bluuebunny/crossref_metadata_2025_split huggingface dataset:
Derivatives of 1: 3‐bis‐Phenylamino‐Propane
Authors: Veer W. L. C. 
Published: September 2010

Abstract1: 3‐Bis‐phenylamino‐propane, an aromatic di‐secondary diamine derived from 1: 3‐diaminopropane, has been investigated, especially as regards its reactivity towards acids and their derivatives, isocyanates, mustard oils, ketenes, chloronitrobenzenes and aldehydes. The amine, which has so far been described in the literature as a liquid, was prepared in a pure state and obtained in the solid condition. It has antioxidant properties for rubber. The nitration of various nitro‐, methyl‐, halogeno‐ and halogenonitroderivatives of 1: 3‐bis‐phenylamino‐propane is also described in this paper.
Second pressure limits in gaseous explosion regions. I. Experimental data on H2O2 and H2air explosions
Authors: Dijksman A. J. 
Published: September 2010

AbstractThe author investigates the explosion limit as a function of the pressure (below about 100 cm Hg). In the system H2‐O2 there are between 8.4 and 9.8% hydrogen always two pressures, between which the mixtures are explosive. This is very much reminiscent of the inflammability regions at higher temperatures. The influence of spark strength, position of the electrodes, etc. on this so‐called “second limit” is described together with the procedure employed.Hydrogen‐air mixtures also give these phenomena.Similar peculiarities were found with carbon monoxide‐air, which will shortly be published.
Sur la Condensation des Aryl‐Halogéno‐meacute;thanes
Authors: Olivier S. C. J. , Wit J. 
Published: September 2010

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

Abstract
In this paper it is demonstrated that the rare‐earth metals: cerium, lanthanum, neodymium and didymium all show a series of at least four reversible allotropic changes; the different phases are discerned as α‐, β‐, γ‐and δ‐states of these metals.
From the study of the specific heat, the thermal expansion, the electrical resistance and the thermoelectrical behaviour in their dependence on the temperature, it becomes obvious that the inner state of all these metals is at each temperature a highly complicated one, it being characterized by the simultaneous co‐existence of several of these modifications. As the transformations between these modifications occur very slowly, in general the instantaneous inner state of these metals is not one of perfect equilibrium and, therefore, depends at each temperature to a high degree on the mode and duration of their preliminary thermal treatment, as well as on the time during which the samples, after treatment, are preserved and again examined.
The transition‐temperatures are, in all cases, situated between −170° and about 720° C; the special character of the accompanying retardation‐phenomena is different in each case. More particularly, neodymium manifests most remarkable cyclic effects, a peculiar internal thermo‐electrical force and an abnormal thermal expansion within the limits of a transition‐interval, — all indicating the physical inhomogenity of the metal investigated.
Quelques 1,3‐Dimercaptans et Leurs Thioacétals Cycliques
Authors: Backer H. J. , Tamsma A. F. 
Published: September 2010

AbstractLe mémoire décrit trois 1,3‐dimercaptans doublement substitués en position 2, le 2,2‐pentaméthylénepropane‐l,3‐dithiol, le 2,2‐diméthylpropane‐1.3‐dithiol et le bis‐hydroxyméthyl‐bis‐mercaptométhyl‐méthane (dithiopentaérythritol).On les obtient en réduisant les disulfures (ou trisulfures) cycliques qui se forment par la réaction entre les 1.3‐dibromures et les polysulfures alcalins. La structure de ces disulfures est, d'autre part, mise en évidence par l'oxydation, qui donne naissance à des acides disulfoniques.Les dimercaptans, chauffés avec les aldéhydes et cétones en présence d'acide chlorhydrique, donnent aisément des thioacétals cycliques.Le dithiopentaérythritol peut réagir avec deux molécules d'aldéhydes ou de cétones en engendrant des acétals‐thioacétals. Si les deux molécules diffèrent, on obtient deux isomères.En condensant le dithiopentaérythritol, d'abord avec la 4‐méthylcyclo‐hexanone et puis avec l'aldéhyde benzoïque, les auteurs ont obtenu deux isomères, qui, par suite de la présence d'un nombre impair de cycles dans le trispirane, peuvent être considérés comme des isomères cis trans.
Die Krystallstruktur des Kaliumfluorochromats
Authors: Ketelaar J. A. A. , Wegerif E. 
Published: September 2010

