bluuebunny/crossref_metadata_2025 huggingface dataset:
Über Relativ Dissymmetrische Synthese und Rotationsdispersion bei Cobaltikomplexen der α‐Aminosäuren
Authors: Lifschitz I.
Published: September 2010

Die Methoden zum Nachweis der relativ dissymmetrischen Synthese bei der Darstellung von Cobaltkomplexen aus activen Liganden und inactiven Cobaltverbindungen werden kurz besprochen. Ein allgemeines Kriterium, das erlauben würde aus polarimetrischen Messungen auf partielle oder totale Aktivität zu schliessen, kann nicht aufgestellt werden. Die Darstellung und Spaltung von Komplexen [Co en2 ams] X2, worin ams eine optisch active α‐Aminosäure bedeutet, wird beschrieben und aus deren polarimetrischem Verhalten eine Reihe von Folgerungen bezüglich der relativ dissymetrischen Synthese und der Beziehungen zwischen Rotationspersion und Konstitution abgeleitet
Diarylmethane derivatives VII: Properties of the diphenylmethyl radical
Authors: Nauta W. Th. , Mulder D.
Published: September 2010

When oxygen is excluded, the interaction of molecular silver on diphenylchloromethane dissolved in benzene gives a quantitative yield of symm.‐tetraphenylethane.

If this reaction is carried out with shaking in an atmosphere of oxygen only traces of the ethane can be isolated from the reaction mixture.

The diphenylmethyl radicals, initially formed by dehalogenation, are removed by the oxygen.

The reaction products obtained in this case, namely, di‐(diphenylmethyl) ether, benzophenone and diphenylmethanol, may be considered as the decomposition products of a peroxide formed initially.

No coloration is observed in the reaction leading to symm.‐tetraphenylethane. On the other hand, during the oxidation the reaction mixture assumes a permanent pale yellow colour.

Various reactions of diphenylmethyl compounds described in the literature as taking unexpected courses, may be readily explained by the occurrence of the diphenylmethyl radical.
The reactivity of the bromine atoms in brominated pyridines; the formation of 1‐methyl‐6‐bromo‐2‐pyridone from 1‐methyl‐2.6‐dibromopyridinium salts
Authors: Wibaut J. P. , Speekman B. W. , van Wagtendonk H. M.
Published: September 2010

2,6‐Dibromopyridine and dimethyl sulphate react to give 1‐methyl‐2,6‐dibromopyridinium methosulphate, which has only been obtained as an aqueous solution. 1‐Methyl‐2,6‐dibromopyridinium iodide has been obtained as a microcrystalline solid. These 1‐methylpyridinium compounds react with dilute alkali at room‐temperature to give 1‐methyl‐6‐bromo‐2‐pyridone.

The constitution of this compound follows from its transformation into 2,6‐dibromopyridine by the action of phosphorus bromide.
The action of immiscible organic liquids on aqueous dispersions
Authors: Bolam T. R. , Bowden G.
Published: September 2010

The distribution of finely‐divided gold or silver iodide between water and an immiscible organic liquid depends upon the nature and concentration of the electrolytes present. A reasonable interpretation of the observed effects may be given in terms of the influence of the electrical double layer upon the adsorption of non‐electrolytes.
Nachweis von Barium und Sulfat durch Tüpfelreaktionen
Authors: Feigl F. , Aufricht W.
Published: September 2010

In Gegenwart von viel KMnO4 gefälltes BaSO4 enthält stets Permanganat und ist dadurch violett gefärbt. Das durch Adsorption oder Gittereinlagerung im Sulfat befindliche Permanganat ist gegenüber Reduktionsmittel weitgehend resistent. Dieser Effekt kann zum Nachweis von Barium und Sulfat in Form von Tropfenreaktionen verwendet werden.
The gradual decomposition by oxidation of fatty acids into their next lower homologues
Authors: Mendel H. , Coops J.
Published: September 2010

A method for the gradual decomposition by oxidation of fatty acids into their next lower homologues is described and tried on palmitic and stearic acids.

The new method comprises the following steps: bromination of the original fatty acid in α‐position, conversion into α‐hydroxy‐fatty acid, oxidation of the latter to aldehyde with lead tetra‐acetate and subsequent immediate oxidation of the aldehyde to the desired lower fatty acid with air and an excess of lead tetra‐acetate.

The various steps of the first reactions are executed in such a manner, that nearly quantitative yields are obtained. The decomposition of the α‐hydroxy‐fatty acid to the lower fatty acid gives a yield of 88 to 89%. The total yield of lower homologues was approximately 84%.
The influence of liver‐extract on the oxygen consumption of mammalian erythrocytes. IV. On the mechanism of the reaction. B. Yellow enzymes
Authors: Overbeek G. A.
Published: September 2010

It is probable that the “original” yellow enzyme system of Warburg is responsible for a part of the Michaelis Salomon reaction.

There are strong arguments against the functioning of amino‐acid oxidase and xanthine oxidase.
On aliphatic polyamines X
Authors: van Alphen J.
Published: September 2010

The reaction between 1 : 2‐diaminoethane hydrate and 1 :6‐dibromohexane furnishes polyamines containing straight chains of dimethylene and hexamethylene groups separated by nitrogen atoms. A small quantity of a cyclic amine, 1‐(2′‐aminoethyl)‐1‐aza‐cyclo‐heptane, is also formed and the yield of the latter is relatively increased when very dilute solutions of the reaction components are used.

A survey is made of the reaction between an excess of 1 : 2‐diaminoethane hydrate and the various αω‐dibromo‐paraffins.
Quelques Acides Arsonocarboxyliques non Saturés
Authors: Backer H. J. , van Oosten R. P.
Published: September 2010

Le mémoire décrit trois représentants simples des acides arsonocarboxyliques non saturés: les acides α‐arsonacrylique, α‐arsonocrotonique et β‐arsonocrotonique. L'action de l'arsénite de potassium sur les acides α‐bromocrotonique et α‐bromoisocrotonique conduit au même acide α‐arsonocrotonique: les acides β‐chlorocrotonique et β‐chloroisocrotonique donnent également le même acide β‐arsonocrotonique.

