bluuebunny/crossref_metadata_2025 huggingface dataset:
Examen Diélectrique et Viscosimétrique de Quelques Nitrates Organiques
Authors: de Kreuk L. J.
Published: September 2010

Pour interpréter les phénomènes d'isomérie présentés par la nitroglycérine et d'autres nitrates organiques, l'auteur érige une hypothèse, qui est contrôlée par des mesures diélectriques et viscosimétriques.
The Raman spectrum and the molecular structure of thiophosphoryl chloride
Authors: Gerding H. , Westrik R.
Published: September 2010

The Raman spectrum of liquid thiophosphoryl chloride PSCl3 has been redetermined and the degree of depolarization of the Raman lines measured. The symmetry of the molecule is that of the point group C3v‐3m. An assignment of the frequency shifts found to modes of vibration of the molecule is given.
Über das Auftreten freier Radikale bei der Kolbe‐Reaktion Aromatischer Carbonsäuren. Die Elektrolyse von Diphenylessigsäure
Authors: v. d. Hoek A. J. , Th. Nauta W.
Published: September 2010

Bei der Elektrolyse von Diphenylessigsäure in methylalkoholischer Kalilauge und Pyridin nach Riccoboni1) wurden als nichtgasförmige Reaktionsprodukte identifiziert: Tetraphenyläthan, Di‐(diphenylmethyl)‐äther, Benzophenon, Diphenylmethyl‐methyläther, Stoffe die, ausgenommen der letztgenannte, auch bei der Halogenentziehung an Diphenylchlormethan mit molekularem Silber unter Sauerstoff gefunden worden sind.

Durch diese Übereinstimmung in den Reaktionsprodukten ist Gleichheit des Reaktionsmechanismus und damit das Auftreten von freien Radikalen bei der Kolbe‐Reaktion als feststehend anzusehen.
The dipole moment of the cyanogen halides: I. The Dipole Moment of Cyanogen Iodide
Authors: Zwartsenberg J. W. , Ketelaar J. A. A.
Published: September 2010

The dipole moment of cyanogen iodide, using benzene as a solvent, has been determined as 3.71 ± 0.02 D.
Specific gravity ‐ composition, boiling point ‐ composition and vapour ‐ liquid equilibria relations for the systems methyl ethyl ketone ‐ water and sec. Butanol ‐ water
Authors: Boeke J. , Hanewald K. H.
Published: September 2010

For mixtures of methyl ethyl ketone and water and of sec. butanol and water, the following data were determined:

specific gravity, 21°/21°

boiling point,

composition of the liquid at boiling temperature,

composition of the vapour at boiling temperature.

Commercially pure products were used.
Water soluble antihemorrhagic substances I: Synthesis of 2‐methyl‐4‐aminonaphthol‐1 hydrochloride and of 2‐methyl‐1,4‐diaminonaphthalene dihydrochloride, the water soluble synthetic vitamins K5and K6
Authors: Veldstra H. , Wiardi P. W.
Published: September 2010

The synthesis is described of 2‐methyl‐4‐aminonaphthol‐1 hydrochloride and of 2‐methyl‐1,4‐diaminonaphthalene dihydrochloride, both water soluble compounds possessing a high vitamin K activity. For the first mentioned substance this has already been reported by Emmett, Kamm and Sharp1), and in America the compound has been termed vitamin K5.

In this communication we prove for the first time the high activity of 2‐methyl‐1,4‐diaminonaphthalene dihydrochloride, for which we propose the name vitamin K6. Information is given about the stability, toxicity and clinical value of the compounds obtained.
Eine Neue Methode zur Berechnung von Dipolmomenten
Authors: Böttcher C. J. F.
Published: September 2010

Starting from considerations of Onsager and of the present writer a method is suggested for calculating dipole moments from measurements of the dielectric constant and the density of liquids containing one or more dipole components. By means of a number of examples it is shown that the dipole moments computed by means of the derived formulae are all but independent of the temperature and the concentration of the dipole substance, and sufficiently agree with those calculated with the aid of the usual methods.
The determination of tungsten as BaWO4
Authors: de Witte M. C.
Published: September 2010

An exact procedure has been worked out for the determination of tungsten as BaWO4. The solubility of the latter is taken into consideration, especially its dependence on the pH. Finally the BaWO4 method is compared with the other methods for determining tungsten and a procedure is given for the quantitative conversion of BaWO4 into WO3, when coprecipitation is to be feared.
2‐amino‐4‐méthylthiazol‐sulfamide‐5 et quelques dérivés
Authors: Backer H. J. , de Jonge J.
Published: September 2010

Le mémoire décrit la préparation de quelques sulfamides qui diffèrent des sulfanilamides en ce qu'elles renferment le nouyau thiazol au lieu du nouyau benzénique.

Une des nouvelles sulfamides (II) est un isomère du “sulfaméthylthiazol”. Une autre sulfamide (IV) renferme deux fois le noyau du méthylthiazol.
Zur analytischen Chemie des Zirkons: III. Die Bestimmung des Zirkons mit Arsensäure
Authors: Claassen A. , Visser J.
Published: September 2010

Die Bestimmung des Zirkons mittels Arsensäure wurde nachgeprüft. Auf Grund von Löslichkeitsbestimmungen des Niederschlages wird eine neue Vorschrift für die Fällung in salzsaurer Lösung vorgeschlagen. Das geglühte Arsenat kann nur durch Abrauchen mit Schwefelsäure und Flusssäure in arsenfreies Oxyd übergeführt werden. Das Verfahren liefert bei einmaliger Fällung eine vollständige Trennung von grossen Mengen Kupfer, Cadmium, Vanadin V, Molybdän VI, Uran VI, Cer III, Eisen, Aluminium, Chrom, Nickel, Kobalt, Zink, Mangan, Magnesium, Calcium, Barium, Strontium und Alkalien. Eine Umfällung ist erforderlich zur Trennung von Wismut, Beryllium, Thorium, Zinn und Titan. Wolfram wird teilweise mitgefällt.
Deacylation of acetylamino compounds containing a nitro group in the ortho or para position
Authors: Verkade P. E. , Witjens P. H.
Published: September 2010

Acetylamino compounds containing a nitro group in the ortho or para position are easily deacylated by boiling with alcohol in the presence of some sodium alcoholate, the acetyl group being split off in the form of an ester.
Die thermische Umlagerung einiger 1‐(Chlorphenyl)‐ und 1‐(Bromphenyl)‐Pyrrole
Authors: Wibaut J. P. , Dhont J.
Published: September 2010

Durch trockene Destillation eines Gemisches von Schleimsäure und einem Halogenanilin wurden die folgenden Pyrrole bereitet: 1‐(4‐Chlorphenyl)‐pyrrol, 1‐(3‐Chlorphenyl)‐pyrrol, 1‐(2‐Chlorphenyl)‐pyrrol und l‐(3‐Bromphenyl)‐pyrrol.

