bluuebunny/crossref_metadata_2025 huggingface dataset:
La Configuration des Acides α‐Hydroxylés Cycliques‐1,1 (II)
Authors: Böeseken J. , van Buuren F. J.
Published: September 2010

La présente étude est la suite de celle faite il y a cinq ans sur l'influence de l'acide borique sur la conductibilité des acides cyclo‐hydroxycarboxyliques‐l,l. Il s'agissait de rechercher si l'augmentation de conductibilité électrique trouvée chez les acides glycoliques bisubstitués est changée par la clǒture de l'anneau. Nous avons trouvé que les acides cycliques de plus de quatre atomes de carbone subissent presque tous le même effet par l'acide borique indépendamment du nombre des atomes de l'anneau.

Par contre, l'acide hydroxycyclobutane‐carboxylique ne montra presque pas d'augmentation de conductibilité. Nous avons répété et amélioré ces mesures et y avons ajouté l'examen de l'acide hydroxycyclopropanecarboxylique.

Il se trouva que l'augmentation de la conductibilité baissa d'environ 1000 × 10−4 unités Kohlrausch‐Holborn pour les acides glycoliques non cycliques ainsi que pour les acides cycliques ayant plus de quatre atomes, jusqu'à environ 125 × 10−4 pour le dérivé du cyclobutane et jusqu'à 66 × 10−4 pour celui du cyclopropane.

Nous en concluons maintenant:

clǒture d'un anneau de plus de quatre atomes;

que la situation des groupes OH et COOH n'est pas changée par la

que dans les anneaux de quatre ou de trois atomes, ces groupes se déplacent (l'angle entre ces groupes s'accroît probablement) sous l'influence de la déviation forcée des affinités et cela, dans l'anneau triatomique plus fortement que dans l'anneau tétratomique;

que dans les anneaux de plus de cinq atomes, l'angle entre les affinités des atomes de l'anneau reste environ 109°28′. Ces atomes ne sont donc pas situés sur le même plan;

que l'acide hydroxycyclobutane‐carboxylique forme très facilement une lactide, ce qui doit être attribué à la situation favorable des groupes OH et COOH dans l'espace.
The formation of a tetrahydrophenanthroline as a by‐product in the skraup synthesis of p‐phenanthroline
Authors: Wibaut J. P. , Spiers C. W. F. , Ouweltjes J. L.
Published: September 2010

A tetrahydrophenanthroline has been isolated as a by‐product in the synthesis of p‐phenanthroline from p‐diaminobenzene by the Skraup reaction. This compound was found to be identical with a tetrahydrophenanthroline, which Matsumura obtained by reduction of p‐phenanthroline.

This compound gives a monoacyl derivative on acetylation or benzoylation. On this evidence a structural formula for this tetrahydrophenanthroline is proposed.
Ueber einige Mesitylenderivate. III : Die Reaktion von Dimesitylchlormethan mit Molekularem Silber
Authors: Nauta W. Th. , Wuis P. J.
Published: September 2010

Wenn Dimesitylchlormethan ‐ Bis‐(2, 4, 6‐trimethylphenyl) ‐chlormethan ‐ unter Ausschliessung von Luft in Benzen mit molekularem Silber geschüttelt wird, tritt eine orange Färbung auf. Die Farbe wird nach Verlauf einiger Zeit weniger intensiv und geht nach ungefähr 15 Minuten in eine violettrote Farbe über, die wochenlang unverändert bestehen bleibt und für das Auge grosse übereinstimmung mit der Farbe von Dimesitylchlormethan in flüssigem Schwefeldioxyd zeigt

Nauta und Wuis, Ibid. 56, 535 (1937).

. Beim Abkühlen nimmt die rote Farbe an Stärke ab, während eine schwache Orangefarbe zum Vorschein kommt, eine Erscheinung, die sich unzählige Male wiederholen lässt.

Die violettrote Lösung folgt nicht dem Gesetz von Beer. Zutritt von wenig Sauerstoff lässt die Farbe verschwinden, beim Erwärmen kommt sie wieder zurück. Dies lässt sich mehrere Male wiederholen, bis am Schluss keine Färbung mehr auftritt.

Wird die Halogenentziehung in einer Sauerstoffatmosphäre ausgeführt, so tritt nur kurze Zeit die rote Farbe auf. Auf 1 Grammolekül Dimesitylchlormethan wird 1½ Grammolekül Sauerstoff aufgenommen. Die hellgelbe Endfarbe ist nur bei grossen Konzentrationen wahrnehmbar.

Aus dem Reaktionsgemisch sind als Hauptprodukte zu isolieren: 2.4.6‐Trimethylphenol (Mesitol),2.4. 6‐Trimethylbenzaldehyd, Bis‐(2 . 4 . 6‐trimethylphenyl )methanon (Dimesitylketon) und ein Stoff, der nach der Analyse die Zusammensetzung des Dimesitylmethylperoxyds (C19H23O)2n hat, dessen Struktur aber noch nicht vollständig festgelegt werden konnte.

Auf dieselbe Weise mit Stickoxyd behandelt wird bei Zimmertemperatur höchstens rund 1¼ Grammolekül für 1 Grammolekül Dimesitylchlormethan aufgenommen. Unter bestimmten Umständen tritt sehr kurz eine stark blaugrüne Farbe auf, welche in eine hellgelbe übergeht. Aus der Lösung liess sich bisher nur Bis‐(2 . 4 . 6‐trimethylphenyl)‐methanol isolieren.

Wird die Halogenentziehung unter Kohlendioxyd ausgeführt, so wird die auftretende Orangefarbe langsam weggenomen. Die Lösung bleibt darauf hellrot gefärbt. Wenn danach weiter mit Sauerstoff geschüttelt wird, verschwindet auch diese Farbe. Die farblose Lösung nimmt bei weiterem Schütteln unter Stickoxyd noch eine Menge davon auf.

Eine Lösung, welche die orange Anfangsfarbe zeigt, wird bei Zuführung von trockenem Salzsäuregas entfärbt und die Flüssigkeit trübe. Die weisse Trübung wird bei starker Belichtung violett, während die Lösung bald darauf klar und farblos wird.