La fonction arsonique ‐AsO3H2 donne lieu à la formation d'ortho‐esters avec les 1,2‐diols.

La formation des acides arsonocarboxyliques aux dépens d'arsénite et d'acides chlorocarboxyliques apparaît, dans certaines conditions, comme une réaction bimoléculaire.

Les acides arsonocarboxyliques sont tribasiques; leurs trois constantes de dissociation ont été déterminées par titrage électrométrique.
On the mechanism of water adsorption in gelatine gel
Authors: Weidinger A. , Pelser H.
Published: September 2010

An attempt is made to bring into a closer correlation the conceptions of “bound” and “intramicellar” water. For this purpose we made use of gelatine gels containing cobaltous chloride, observed the colour, typical for different amounts of adsorbed water (an indication for “free” or “bound” water) and found by means of X‐ray spectrography the magnitude of the “side chain spacing” (measure for intramicellar water) in dependance on the amount of adsorbed water. The results obtained for gels of low cobaltous chloride content are valid for pure gelatine gels.
The essential oils from Litsea Cubeba Pers
Authors: van Hulssen C. J. , Koolhaas D. R.
Published: September 2010

A research has been carried out with regard to the composition of the essential oils distilled from the leaves of Litsea cubeba Pers. Two types of oil were found to be present, namely, Litsea oil with a relatively high content of the aldehydes citronellal and citral and Krangean oil with a small content of aldehydes, but with a high content of cineol. The constituents of both oils were isolated and identified and the quantitative composition was determined.
On the influence of the solvent and the temperature on the speed of oxidation of some organic substances by chromic acid. II
Authors: Snethlage H. C. S.
Published: September 2010

The velocity (v) of the reaction between oxalic acid (1) and chromic acid (2) has been measured in mixtures of sulph. ac. and water, containing from 0 to 95.8% sulph. ac. at 303.0° K and 323.0° K. The most appropriate method to investigate the influence of the solvent was to calculate n1 and n2 from v = k × c1n1 × c2n2.

n1 was found to vary between 1 and 2, n2 between 1 and 1.51. In consequence, the effect of the composition of the solvent varies with the concentration of the reactants. The addition of sulph. ac. to water decreases the velocity of the reaction until a minimum is reached, at ± 70% sulph. ac. an optimum exists. The initial stage of the reaction shows, in solvents which contain more than 60% sulph. ac. abnormal (too low) velocities, a phenomenon which is not caused by the effect of any product of the reaction, nor by any reaction between the solvent and the reactants. It is supposed to be the consequence of the slow formation of a compound between the reactants, prior to the actual decomposition.

The temperature coefficients are largely dependent on the composition of the solvent, they vary between 4.32 (water) and 8.8 (70% sulph. ac.) for 20° (303.0‐323.0° K). An optimum is found at 70%, a minimum at 80% sulph. ac. In water and diluted sulph. ac. no complete oxidation can be obtained as part of the oxalic acid is bound by the reduction product of the chromic acid. Taking this into consideration the initial stage of the reaction in water may be represented by the formula for a termolecular reaction, which can also be applied to solutions in 13.4% sulph. ac., where complete oxidation is obtained.
o‐Nitrobenzazide as a reagent for the identification of phenols
Authors: Sah Peter P. T. , Yin Wen‐Hou
Published: September 2010

Twenty‐eight crystalline o‐nitrophenyl‐urethanes were prepared by the action of o‐nitrobenzazide on various phenols in boiling ligroin solution. In the cases of ortho‐substituted phenols, the condensation took place in the presence of dimethylaniline as catalyst. These urethanes possess excellent properties and are suitable derivatives for the identification of phenols.
Die Elektrochemische Kohlenwasserstoffsynthese mit Aromatischen Säuren
Authors: Fichter Fr.
Published: September 2010

Nach einer Besprechung der verschiedenen Gründe, die bei der Benzoesäure das Zustandekommen einer Kolbe'schen Elektrosynthese besonders erschweren, wird eine Elektrolysemethode unter Verwendung von Pyridin allein oder mit Methylalkohol zusammen als Lösungsmittel ausgearbeitet, mit Hilfe deren verschiedene aromatische Säuren, deren Carboxyl nicht unmittelbar am Benzenkern sitzt, die Kohlenwasserstoffsynthese mit brauchbarer Ausbeute durchzuführen gestatten.

Schliesslich wird eine halb mit Diäthylamin neutralisierte Lösung von Benzoesäure in unvermischtem Pyridin elektrolysiert, mit dem Ergebnis, dass bei dieser solange widerstrebenden Säure nicht nur die Synthese des Biphenyls glückt, sondern dass die genaue Untersuchung der Produkte den Beweis der intermediären Bildung von Di‐benzoyl‐peroxyd erbringt, womit die seit mehr als zwanzig Jahren verfochtene Peroxydtheorie

F. Fichter und E. Krummenacher, Helv. Chim. Acta 1, 146 (1918).

;) der Kolbe'schen Elektrosynthese eine neue und besondere überzeugende experimentelle Stütze erhält.
La Composition D'extraits Aqueux de la Semence de Beta Saccharifera
Authors: Gillis J.
Published: September 2010

Les expériences de Fröschel ayant révélé une action retardatrice sur la germination de certaines graines, produite sous l'influence d'extraits aqueux de certaines semences, la question s'est posée de connaître la composition de ces extraits aqueux en vue de rechercher s'il existe une ou plusieurs substances responsables de l'effet retardateur en question.

L'analyse a porté en premier lieu sur le dosage des constituants ionisés de quelques extraits aqueux d'akènes de Beta saccharifera, notamment des cations: Na, K, Mg, Ca et des anions: Cl, NO3, SO4, C2O4.