Bei der thermischen Umsetzung des 1‐(4‐Chlorphenyl)‐pyrrols bei 700° wurde ein einheitliches C‐(4‐Chlorphenyl)‐pyrrol erhalten; diese Verbindung war mit dem 2‐(4‐Chlorphenyl)‐pyrrol identisch, das aus 4‐Chlorbenzoylessigester, α,β‐Dichloräther und Ammoniak synthetisiert worden war.

Die thermische Umlagerung des 1‐(3‐Chlorphenyl)‐pyrrols liefert ebenfalls ein einheitliches C‐(3‐Chlorphenyl)‐pyrrol; auch bei der Umlagerung des 1‐(2‐Chlorphenyl)‐pyrrols und des 1‐(3‐Bromphenyl)‐pyrrols werden wahrscheinlich einheitliche C‐(Halogenphenyl)‐pyrrole gebildet. Diese C‐Pyrrole müssen in Analogie mit dem 2‐(4‐Chlorphenyl)‐pyrrol als 2‐Pyrrolderivate aufgefasst werden.
The dipole moment and the constitution of nitrosyl chloride and nitrosyl bromide
Authors: Ketelaar J. A. A.
Published: September 2010

The dipole moments of nitrosyl chloride and nitrosyl bromide were determined as 1.83 ± 0.01 D and 1.87 D, respectively. These values are compared to those estimated for a pure homopolar structure ClNO. The conclusion is reached that an ionic structure: Cl−[N≡O]+ makes a considerable contribution to the stationary state. This type of resonance, already deduced from a discussion of bond distances, is thus confirmed.

The dielectric constant of the pure liquid was found to be ϵ = 18.2 at 12° for NOCl and ϵ = 13.4 at 15.2° for NOBr, respectively.
Wasserdampfdestillation
Authors: Schoorl N.
Published: September 2010

Destillation von vollständig mit Wasser mischbaren flüchtigen Stoffen.
Wasserdampfdestillation
Authors: Schoorl N.
Published: September 2010

Besonderer Fall der Destillation von vollständig mit Wasser mischbaren flüchtigen Stoffen.
Ascorbic acid as inductor and as oxidation catalyst
Authors: Jorissen W. P. , Dekking A. C. B.
Published: September 2010

The system ascorbic acid‐glucose–oxygen compared with the system ascorbic acid‐arsenite‐oxygen.
“Associated” mixtures. II
Authors: van Santen J. H.
Published: September 2010

The shift of the absorption band of diethyl ether at 8.9 μ upon mixing with chloroform and several related compounds was measured.

The measured shifts can, like several frequency changes mentioned in the literature, be calculated with a plausible distribution of charge of the molecules concerned.

From the measurements conclusions are drawn about the charge of the hydrogen atom in the compounds investigated.
On the influence of electrolytic copper on the oxidation of aromatic free mineral oil
Authors: Kreulen D. J. W.
Published: September 2010

The influence of copper on the oxidation of an aromatic free mineral oil is investigated. The reaction is catalyzed by solid as well as by dissolved copper. Copper oxide was also found to be a catalyst.

Using quantities of solid copper up to 10 g/250 cm3 of oil, however, the catalytic effect is so slight that it falls within the experimental error.

Copper, and also CuO, affects the length of the period of induction. With increasing quantities of copper the length of the period of induction first decreases (adsorption of antioxidants from the oil), but with still larger quantities this decrease turns into an increase (breaking of reaction chains).

The phenomena observed are discussed in connection with the study of the mechanism of oil oxidation.
Des Quinoléines Substituées. I: Synthèse des 2. et 3. (α‐quinoléyl)‐phénanthrènes
Authors: Buu‐Hoï Ng. Ph. , Cagniant P.
Published: September 2010

On décrit dans le présent mémoire la préparation et les principales propriétés de 2 phénanthrènes substituées par le radical quinoléïqe.
Der Dampfdruck des Jodcyans
Authors: Ketelaar J. A. A. , Kruyer S.
Published: September 2010

Es wurde der Dampfdruck des Jodcyans im Temperaturgebiet 64°‐153° gemessen. Es ergab sich für den Dampfdruck der festen Phase: \documentclass{article}\pagestyle{empty}\begin{document}\[{\rm log \rho }_{{\rm mm}} = - \frac{{14310}}{{4.574}} + 10.46\]\end{document} für die flüssige Phase \documentclass{article}\pagestyle{empty}\begin{document}\[{\rm log \rho }_{{\rm mm}}= - \frac{{9560}}{{4.574T}} + 7.77\]\end{document}. Der Tripelpunkt wurde zu t = 146°. p = 993 mm Hg bestimmt. Sublimationswärme: 14.31 ± 0.04 kcal/Mol. Verdampfungswärme : 9.56 ± 0.08 kcal/Mol, Schmelzwärme : 4.75 ± 0.09 kcal/Mol.
Über das Addukt von β‐Elaeostearinsäure und Maleinsäureanhydrid
Authors: Rinkes J.
Published: September 2010

Es glückte mir, das Addukt von β‐Elaeostearinsäure und Maleinsäureanhydrid zu einem bekannten Benzenderivat, Terepthalsäure, abzubrechen und auch das Zwischenprodukt 1‐Hexyl‐4‐heptylbenzen mit einem synthetisch hergestellten Produkt zu identifizieren.
Untersuchungen über Wolframhalogenide. 2. Mitteilung). Dampfdrücke von Wolframhexachlorid
Authors: Ketelaar J. A. A. , v. Oosterhout G. W. , Braun P. B.
Published: September 2010