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

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

AbstractNous avons mesuré la conductibilité électrique de la saligénine et de la 4‐méthylsaligénine dans une solution 0.5 molaire d'acide borique. Il s'est révélé que, à la concentration 0.25 mol., la saligénine provoque une augmentation de la conductibilité de l'acide borique comparable à celle que produit un ortho‐diphénol.Le calcul de la distance qui sépare les atomes d'oxygène dans la position la plus rapprochée des groupes hydroxyle montre que cette position est tres favorable à la formation d'un complexe avec du bore coordinativement tétravalent; il est donc très probable que dans un nombre considérable de molécules de saligénine, les groupes hydroxyle se trouvent dans cette position. La 4‐méthylsaligénine ne produit qu'une augmentation très minime de la conductibilité de l'acide borique, ce qui indique que le groupe méthyle exerce une influence défavorable sur la position des groupes hydroxyle.
The diffusion potentials in electrolytic mixtures: I. The formula of Henderson
Authors: Hermans J. J. 
Published: September 2010

AbstractIn § 1 a short review of experiments is given. In § 2 the differential equations of electrolytic diffusion and their solution by Planck and by Henderson are discussed, and attention is drawn to the fact that a series of solutions is principally different from a diffusion layer of similar structure. In § 3 an expansion in powers of y = x/2 √t leads to the conclusion that no foundation exists for the formula of Henderson which is so commonly used in practice
Iodometric determination of small quantities of glucose
Authors: Noyons E. C. 
Published: September 2010

AbstractIn the following paper an account is given of an exact hypoiometric method for the determination of small quantities of glucose.The accuracy of the method was greatly increased by using buffered solutions in the oxidation.Probably, it is also possible to determine glucose in blood by this method.The results of a research now being carried out, may show what substances have a disturbing influence on the estimation of bloodsugar by this method.
Les Éthers de L'acide Méthanetétracarboxylique
Authors: Backer H. J. , Lolkema J. 
Published: September 2010

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

AbstractThe hydrogenation of pure anthracene was studied quantitatively using nickel‐on‐kieselguhr as a catalyst and hydrogen at high pressure.On hydrogenating anthracene the main part of the latter product is converted first into octahydroanthracene. This compound could be isolated in high yields from the reaction product from the first stage of the hydrogenation.On hydrogenating the octahydroanthracene under similar conditions using a fresh portion of catalyst, a mixture of saturated products was obtained, partly solid, partly liquid at room temperature. Since it could be proved that no destruction occurred during the hydrogenation, and the hydrogen consumption amounted to 14 hydrogen atoms per molecule of anthracene, the products must have the ultimate composition C14H24.Most probably a mixture of perhydroanthracenes was formed. From this mixture a solid isomer could be isolated in a purer state.On prolonged heating of the saturated reaction mixture from the second hydrogenation and of the liquid part of this reaction product, isomerisation occurred in which (a) solid isomer(s) was (were) formed from the liquid products. In these isomerisations the refractivity and density of the products changed noticeably, but the specific refraction did not change much, and pointed in all cases to 2.9 rings per molecule in the products. In one case also the specific parachor was determined. The number of rings deduced from this constant was 2.8.
Sur L'oxydation du Dihydroxy‐1.8‐Naphtalène et de Son Éther Monométhylique par L'acide Peracétique
Authors: Böeseken J. , Smitt L. G. 
Published: September 2010