Grâce aux données de ces dosages, il a été possible de réaliser une première expérience marquant nettement l'action inhibitrice des ions oxaliques sur la germination des graines de Lepidium sativum. d'autres expériences devront être entreprises pour reconnaître si les ions oxaliques sont les seuls responsables de l'effet retardateur de la germination de certaines graines ou bien pour savoir s'il existe encore d'autres substances capables de “freiner” la germination.
Vitamin‐C in tea leaf
Authors: Deijs W. B.
Published: September 2010

An investigation has been carried out on the content of vitamin‐C in fresh and manufactured tea (both green and black teas). Three methods of determining ascorbic acid have been mutually compared. At the same time we have investigated how the contents of ascorbic and dehydroascorbic acids alter during the various stages of tea manufacture.

An examination has been made of how green tea can be prepared so that the final product is still rich in vitamin‐C.

An enzyme preparation has been obtained from tea leaf, which possesses in a high degree the properties of an ascorbic acid‐oxidase.

Finally we have examined the effect of ascorbic acid and ascorbic acid‐oxidase on the fermentation of tea. Investigations on the chemistry of the fermentation of tea are being continued.
Bis repetita desiderantur. Wer hat zum ersten Mal ein Gas verflüssigt?
Authors: Cohen Ernst , Cohen‐de Meester W. A. T.
Published: September 2010

„……während die Erfahrung aller Zeiten uns belehrt, wie schwierig es selbst für geübte Intelligenzen ist, Begriffe aufzugeben, welche sie seit langer Zeit als Wahrheiten betrachteten, obwohl deutlich nachgewiesen war, dass ihre Begriffe unbegründet waren.„

Im holländischen Original: „……terwijl de ondervinding van alle tijden geleerd heeft, hoe bezwaarlijk geoeffende verstanden zelven zodanige begrippen kunnen laaten vaaren, welken zy zederd eenen geruimen tijd voor waarheid hebben aangenomen, of schoon het ongegronde hunner begrippen duidelyk is aangetoond.”︁
Präparative Studien mit monomolekularen Filmen III. Lactonbildung in monomolekularen Schichten
Authors: Kögl F. , Havinga E.
Published: September 2010

Wie sich in der vorliegenden Arbeit gezeigt hat, findet die Lactonisierung von ω‐Oxyaethyl‐stearyl‐malonsäure bei pH 3 bis 6 in monomolekularer Schicht mit einer Geschwindigkeit statt, welche 103 bis 104 mal grösser ist als jene in einer gewöhnlichen Lösung von gleicher Wasserstoffionenkonzentration.
Experiments on a synthesis of dl‐pelletierine. I
Authors: Wibaut J. P. , Beets M. G. J.
Published: September 2010

β‐(2‐Pyridyl)‐propionaldehyde‐acetal has been prepared from bromoacetal and α‐picolyl lithium.

The preparation of this compound forms the first step in a synthesis of dl‐pelletierine.
The ceric hydroxide sol
Authors: Kruyt H. R. , Meilink N. , Hintzer H. M. R.
Published: September 2010

Investigations have been made to prepare a pure and stable ceric oxide sol by hydrolysis of ceric ammonium nitrate in an electro‐dialyser. The problem cannot be solved completely in consequence of the conflicting requirements with regard to pH and the removal of the cerous nitrate.
The potentiometric titration of calcium. II
Authors: Tendeloo H. J. C. , Heeres H.
Published: September 2010

The reversible electrode of the third order, lead amalgam ‐ lead oxalate ‐ calcium oxalate, is useful for the potentiometric titration of calcium ions with ammonium oxalate. The titration is however disturbed when magnesium and chlorine ions are present in too great a concentration.
Quelques Remarques sur le Pouvoir Réducteur du gaz à L'eau
Authors: Meyer G. , Scheffer F. E. C.
Published: September 2010

L'équilibre entre un métal et son oxyde exige, à une température donnée, une valeur déterminée de la tension d'oxygène. Si on chauffe donc un mélange du métal et de son oxyde dans un gaz quelconque, la tension d'oxygène de ce dernier détermine le sens de la transformation dans la masse solide. Nous avons calculé ces tensions d'oxygène dans le gaz à l'eau, préparé par l'action de la vapeur d'eau sous la pression d'une atmosphère sur le carbone à des températures différentes.
Preparation of the (4′‐pyridyl)‐pyrroles
Authors: Overhoff J.
Published: September 2010

The preparation of N‐(4′‐pyridyl)‐pyrrole and its conversion into the two isomeric C‐(4′‐pyridyl)‐pyrroles is described.
The dipole moment of pentachlorobenzene and of 1.2.3 vic. trichlorobenzene
Authors: Ketelaar J. A. A.
Published: September 2010

The dipole moments of monochlorobenzene, 1.2.3 vic. trichlorobenzene and pentachlorobenzene, using benzene as a solvent, were determined as 1.545 D, 2.31 D and 0.87 D respectively.
The composition of the humins produced by the action of sulphuric acid on some organic substances
Authors: Schweizer A.
Published: September 2010

Various humins, which have obtained technical importance under the name of “collactivit”, have been examined analytically. The yields obtainable from various starting materials have been studied.
On octene‐3
Authors: Wibaut J. P. , Gitsels H. P. L.
Published: September 2010

A method is described for the preparation of octene‐3 in a high degree of purity. Exact values for the refraction indices at different wave lengths and for the density are given; the molecular refraction and molecular dispersion is calculated.
Chemischer Beitrag zur Kenntnis Xanthomatöser Geschwülste
Authors: Veer W. L. C. , Beekman E. M. , Boer P. W.
Published: September 2010

Chemische Lipoidanalyse einer xanthomatösen Knochengeschwulst. Bestimmt wurden Neutralfette, Cholesterin, Cholesterinester, Glycerinphosphatide (Lecithin, Kephalin), Diaminophosphatide (Sphingomyelin). Cerebroside konnten nicht nachgewiesen werden.

