which may be prepared from 7‐dehydrocholesteryl rhodanide, could also be reduced by means of LiAlH4 to the same sulphur analogue of provitamin D3.
Syntheses of polychloro compounds with aluminium chloride IX. The preparation of octochlorocyclopentene by the direct condensation of trichloroethene and carbon tetrachloride
Authors: Prins H. J. 
Published: September 2010

AbstractThis paper describes the preparation of octochlorocyclopentene in one step from trichloroethene and carbon tetrachloride by the slow addition of trichloroethene to an excess of boiling carbon tetrachloride in the presence of aluminium chloride.
An interpretation of the influence of temperature on the bromination of bromobenzene
Authors: Wibaut J. P. , Sixma F. L. J. , Lips H. 
Published: September 2010

AbstractAt high temperatures a sudden change in substitution type occurs in the bromination of the halogeno‐benzenes. The theory, wich was developed for the bromination of naphthalene vapour, is applied to these cases and gives satisfactory agreement with the experimental results. The absence of a similar change in the substitution type in the bromination of phenol is discussed.The bromination of bromobenzene vapour under the influence of light was studied; illumination results in a lowering of the temperature range in which the substitution type changes. This is a further proof of the correctness of the hypothesis underlying our theory, i.e. the development of a radical type of reaction at high temperatures.
Catalytic hydro‐desulphurization of gas oil: Contribution of hydrofining studies to the clarification of the structure of the sulphur compounds present in gas oil
Authors: Hoog H. 
Published: September 2010

AbstractIn the course of a study on desulphurization of mineral oils by catalytic hydrogenation, it was recognized that this hydro‐desulphurization reaction may also contribute to the clarification of the nature of the sulphur compounds present.To this end, by means of model experiments with pure synthetic sulphur compounds, an analysis was first made of the gross type of reactions occurring when sulphur compounds are decomposed by hydrogenation into H2S and hydrocarbon fragment(s). The results conclusively indicate that under the conditions chosen and with the type of catalyst used the picture definitely is not that known from hydrocracking: the reaction is virtually limited to a rupture of C‐S‐bonds and hydrogen‐saturation of free valency. Our type of catalyst did effect hardly, if at all, the hydrogenation of aromatic rings present in the sulphur compounds. Only in the case of dibenzothiophene was partial hydrogenation of the rings observed. Parallel experiments with more aggressive catalysts invariably showed considerable aromatic saturation.The results of these model tests were then used in the interpretation of hydrogenation experiments made with a full range gas oil of Middle East origin.In a large number of experiments carried out on this gas oil, the reaction product was scrutinized for the presence of low boiling hydrocarbons. As in no case more than traces of gaseous hydrocarbons or liquid hydrocarbons distilling below 200°C could be found, it is evident that no sulphides and di‐ or polysulphides can have been present in the feed stock. As it was known from chemical analysis that no mercaptans are present either, the sulphur compounds in our specific gas oil must preponderantly be of the thiophene (or thiophane) type.By hydrogenation of a concentrate of the sulphur compounds (obtained by extraction of the gas oil with liquid anhydrous hydrogen fluoride), it was possible to study the corresponding hydrocarbons more closely. By means of careful chromatographic analysis it was shown that these were for about 60 % of aromatic and for 40 % of naphthenic nature, and that only few, if any, non‐cyclic hydrocarbons were present. Consequently, the original thiophene or thiophane compounds present in the gas oil investigated are not of the alkyl thiophene or alkyl thiophane type. They presumably consist as to about 30‐40 % of thiophenes (thiophanes) which contain one homocyclic ring and in about 70‐60 % two homocyclic rings which are not in the condensed configuration are present next to the thiophene (thiophane) ring.No conclusion can be drawn as to the relative proportion of naphthene and aromatic rings in the original sulphur compounds.
Transposition intramoléculaire de nitrophénylsulfonylurées: (Les propriétés du groupe sulfonyle XIII)
Authors: Backer H. J. , Groot J. 
Published: September 2010

AbstractLa transposition intramoléculaire des nitrophénylsulfonyl‐urées 2) est un processus assez général, auquel les auteurs ont soumis les dérivés o‐ et p‐nitrophénylsulfonyle de plusieurs urées et iso‐urées. En perdant le soufre sous forme d'anhydride sulfureux, les composés donnent des nitrophénylurées et éventuellement des produits de réactions secondaires.Aux dépens des o‐ et p‐nitrophénylsulfonyl‐alkyl‐iso‐urées, on n'obtient pas les nitrophénylalkyl‐iso‐urées, mais leurs produits d'hydrolyse, les nitrophénylurées.Les o‐ et p‐nitrophényl‐alkyl‐isothio‐urées, soumises à l'action de bases, n'obtiennent pas la chance de se transposer parce qu'elles perdent directement une molécule de mercaptane. Le produit final de la décomposition est un thioéther.En étudiant, pour quelques nitrophénylsulfonylurées, la vitesse de la transposition — au moyen d'un dosage de l'acide sulfureux à des temps définis ‐ les auteurs ont pu vérifier l'hypothése sur le mécanisme.
The structure of cyclized rubber
Authors: van Veersen G. J. 
Published: September 2010