Es wird eine Reinigungsmethode zur Darstellung von reinem Wolframhexachlorid ausgearbeitet welche in einigen wichtigen Punkten, in denen die Dissoziation berücksichtigt wird, von den üblichen Verfahren abweicht. Von dem so erhaltenen reinsten WCl6 wurden die Dampfdrücke im Temperaturgebiet 150°‐360°C bestimmt. Die Dampfdrücke folgen sehr gut den Formeln:magnified image

Es ergab sich für die Sublimationswärme der sogenannten α‐bzw. der Hochtemperatur oder β‐Modifikation 20.94 bzw. 17.54 kcal/mol; für die Verdampfungswärme der Schmelze wurden 15.24 kcal/mol gefunden. Hieraus ergibt sich für die Umwandlungswärme 3.4 und für die Schmelzwärme 2.3 kcal/mol. Die Umwandlungswärme beträgt also etwa das Anderthalbfache der Schmelzwärme. Zur genaueren Festlegung des Umwandlungspunktes und des Tripelpunktes wurden Aufwärmungskurven aufgenommen. Daraus ergab sich für den Umwandlungspunkt 226.93 ± 0.03°C und für den Tripelpunkt 284.0 ± 0.1°C; ausserdem ein bisher unbekannter Umwandlungspunkt, bei 167.9‐169.5°C Hierfür sind auch andere Anzeigen vorhanden. Der Siedepunkt berechnet sich zu 336.5°C; der Troutonsche Konstante zu 24.9 cal/Grad. An Präparaten mit einer von dem stoechiometrischen Verhältnis abweichenden Zusammensetzung wurde eine merkwürdige Anomalie des Dampfdruckes in der Umgebung des Umwandlungspunktes gefunden, deren Erklärung in Zusammenhang mit der hier auftretenden Strukturänderung gebracht wird.
On the three‐phase pressures for solid salt‐solution‐vapour II
Authors: Korvezee A. E. , Dingemans P.
Published: September 2010

In the previous paper

Miss A. E. Korvezee and P. Dingemans, Rec. trav. chim. 62, 625 (1943).

) we showed that the relative vapour pressure of saturated salt solutions (i.e. the vapour pressure of the solution divided by the vapour pressure of water at the same temperature), plotted as a function of the temperature, is in many cases a straight or only very slightly curved line.

When a salt occurs in two crystalline forms which are converted into each other at a definite temperature, the p‐T curve of the saturated solutions will possess two maxima (stable or metastable), and there are three different types of curve possible. An example of each type has been exhaustively studied in this laboratory. By making use of all the vapour pressures measured over a wide temperature range, the equations of the relative vapour pressure curves are given for these saturated solutions. With the help of these equations the position of the maxima in the p‐T curves can be accurately determined.

From the difference in the slope of the relative vapour pressure curves at the transition point, the heat of transition between the two modifications of the salt can be calculated. This heat effect can also be calculated as the difference in heat of crystallization of the two salt modifications at the temperatures of the maxima.
Polymerization with atomic hydrogen
Authors: Houtman J. P. W. , van den Berg K. , Heertjes P. M.
Published: September 2010

The activity of atomic hydrogen as a polymerization agent for unsaturated organic compounds has been investigated. Two methods were used to prepare pure atomic hydrogen. The first was a modified Langmuir method, passing hydrogen over a glowing tungsten wire, and removing the hydrogen ions formed. The second was Cario and Frank's method, by which atomic hydrogen is prepared by means of ultraviolet light. It could be shown that atomic hydrogen causes polymerization as well as hydrogenation of unsaturated organic compounds.
Order‐disorder transformations in the lattice of organic molecules. II. The crystal structure of C(SCH3)4 below 23.2°C
Authors: Perdok W. G. , Terpstra P.
Published: September 2010

In this article the X‐ray investigation of tetramethylorthothiocarbonate C(SCH3)4 is described, a compound of particular interest with regard to its physical properties1). The modification stable below 23.2°C proved to be tetragonal, space group P421c (D2d4) Z = 2, a = 8.536 Å, c = 6.949 Å.

A Bragg synthesis showed that the molecule C(SCH3)4 is built tetrahedrally with C ‐ S = 1.81 Å. The structure can be simply described as a packing of methyl groups (r = 2 Å) arranged in a pattern resembling a body‐centred lattice, the interstices of which are alternately empty, or filled with a CS4 group.
Des Quinoléines Substituées. III. Quinoléines 2‐substituées dérivées du fluoranthène et du thionaphtène
Authors: Buu‐Hoï Ng. Ph. , Cagniant Paul
Published: September 2010

Les auteurs décrivent la synthèse de nouvelles 2‐arylquinoléines dérivées du fluoranthène et du thionaphtène, et, à cette occasion, signalent de nouveaux résultats concernant la chimie de ces 2 carbures aromatiques.
Sur la Couleur et la Constitution de Quelques Dérivés Benzéniques Aminés. II
Authors: Heertjes P. M. , van Kerkhof J. C. , de Vries K. A.
Published: September 2010

Le mémoire donne quelques règles sur l'influence du groupe diméthylamino, introduit dans le triphénylméthane et son carbinol, sur le spectre d'absorption. Ces règles et le comportement spectroscopique des composés mentionnés dans des solutions aqueuses acides, conduisent à la conclusion, que dans le changement de constitution qui a lieu lors de la formation des colorants basiques du triphénylméthane, l'atome C central, un groupe basique et le noyau phénylique qui porte ce groupe jouent un rôle.
The AZO chromophor(X)
Authors: Blumberger J. S. Petrus
Published: September 2010

The ionization constant of 24 azo dye cations of the type: benzene‐azo‐1‐amino‐naphthalene‐6,8‐disulphonic acid: magnified image

was determined at five temperatures from 40 to 80°C.

The heat of ionization can be influenced by substitution in the diazo component, but there is only a very limited correlation to be found with the influence of the substituent in question on the colour. Within the limits of accuracy of the method this heat of ionization is in most cases insensitive to temperature, which could also be deduced from the “isoelectric” character of the equilibrium.