Die erhaltenen Lipoidwerte werden verglichen mit denjenigen anderer Cholesterin enthaltenden Geschwülste und mit normaler Haut. In der xanthomatösen Geschwulst sind nicht nur Cholesterin, sondern auch die Phosphorlipoide, insbesondere das Lecithin, in höherer Konzentration erhalten als in normaler Haut.
Les Pinacols de la p.Méthylacétophénone et la Sulfone du 3,4‐di‐p. Tolylthiophène
Authors: Backer H. J. , Stevens W. , van der Bij J. R.
Published: September 2010

Ayant besoin du 2,3‐di‐p‐tolylbutadiène, les auteurs ont préparé d'après plusieurs procédés le pinacol de la p‐méthylacétophènone. L'addition d'un excès d'iodure de méthylmagnésium à la p‐tolile, a donné naissance à trois produits qui diffèrent par les propriétés cristallographiques et par le point de fusion.

Deux de ces produits (136‐137° et 134.5‐135°) sont des diols stéréoisomères qui, oxydés par le tétracétate plombique, présentent des constantes de vitesse tout‐à‐fait différentes. Le troisième produit, fondant à 93‐94°, se comporte pendant l'oxydation comme un mélange; c'est une combinaison moléculaire du diol 134.5–135° (1 mol.) et d'un cétol fusible à 80‐81° (2 mol.), qui s'est formé par addition d'une seule molécule du composé magnésien à la p‐tolile.

La déshydratation du pinacol 136‐137° conduit au 2,3‐di‐p‐tolylbutadiène qui, additionnè d'anhydride sulfureux, fournit la sulfone cyclique. La méme sulfone prend naissance par hydrogénation partielle de la sulfone incolore de 2,3‐di‐p‐tolylthiophène.
On the determination of the number of intermediate stages through which a chemical reaction passes
Authors: Kreulen D. J. W. , ter Horst D. Th. J.
Published: September 2010

In order to obtain an insight into the course of reactions it is important to know whether the final products are formed directly or by way of intermediate products. A method is developed in the following which makes it possible to obtain this information in the case of slow reactions.

From the relation existing between the concentration of the substance formed and the reaction time, it may be concluded whether the substance in question is formed directly or by one or more intermediate stages.

In the first part the general method is dealt with on a mathematical basis. The second part is devoted to several examples, whereby reactions are discussed not only in a one‐phase system (liquid) but also in a two‐phase system (solid‐gas and liquid‐gas).
The preparation of unsaturated hydrocarbons by the thermal decomposition of acetates : Second communication
Authors: van Pelt A. J. , Wibaut J. P.
Published: September 2010

The thermal decomposition of acetic acid esters is used as a method for the preparation of unsaturated hydrocarbons of different types. Auxiliary reactions, with the formation of isomers of the hydrocarbons, do not occur, so that this method is very suitable for the preparation of unsaturated hydrocarbons, in large as well as small quantities. The yields with respect to the acetate vary from 60 to 90 per cent.
The density and sorptive capacity of some samples of cotton, silk and wool
Authors: Heertjes P. M.
Published: September 2010

By means of the determination of the true densities in helium and the apparent densities in air, hydrogen, benzene and water of some samples of wool, the dyeing process of wool with acid and basic dyes and the felting process of wool are studied, and some conclusions with regard to these processes are drawn.

Moreover the sorptive capacities of wool for air and hydrogen are calculated, and the nature of these sorption phenomena is discussed.
The refractometric constants of 3, 3‐dimethylbutene‐1
Authors: Wibaut J. P. , Gitsels H. L. P.
Published: September 2010

Using a pure sample of 3.3‐dimethyl‐butene‐1, we have determined the refractive indices at different wave lengths and the specific gravity. From these data the refractometric constants of this hydrocarbon have been calculated. magnified image

has been examined by a number of investigators; the values given for specific gravity and refractive index differ, as shown by table I, in which we have collected the relevant literature data.
Die Quantitative Bestimmung des Mangans im Weidegras
Authors: de Wael J.
Published: September 2010

Bei der Bestimmung des Mangangehaltes von Weidegras gibt die Methode von Richards unzuverlässige Ergebnisse. Wir konnten zeigen, dass die nachfolgenden Fehlerquellen bestehen:

Das Abrauchen mit Schwefelsäure veranlasst zu niedrige Resultate.

Die Asche des Grases schliesst Mangan ein.

Es gelang uns die genannte Fehlerquellen zu beseitigen, nämlich durch Ersetzen der Schwefelsäure durch Phosphorsäure. Bei Anwendung dieser Säure werden viel höhere und besser reproduzierbare Werte für den Mangangehalt des Grases gefunden.
Über das Reine Silberbromidsol II
Authors: Basiński A.
Published: September 2010

Es werden elektrometrische Messungen an reinen negativen Silberbromidsolen beschrieben. Auf Grund von Titrationen mit Silbernitrat konnte der Ladungsnullpunkt des Silberbromids auf eine Bromionenaktivität von 2‐4 × 10−7 bestimmt werden, also ein wenig nach der Silberseite vom Aequivalenzpunkt verschoben. Durch Hinzufügen von K+, Ba++, La+++ und Th++++ Salze, sowie von einem Salz eines 4‐wertigen komplexen Kations wird die Bromionenaktivität im Sinne einer Entladung (Herabsetzung des ξ Potentials) geändert, wahrend die 6‐ und 9‐wertigen komplexen Kationen zu einer Umladung im Stande sind.

Bei der Messungen mit 6‐wertigem Hexolsalz hat sich herausgestellt, dass die Potentialdifferenz zwischen einer Ag‐AgBr‐Elektrode und einer Lösung von Hexolsalz stark durch Rühren beeinflusst wird. Es wurde der Einfluss von Ag+, Bi− und Hexosalzkonzentration auf diesen „Rühreffekt”︁ bestimmt.
Untersuchungen über Pyrrolderivate: 5. Mitteilung
Authors: Rinkes I. J.
Published: September 2010

Terentjew und Tschelinzew

A. P. Terentjew und W. W. Tschelinzew, 58, 69 (1925).

behaupten, dass bei Dijodierung des 2‐Acetylpyrrols 2‐Acetyl‐3.4‐dijodpyrrol entsteht, da diese Verbindung bei Oxydation mit Salpetersäure Dijodmaleinimid liefert. Es gelang mir zu zeigen, dass dieses Argument wertlos ist und dass nach der Theorie 2‐Acetyl‐4.5‐dijodpyrrol zu erwarten ist.