Wahrscheinlich kommt die violettrote Farbe dem Radikal Dimesitylmethyl zu.

Die vorübergehende Orangefarbe ist möglicherweise eine Silberverbindung.

Bisher glückte es uns nicht, den farblosen Stoff zu isolieren, der nach dem Verhalten der benzenischen Lösung bei Temperaturerhöhung und Konzentrationserniedrigung als Quelle des Radikals fungiert.

Wohl wurde Dimesitylmethan gefunden. Das Material zeigt also Neigung zur Disproportionierung. Diese letzte Auffassung wird gestützt durch eine Reihe von Molekulargewichtsbestimmungen.
London‐V. D. waals forces in colloidal systems
Authors: Hamaker H. C.
Published: September 2010

In a previous paper the London‐ v. d. Waals forces between spherical particles have been calculated as a function of the diameters and the distance separating the particles. On the basis of these data the probable magnitude and range of these forces in colloidal systems is discussed in this paper.

The “range”, defined as that distance at which the energy of interaction equals the kinetic energy of Brownian motion, is found commonly to be of the order 0.06 to 0.2 times the diameter of the smallest particle: the size of the second particle is relatively of little importance.

Comparing with experiment it is demonstrated that the adhesive forces observed under various circumstances are of the order of magnitude theoretically expected.

Finally it is maintained that our concept of the range of a force will depend on the size of the particles considered. Different definitions of the range are compared with each other. The discussion illustrates that a correct comparison of observations of adhesive forces made by different methods or on different scales cannot be made without theoretical knowledge of the nature of the forces acting.
Sur un Composé se Décomposant Facilement à L'état pur sous L'influence Catalytique de la Matière des Parois
Authors: Olivier S. C. J. , Wit J.
Published: September 2010

Le bromométhyl‐2‐naphtaléne, bouillant d'aprés la littérature à 213°/100 mm, ne peut être distillé sous pression réduite (14 mm) quand on a affaire à un produit pur. Celui‐ci commence déjà à se décomposer, avec violence, en dégageant de l'acide bromhydrique, lorsqu'on le chauffe à 70° dans un ballon en verre de Bohême. On a démontré que ce phénomène curieux est causé par une action catalytique de la matière de la paroi, action de contact, dont l'intensité varié avec la sorte de verre employée.

Le produit de la décomposition du bromométhyl‐2‐naphtalène possède la composition centésimale du di‐β‐naphtostilbène (C22H16). Mais on a affaire à un composé amorphe et de polymérisation élevée, montrant néanmoins certaines régularités dans la structure de la molécule.

Dans la préparation du bromométhyl‐2‐naphtalène, effectuée par bromuration du β‐méthylnaphtalène sous l'influence de la lumière, une lampe dite. “lumière solaire” s'est montrée plus efficace que la lampe à vapeur de mercure.
Methode zur Bestimmung des Chiningehaltes in Blut
Authors: Kaiser F. J.
Published: September 2010

Es wird eine Methode angegeben um den Chiningehalt in Blut zu bestimmen. Nach Zuführung dieses Therapeutikums liegen die Chininkonzentrationen im Blute unter 10 γ für 1 cm3. Um das Chinin zu extrahieren wird vom Blut durch Zusatz von Natronlauge eine Lösung gemacht und hiernach in einem Extraktionsapparat nach Schoorl extrahiert. Nach dem Verdunsten des Chloroforms ist der Rückstand, nach einer kurzen Bearbeitung und Lösung in Schwefelsäure, für die Bestimmung geeignet.

Dazu wird das Fluorescenzlicht, das eine Chininsulfatlösung gibt, wenn ultraviolettes Licht einfällt, verglichen mit dem Licht einer Standardlampe visuell.
Grignard compounds derived from pyridine. I
Authors: Overhoff J. , Proost W.
Published: September 2010

The reaction between magnesium and the bromopyridines has been studied and it is shown that the compounds obtained react like pyridyl‐magnesium bromides. The reaction mechanism of the method of preparation is discussed.
La Biréfringence Magnétique de Solutions Colloidales D'oxyde de Fer
Authors: Errera J. , Oostveen W. , Sack H.
Published: September 2010

L'effet d'un champ magnétique de 50 périodes est comparé à celui observé dans un champ continu.

On peut en conclure que, pour les solutions étudiées, l'effet Major ana peut se décomposer en deux parties ayant des temps de relaxation différents.
Die Addition und die Additionsprodukte der Halogene und Benzenderivate. VIII: die Chlorierung der Benzenhexachloride
Authors: van der Linden T.
Published: September 2010

Die Chlorierung von α‐, β‐ und γ‐Benzenhexachlorid wurde durchgeführt, und die Reaktionsprodukte wurden identifiziert. Die Stereostruktur des β‐p‐Dichlorbenzenhexachlorids wurde festgestellt. Beim Chlorieren dieser letzteren Substanz wurde das noch nicht bekannte Endekachlorcyclohexan C6HCl11 isoliert.
The diffusion of hydrogen through regenerated cellulose and some cellulose derivatives
Authors: de Boer J. H. , Fast J. D.
Published: September 2010

Bei der Diffusion von Wasserstoff durch Metalle werden bekanntlich Moleküle in Atome gespalten; in anderen Medien, z. B. Acetylcellulose, löst Wasserstoff sich in molekularer Form, so dass auch eine Diffusion von Molekülen (proportional p) erwartet werden kann (§ 1). Die Struktur von Cellulose und Cellulosederivaten liess schon einigermassen erwarten, dass die Diffusion bei den Cellulosederivaten leichter vor sich geht als bei Cellulose selbst (§ 2). Durch Nitrocellulose und Acetylcellulose diffundiert praktisch keine Luft hindurch, wohl aber Wasserstoff; regenerierte Cellulose ist praktisch dicht für beide Gase (§ 3). Die Temperaturabhängigkeit der Wasserstoffdiffusion wurde studiert und daraus die Konstanten A und E der Formel QM = Ae−E/RT bestimmt (§§4 und 5), während bei Nitrocellulose die Druckabhängigkeit gemessen wurde (proportional dem Druck, Abb. 5). Die E‐ und A‐Werte für Nitrocellulose sind praktisch dieselben wie die für technisches Celluloid (§6). Ein Vergleich der E‐ und A‐Werte (Tabelle IX, Abb. 8) lehrt, dass die, regenerierter Cellulose gegenüber, erhöhte Wasserstoffdurchlässigkeit bei Acetylcellulose (300 X) nicht der Aktivierungsenergie, sondern dem A‐Wert zuzuschreiben ist, bei Nitrocellulose aber auch mit von dem niedrigeren A‐Wert stammt.
Zur Stereochemie der Böeseken'schen Sauren Borsäureverbindungen der Diole
Authors: Hermans P. H.
Published: September 2010