Strong ortho effects can be explained by chelate binding, while colouristic deviations of vicinally substituted diazo components could also be detected in the case of these aminoazo dyes.
Researches on adsorption electrodes V. Glass electrode, ion exchange and electrode properties
Authors: Tendeloo H. J. C. , Voorspuij A. J. Zwart
Published: September 2010

The incorporation of Al2O3 in a network of SiO4 tetrahedra has a marked influence on the electrode properties of a glass.

From theoretical considerations it follows, as could be proved experimentally in this paper, that the exchange capacity and the hydration is less for a glass containing Al2O3 than for Corning glass 015, which does not contain Al2O3.
The crystal structure of chalcopyrite (CuFeS2) and AgFeS2: The permutoidic reactions KFeS2 → CuFeS2 and KFeS2 → AgFeS2
Authors: Boon J. W.
Published: September 2010

New evidence has been given that chalcopyrite (CuFeS2) has a crystal structure according to Pauling and Brockway3)

and not according to Burdick and Ellis 2) : in a rotation diagram taken with CoK radiation of a cylindrical chalcopyrite crystal around the [001] axis weak interzones can be seen which are only compatible with the Pauling‐Brockway structure (see fig. 2).

AgFeS2 prepared by pseudomorphic transformation of KFeS2 in a AgNO3 solution has the same structure as chalcopyrite. The cell constants are a = b = 5.66 Å and c = 10.30 Å. The space group is also D122d‐142d with 4 molecules of AgFeS2 per cell. The atomic positions are the same as those given for chalcopyrite by Pauling and Brockway, with a parameter value x8 of about 1/4. The “chain” direction (i.e. the [001] direction of the KFeS2 crystal from which the AgFeS2 crystal was prepared) is [100]. The fact that AgFeS2 may be considered as having originated from CuFeS2 by isomorphic substitution is new, almost superfluous evidence that chalcopyrite has the Pauling‐Brockway structure.

The artificial CuFeS2, prepared by pseudomorphic transformation of KFeS2, has a crystal structure showing great similarity to the structure of chalcopyrite, but from the X‐ray diagram it is impossible to deduce whether this similarity is also valid for the details. From the fact that AgFeS2 is isomorphic with chalcopyrite it follows that the artificial CuFeS2.will probably have the same Pauling‐Brockway structure as chalcopyrite, and that here also the “chain” direction will be [100].

Finally the permutoidic reactions KFeS2 → AgFeS2 and KFeS2 → CuFeS2 are discussed.
Über die Struktur und Disproportionierung einiger 2‐(Halogenphenyl)Pyrroline
Authors: Dhont J. , Wibaut J. P.
Published: September 2010

Gezeigt wird, dass das durch Reduktion des 2‐(4‐Chlorphenyl)‐pyrrols mit Zink und Salzsäure erhaltene Pyrrolin das 2‐(4‐Chlorphenyl)‐2,3‐dihydropyrrol ist. Nach Analogie wird für das 2‐(3‐Chorphenyl)‐ das 2‐(2‐Chlorphenyl)‐ und das 2‐(3‐Bromphenyl)‐pyrrolin dieselbe Struktur angenommen. Diese Pyrroline unterliegen alle einer Disproportionierung, wobei das entsprechende Pyrrol‐ und Pyrrolidinderivat gebildet wird.
Synthetic lubricating oil fractions from ethene and gases containing ethene by polymerization II
Authors: Heertjes P. M. , Hessels W. J. , Waterman H. I.
Published: September 2010

The lubricating properties of the synthetic lubricating oil prepared as described in the first communication were tested in a standard engine under very drastic conditions (ring sticking test). The lubricating properties of the oil in general were very good.

The cetane number of the middle oil obtained by polymerization of ethene was 32.

The use of a liquid diluent in the catalytic polymerization of ethene is not essential.

Besides nickel or nickel alloys, other compounds such especially as cobalt and also aluminium, and to a certain extent also dry hydrochloric acid can exercise a favourable influence on the polymerization of ethene with aluminium chloride.
L'acide Disulfoadipique
Authors: van der Zanden J. M.
Published: September 2010

Poursuivant les recherches concernant l'action de l'anhydride sulfurique sur les acides bibasiques, nous avons étudié la sulfonation directe de l'acide adipique ainsi que l'acide disulfonique préparé en partant de l'acide dibromoadipique.
Some remarks about the connection between the constitution and dipole moment of some indole derivatives
Authors: Janetzky E. F. J. , Lebret M. C.
Published: September 2010

In the preparation of indoles substituted in the pyrrole nucleus starting from α‐arylaminoketones, two types of indoles may be obtained according as they are formed by ring closure or by rearrangement. The dipole moment of a number of indoles whose constitution had been definitely determined by other methods was measured. It was found that in some cases it is possible to distinguish between the two ways of indole formation by means of the dipole moment.
A simple synthesis of isopelletierine: Research on the synthesis of compounds from the group of alkaloids from Punica Granatum 3rd communication
Authors: Wibaut J. P. , Kloppenburg C. C. , Beets M. G. J.
Published: September 2010

By the action of acetic anhydride on lithium picolyl 1‐(2‐pyridyl)‐propanon‐2 is prepared; by partial reduction of this compound 1‐(2‐piperidyl)‐propanon‐2 or dl‐isopelletierine is obtained.
The preparation of pyridine‐4‐carboxylic acid and of piperidine‐4‐carboxylic acid by catalytic reduction of 2,6‐dichloropyridine‐4‐carboxylic acid
Authors: Wibaut J. P.
Published: September 2010

2,6‐Dichloropyridine‐4‐carboxylic acid (II) is converted by catalytic reduction with nickel in alkaline medium into pyridine‐carboxylic acid (III). If the catalytic reduction ofIIis carried out in glacial acetic acid and with platinum (Adams) as a catalyst, piperidine‐4‐carboxylic acid (IV) is formed in one operation which substance is also obtained by the catalytic reduction ofisonicotinic acid under the same circumstances.