Weiter konnte ich zeigen, dass die durch Dibromierung des 2‐Pyrrol‐carbonsäure‐methylesters entstehende Verbindung die Bromatome wahrscheinlich an den Stellen 4 und 5 hat weil das Produkt nicht identisch war mit dem von mir bereiteten 3.4‐Dibrom‐2‐pyrrolcarbonsäure‐methylester.
Die Dampfspannung von Gesättigten NH4NO3‐Lösungen
Authors: Dingemans P.
Published: September 2010

Die Dampfspannung von gesättigten, wässrigen Lösungen von NH4NO3 wurde von 10° C an bis zum Schmelzpunkt des Salzes (169° C) gemessen. Es zeigte sich, dass die gefundene Kurve zwei Maxima besitzt, eine Tatsache, die bislang für gesättigte, wässrige Lösungen noch niemals gefunden worden ist.

Eine theoretische Betrachtung und eine Besprechung der Bedingungen für das Auftreten von 2 Maxima wird gegeben.
Solvent and dissociating power of chlorinated hydrocarbons: Part III. (Experiments)
Authors: van Braam Houckgeest J. P. W. A.
Published: September 2010

In order to estimate the value of the theory and the calculations carried out in Parts I

J. P. W. A. van Braam Houckgeest, Rec. trav. chim. 59, 560 (1940), 60, 65 (1941).

and II2 experiments on the conductivity of solutions of tetra‐alkylammonium halides in chlorinated hydrocarbons and their solubility in these solvents were performed. It appears that the calculations are only accurate enough to account for very marked differences. The solubilities and degrees of dissociation of one electrolyte in a series of solvents correspond better with the theory than the solubilities of a series of electrolytes in one solvent. This is probably because the solvatation energies can be calculated with a greater accuracy than the lattice energies.
The heat of mixing of some chloro‐alkanes with ethyl ether
Authors: Staverman A. J. , Lebbink F. J.
Published: September 2010

The cohesion forces of molecules with an asymmetric distribution of the electrical charge depends on this asymmetry; the dipole moment is not a suitable quantity for the description of cohesion forces, but some other quantity depending on the distance of the charges from the surface.

In order to obtain the values of this quantity for a number of molecules, many data on heat of evaporation and heat of mixing are necessary. Therefore we have measured the heat of mixing of chloroform, pentachloroethane and methyl chloroform with ethyl ether at infinite dilution, both of the ether and of the chloro‐alkane. The results confirm the above considerations.
Eine Einfache Methode zur Bestimmung der Diffusionskonstante von Metallen
Authors: van Liempt J. A. M.
Published: September 2010

Es wird eine einfache Methode zur Bestimmung der Diffusionskonstante von Metallen entwickelt, nach der ein dünner Draht (Band) des einen Metalls in eine Masse des zweiten unedleren Metalls metallkeramisch eingebettet und die Erhitzungsdauer und ‐temperatur festgestellt wird, nachdem die Diffusion so weit fortgeschritten ist, dass die Resistenzgrenze im ganzen Draht‐(Band) querschnitt gerade erreicht ist.
On the influence of solvent and temperature on the speed of oxidation of some organic substances by chromic acid. IV
Authors: Snethlage H. C. S.
Published: September 2010

The velocity of the reaction between adipic acid and chromic acid has been measured in mixtures of sulphuric acid and water containing from 50% to 95.9% sulph. ac. at temperatures between 313.1° and 353.1° K. The formula for a bimolecular reaction does not hold. Temperature coefficients were found to be practically independent of the degree of decomposition of the adipic acid for the first 20‐30% of the reaction in dilute sulph. ac., and to change slowly in 80% and 95.9% sulph. ac. They do not obey the formula of Arrhenius and their relation to the composition of the solvent is of the same nature as in the case of succinic acid.
De la Composition des Cristaux Mixtes D'Un Système Binaire
Authors: Korvezee Mlle A.‐E. , Scheffer M. F.‐E.‐C.
Published: September 2010

Nous avons calculé la composition moyenne d'un cristal mixte, qui se sépare par refroidissement d'une solution binaire, à condition que la diffusion dans la phase solide soit nulle. La courbe qui représente la composition moyenne des cristaux en fonction de la température du système se termine par une tangente horizontale ou verticale suivant la valeur limite dxs/dxL au point de solidification du deuxième constituant.

Les mêmes calculs s'appliquent aux solutions volatiles binaires qu'on distille sans rectification. La courbe calculée se rapporte alors à la composition du distillat.
The crystal structure of the ice‐like form of sulphur trioxide (γ‐modification)
Authors: Westrik R. , Mac Gillavry C. H.
Published: September 2010

The crystal structure of the γ‐modification of sulphur trioxide has been completely determined.

The cell is orthohombic, with cell constants a = 12.3 Å, b = 10.7 Å and c = 5.3 Å and contains 12 units of SO3; the X‐ray density is 2.29.

The structure is a molecule lattice built up of molecules S3O9; a [001] projection is seen in fig. 7, the atomic positions are given on p. 806, 807.

The molecule S3O9 contains a puckered (SO)3 ring (fig. 4b), in agreement with the latest results of Raman and infrared investigation.
On the influence of solvent and temperature on the speed of oxidation of some organic substances by chromic acid V.
Authors: Snethlage H. C. S.
Published: September 2010

The velocity of the reaction between formic acid and chromic acid has been measured in mixtures of sulphuric acid and water, containing from 0‐87% sulph. ac. at temperatures between 273° and 353° K.

This velocity is nearly proportional to the concentrations of the reactants

In very dilute sulph. ac. the acceleration caused by this substance is about proportional to its concentration, in more concentrated solutions it is greater. Between 60 and 87% there is an optimum.

Between 5 and 60% sulph. ac. the velocity constants at 293° increase to the 33000 fold, they can be calculated from Hammett and Deyrup's acidity function H0 (which is based on measurements with basic indicators at 298° K). At other temperatures the relation of Hammett and Deyrup fails to represent the experimental results. It is supposed that the relative acidity, at least in dilute sulph. ac, changes with the temperature. Between 13.5 and 40% sulph. ac. there exists a simple relation between the composition of the solvent and the velocity of the reaction at any temperature.