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

AbstractThe rate of coagulation was determined by means of the Tyndall effect, measured by a photocell which was connected with a galvanometre. Plotting the deflection of the galvanometre against the time t, a curve was obtained the slope of which at t = 0 was called rate of coagulation.§ 1. The general features of the method are discussed. The particle radius is computed from the scattering power. This particle radius (0.8. 10−5 cm) represents the upper limit rather than the mean value.§ 2 and 3. The apparatus and the general course of the experiments are described.§ 4. The rate of coagulation in the absence of a sonic field conforms to Paine's equation. The coagulation is always accelerated by the sonic waves; this influence is negligible with high electrolytic concentration and becomes more pronounced with low electrolytic concentration.§ 5. The rate of the so‐called slow coagulation is almost linear in the concentration of the sol, but tends to increase more rapidly with this concentration if a sonic field is applied.§ 6. Experiments on the influence of the field strength.§ 7. It is shown that neither the cavitation nor the temperature rise are reponsible for the experimental results. Further, the kinetic energy of oscillation, the orthokinetic coagulation, the accumulation of the particles and the hydrodynamic interaction all are insufficiently effective to account for the influence of the sonic field. The most promising explanation of this influence at present seems to be the dipolar interaction of the particles (“migration dipoles”), which results from the distortion of the double layer.
New constituents of derris root I
Authors: Meyer Th. M. , Koolhaas D. R. 
Published: September 2010

AbstractA survey of the substances isolated from Derris root is given.The isolation and the properties of a substance, first discovered by Buckley, are described.A new optically active substance, termed derride, isomeric with Buckley's compound is recorded. Its formula is given and a few of its properties are described. Some derivatives of this substance have been prepared.A tabular comparison of Buckley's compound and derride is given.A new, optically active substance has been isolated from a sample of derris root of the Sumatra type. Its formula is suggested and a few of its properties are given.Sumatrol and l‐toxicarol have been isolated.
New aspects on the cohesion of simple compounds. II
Authors: Stevels J. M. 
Published: September 2010

AbstractIn the preceding paper it is shown theoretically, that the sum of the contributions of the Debye and Keesom energy to the boiling point of halogenated methane, ethane and ethene derivatives should be about a constant. In this paper it is shown, how far this holds experimentally.An up to date complete list of the boiling points of the ethane and ethene derivatives is given. For the methane derivatives only those are given which have not been published before by van Arkel and coworkers.The boiling points of all these compounds are split up into several parts, according to the different kinds of cohesion effects. Special methods are developed for the 1.1‐ and cis‐ and trans‐1.2‐isomers C2H2X2. The “anomalies” of the boiling points of the C2H2I2 and C2H2ClI can easily be understood on the basis of the new theory.
A quantum mechanical discussion of the dipole moments of monochlorobenzene and of vinylchloride
Authors: Ketelaar J. A. A. 
Published: September 2010

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

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

AbstractOur research on the occurrence of free radicals with only two unconnected aromatic groups on the central atom, has now been extended to reactions of molecular silver with:
bis‐phenyl‐chloromethane;
bis‐(4‐methoxyphenyl)‐chloromethane;
bis‐(2:4:6‐triethylphenyl)‐chloromethane.
We always found indications of the occurrence of free radicals.We shall report on these reactions in detail in a subsequent communication. Of the substances required for this investigation, only bis‐(2:4:6‐triethylphenyl)‐chloromethane has not been described in the literature.Therefore in this communication we describe the preparation of this compound.
Die Quantitative Bestimmung von Wasserstoffsuperoxyd und Persulfat in derselben Lösung
Authors: van der Meulen J. H. 
Published: September 2010

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

katalytisch beschleunigen. Ein vorheriger Zusatz von Mangansalzen ist durchaus unzulässig und begünstigt diese Zersetzung noch bedeutend.Nicht nur die H2O2‐, sondern auch die K2S2O8‐Werte zeigen denselben Mindergehalt. Die Methode von Mudlagiry Nayak gestattet genauere Zahlen zu erhalten, während auch die von Skrabel und Vaček richtige Werte gibt.Weiter wird eine Methode beschrieben, nach der das Wasserstoffsuperoxyd mit Osmiumsäure restlos, ohne Zerstörung des Persulfats, aus der Lösung entfernt wird. Das Persulfat wird darauf nach der Ferro‐Permanganat‐Methode oder acidimetrisch bestimmt, während der totale Oxydationswert (H2O2 + K2S2O8) ebenfalls nach der Ferro‐Permanganat‐Methode festgestellt wird.
Investigation of the volatile constituents of strawberry juice (Fragaria eliator Ehrh.)
Authors: Coppens A. , Hoejenbos L. 
Published: September 2010