2,6‐Dichloro‐4‐cyanopyridine (V) was treated under varying conditions with hydrogen in the presence of catalysts; in these experiments the substance V was recovered unchanged.
The vulcanization of rubber with phenol formaldehyde derivatives
Authors: van der Meer S.
Published: September 2010

After some remarks on the importance of phenol formaldehyde resins as vulcanizing agents for rubber, the introductory investigations which led to the methylene quinone theory of the vulcanization are described. Finally this theory is illustrated with the compound 2.6‐di‐bromomethyl‐4‐methylphenol as an example.
The vulcanization of rubber with phenol formaldehyde derivatives
Authors: van der Meer S.
Published: September 2010

Referring to the preceding article describing the methylene quinone theory of the vulcanization of rubber with phenol formaldehyde derivatives, in this paper the arguments in favour of that theory are considered in detail. The results of the investigations in question can be summarized as follows.

The vulcanizing properties of the pseudo‐phenol halides are based on the easy transformation of these compounds into methylene quinones with the liberation of gaseous hydrogen halide.

The vulcanizing properties of the phenol‐dialcohols are also based on the formation of methylene quinones as intermediates, however at higher temperatures only.

Phenol‐dialcohols vulcanize slowly, at temperatures lying only little below their decomposition temperatures, and yield comparatively good vulcanizates.

Pseudo‐phenol halides vulcanize rapidly, at temperatures lying considerably below their decomposition temperatures, and yield comparatively poor vulcanizates.

The vulcanization temperature of 4,6‐di‐hydroxymethyl‐2‐methylphenol (about 200° C) is higher than that of 2,6‐di‐hydroxymethyl‐4‐methylphenol (about 155° C), as in the first case the vulcanization is based on the formation of an ortho‐methylene quinone as well as a para‐methylene quinone and in the second case on the formation of ortho‐methylene quinones exclusively. Generally these last compounds are formed more/easily than the para isomers.

The vulcanizing properties of 2,6‐di‐hydroxymethyl‐4‐methylphenol at 155° C are reduced by the addition of 4,6‐di‐hydroxymethyl‐2‐methylphenol, in consequence of the formation of molecular complexes which are unable to form ortho, but only para‐methylene quinones.

The vulcanizing properties of the phenol formaldehyde derivatives are entirely destroyed by hexamethylene tetramine, as that substance combines with the primarily formed methylene quinones.

The vulcanization reactions of the phenol formaldehyde derivatives are not based on the formation of an irregular knot of entangled rubber and resin molecules, but on primary chemical bonds between these two.

The vulcanizing properties of the esters of the phenol‐dialcohols as well as those of the pseudo‐phenol halides, are based on the formation of methylene quinones as intermediates with the liberation of acids. The higher fatty acid esters of 2,6‐dihydroxymethyl‐4‐methylphenol are unstable, showing the liberation of acids already at room temperature.

Compounds which may be supposed to be derived from phenol‐dialcohols by a change in their configuration do not show vulcanizing properties if the formation of methylene quinones is impossible. If a repeated formation of these intermediates is only possible to a very limited extent, as is the case with phenol‐monoalcohols, vulcanizing properties are also present on a minor scale.
Makromoleküle in Lösung
Authors: Hermans J. J.
Published: September 2010

Es werden die von W. Kuhn und H. Kuhn erhaltenen Formeln für die Viskosität und die Strömungsdoppelbrechung mit den unsrigen verglichen. Es zeigt sich dabei von grosser Bedeutung, dass der Auslöschwinkel sehr empfindlich ist für geringe Abweichungen des Polymerisationsgrades von dem Mittelwert. Aus diesem Grunde lässt sich zur Zeit nicht entscheiden, welche Formeln den Vorzug verdienen.
Die Sedimentationsgeschwindigkeit Langkettiger Makromoleküle
Authors: Hermans J. J.
Published: September 2010

The sedimentation velocity of a long‐chain molecule is greatly increased by the hydrodynamic interaction of its constituent parts. If Kuhn's model of randomly kinked molecules is accepted, the application of a formula obtained by Burgers leads to an expression for the sedimentation velocity which is shown to account for experimental results mentioned in the literature.

This hydrodynamic interaction manifests itself in a way‐which illustrates the hydrodynamic meaning of the “undurchspülte Knäuel” assumed by Kuhn and makes his assumption very acceptable. It is emphasized, however, that this interaction is much less effective in the presence of a velocity gradient. This explains the experimental fact that various substances conform to Staudinger's viscosity rule, while at the same time their sedimentation constant is dependent on molecular weight.
Préparation et Structure du 2‐Acétylamino‐5‐Bromothiazol
Authors: Backer H. J. , Buisman J. A. Keverling
Published: September 2010

Par bromuration du 2‐acétylaminothiazol, on obtient le 2‐acétylamino‐5‐bromothiazol, dont la structure est établie.
Die Bestimmung der p‐Aminobenzoesäure und des Sulfapyridins ‐ bzw. ähnlicher Verbindungen ‐ Nebeneinander
Authors: Havinga E.
Published: September 2010

Para‐aminobenzoic acid, sulphapyridine and other sulphonamides can be determined by measuring the extinction of the coloured solutions formed by diazotization, coupling with β‐naphthol and extracting the dye from the neutralized solution with amyl alcohol. Extraction of a weak alkaline solution with chloroform results in a separation of the p‐aminobenzoic acid dye and the sulphapyridine dye, the former remaining in the alkaline water phase. This offers a very simple solution for the problem of determining sulphapyridine and its antagonist p‐aminobenzoic acid in a solution containing both substances.
Photometric determination of micro‐quantities of mercury as mercury dithizonate
Authors: Reith J. F. , Gerritsma K. W.
Published: September 2010

It is possible to determine 2.5 to 250 γ of mercury photometrically by extracting the mercury salt solution with an excess of dithizon solution in chloroform and measuring the extinctions of the chloroform layer at 500 and 610 mμ. The amount of mercury is calculated from the volume of dithizon solution used and the extinctions E500 and E610 measured, thus standardization of the dithizon solution is unnecessary.