Es wird gezeigt, dass mit Hilfe der neuesten röntgenographisch ermittelten Daten über die Atomabstände in der Borsäure und den Boraten, eine Erklärung gegeben werden kann für die bisher unverständlich gebliebene Tatsache, dass es sowohl neutrale als auch saure cyclische Monodiolborsäure‐Verbindungen gibt.

In den ersteren tritt das Bor als dreizähliges Zentralatom auf, mit ebener Ausbreitung der drei Valenzrichtungen und einem Abstand zwischen den Sauerstoffatomen von 2.3 Å in letzteren ist das Boratom vierzählig mit räumlicher Ausbreitung der vier Valenzrichtungen, und der Abstand zwischen den Sauerstoffatomen beträgt mindestens 2.42 Å, während auch der Abstand des Sauerstoffs vom Bor beträchtlich grösser ist als bei der neutralen Verbindung.
On the catalytic influence of the reaction‐products on the speed of decomposition of chromic acid in solutions of sulphur trioxide in water
Authors: Snethlage H. C. S.
Published: September 2010

The speed of decomposition of solutions of chromic acid in strong (e.g. 100%) sulphuric acid is reduced by the product of the reaction, a nearly colourless substance which precipitates when its solution is heated.

The formation of this precipitate and the reduction of the speed of reaction may be observed also when a slight amount of water is present, both effects increasing with increasing sulphuric acid content.

A positive autocatalytic effect in more diluted sulphuric acid is already known

H. C. S. Snethlage. Rec. trav. chim. 55, 874 (1936).

.

In combination with the hypothesis which was developed for the explanation of the variations of the speed of decomposition, which result from a change in the composition of the solvent

H. C. S. Snethlage, Rec. trav. chim. 55, 712 (1936).

.), these two catalytic effects allow the understanding of the behaviour of decomposing solutions of chromic acid at any composition of the solvent (at least above 60% acid) and at any stage of the decomposition.
Action de L'acide Bromhydrique sur L'acide Époxy‐2‐6‐heptane Carboxylique‐3.‐Heptène‐5‐ol‐2
Authors: Delépine Marcel
Published: September 2010

Cette action donne naissance, par ouverture du cycle, à un acide bromé que les alcalis décomposent en bromo‐2‐heptène‐5 et en une lactone. Le bromoheptène a pu être changé en heptène‐5‐ol‐2.
Some carbonate derivatives of the sugars
Authors: Haworth W. N. , Porter C. R. , Waine A. C.
Published: September 2010

The condensation of galactose, xylose and mannose with phosgene under a variety of conditions is described. In acetone solution galactose gives diacetone 6‐chloroformyl galactose from which is prepared a number of 6‐substituted derivatives. 5‐Carbomethoxy monoacetone xylofuranose is described and a method for the preparation of β‐methylmannofuranoside dicarbonate is given. By oxidation of mannose dicarbonate, methyl mannonate dicarbonate is isolated.
The redox potentials of complex iron salts with the sodium salts of organic acids
Authors: Reinders W. , de Minjer C. H.
Published: September 2010

In order to prepare solutions with well buffering oxidation potential, mixed solutions of ferrous sulphate and ferric sulphate were potentiometrically titrated with the alkali salts of citric acid, malonic acid, oxalic acid, tartaric acid and lactic acid.

Solutions resulted, very well answering the purpose, the oxidation potential of which varied between +0.640 and −0.100 Volt, according to the concentration of the organic salt.

The influence of an addition of acid and base on the potential was measured.

From the curves the existence of the complex ferric ions Fe2(C6H5O7)3‴, Fe(C3H2O4)3‴ and Fe(C2O4)3‴ could be deduced.
On the simultaneous conductometric titration of sulphuric acid and nitric acid
Authors: van Nieuwenburg C. J.
Published: September 2010

A method is described by which it is possible to determine sulphuric acid and nitric acid in one single conductometric titration. It is based on the principle of reducing the H˙‐ions concentrations by adding an excess of an alkali salt of a moderately strong acid in such a way as to cause the SO4″‐ion effect to become visible besides the H˙‐effect, without impairing in any way the determination of the sum of both acids together. A procedure is described in which sodium monochloroacetate is used to this end.
Syntheses of polychloro‐compounds with aluminium chloride V. The condensation of hexachloropropene with trichloroethene
Authors: Prins H. J.
Published: September 2010

The action of hexachloropropene on trichloroethene gives rise to a condensation with one or two molecules of the latter. With one molecule of trichloroethene, a nonachloropentene is formed, which reacts with sulphuric acid giving a mixture of hexachlorobutene carboxyle acids. The latter is transformed into a mixture of pentachlorobutadiene carboxylic acids by the action of alcoholic potash solution.

When hexachloropropene reacts with two molecules of trichloroethene, two isomeric dodecachloroheptenes are formed.