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

AbstractIf HCl is added to Na2WO4, and the turbidity of the mixture plotted against the time, S‐shaped curves are obtained. It is shown in § 1 that the maximum slope sm of these curves conforms to laws similar to those which apply to the initial slope si of the preceding paper.In § 2 the coagulating action of BaCl2 on sols of tungstic acid is studied. The influence of an electric field on this coagulation is described in § 3. The coagulation is always slowed down. If the external field is switched on after the coagulation has been allowed to proceed for some time, the turbidity falls abruptly.Some aspects of the problem are discussed in § 4. An explanation is not put forward since it would necessarily be of a highly speculative character.
Anthraquinones Complètement Substituées et Anthracènes Correspondants: I. Composés Substitués Symétriquement
Authors: Backer H. J. , Strating J. , Huisman L. H. H. 
Published: September 2010

Le mémoire décrit les produits symétriques qu'on obtient en faisant réagir la benzoquinone sur le 1,2,3.4‐tétraméthylbutadiène, sur le 1,′‐dicyclopentényle et sur le 1,′‐dicyclohexényle. Ces produits se composent de plusieurs octahydroanthraquinones stéréoisomères et donnent, par oxydation, des anthraquinones complètement substituées.La réduction des anthraquinones par le procédé Clemmensen légèrement modifié fournit les dihydroanthracènes, dont la déshydrogénation au moyen de sélénium conduit aux anthracènes substitués symétriquement
Investigations on pyridine and quinoline derivatives: (42nd. Communication) The formation of (4‐pyridyl)‐pyridinium compounds from 4‐chloropyridine and 4‐bromopyridine
Authors: Wibaut J. P. , Broekman F. W. 
Published: September 2010

Abstract4‐Chloropyridine undergoes slow conversion into N‐(4‐pyridyl)‐4′‐chloropyridinium chloride from which the already known N‐(4‐pyridyl)‐4′‐pyridone is obtained on hydrolysis. 4‐Bromopyridine changes rapidly into N‐(4‐pyridyl)‐4′‐bromopyridinium bromide, which also affords N‐(4‐pyridyl)‐4′‐pyridone on hydrolysisImproved recipes are given for the preparation of 4‐chloro‐ and 4‐bromopyridines in yields of 75% and 45%, respectively
Adsorption of iodine vapour by powders
Authors: Hamaker H. C. 
Published: September 2010

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

AbstractIt is shown that the boiling points of all halogenated methane derivatives can be calculated as the sum of the contributions of three effects (London‐, Keesom‐ and Debije effect), even in the cases of the rather large deviations reported previously.The three effects are studied here to a higher approximation than was done formerly. It turns out that in a few cases the values calculated with the old formula for the London effect need a slight correction (refraction effect), but generally the formula holds without that.The formula for the Keesom effect seems to be correct in all cases.It can be understood that the formula for the Debije contribution to the boiling point according to van Arkel and Snoek does not hold so well. As a consequence of this fact we can easily understand the rather high TD + TK′ values for the fluorinated ethane and ethene derivatives previously reported (fluorine effect).Applying the combination of the refraction effect and the fluorine effect it is possible to predict the trends of the boiling points of isomers of the same type. All cases known in the literature are checked and no deviations are found.
Symétrie Moléculaire du Tétrathioorthosilicate Monoisopropylique Tritertiobutylique
Authors: Klasens H. A. , Backer H. J. 
Published: September 2010

AbstractLes cristaux du tétrathioorthosilicate monoisopropylique tritertiobutylique sont tétragonaux et isomorphes avec ceux des tétramercaptides tertiobutyliques de silicium, de germanium et d'étain.La maille unité est la même pour ces quatre composés (a = 11.2, c = 9.3 Å); elle correspond à deux molécules. Le groupe de recouvrement est D2d (P421c). On trouve done au moins la symétrie S4 pour l'atome central, autour duquel quatre groupes se rangent de façon tétraédrique.Le fait que, pour le premier composé, la présence d'un groupe isopropylique ne change pas la structure tétragonale peut être attribué à une „symétrie statistique”︁.
Die Krystallstruktur des Cäsiumfluorochromats
Authors: Ketelaar J. A. A. , Wegerif Frl. E. 
Published: September 2010

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