The pure solution of the orange coloured mercury dithizonate in chloroform turns a dirty greenish orange in daylight, in direct sunlight it becomes bluish purple in a few minutes. The original colour is quickly recovered again in the dark. This reversible photochemical process is completely inhibited by acetic acid.
On the bromination of naphthalene: The influence of temperature and catalysts on the proportions of 1 and 2‐bromonaphthalene formed I
Authors: Suyver J. F. , Wibaut J. P.
Published: September 2010

The bromination of gaseous naphthalene in the presence of glass wool or pumice was investigated in the temperature range from 250° to 650° C. The content of 2‐bromonaphthalene in the mixture obtained was determined; the more highly brominated products were not investigated. It was found that from 250° to 300° a small amount of 2‐bromonaphthalene is formed; between 300° and 500° C the amount of 2‐bromonaphthalene increases rapidly with the temperature. At still higher temperatures the ratio of 1‐bromonaphthalene to 2‐bromonaphthalene changes only little and is approximately equal to unity.

The bromination of liquid naphthalene without a catalyst was examined in the temperature ranges from 85° to 215° C. Under these conditions little 2‐bromonaphthalene is formed and the amount increases regularly with the temperature. This increase can be represented by the formula of Scheffer.

Attention is called to the specific catalytic action of ferric compounds, by which not only in the bromination in the gas phase, but also in that in the liquid phase the formation of 2‐bromonaphthalene is considerably promoted.

An example is given of the preparation of 2‐bromonaphthalene by the bromination of liquid naphthalene at 150° with ferric bromide as catalyst.
Préparation et Activité Sulfonamide de Quelques Aminosulfures et ‐Sulfones
Authors: Backer H. J. , Buisman J. A. Keverling
Published: September 2010

Pour étudier leur activité sulfonamide, les auteurs ont préparé quelques sulfures et sulfones mixtes des types 4‐NH2˙ C6H4 ˙ SR et 4‐NH2 ˙ C6H4 ˙ SO2R.
Raman spectra of the seven isomeric pentenes and quantitative analysis of two mixtures by means of the raman effect
Authors: Gerding H. , van Der Vet A. P.
Published: September 2010

The Raman spectra of the six open‐chain pentenes C5H10 and the spectrum of cyclopentene C5H8 are reported on. Polarization measurements of the latter compound were made and a short discussion of its symmetry is given.

Measurements concerning the intensities of Raman lines were carried out for the quantitative analysis of a binary mixture of pentene‐1 and 2‐methylbutene‐1 and of a ternary mixture containing trans‐ and cis‐pentene‐2 and 2‐methylbutene‐2.
The crystal structure of aluminium bromide
Authors: Renes P. A. , MacGillavry C. H.
Published: September 2010

Aluminium bromide crystallizes in a monoclinic molecule lattice. The molecules are of the same type as those found in the gaseous and liquid phase; they consist of two tetrahedra sharing one edge.
Die Bestimmung der quantitativen Zusammensetzung von Mischungen, welche als Komponente Mahlprodukte von Roggen und Weizen enthalten, insbesondere mit Hilfe einer Nephelometrischen Methode. II: Roggen, Weizen and Kartoffelmehl als Komponente
Authors: Openti E. C. , van der Lee T.
Published: September 2010

Nachdem in der Abhandlung I

Sehe H. M. R. Hintzer und J. van der Lee, Rec. trav. chim. 63, 53‐68 (1944).

) die Methodik der nephelometrischen Bestimmung von Mischungen von Roggen‐ und Weizenmehl behandelt wurde, wird in folgender Abhandlung beschrieben, in welcher Weise diese Methode nutzbar gemacht werden kann für die Untersuchung von Mischungen, die als dritte Komponente noch Kartoffelmehl enthalten.
The qualitative analysis of organic substances by hydrogenation
Authors: Slooff A.
Published: September 2010

By the method of hydrogenation of Ter Meulen phosphorus can be detected in organic substances simultaneously with nitrogen, sulphur, halogen, volatile metals and components of the ash.
The molecular refraction of aqueous solutions of electrolytes
Authors: Böttcher C. J. F.
Published: September 2010

The complicated deviations from the additivity of the molecular refraction found in electrolyte solutions by Fajans and his collaborators, appear to be the simple consequence of the correction introduced by the author in the Lorentz‐Lorenz formula.
On the structure of leucaenine (leucaenol) from leucaena glauca bentham
Authors: Bickel A. F. , Wibaut J. P.
Published: September 2010

From the seeds of Leucaena glauca B, obtained from the Netherlands Indies, we isolated leucaenine which, under the name leucaenol, was first described in 1937 by Mascré, who determined for this compound the empirical formula C4H5O2N. We obtained about 16 g of pure leucaenine (melting point 226°–227° with decomposition) from 1 kg of seeds.

From an electrometrical titration the molecular formula of the substance is found to be C8H10O4N2; leucaenine is an α‐amino acid in the molecule of which a pyridine ring substituted by hydroxyl occurs. By the action of dimethyl sulphate and alkali on leucaenine we obtained a compound C7H11O3N (I) which could be converted into a N‐methylhydroxypyridone having the composition C6H7O2N (II). This compound is not identical with N‐methyl‐6‐hydroxypyridone‐2 or with N‐methyl‐3‐hydroxypyridone‐2, which hitherto unknown pyridones were obtained by synthesis, and it is likewise not identical with the N‐methyl‐4‐hydroxypyridone‐2 (or N‐methyl‐2‐hydroxypyridone‐4) described by Späth. To the compound C6H7O2N therefore the structure of an N‐methyl‐3‐hydroxypyridone‐4 or of an N‐methyl‐5‐hydroxypyridone‐2 must be assigned; for the present we consider the first structure mentioned the more probable.

Leucaenine itself must be considered as a β‐[hydroxypyridyl‐oxy] ‐α‐aminopropionic acid; the positions at which the hydroxyl group and the serine radical are substituted in the pyridine nucleus have not yet been determined, although it follows from our investigation that several positions are impossible. The most probable formula for leucaenine is in our opinion: β‐[3‐(4‐hydroxypyridyl)‐oxy]‐α‐aminopropionic acid. Since the compound isolated by us must therefore be classed among the naturally occurring amino acids we propose to call this substance leucaenine.