The temperature coefficients in most solvents used change very little with the temperature, in consequence the formula of Arrhenius does not hold.
Vapour pressure measurements of phosphorus tribromide
Authors: van Driel M. , Gerding H.
Published: September 2010

The vapour pressures of liquid phosphorus tribromide between 59.4° and 185.6° C are given. The temperature of the boiling point is 173.3° C. The heat of evaporation amounts to 9.5 kcal/mol.
Das Fette Oel der Samen von Onopordon Acanthium L.
Authors: Steger Alph. , van Loon J.
Published: September 2010

Das fette Öl der Samen von Onopordon acanthium L. ist dem Mohnöl u.d. in seinen Eigenschaften und in der Zusammensetzung sehr ähnlich.
Das Fette Oel der Samen von Hesperis Matronalis L.
Authors: Steger Alph. , van Loon J.
Published: September 2010

Das fette Oel der Samen von Hesperis matronalis L. gehört zu den trocknenden Oelen und besitzt eine leinölähnliche Zusammensetzung, sodass es als Leinölersatz Verwendung finden kann.
The colour of N,N′‐diethylindigo (on indigo VII)
Authors: van Alphen J.
Published: September 2010

In the solid state N,N′‐diethylindigo forms dark blue needles with a metallic lustre. Its solutions in different solvents are an intense malachite green in colour.

Depending on the method of crystallization N,N′‐dibenzylindigo forms dark green to nearly black needles. Its solutions however are the same colour as those of N,N′‐diethylindigo.
A quantitative colorimetric determination of small amounts of trigonelline
Authors: Roggen J. C.
Published: September 2010

When trigonelline is heated with alkali, methylamine is split off and the remaining dialdehyde, formed by ring opening, is conjugated to aniline in acid medium.

A yellow colour appears almost instantly, suitable for colorimetric determination.

No turbidities occur, the colour is sufficiently stable in full daylight and 10 γ per ml can be determined with an accuracy of about 5%.
On the influence of solvent and temperature on the speed of oxidation of some organic substances by chromic acid. VI
Authors: Snethlage H. C. S.
Published: September 2010

The velocity of the reaction between malonic acid and chromic acid has been measured in mixtures of sulphuric acid and water containing from 10 to 96.55% sulph. ac. at temperatures between 273.0° and 353.0° K. The formula for a bimolecular reaction does not hold, but the initial velocity is approximately proportional to the concentration of both reactants.

In this case also the initial velocity has an optimum between 70 and 96% sulph. ac. Proportionality between acidity (measured colorimetrically) and velocity does not exist, in contrast to the case of the oxidation of formic acid.

The temperature coefficients are largely dependent on the composition of the solvent. For most of the solvents used the formula of Arrhenius does not hold, in accordance with what was found for all substances investigated until now (exception in this case: 10 and 20% sulph. ac.).

The temperature cofficients and both the parameters of the equation of Arrhenius show a minimum at about 60% sulph. ac., corresponding to what was found with other substances. Between the parameters a close correlation exists.

It is supposed that the large changes in the temperature coefficient, which accompany relatively slight changes in the composition of the solvent, are to be ascribed to the presence of solution components whose concentration is dependent on the temperature and does not increase continuously with the increase of the sulph. ac. content of the solvent. These might be the hydrates SO35 aq. and SO33 aq. or an intermediate compound of CrO3, malonic acid and perhaps hydrates. This supposition could also explain the deviations from the equation of Arrhenius.
Produits de Réduction de L'Acide γ‐Anisoyl‐n‐Butyrique, de son Oxime et des Homologues Éthoxy
Authors: van der Zanden J. M.
Published: September 2010

Pour étudier les qualités physiologiques des produits en question, nous avons préparé les produits décrits ci‐après.

Ayant réduit l'acide γ‐anisoyl‐n.butyrique, CH3O. C6H4. CO(CH2)3. COOH, nous avons obtenu la lactone de l'acide δ‐p.méthoxyphényl‐δ‐hydroxy‐nvalérique, magnified image l'acide 5,6‐di‐p‐méthoxyphényl‐5,6‐dihydroxy‐sébacique, magnified image et l'acide δ‐p. méthoxyphényl‐n.valérique, CH3O. C6H4(CH2)4. COOH, décrit dans un mémoire précédent

J. M. van der Zanden, Rec. trav. chim. 60, 292 (1941).

).

La réduction de l'oxime nous a donné l'acide δ‐p.méthoxyphényl‐δ‐amino‐nvalérique, CH3O. C6H4. CH(NH2). (CH2)3. COOH. le lactame correspondant. magnified image puis la 2‐anisylpipéridine.

magnified image

Les homologues éthoxy ont donné les produits correspondants.
Pseudosymétrie Présentée par les Esters de L'acide Tétrathioorthosilicique
Authors: Klasens H. A. , Backer H. J.
Published: September 2010

En examinant la structure de cristaux à l'aide des rayons Röntgen, on trouve une équivalence complète entre les places qui ont la même chance d'être occupées par des atomes ou des groupes différents. Dans ce cas, on trouve pour la cellule du réseau cristallin des éléments de symétrie qui n'existent pas en réalité, de sorte qu'on attribue aux molécules une symétrie trop élevée. Dès lors, il peut arriver que la symétrie trouvée soit en contradiction avec la composition chimique.

Il n'est pas nécessaire ‐ et dans certains cas il est impossible ‐ d'attribuer de telles pseudo‐symétries à une rotation des molécules dans le réseau. Souvent cette pseudo‐symétrie est causée par une repartition statistique des groupes atomaires entre des positions différentes. C'est ce qui se passe dans le cas de quelques esters asymétriques de l'acide tétrathioorthosilique, esters qui sont isomorphes de l'ester tétratertiobutilique.
Determination of nicotinic acid in human blood (I)
Authors: Roggen J. C.
Published: September 2010

After improving the König BrCN‐reaction and applying it to human blood the following results were obtained. When haemolyzed blood is deproteinized by means of metaphosphoric acid, no cozymase is precipitated, but all of the pyridine compounds remain in the aqueous solution.