The course of the reactions and the constitutions of the compounds are discussed.
Derivatives of 1,4‐dioxan VII
Authors: Tellegen F. Ph. A.
Published: September 2010

The 2,3‐bis‐(2′‐iodo‐ethoxy)‐, 2,3‐bis‐(2′‐bromo‐ethoxy)‐ and 2,3‐bis‐(2′‐diphenylethoxy)‐derivatives of 1,4‐dioxan and the diethers of 2,3‐dichloro‐1,4‐dioxan with phenol and p‐nitrophenol respectively have been synthesised and their properties determined. The preparation of the acetal of ethanediol‐1,2 and dichloroacetaldehyde, an isomeride of 2,3‐dichloro‐1,4‐dioxan, is described.
Cyklische Aceatale von Diacetyl mit Brenzcatechol
Authors: van der Spek J. J.
Published: September 2010

Bei direkter Kondensation von Diacetyl mit Brenzcatechol bildet sich ein Sechsringacetal (Dioxanderivat), bei dem Cis‐transisomerie vorkommen kann. Wahrscheinlich wird nur die Cis‐Konfiguration gebildet, obwohl eine spannungsfreie Translage möglich ist.
The first dissociation constant of ethyl‐ and phenyl‐substituted succinic acids
Authors: Hartman H.
Published: September 2010

This paper contains the results of measurements of the first dissociation constant of ethyl‐ and phenyl‐substituted succinic acids.
Studies in diazo‐chemistry. The tetrazotisation of o‐diaminobenzene
Authors: Schoutissen H. A. J.
Published: September 2010

A short summary is given of investigations on the subject of diazochemistry, begun in Prof. Böeseken's laboratory and continued at Rotterdam.

o‐Diaminobenzene may be tetrazotised in very good yield by the phosphoric acid method previously given, and also by the acetic acid method of Misslin.

The strongly negative character of the diazonium group, previously tested in various ways, is confirmed by the one sided coupling of tetrazotised o‐diaminobenzene with phenol, β‐naphthol and also with anisole, phenetole and even with mesitylene.

It also appears that the alkyl group is split off during coupling with anisole and phenetole.

Reduction of tetrazotised o‐diaminobenzene with stannous chloride in concentrated hydrochloric acid leads to the formation of the hydrochloride or sulphate of the starting product.
Proof of the constitution of cetene
Authors: Schoorl N.
Published: September 2010

It has been shown by a refractometric method that the double bond is really situated in the terminal position in cetene prepared by Langedijk and Stedehouder.
Über die Bedeutung von Biotin für das Wachstum von Staphylococcus Pyogenes Aureus: 27. Mitteilung über pflanzliche Wachstumstoffe
Authors: Kögl F. , van Wagtendonk W. J.
Published: September 2010

Ausser Aneurin und Nicotinsäureamid, den von B. C. J. G. Knight aufgefundenen Wachstumsfaktoren von Staphylococcus pyogenes aureus ist bei dieser Bakterienart für optimales Wachstum in “synthetischem” Milieu auch Biotin erforderlich.
La Présence et la Détermination de Traces D'alcool Méthylique Dans des Produits de Parfumerie
Authors: Honig P.
Published: September 2010

The presence of methyl alcohol in alcohol containing products is considered to be the result of an illegal, prohibited practice of the producer by using denaturated alcohol (perhaps purified in some way) in stead of pure ethyl alcohol, for which the prescribed taxes have been paid. It is shown that methyl alcohol or formaldehyde can be formed in alcoholic perfumes during long storage. It is shown that it is unreasonable to conclude from the presence of methyl alcohol in small amounts, that denaturated alcohol has been used in the manufacturing process. It is necessary that the allowable percentage of methyl alcohol in products ready for sale, should be fixed, for instance, at 0.1 % methyl alcohol.
The acceleration of the vulcanisation process by arsenic compounds
Authors: van Rossem A. , Bouwens H. S. V.
Published: September 2010

Systematic vulcanisation experiments have confirmed and extended the observation of Eaton and Bishop, that small amounts of arsenious oxide show a large acceleration in rubber‐sulphur mixings. Vulcanisation experiments with various arsenicals showed that arsenious oxide and arsenious sulphide are the most active accelerators, arsenic oxide and the pentasulphide being less active, followed by elementary arsenic and sodium cacodylate.

In quick curing mixings with modern organic accelerators and zinc oxide arsenicals do not show any effect.

Neither extraction with acetone nor deproteinisation of the rubber has much influence on the acceleration of arsenious oxide. The vulcanisates show bright yellow spots, which appear to be hollow globules of arsenious sulphide. In considering this fact, some suggestions are made as to the mechanism of the acceleration by arsenious oxide. It is supposed that the presence of nascent hydrogen sulphide plays an important role during vulcanisation.
On the refraction of simple organic isomers
Authors: Stevels J. M.
Published: September 2010

The theory developed previously for the calculation of the refraction of halogenated methane derivatives is extended to similar ethane and ethene derivatives. In this way we can predict the differences of the refractions of isomers of these compounds.

It turns out, that the old conception that accumulation of hydrogen gives rise to higher refraction is not general. The exceptions can easily be understood with the new method of calculation.
Contribution a L'étude des Médicaments de Synthèse Contre la Malaria
Authors: Altman R. F. A.
Published: September 2010

On a donné en premier lieu la Synthèse de quelques dérivés de la quinoléine, homologues en chaînes linéaires (chaînes à 7, 8 et 9 atomes de carbone) de la série de la plasmoquine.

Cette synthèse passe par trois Stades:

Synthèse de la méthoxy‐6‐amino‐8‐quinoléine.

Préparation des diéthylamino‐chloro'alcanes.

Condensation des composés mentionnés sous 1 et 2.

Quant aux modifications qu'on a apportées à la molécule de la quinine, celles‐ci se limitent au groupement alcoolique secondaire et au groupement vinylique. D'autre part, on a donné des méthodes perfectionnées pour la préparation de la quiténine et du chlorure de quinyle.

Les dérivés de la quinoléine se sont montrés tres actifs contre la malaria des oiseaux. Par contre, les “variantes” de la quinine n'ont aucune action digne de mention.
Les pinacols de la pinacoline
Authors: Backer H. J.
Published: September 2010

Le “pinacol de la pinacoline” (diméthyl‐ditertiobutyl‐éthanediol sym.) décrit dans la littérature est une combinaison moléculaire de deux stéréoisoméres dont la préparation à l'état pur est décrite dans ce mémoire. Ces isomères présentent des différences notables dans leurs propriétés: points de fusion et d'ébullition, stabilité sous l'action de la chaleur et des acides, formation d'un acétal, vitesse de l'oxydation.