The substance mimosine isolated by Renz and by Nienburg and Tauböck from the leaf stems of Mimosa pudica L. and of Leucaena glauca B is very probably identical with leucaenine.

From experiments on animals it was found that the administering of leucaenine or of seeds of Leucaena glauca B to rats or mice did not cause the hair to fall out. This result is not in agreement with several statements in the literature, according to which larger mammals, such as horses and donkeys, showed loss of hair after being fed on seeds or leaves of the plant.
A method for calculating the polarizability of the particles of a substance from the index of refraction and the density of dilute solutions of that substance
Authors: Böttcher C. J. F.
Published: September 2010

A formula is derived with the aid of which it is possible to compute the polarizability of the particles of a substance from measurements of the variations which the index of refraction and the density of a solvent undergo when a small quantity of the substance is dissolved in it.

As an application of this formula the polarizabilities of the alkali and halogen ions are calculated, starting from the measurements by Heydweiller and others on dilute aqueous solutions of the alkali halides.
The reaction between phenylhydrazine and ω‐chloroacetophenone. (The reaction between ω‐halogenoketones and phenylhydrazine, V)
Authors: van Alphen J.
Published: September 2010

The compound obtained by Hess, the condensation product of phenylhydrazine and ω‐chloroacetophenone has been investigated and its properties can be explained by assigning to it the constitution 1: 3‐diphenyl‐(1: 2‐diazacyclobutene‐2).

The structure of the compound obtained by Scholtz from phenylhydrazine and ω‐chloroacetophenone, has been elucidated and proved to be the bis‐phenylhydrazone of diphenacyl.
Some remarks on mesomerism. (The reaction between α‐halogenoketones and phenylhydrazine, VI)
Authors: van Alphen J.
Published: September 2010

It is demonstrated that the groupings magnified image are not mesomeric and are not even easily convertible one into the other.
On the reactivity of the bromine atoms in brominated pyridines: The preparation of brominated 2‐ and 4‐aminopyridines
Authors: Den Hertog H. J.
Published: September 2010

A description is given of the preparation and proof of the structure of nine brominated 2‐amino‐ and of three brominated 4‐aminopyridines.

A survey is given of these two groups of pyridine derivatives, all the possible members of which are now known.

In connection with the preparation of brominated aminopyridines by the action of ammonia on bromopyridines, the reactivity of the bromine atoms towards ammonia is discussed.

Finally, in connection with one of the above‐mentioned preparations, an improved procedure is given for the synthesis discovered by Errera of 2,4‐dihydroxypyridine‐4‐carboxylic acid ethyl ester.
The Raman spectrum of the compound C6Cl6O
Authors: van Brederode H. , Gerding H. , Prins H. J.
Published: September 2010

The Raman spectrum of C6Cl6O, obtained by the reaction of C6Cl8 183° with sulphuric acid in glacial acetic acid, was determined for solutions in CCl4 and CS2.

The Raman effect data prove the presence in the molecule of a C = O group. Further two intense v(C = C) frequency shifts have been found. Of the two C = C bonds indicated by the formula C6Cl6O, at least one is probably conjugated with the C = O group, as is shown by the rather low frequency value for v(C = O) in this cyclic compound.
A new method of preparing 1‐Halogeno‐ and 1‐Alkoxy‐2‐Amino‐4‐Nitrobenzenes
Authors: Blanksma J. J.
Published: September 2010

The method consists of converting the cyano group in 1‐halogeno‐ or 1‐alkoxy‐2‐cyano‐4‐nitrobenzenes

Prepared according to H. Ph. Baudet, Diss. Leiden, 1920, pp. 16, 20 and 21. Rec. trav. chim. 43, 709 (1924).

into the amide grouping, by boiling with a dilute alkaline solution of 3% hydrogen peroxide. The amide is then converted into the corresponding amino‐compound by treatment with sodium hypochlorite or hypobromite. The intensely sweet 1‐alkoxy‐ and 1‐halogeno‐2‐amino‐4‐nitrobenzenes, so obtained, are identical with those obtained by partial reduction of the 1‐halogeno‐ and 1‐alkoxy‐2:4‐dinitrobenzenes so that a new proof of the structure of these compounds has been furnished

Other proofs of structure see J. J. Blanksma, Chem. Weekblad 9, 437 (1912); Rec. trav. chim. 59, 630 (1940).

. The formation of intensely sweet 1‐alkoxy‐2‐amino‐4‐nitrobenzenes from the corresponding amides, which are tasteless, can be used as a test for these amides.
Action Catalytique du Zinc Sur la Précipitation de sb ET SbSn dans les Alliages Riches en Plomb
Authors: de Decker H. C. J.
Published: September 2010

Wenn es in einer Legierung eine Komponente gibt, die bei höherer Temperatur immer besser löslich wird, so kann eine solche Legierung durch Erhitzen gegebenenfalls homogen gemacht werden. Nach Abschrecken bis auf eine viel niedrigere Temperatur bleibt dann der homogene Zustand zuerst metastabil erhalten. Im Laufe der Zeit spielt sich eine Alterung ab, welche schliesslich zur Ausscheidung der schwer löslichen Komponente führt, durch welche Ausscheidung der Gleichgewichtszustand erreicht wird. Am Anfang der Alterung steigt die Härte der Legierung. (Aushärtung).

Es wurden mit einer Reihe von Legierungen, welche ungefähr 98% Pb enthielten, Untersuchungen ausgeführt. Es sind Sb und/oder Sn als Legierungsbestandteile vorhanden. Derartige Legierungen zeigen die oben genannten Erscheinungen. Ein Teil der Legierungen enthält ausserdem eine kleine Menge Zn. Die Zusammensetzung der Legierungen ist gegeben in Zahlentafel 1.

Kleine Konzentrationen Zn (etwa 0.1%) hemmen ein Ansteigen der Härte und befördern die Ausscheidung in diesen Legierungen (s. Fig. 2 und Zahlentafel 2).

Aus Literaturangaben geht hervor, dass geringe Mengen von As oder Cu die Aushärtung derartiger Legierungen beschleuningen ohne merkbare Beförderung der Ausscheidung.