AbstractThe history of cyclized rubber, including a series of structural formulae previously proposed for this polymer, is reviewed briefly.A new formula for cyclized rubber is suggested by applying electronic interpretations of reactions between electrophilic agents and tertiary alkyl olefins and tertiary halides respectively, to the corresponding reactions with rubber and rubber halides.It is shown that hydrochlorination can be used for the determination of the unsaturation of cyclized rubber. By varying the conditions of hydrochlorination two types of double bonds can be detected in cyclized rubber, a fact which is in agreement with the structure suggested.By using our method for the determination of the unsaturation, the rate of cyclization at different temperatures and the influence of solvents on the rate of reaction have been determined.
Preparation and properties of 1‐methylcyclohexadiene‐1,4
Authors: Haak F. A. , Wibaut J. P. 
Published: September 2010

Abstract1‐Methylcyclohexadiene‐1,4 (C7H10) is obtained by reducing toluene by the method of Wooster. The structure of this hydrocarbon follows from the formation of acetone on decomposing the oxidation products with dilute hydrochloric acid. The addition products C7H10Br2, C7H10 Br4 and C7H11Br3 are described.
Etudes dans la sêrie du thiophène VI. La chimie du 2‐p‐tolylthiophène et du 2‐p‐chlorophénylthiophène
Authors: Buu‐Hoï Ng. Ph. , Hoán Nguyen 
Published: September 2010

AbstractDans ce travail, les auteurs étudient la réactivité de 2 arylthiophènes: le 2‐p‐tolylthiophéne et le 2‐p‐chlorophénylthiophéne, préparés à l'aide de la réaction de Gomberg à partir du thiophène et des chlorures de p‐tolyl et p‐chlorophényldiazonium en milieu alcalin. II est montré que dans cette réaction, il se forme comme sous‐produits au moins deux ditolylthiophènes et deux bis(chlorophényl)thiophènes. Le 2‐p‐tolylthiophène et le 2‐p‐chlorophénylthiophène possèdent une forte réactivité, dûe à la présence d'une position x libre sur le noyau thiophénique, comme le montrent la bromuration par la N‐bromosuccinimide et les réactions de Friedel‐Crafts. A partir des cétones ainsi obtenues, de nombreux corps nouveaux ont été synthétisés: acides, indoles, quinoléines, pyrrocolines, pyrimidazoles, α,β,β‐triaryléthénes, etc.…, dont certains font d'objet d'études biologiques.
The ionic conductivity of Li‐halide crystals
Authors: Haven Y. 
Published: September 2010

AbstractThe ionic conductivity of mixed crystals of Li halides and Mg halides has been measured. From these measurements the mobility of Li vacancies and the concentration of vacancies in pure Li halides has been derived, with the two assumptions that the defects in Li halides are Schottky defects and the mobility of halide vacancies is negligibly small.The conductivity can be represented by an equation of the form:x = A exp(‐U/kT)[1 + {1 + (4 A′/a2) exp(‐E/kT)}½]in which x is the specific conductivity, U the height of the potential barrier which must be surmounted by the Li+ ions when moving through the crystal, E the energy required for the formation of a pair of vacancies, a the concentration of Mg halide and A′ and A constants.The magnitude of E, U, A and A′ (table I) have been compared with theoretical estimates.
Untersuchungen über Rotationsdispersion III
Authors: Lifschitz I. 
Published: September 2010

AbstractIn Ergänzung früherer Mitteilungen wird über weitere Untersuchungen der Metallkomplexverbindungen des Oxymethylencamphers berichtet. Insbesondere werden die bemerkenswerten Rotations‐ und Razemisationsverhältnisse der Chromiverbindung beschrieben. Die Absorptionsspektra und Dipolmomente der Oxymethylencamphorate und Acetylacetonate der dreiwertigen Metalle Al, Cr, Co und Fe werden mitgeteilt und kurz diskutiert.
The solubility of MgF2 in solid LiF
Authors: Haven Y. 
Published: September 2010

AbstractFrom work on the ionic conductivity of LiF‐MgF2 mixed crystals the solubility of MgF2 in solid LiF has been derived at temperatures from 400 to 700° C. The solubility is of the order of magnitude of several percent. The rules given by Goldschmidt for the miscibility of ionic substances have been extended. Apart from the similarity in ionic radius which was emphasized by Goldschmidt, the gain in polarization energy upon solution of the solute also has to be considered. This polarization energy is particularly important in cases where the solute contains ions with a valency different from that of the solvent ions.