La grande différence entre les deux isomères (méso et racémique) s'explique nettement par l'influence stérique des deux groupes volumineux de butyle tertiaire qui empêchent la rotation libre des deux atomes de carbone centraux et qui imposent ainsi aux deux diols le caractère d'isomères cis et trans.
Derivatives of 1: 3‐bis‐Phenylamino‐Propane
Authors: Veer W. L. C.
Published: September 2010

1: 3‐Bis‐phenylamino‐propane, an aromatic di‐secondary diamine derived from 1: 3‐diaminopropane, has been investigated, especially as regards its reactivity towards acids and their derivatives, isocyanates, mustard oils, ketenes, chloronitrobenzenes and aldehydes. The amine, which has so far been described in the literature as a liquid, was prepared in a pure state and obtained in the solid condition. It has antioxidant properties for rubber. The nitration of various nitro‐, methyl‐, halogeno‐ and halogenonitroderivatives of 1: 3‐bis‐phenylamino‐propane is also described in this paper.
Second pressure limits in gaseous explosion regions. I. Experimental data on H2O2 and H2air explosions
Authors: Dijksman A. J.
Published: September 2010

The author investigates the explosion limit as a function of the pressure (below about 100 cm Hg). In the system H2‐O2 there are between 8.4 and 9.8% hydrogen always two pressures, between which the mixtures are explosive. This is very much reminiscent of the inflammability regions at higher temperatures. The influence of spark strength, position of the electrodes, etc. on this so‐called “second limit” is described together with the procedure employed.

Hydrogen‐air mixtures also give these phenomena.

Similar peculiarities were found with carbon monoxide‐air, which will shortly be published.
Sur la Condensation des Aryl‐Halogéno‐meacute;thanes
Authors: Olivier S. C. J. , Wit J.
Published: September 2010

Dans le présent mémoire on trouve les résultats de nouvelles recherches sur la condensation du bromométhyl‐2‐naphtalène. On a constaté que pour cette réaction l'oxyde ferrique est un catalyseur incomparablement plus puissant que la matière des parois de la verrerie (ce Rec. 57, 90), de sorte que l'influence catalytique de celle‐ci est probablement liée à sa teneur en oxyde ferrique. Puis on a décelé la nature du produit de réaction des condensations du type:
X. The exact measurement of the specific heat of solid substances at high temperatures: Specific heat, electrical resistance, thermoelectrical behaviour and thermal expansion of some rare‐earth metals
Authors: Jaeger F. M. , Bottema J. A. , Rosenbohm E.
Published: September 2010

In this paper it is demonstrated that the rare‐earth metals: cerium, lanthanum, neodymium and didymium all show a series of at least four reversible allotropic changes; the different phases are discerned as α‐, β‐, γ‐and δ‐states of these metals.

From the study of the specific heat, the thermal expansion, the electrical resistance and the thermoelectrical behaviour in their dependence on the temperature, it becomes obvious that the inner state of all these metals is at each temperature a highly complicated one, it being characterized by the simultaneous co‐existence of several of these modifications. As the transformations between these modifications occur very slowly, in general the instantaneous inner state of these metals is not one of perfect equilibrium and, therefore, depends at each temperature to a high degree on the mode and duration of their preliminary thermal treatment, as well as on the time during which the samples, after treatment, are preserved and again examined.

The transition‐temperatures are, in all cases, situated between −170° and about 720° C; the special character of the accompanying retardation‐phenomena is different in each case. More particularly, neodymium manifests most remarkable cyclic effects, a peculiar internal thermo‐electrical force and an abnormal thermal expansion within the limits of a transition‐interval, — all indicating the physical inhomogenity of the metal investigated.
Quelques 1,3‐Dimercaptans et Leurs Thioacétals Cycliques
Authors: Backer H. J. , Tamsma A. F.
Published: September 2010

Le mémoire décrit trois 1,3‐dimercaptans doublement substitués en position 2, le 2,2‐pentaméthylénepropane‐l,3‐dithiol, le 2,2‐diméthylpropane‐1.3‐dithiol et le bis‐hydroxyméthyl‐bis‐mercaptométhyl‐méthane (dithiopentaérythritol).

On les obtient en réduisant les disulfures (ou trisulfures) cycliques qui se forment par la réaction entre les 1.3‐dibromures et les polysulfures alcalins. La structure de ces disulfures est, d'autre part, mise en évidence par l'oxydation, qui donne naissance à des acides disulfoniques.

Les dimercaptans, chauffés avec les aldéhydes et cétones en présence d'acide chlorhydrique, donnent aisément des thioacétals cycliques.

Le dithiopentaérythritol peut réagir avec deux molécules d'aldéhydes ou de cétones en engendrant des acétals‐thioacétals. Si les deux molécules diffèrent, on obtient deux isomères.

En condensant le dithiopentaérythritol, d'abord avec la 4‐méthylcyclo‐hexanone et puis avec l'aldéhyde benzoïque, les auteurs ont obtenu deux isomères, qui, par suite de la présence d'un nombre impair de cycles dans le trispirane, peuvent être considérés comme des isomères cis trans.
The determination of the cocaines in coca leaves
Authors: de Jong A. W. K.
Published: September 2010

The method published in the Bulletin of the Health Organisation of the League of Nations, Vol. VII (1938) is discussed and another method giving the same result is also communicated.
Die Krystallstruktur des Kaliumfluorochromats
Authors: Ketelaar J. A. A. , Wegerif E.
Published: September 2010

Die Krystallstruktur des Kaliumfluorochromats, KCrO3F, wurde bestimmt. Die Abmessungen der tetragonalen Elementarzelle sind: a = 5.46 ± 0.01 Å, c = 12.89 ± 0.02 Å. Die Struktur in der Raumgruppe C64h gehört zum Scheelit oder HO4 ‐ Typus. Die drei Parameter der gemeinschaftliche Punktlage der Sauerstoff‐ und Fluoratome werden aus den Intensitäten bestimmt. Die Stellung des KCrO3 F im Strukturschema der Verbindungen ABX4 wird angegeben.
On the influence of the solvent and the temperature on the velocity of decomposition of chromic acid
Authors: Snethlage H. C. S.
Published: September 2010