Aus den unterschiedlichen Tatsachen kann man folgern, dass die Aushärtung bei den untersuchten Legierungen stattfindet in der noch homogenen, metastabilen Phase und nicht mit dem Beginn der Ausscheidung verknüpft ist.

Auch über den Einfluss der neben Sb vorhandenen Menge Sn lassen sich Folgerungen aus den Versuchen ableiten.
Amine salts of ethane αβ‐disulphonic acid
Authors: Blanksma J. J.
Published: September 2010

αβ‐Dichloroethane (ethylene dichloride) gives with sodium disulphide in alcoholic solution the bitter, unpleasant smelling diethylene‐1: 2: 5: 6‐tetrasulphide, which on oxidation with nitric acid affords the odourless ethane αβ‐disulphonic acid1).

In alcoholic solution this acid gives beautiful, odourless, crystalline salts with aniline, p‐toluidine and benzidine, which have a weakly acid but no bitter taste. The benzidine salt, like benzidine sulphate, is difficultly soluble in water.

The substance responsible for the bitter taste and garlic‐like smell of diethylene tetrasulphide (1:2:5:6‐tetrathiacyclooctane), does not entirely disappear on oxidation with nitric acid, which produces sulphuric acid as well as ethane αβ‐disulphonic acid. Neutralisation with barium carbonate produces the tasteless barium ethane disulphonate and barium sulphate on which the bitter substance is adsorbed.
The synthesis of “vitamin A acid”, a biologically active substance
Authors: van Dorp D. A. , Arens J. F.
Published: September 2010

By dehydration and subsequent saponification of the reaction product obtained from β‐ionone and γ‐bromocrotonic ester we prepared β‐ionylidene crotonic acid III, which substance was transformed into the “C18 ketone” IV by means of lithium methyl. From this ketone we prepared “vitamin A acid” VII, by means of a Reformatski reaction with methylbromoacetate. This substance proved to have a strong vitamin A activity.
Syntheses of polychloro compounds with aluminium chloride. VI: The elimination of hydrogen chloride from polychloro compounds and the formation of cyclic compounds. The synthesis of perchlorocyclopentadiene
Authors: Prins H. J.
Published: September 2010

The present paper describes several instances of the catalytic liberation of hydrogen chloride from polychloro compounds by the action of aluminium chloride and the subsequent formation of five‐membered rings. The formation of these rings furnishes a simple synthesis of perchlorocyclopentadiene.

It is shown that chloroform is added to perchlorocyclopentadiene, giving a nona‐chloromethylcyclopentene which is also formed when trichloroethene is acted upon by chloroform at the boiling temperature of the latter.

The reaction between perchlorocyclopentadiene and sulphuric acid at different temperatures is described, as also the reaction between octochloropentadiene‐1,3 and the same reagent.
The vapour pressure of solutions saturated with silver nitrate and with lead nitrate
Authors: Dingemans P. , Dijkgraaf L. L.
Published: September 2010

The vapour pressure of the four‐phase equilibrium solid AgNO3‐solid Pb(NO3)2‐saturated solution‐water vapour was measured from 10° C to the end point of this four‐phase line. This end‐point is the eutectic of the binary system AgNO3‐Pb (NO3)2. This eutectic was subjected to exact investigation; the eutectic temperature was found to lie at 203.1° C, while the eutectic melt consists of 92.8 percent by weight of AgNO3 and 7.2 percent by weight of Pb (NO3)2.

The measured vapour pressure line appears to possess 2 stable maxima, namely at 155.8°C and at 163.1° C; the corresponding values of the vapour pressure are 824 and 822 mm Hg, respectively.

This system exhibits the phenomenon of 2 boiling points at atmospheric pressure, namely at 140.9° C and at 176.1° C.

Neither the presence of 2 stable maxima, nor the occurrence of 2 boiling points (at 1 at) had till now ever been observed in solutions saturated with two salts.
Lattice structure of the free surface of alkali halide crystals
Authors: Verwey E. J. W.
Published: September 2010

Calculations have been made of the lattice distortion at the free crystal surface of the cube face of alkali halide crystals on the basis of Born's lattice theory, with the result that the displacement of the positive surface ions in a direction perpendicular to the surface differs considerably from that of the negative. A kind of ionic double layer is formed with the negative ion pointing away from the crystal. The corresponding dipole is more or less compensated by the dipole moment induced in the negative ions. This distortion lowers the surface energy as is illustrated by the calculation for the case of NaBr.
Flocculation and peptization in oil as dispersion medium
Authors: van der Minne J. L.
Published: September 2010

Experiments on the flocculation of suspensions in a mineral oil show that high viscosity gives rise not only to low flocculation velocity but also to very slight adhesion of the particles. In a mineral oil as a viscous non‐aqueous liquid the influence of viscosity and temperature on the kinetics of colloidal phenomena can be investigated over a much wider range than in water.

The effect of peptizers is investigated and a case is described in which two peptizers counteract each other. This is remarkable in view of the fact that the current explanation involving ions of opposite charge cannot be given.
A remark on the determination of surface areas by adsorption methods
Authors: de Boer J. H.
Published: September 2010

Although adsorption isotherms of iodine on barium chloride or calcium fluoride layers show a pronounced sigmoid shape, the adsorption is not of a multimolecular character. The application of the Brunauer‐Emmett‐Teller method leads in these cases to values for the surface areas which are 2 to 4 times too small.
A simple capillary viscosimeter
Authors: van Gils G. E.
Published: September 2010

A pipette viscosimeter is described which can easily be cleaned and, as far as accuracy is concerned, is almost equal to the Ostwald viscosimeter.

In the theoretical part the maximum velocities permissible are calculated for capillaries with different diameters and for water at 30° C.

From this the lowest viscosities permissible and the lowest flowing times permissible are calculated.
Note on a “precursor” of niacine
Authors: Roggen J. C.
Published: September 2010

The precursor of nicotinic acid discovered in wheat bran by a micro‐biological method in the United States is different from the 3‐pyridine derivative described by us possessing a complex side‐chain and occurring in human urine. In the alcoholic extract from wheat bran we could find chemically only nicotinic acid and no pyridine derivative of the structure type of the compound found in urine.

Simple directions are given for the chemical determination of niacine in all possible milling fractions of the grainkernel.