Probably nicotinamide is then present, but as the amount of nicotinic acid found after hydrolysis is much larger, there must be some other pyridine compound present in blood, which also yields nicotinic acid after hydrolysis.

There is strong evidence that the pyridine compound determined after hydrolysis is indeed nicotinic acid.

A routine method for the estimation of nicotinic acid in blood is described.
Nitration of the three isomeric N‐cyclohexyl‐N′‐toluyloxamides
Authors: de Vries K. A.
Published: September 2010

A description is given of the three isomeric N‐cyclohexyl‐N′‐toluyloxamides and their nitration in anhydrous nitric acid. Upon the nitration of N‐cyclohexyl‐N′‐(4 methylphenyl)‐oxamide the final product was N‐cyclohexylnitro‐N′‐(4‐methylphenyl)‐oxamide, upon the nitration of N‐cyclohexyl‐N′‐(3‐methylphenyl)‐oxamide it was N‐cyclohexyl‐N′‐(2,4,6‐trinitro‐3‐methylphenyl)‐oxamide and upon the nitration of N‐cyclohexyl‐N′‐(2‐methylphenyl)‐oxamide it was a mixture probably of N‐cyclohexylnitro‐N′‐(4,6‐dinitro‐2‐methylphenyl)‐oxamide and N‐cyclohexylnitro‐N′‐(4,6‐dinitro‐2‐methylphenylnitro)‐oxamide.
The determination of carotene in plant material and feces
Authors: van Eekelen M. , Engel Chr. , Bos A.
Published: September 2010

In order to find a quantitative method for determining the carotene content in plant material and feces (for use in physiological resorption experiments) we have worked over again and compared the methods known from various earlier publications. A secondary aim was to find a useful method which may be applied as routine analysis in other laboratories to obtain reproducible and comparable results. None of the known methods proved to be generally applicable, although for some materials they sufficed.

The following points were specially studied: 1. The determination of carotene concentration with the aid of the Zeiss Stufenphotometer. The extinction values published in earlier studies have been checked. 2. The separation of carotene from other pigments. This is only possible with adsorbents as aluminium oxide and calcium hydroxide. The losses which usually occur could be eliminated by a slight modification of the adsorption‐elution technique. 3. The extraction of the material. Simple continual extraction with ethyl alcohol in a Berntrop flask gives quantitative results. It is suitable for routine analysis. In the case of grass ensilated with acid, the extraction with alcoholic potassium hydroxide according to Guilbert is necessary. However this method gave no quantitative results with other materials. Results and description of the methods are given below.
Melanin and its precursors III. The influence of adrenochrome on the migration of bone marrow in vitro, compared with that of liver extract
Authors: Veer W. L. C. , Gaillard P. J.
Published: September 2010

Adrenochrome has a promoting effect on the migration of bone marrow in vitro, in experiments as described by Overbeek, Gaillard and de Jongh to test and standardize liver extract on its anti‐anaemic properties. This promoting effect, however, is atypical in comparision with that of liver extract. (The commercial preparation Pernaemon was used).
The dipole moments of cyclanes
Authors: van Arkel A. E. , Meerburg P. , v. d. Handel C. R.
Published: September 2010

The determination of the dipole moments of some cyclanes was carried out in the undiluted liquid.

For purposes of comparison and for the determination of the refraction some other hydrocarbons were also measured.
Synthèse de Quelques Butadiènes Substitués
Authors: Backer H. J. , Blaas Th. A. H.
Published: September 2010

Ce mémoire décrit les propriétés de la sulfone du 2‐chloro‐3‐méthylbutadiène (A) et les produits (B), qu'on obtient en remplaçant le chlore par des groupes SR. Par chauffage, ces produits perdent de l'anhydride sulfureux et engendrent des butadiènes nouveaux:

CH2:C(CH3).C(SR):CH2

La sulfone du chloroprène a également un atome de chlore actif, et ses dérivés se prêtent de même à la préparation de butadiènes substitués: CH2:CH. CX:CH2.

Les butadiènes sont peu stables. Si l'on veut les utiliser pour une “condensation diénique”, on pourrait les préparer sur le champ. Mais il est plus pratique de combiner la formation et la condensation, et de chauffer directement la sulfone avec le composé non‐saturé.
Dilatometric investigation of the phase transition in 1,2‐dibromoethane
Authors: Meerman P. G.
Published: September 2010

The phase transition in 1,2‐dibromoethane was studied dilatometrically. The transition was not accompanied by thermal hysteresis, but there were comparatively large superheating and supercooling effects. The transition temperature was found to be in excellent agreement with Pitzer's determination from heat content values.
The physical properties of glass II: The density of silicate glasses
Authors: Stevels J. M.
Published: September 2010

A new formula is given according to which it is possible to calculate the volume V of a block of a glass containing one gram atom of O=ions. Over a very wide range V is independent of the number and the nature of the metallic ions present. The two constants occurring in the formula have a well defined physical meaning, which can be understood satisfactorily on the basis of the well‐known theory of the structure of glass by Zachariasen and Warren c.s. and its extensions by Dietzel. The limits of the validity of the formula are also discussed on the basis of Zachariasen's theory.