The velocity of decomposition of chromic acid, dissolved in sulphuric acid from 75.0% to 14% oleum has been measured at different temperatures. The initial velocity constants, the velocity‐constants of the mono‐ and bimolecular decomposition at different temperatures and the corresponding values of E and A in \documentclass{article}\pagestyle{empty}\begin{document}$$ k = Ae^ - \frac{E} {{RT}} $$\end{document} are calculated. The existence of an optimum in the curve which relates the velocity to the composition of the solvent and the shift of this optimum with change of the temperature is caused by the dependence of A and E for the bimolecular reaction on the composition of the solvent. The optimum disappears for any temperature at a sufficiently low concentration of the chromic acid and, for any concentration of chromic acid, at a sufficiently high temperature. Some conclusions concerning the nature of the reaction and the state of the solvent are drawn
L'influence de la Saligénine (o‐Hydroxyméthylphénol) et de la 4‐Méthylsaligénine (4‐Méthyl‐2‐Hydroxyméthylphénol) sur la Conductibilité Électrique de L'acide borique
Authors: Böeseken J.
Published: September 2010

Nous avons mesuré la conductibilité électrique de la saligénine et de la 4‐méthylsaligénine dans une solution 0.5 molaire d'acide borique. Il s'est révélé que, à la concentration 0.25 mol., la saligénine provoque une augmentation de la conductibilité de l'acide borique comparable à celle que produit un ortho‐diphénol.

Le calcul de la distance qui sépare les atomes d'oxygène dans la position la plus rapprochée des groupes hydroxyle montre que cette position est tres favorable à la formation d'un complexe avec du bore coordinativement tétravalent; il est donc très probable que dans un nombre considérable de molécules de saligénine, les groupes hydroxyle se trouvent dans cette position. La 4‐méthylsaligénine ne produit qu'une augmentation très minime de la conductibilité de l'acide borique, ce qui indique que le groupe méthyle exerce une influence défavorable sur la position des groupes hydroxyle.
The diffusion potentials in electrolytic mixtures: I. The formula of Henderson
Authors: Hermans J. J.
Published: September 2010

In § 1 a short review of experiments is given. In § 2 the differential equations of electrolytic diffusion and their solution by Planck and by Henderson are discussed, and attention is drawn to the fact that a series of solutions is principally different from a diffusion layer of similar structure. In § 3 an expansion in powers of y = x/2 √t leads to the conclusion that no foundation exists for the formula of Henderson which is so commonly used in practice
Bis‐arylmethanderivate iv
Authors: Wuis P. J. , Mulder D.
Published: September 2010

Einige Eigenschaften des Bis‐α‐naphthylmethylradikals‐ und ‐ions
Iodometric determination of small quantities of glucose
Authors: Noyons E. C.
Published: September 2010

In the following paper an account is given of an exact hypoiometric method for the determination of small quantities of glucose.

The accuracy of the method was greatly increased by using buffered solutions in the oxidation.

Probably, it is also possible to determine glucose in blood by this method.

The results of a research now being carried out, may show what substances have a disturbing influence on the estimation of bloodsugar by this method.
Les Éthers de L'acide Méthanetétracarboxylique
Authors: Backer H. J. , Lolkema J.
Published: September 2010

Les propriétés des “molécules remplies” se manifestent dans les éthers de l'acide méthanetétracarboxylique. Les éthers simples de méthyle et d'isopropyle (groupes compacts et symétriques) sont cristallins, alors que leurs éthers mixtes sont liquides. En comparant les éthers des acides méthanetétracarboxylique et méthanetétracétique, on constate que les premiers, qui sont plus compacts, présentent des points de fusion plus élevés et des intervalles de liquidité plus limités.
The hydrogenation of anthracene and the investigation of some of the resultant products
Authors: Waterman H. I. , Leendertse J. J. , Cranendonk A. C.
Published: September 2010

The hydrogenation of pure anthracene was studied quantitatively using nickel‐on‐kieselguhr as a catalyst and hydrogen at high pressure.

On hydrogenating anthracene the main part of the latter product is converted first into octahydroanthracene. This compound could be isolated in high yields from the reaction product from the first stage of the hydrogenation.

On hydrogenating the octahydroanthracene under similar conditions using a fresh portion of catalyst, a mixture of saturated products was obtained, partly solid, partly liquid at room temperature. Since it could be proved that no destruction occurred during the hydrogenation, and the hydrogen consumption amounted to 14 hydrogen atoms per molecule of anthracene, the products must have the ultimate composition C14H24.

Most probably a mixture of perhydroanthracenes was formed. From this mixture a solid isomer could be isolated in a purer state.

On prolonged heating of the saturated reaction mixture from the second hydrogenation and of the liquid part of this reaction product, isomerisation occurred in which (a) solid isomer(s) was (were) formed from the liquid products. In these isomerisations the refractivity and density of the products changed noticeably, but the specific refraction did not change much, and pointed in all cases to 2.9 rings per molecule in the products. In one case also the specific parachor was determined. The number of rings deduced from this constant was 2.8.
The absence of l‐benzoylecgonine and the presence of an ester very probably the methylester of l‐ecgonine in java coca leaves
Authors: de Jong A. W. K.
Published: September 2010

Methods are indicated by which the absence of l‐benzoylecgonine and the presence of an ester of l‐ecgonine in Java coca leaves can be established.
Sur L'oxydation du Dihydroxy‐1.8‐Naphtalène et de Son Éther Monométhylique par L'acide Peracétique
Authors: Böeseken J. , Smitt L. G.
Published: September 2010

Cette communication se rapporte à de nouvelles recherches sur l'oxydation des phénols et de quelques dérivés par l'acide peracétique. Nous avons constaté que, dans cette oxydation, le dihydroxy‐1,8‐naphtalène est résinifié mais que son éther monométhylique se comporte comme l'α‐naphtol et forme un mélange de méthoxy‐8‐α‐naphtoquinone (éther méthylique de juglone) et d'un produit de déshydratation de l'acide méthoxy‐3‐carboxy‐2‐allocinnamique.
The influence of an ultrasonic field on the rate of coagulation of negative AgJ‐sols by electrolytes
Authors: Hermans J. J.
Published: September 2010

The rate of coagulation was determined by means of the Tyndall effect, measured by a photocell which was connected with a galvanometre. Plotting the deflection of the galvanometre against the time t, a curve was obtained the slope of which at t = 0 was called rate of coagulation.

