bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simple instructions for crystal measurement with a new model of the two circle goniometer, especially adapted to the use in chemical laboratories
Authors: Terpstra P. 
Published: September 2010

AbstractThe usual extensive descritions of methods of preparation and purification often do not allow of an adequate definition of new compounds. In addition some physical constants should be mentioned, such as the melting point, the density, the refractive indices and especially the crystal form. The latter may be determined in a simple way with the aid of the goniometer of which the description follows. This goniometer has been specially constructed for the measurement of small crystals. The method of measurement is explained by a series of examlpes.
The freezing point diagram of the system N.hexadecane‐N.hexadecene‐1 (cetene)
Authors: Langedijk S. L. , Smithuysen W. C. Brezesinska 
Published: September 2010

AbstractA. From the determination of the freezing points of n. hexadecane, n ‐hexadecene‐l (cetene and 8 mixtures of these substance it appared that the freezing point curve in this system can be represented by a very weakly curved line, so that this condensed system consists of an uninterrupted series of mixed crystals. The crystals that are in equilibrium with the mother liquor are somewhat richer in hexadecane than the liquid phase.The addition of hexadecane to cetene raises the freezing point of the latter.
The preparation of thioureas and thiuram‐disulphides
Authors: Fry H. Shipley , Farquhar Bruce S. 
Published: September 2010

AbstractA standardized method, markedly efficient, for the preparation of symmetrically substituted thioureas and thiuram disulphides from primary and secondary amines has been developed in conformity with the following equations:magnified imageIts uniformity of application to seven primary amines and to seven secondary amines has made possible a comparative study of the times required, the extent of completion of the reactions, and the effect of various substituents, in the preparation of the corresponding thioureas and thiuram‐disulphides.The preparation and identification by quantitative analysis of five thioureas and five thiuram disulphides, not previously recorded in the literature, has been effected.Three new unsymmetrical tri‐substituted thioureas have been prepared in conformity with the general equation, RNCS+R′R″NH → RNH. CS. NR′R″. Their identity has been established by quantitative analyses.
Colorimetric determination of α‐tocopherol (vitamin E)
Authors: Emmerie A. , Engel Chr. 
Published: September 2010

AbstractA colorimetric method of determination of tocopherol based on the reducing properties of tocopherol towards ferric chloride is described. The ferrous salt which is formed in the reduction is determined colorimetrically with α: α'‐dipyridyl (similar coloured complex salts are formed with α:α' dipiperidyl and by o‐phenanthroline). Not only is this method much more rapid and simple than the Potentiometric titration with gold chloride, but it also allows of the determination of much smaller quantities of tocopherol. Although o‐phenanthroline gives a somewhat deeper colour than dipyridyl with ferrous ions, we have found dipyridyl preferable because the depth of colour produced with o‐phenanthroline is not directly proportional to the concentration of ferrous ions and tocopherol.
Ueber die Einwirkung von Salpeter‐Schwefelsäure Auf 3,6‐Dinitro‐5‐Brompseudocumen
Authors: Rinkes I. J. 
Published: September 2010

AbstractHuender1) hatte gefunden, dass durch Einwirkung von Salpeter‐Schwefelsäure auf 3,6‐Dinitro‐5‐brompseudocumen eine Verbindung vom Schmelzpunkte 150° entsteht, von ihm “Nitrat” genannt, für dessen Struktur er drei Möglichkeiten in Erwägung zieht. Es ergab sich, dass seine dritte Annahme die richtige war, dass nämlich in einer der Methylgruppen ein Wasserstoffatom durch die Gruppe ONO2 ersetzt wurde
m‐bromobenzazide as a reagent for the identification of amines
Authors: Sah Peter P. T. , Chang Lung—Hsiang 
Published: September 2010

Abstractm‐Bromobenzazide was prepared in good yield by the treatment of m‐bromobenzhydrazide with nitrous acid in glacial acetic acid solution. The azide, reacted with amines, amides aminophenols, and aminoacids in boiling toluene solution, to give, well defined crystalline m‐bromophenylureas with sharp melting points. These derivatives are suitable for the purpose of identification.
Contributions to the knowledge of the mechanism of deformation of cellulose hydrate. VI: On the tensile strength of cellulose fibres and the energy involved in the process of rupture
Authors: Hermans P. H. 
Published: September 2010

AbstractA discussion of the properties of an “ideal” cellulose fibre consisting of a cellulose single crystal reveals, that there is not only a large discrepancy between the theoretical tensile strength of such a fibre and the highest experimentally observed strength of actual fibres, (as already pointed out by Meyer, Mark and de Boer) but that also the ideal fibre would have an extensibility of more than 40 %, whereas the actual elongation at rupture of well oriented cellulose fibres is very much lower. From a calculation of the amount of energy necessary to bring about the rupture of the ideal fibre, it follows, that this fibre would explode after rupture.It appears therefore, that the ideal fibre as hitherto postulated, is to be regarded as a mere theoretical abstraction, which has little if any bearing on the problem of the actual mechanism of rupture.There is no certain evidence for the assumption made by previous authors, that in the actual process of rupture only cohesional attractions between primary valence chains are overcome and that there would be no rupture of the chains themselves.Irrespective as to whether in the real process of rupture primary valencies are actually broken or not, it can be shown, that the energy involved in this process, ranging between 2.108 and 6.108 erg/cm3, would be sufficient to bring about a considerable drop in the average chain length of the molecules in the fibre. If the energy of rupture is to any appreciable percentage connected with the rupture of molecular chains, the effect should be easily detectable by viscosity determinations. Experiments with the purpose to investigate if this effect actually exists will be undertaken.New experimental data on the energy at rupture of artificial cellulose fibres of different degrees of orientation (ranging from isotropic to extremely well oriented ones) and of commercial viscose rayon filaments, are given.
New aspects on the cohesion of simple compounds. I
Authors: Stevels J. M. 
Published: September 2010