Beside giving much new information concerning the structure of glasses in general, the formula can be transformed very easily into a simple density formula for glasses. This formula has been tested for 44 arbitrarily chosen glasses and it is found that the accuracy of the formula is the same as of the earlier purely empirical formulae of Winkelmann and Schott, English and Turner etc.
Quelques acides α‐sulfocarboxyliques non saturés simples
Authors: Backer H. J. , Mulder R. D.
Published: September 2010

Le mémoire décrit les acides α‐sulfoacrylique, α‐sulfocrotonique, α‐sulfovinylacétique et α‐sulfo‐β,β‐diméthylacrylique.
Préparation D'Acides α,β‐Disulfocarboxyliques Simples
Authors: Backer H. J. , Mulder R. D.
Published: September 2010

On obtient les acides α,β‐disulfocarboxyliques en chauffant les sels des acides α‐sulfocarboxyliques non saturés (αβ) avec du sulfite acide. Leur structure est établie par le fait qu'on peut en isoler les composants optiquement actifs.
The raman spectrum of sulphur in the liquid viscous state
Authors: Gerding H. , Westrik R.
Published: September 2010

The Raman spectra of solutions of sulphur in carbon disulphide at 18°, of sulphur in molten naphthalene at 110°, of liquid sulphur at 120° and of viscous liquid sulphur at 190° have been determined. In both solutions and in the liquid at 120° sulphur is mainly present as S8. New frequency shifts are found for the liquid at 190°, proving that transformations in the liquid have taken place. It is not possible however to draw a definite conclusion about the molecular structure of Sμ Probably it consists of open chains of sulphur atoms as K. H. Meyer assumes, coupled with each other to a certain extent, so that a quasi‐crystalline structure of high viscosity occurs. The presence of a low vibrational frequency in the Raman spectrum of the liquid at 190° may be explained in this way.
Über die Anomale Rotationsdispersion der l‐Pyrrolidon‐5‐Carbonsäure‐2 und ihres Äthylesters
Authors: Froentjes W.
Published: September 2010

Die Rotationsdispersionskurven der Pyrrolidoncarbonsäure (im folgenden mit Prolon bezeichnet) und ihres äthylesters wurden in Abhängigkeit von Lösungsmittel, Konzentration und Temperatur gemessen. Nimmt man als Kriterium für den Verlauf der Dispersion die graphische Analyse nach Biot‐Lowry, so zeigt sich, dass hier Anomalien auftreten.

Die für eine Erklärung dieses Verhaltens in Betracht kommenden Hypothesen werden diskutiert. Es stellt sich dabei heraus, dass durch die Annahme eines Gleichgewichtes zwischen Molekülen mit innermolekularer Wasserstoffbrücke (zwischen dem N‐Atom und einem O‐Atom der Carboxylgruppe) und Molekülen ohne diese Wasserstoffbrücke, die Anomalie in der Rotationsdispersion und das Verhalten gegen Verdünnung und Lösungsmittel erklärt werden können. Daneben muss in einigen Fällen noch eine Assoziation berücksichtigt werden. Aus einem Vergleich der Elektronenstrukturformeln und möglichen Resonanzen in den Molekülen des Prolons, Prolins und 4‐Hydroxyprolins können die charakteristischen Unterschiede in Rotation, Komplexbildung und Acidität zwischen diesen Säuren erklärt werden.
“Associated” mixtures I
Authors: van Santen J. H.
Published: September 2010

The dielectric constants of mixtures of chloroform and some related compounds with ether were measured. The results are discussed with the aid of the theory of Onsager and Böttcher.
Eine Methode zur Berechnung der Polarisierbarkeit und des Radius von Molekülen und Ionen
Authors: Böttcher C. J. F.
Published: September 2010

With the aid of a new formula for the internal field a method is developed for computing the mean polarisability and the mean radius of molecules and ions from measurements of the density and the dielectric constant (or, alternatively, the index of refraction) of liquids.

As examples, the radii and the polarisabilities of the CCl4‐molecule and of the I‐, CL−, Cs+ and Rb+ ions are calculated. The values obtained for the radii of the ions are in good agreement with those of Pauling and Goldschmidt.
Pyrazolenines and their rearrangement to form pyrazoles, I* ): (Pyrazole and pyrazoline derivatives, III)
Authors: van Alphen J.
Published: September 2010

By the addition of diphenyldiazomethane to the methyl esters of acetylene dicarbonic acid, of phenyl propiolic acid and of propiolic acid, pyrazolenines are formed, which, under different circumstances and with a migration of several groups, undergo a rearrangement into pyrazoles.
Pyrazolines and their rearrangement to form pyrazoles. II. (Pyrazole and pyrazoline derivatives, IV)
Authors: van Alphen J.
Published: September 2010

Upon the addition of diphenylenediazomethane to the methyl esters of acetylene dicarbonic acid, of phenylpropiolic acid and of propiolic acid, pyrazolenines are formed which, under different circumstances and with the migration of several groups, undergo rearrangement to give pyrazoles.
Sur la Structure de la Pelletiérine
Authors: Beets M. G. J.
Published: September 2010

Le mémoire discute les possibilités de mésomérie et de tautomérie de la structure attribuée par H e s s à la pelletiérine.

On a obtenu une première indication pour le fait que dans la pelletiérine une structure bicyclique peut jouer un rǒle.
Untersuchungen über Pflanzliche Wuchsstoffe. VII. Über Struktur und Wirkungsmechanismus der Pflanzlichen Wuchs‐ und Hemmstoffe
Authors: Veldstra H. , Havinga E.
Published: September 2010

The view of the mechanism of the action of plant growth substances developed elsewhere has led to the assumption that growth substances and inhibitors in plants may be closely related1). The results of some recent investigations10) 11), which in our opinion support this view, are discussed, and in the case of cis‐cinnamic acid coumarin (lactone of o‐oxy(cis)cinnamic acid) such a structurally related pair of growth substance and inhibitor is indicated.

In the pea test, inhibitor (coumarin) and growth substance (naphthalene acetic acid) prove to be antagonists, while such an influence cannot be established in the blastokolin test. A number of compounds with the structure of inhibitors (unsaturated lactones) are examined in the blastokolin test. Furthermore the importance of these investigations for the natural auxins is outlined. The formation of unsaturated δ‐lactones, being possible in that case, does really occur in the photo‐inactivation of auxin‐a‐lactone (conversion into lumi‐auxone). On account of this the hypothesis is developed that lumi‐auxone (or a closely related compound) may perform the function of an inhibitor.

Finally a number of facts from botanical investigations are summarized, which point to the close relationship between growth substance and inhibitor and which, moreover, support the view of the function of lumi‐auxone (or related compound)