§ 1. The general features of the method are discussed. The particle radius is computed from the scattering power. This particle radius (0.8. 10−5 cm) represents the upper limit rather than the mean value.

§ 2 and 3. The apparatus and the general course of the experiments are described.

§ 4. The rate of coagulation in the absence of a sonic field conforms to Paine's equation. The coagulation is always accelerated by the sonic waves; this influence is negligible with high electrolytic concentration and becomes more pronounced with low electrolytic concentration.

§ 5. The rate of the so‐called slow coagulation is almost linear in the concentration of the sol, but tends to increase more rapidly with this concentration if a sonic field is applied.

§ 6. Experiments on the influence of the field strength.

§ 7. It is shown that neither the cavitation nor the temperature rise are reponsible for the experimental results. Further, the kinetic energy of oscillation, the orthokinetic coagulation, the accumulation of the particles and the hydrodynamic interaction all are insufficiently effective to account for the influence of the sonic field. The most promising explanation of this influence at present seems to be the dipolar interaction of the particles (“migration dipoles”), which results from the distortion of the double layer.
New constituents of derris root I
Authors: Meyer Th. M. , Koolhaas D. R.
Published: September 2010

A survey of the substances isolated from Derris root is given.

The isolation and the properties of a substance, first discovered by Buckley, are described.

A new optically active substance, termed derride, isomeric with Buckley's compound is recorded. Its formula is given and a few of its properties are described. Some derivatives of this substance have been prepared.

A tabular comparison of Buckley's compound and derride is given.

A new, optically active substance has been isolated from a sample of derris root of the Sumatra type. Its formula is suggested and a few of its properties are given.

Sumatrol and l‐toxicarol have been isolated.
New aspects on the cohesion of simple compounds. II
Authors: Stevels J. M.
Published: September 2010

In the preceding paper it is shown theoretically, that the sum of the contributions of the Debye and Keesom energy to the boiling point of halogenated methane, ethane and ethene derivatives should be about a constant. In this paper it is shown, how far this holds experimentally.

An up to date complete list of the boiling points of the ethane and ethene derivatives is given. For the methane derivatives only those are given which have not been published before by van Arkel and coworkers.

The boiling points of all these compounds are split up into several parts, according to the different kinds of cohesion effects. Special methods are developed for the 1.1‐ and cis‐ and trans‐1.2‐isomers C2H2X2. The “anomalies” of the boiling points of the C2H2I2 and C2H2ClI can easily be understood on the basis of the new theory.
A quantum mechanical discussion of the dipole moments of monochlorobenzene and of vinylchloride
Authors: Ketelaar J. A. A.
Published: September 2010

The charge distributions in monochlorobenzene and in vinylchloride calculated by quantum mechanics provided a satisfactory explanation of the apparent differences in the partial electric moment of the C‐Cl bond depending on whether the carbon atom is single bonded, or whether it carries multiple bonds, or belongs to an aromatic nucleus.
p‐Xenylsemicarbazide as a reagent for the identification of aldehydes and ketones
Authors: Sah Peter P. T. , Kao I‐Shang
Published: September 2010

p‐Xenylsemicarbazide, prepared by the condensation of p‐xenylurea with hydrazine hydrate, was found to be a very good reagent for the preparation of derivatives suitable for the identification of carbonyl compounds. Twenty‐eight p‐xenylsemicarbazones, made by the interaction of the reagent and various types of aldehydes and ketones, are reported in this paper.
Bis‐Arylmethane derivatives. V. [Derivatives of bis‐(2:4 t 6‐triethylphenyl)‐methane]
Authors: Nauta W. Th. , Mulder D.
Published: September 2010

Our research on the occurrence of free radicals with only two unconnected aromatic groups on the central atom, has now been extended to reactions of molecular silver with:

bis‐phenyl‐chloromethane;

bis‐(4‐methoxyphenyl)‐chloromethane;

bis‐(2:4:6‐triethylphenyl)‐chloromethane.

We always found indications of the occurrence of free radicals.

We shall report on these reactions in detail in a subsequent communication. Of the substances required for this investigation, only bis‐(2:4:6‐triethylphenyl)‐chloromethane has not been described in the literature.

Therefore in this communication we describe the preparation of this compound.
Die Quantitative Bestimmung von Wasserstoffsuperoxyd und Persulfat in derselben Lösung
Authors: van der Meulen J. H.
Published: September 2010

Die Methoden zur Bestimmung des Wasserstoffsuperoxyds und Persulfats in derselben Lösung, wobei das H2O2 unmittelbar mit Permanganat titriert wird, geben alle zu niedrige Resultate, weil Mangansalze die Reaktion:

katalytisch beschleunigen. Ein vorheriger Zusatz von Mangansalzen ist durchaus unzulässig und begünstigt diese Zersetzung noch bedeutend.

Nicht nur die H2O2‐, sondern auch die K2S2O8‐Werte zeigen denselben Mindergehalt. Die Methode von Mudlagiry Nayak gestattet genauere Zahlen zu erhalten, während auch die von Skrabel und Vaček richtige Werte gibt.

Weiter wird eine Methode beschrieben, nach der das Wasserstoffsuperoxyd mit Osmiumsäure restlos, ohne Zerstörung des Persulfats, aus der Lösung entfernt wird. Das Persulfat wird darauf nach der Ferro‐Permanganat‐Methode oder acidimetrisch bestimmt, während der totale Oxydationswert (H2O2 + K2S2O8) ebenfalls nach der Ferro‐Permanganat‐Methode festgestellt wird.
Investigation of the volatile constituents of strawberry juice (Fragaria eliator Ehrh.)
Authors: Coppens A. , Hoejenbos L.
Published: September 2010

An investigation has been made of the volatile constituents of strawberry juice, i. e. the substances causing the aroma of the fruit. In addition to the so‐called fruit ethers, ethyl acetate, butyric ester (probably ethyl butyrate), a caproic ester, iso‐amyl esters, other constituents, responsible for the “earthy” part of the strawberry flavour and odour, borneol, terpineol and probably isofenchyl alcohol and some other substances were identified.
The influence of an alternating electric field on the rate of coagulation. II. Sols of tungstic acid
Authors: Hermans J. J.
Published: September 2010

If HCl is added to Na2WO4, and the turbidity of the mixture plotted against the time, S‐shaped curves are obtained. It is shown in § 1 that the maximum slope sm of these curves conforms to laws similar to those which apply to the initial slope si of the preceding paper.

In § 2 the coagulating action of BaCl2 on sols of tungstic acid is studied. The influence of an electric field on this coagulation is described in § 3. The coagulation is always slowed down. If the external field is switched on after the coagulation has been allowed to proceed for some time, the turbidity falls abruptly.

Some aspects of the problem are discussed in § 4. An explanation is not put forward since it would necessarily be of a highly speculative character.
A new method for the identification of ethers
Authors: Sah Peter P. T.
Published: September 2010

Ethers, when pyrolysed in the vapour phase at 500°, are decomposed into a hydrocarbon and an aldehyde or ketone. The carbonyl compound from the pyrolysis may be easily identified as a solid semicarbazone or substituted benzoylhydrazone
Anthraquinones Complètement Substituées et Anthracènes Correspondants: I. Composés Substitués Symétriquement
Authors: Backer H. J. , Strating J. , Huisman L. H. H.
Published: September 2010

Le mémoire décrit les produits symétriques qu'on obtient en faisant réagir la benzoquinone sur le 1,2,3.4‐tétraméthylbutadiène, sur le 1,′‐dicyclopentényle et sur le 1,′‐dicyclohexényle. Ces produits se composent de plusieurs octahydroanthraquinones stéréoisomères et donnent, par oxydation, des anthraquinones complètement substituées.

La réduction des anthraquinones par le procédé Clemmensen légèrement modifié fournit les dihydroanthracènes, dont la déshydrogénation au moyen de sélénium conduit aux anthracènes substitués symétriquement
Das System HgCl2‐HgBr2
Authors: Meerman P. G. , Scholten W.
Published: September 2010

Das System HgCl2‐HgBr2 wurde röntgenanalytisch bei Zimmertemperatur untersucht. Es wird gezeigt, dass in der Nähe der Zusammensetzung HgClBr eine neue Phase (β) auftritt1). Diese geht bei Temperatursteigerung in die mit HgCl2 isomorphe Phase (α) über. Die Temperaturabhängigkeit dieses Uebergangs wird bestimmt
Investigations on pyridine and quinoline derivatives: (42nd. Communication) The formation of (4‐pyridyl)‐pyridinium compounds from 4‐chloropyridine and 4‐bromopyridine
Authors: Wibaut J. P. , Broekman F. W.
Published: September 2010

4‐Chloropyridine undergoes slow conversion into N‐(4‐pyridyl)‐4′‐chloropyridinium chloride from which the already known N‐(4‐pyridyl)‐4′‐pyridone is obtained on hydrolysis. 4‐Bromopyridine changes rapidly into N‐(4‐pyridyl)‐4′‐bromopyridinium bromide, which also affords N‐(4‐pyridyl)‐4′‐pyridone on hydrolysis

Improved recipes are given for the preparation of 4‐chloro‐ and 4‐bromopyridines in yields of 75% and 45%, respectively
Adsorption of iodine vapour by powders
Authors: Hamaker H. C.
Published: September 2010

According to a method developed by de Boer powder samples baked out in vacuo are exposed to iodine vapour which is adsorbed at the powder surface. The amount adsorbed is determined by a simple chemical titration. The precautions necessary and the reproducibility of the observations are discussed in detail. Surface reactions and the effect of milling in a ball mill can clearly be traced by corresponding changes in the adsorption.
New aspects on the cohesion of simple compounds. III
Authors: Stevels J. M.
Published: September 2010

It is shown that the boiling points of all halogenated methane derivatives can be calculated as the sum of the contributions of three effects (London‐, Keesom‐ and Debije effect), even in the cases of the rather large deviations reported previously.

The three effects are studied here to a higher approximation than was done formerly. It turns out that in a few cases the values calculated with the old formula for the London effect need a slight correction (refraction effect), but generally the formula holds without that.

The formula for the Keesom effect seems to be correct in all cases.

It can be understood that the formula for the Debije contribution to the boiling point according to van Arkel and Snoek does not hold so well. As a consequence of this fact we can easily understand the rather high TD + TK′ values for the fluorinated ethane and ethene derivatives previously reported (fluorine effect).

Applying the combination of the refraction effect and the fluorine effect it is possible to predict the trends of the boiling points of isomers of the same type. All cases known in the literature are checked and no deviations are found.
Symétrie Moléculaire du Tétrathioorthosilicate Monoisopropylique Tritertiobutylique
Authors: Klasens H. A. , Backer H. J.
Published: September 2010

Les cristaux du tétrathioorthosilicate monoisopropylique tritertiobutylique sont tétragonaux et isomorphes avec ceux des tétramercaptides tertiobutyliques de silicium, de germanium et d'étain.

La maille unité est la même pour ces quatre composés (a = 11.2, c = 9.3 Å); elle correspond à deux molécules. Le groupe de recouvrement est D2d (P421c). On trouve done au moins la symétrie S4 pour l'atome central, autour duquel quatre groupes se rangent de façon tétraédrique.

Le fait que, pour le premier composé, la présence d'un groupe isopropylique ne change pas la structure tétragonale peut être attribué à une „symétrie statistique”︁.
Die Krystallstruktur des Cäsiumfluorochromats
Authors: Ketelaar J. A. A. , Wegerif Frl. E.
Published: September 2010

Die Krystallstruktur des Cäsiumfluorochromats, CsCrO3F, wurde bestimmt. Die Struktur ist isomorph mit der des KCrO3F und gehört zum Scheelit‐ oder HO4‐Typus.