AbstractIt is shown again that it is better to describe the contribution of the partial dipole moments to the cohesion as a Keesom effect in an extended sense, as was introduced recently by Staverman. The Debije effect can be described as mainly due to the total dipole moment of the molecules. These conceptions solve several problems, which existed hitherto in the theory of the boiling points. They show why we can expect constant “TD values” for each “type” of methane derivatives i.e. constant differences between the boiling point and the London contribution to the boiling point, and they similarly predict constant “TD values” for the halogenated ethane and ethene derivatives.We can further understand, why the completely halogenated ethane and ethene derivatives do not show “TD values”, although they possess at least two partial dipole moments.A complete survey is given of all the effects, which give rise to contributions to the boiling points.
The complex compounds P(OH)4. ClO4 and Se(OH)3. ClO4
Authors: Arlman E. J. 
Published: September 2010

AbstractAs is the case with H3PO4 and HClO4, H2SeO3 and HClO4 react with each other to form a compound of the composition H2SeO3. HClO4. Its behaviour on electrolysis of its solution in CH3NO2 leads to the formulation [Se(OH)3]+.ClO4−.The crystal system of both the compounds mentioned was determined. We could not elucidate their crystal structure and no substances isomorphous with them were found. Their heat of solution in water was determined and the conductivity of their solutions in CH3NO2 was compared with that of some other perchlorates.
On the reactivity of the bromine atoms in brominated pyridines. the formation of 2,6‐diamino‐4‐bromopyridine by the action of ammonia on 2,4,6‐tribromopyridine
Authors: Wibaut J. P. , Bickel A. F. , Brandon L. 
Published: September 2010

AbstractWhen 2,4,6‐tribromopyridine was heated with an excess of ammonia, a diaminobromopyridine of melting point 126° was obtained. This compound was submitted to catalytic reduction, when 2,6‐diaminopyridine was formed; therefore the diaminobromopyridine of m.p. 126° must be 2,6‐diamino‐4‐bromopyridine.
Das Fette Oel der Samen von Canarium Commune L
Authors: Steger Alph. , van Loon J. 
Published: September 2010

AbstractVerschiedene Forscher berichten über die Eigenschaften und die Zusammensetzung des “Canari‐Öls”. Ihre Angaben stimmen aber nicht überein. Hier wird gezeigt, dass das Öl nur aus Glyceriden der Palmitin‐, der Stearin‐, der Öl‐, der Linol‐ und der Linolensäure zusammengesetzt ist.
The effect of cyclisation on the electric moment of organic molecules
Authors: de Vries Robles H. 
Published: September 2010

AbstractI. In a previous publicationThis journal 58, 111 (1939).
the dipole moments of a number of heterocyclic parent nuclei were measured.II. The most probable structure of these molecules is calculated according to a simple principle of minimum energy described in this publication.III. The object of this publication is to investigate in how far dipole moments of heterocyclic molecules agree to those of the corresponding open‐chain molecules. It was found that the bond moments calculated from cyclic molecules are always greater than those which can be calculated for the corresponding open‐chain molecules. The bond moments calculated from open‐chains molecules are therefore inapplicable for the calculation of the valency angles in heterocyclic molecules from their dipole moments.IV. Description of the results.
The essential oil of Massoi bark
Authors: Meijer Th. M. 
Published: September 2010

AbstractIt is shown that in various cases where oil of Massoi bark has been described in the literature, the description really refers to the oil of Lawang bark.Oil of Massoi bark does not contain eugenol, whereas oil of Lawang bark contains a considerable amount of eugenol.The oil of Massoi bark contains a lactone which has been investigated. On hydrogenation it takes up one molecule of hydrogen.Oxidation of the dihydrolactone with potassium bichromate and sulphuric acid leads to the formation of valeric, caproic, succinic and glutaric acids and a keto‐acid, δ‐keto‐caprinic acid.Oxidation of the dihydrolactone with potassium permanganate also gives rise to the formation of caproic acid and succinic acid.Caproic acid is also obtained by oxidising massoilactone with permanganate and by oxidising it with bichromate and sulphuric acid. In the latter case fumaric acid is also formed.From these degradation products massoilactone is regarded as 1‐pentylpentene‐oil‐3‐olide (1,5).
Über die Beschleunigung der Korrosionsgeschwindigkeit des Eisens durch hochfrequente Wechselströme
Authors: Beck W. 
Published: September 2010

AbstractEs werden mit Hilfe einer manometrischen Methode kontinuierliche Messungen der Rostgeschwindigkeit von Eisenelektroden in verdünnter Kaliumchloridlösung angestellt. Die Prüfkörper befanden sich in einem Hochfrequenzfeld, das mit Hilfe eines Schwingungskreises erzeugt wurde.Verschiedene auf diese Versuche bezügliche Theorien werden einer kritischen Betrachtung unterzogen und die besondere Bedeutung der gewonnenen Ergebnisse kurz erörtert.
Über das Reine Silberbromidsol. I
Authors: Basiński A. 
Published: September 2010

AbstractIn dieser Arbeit ist die Methode der Herstellung von Silberbromidsol in grosser Reinheit und grosser Konzentration bearbeitet worden. Die, durch Elektrodialyse gereinigten und durch Elektrodekantation konzentrierten Sole, enthielten: ca 250 mmol AgBr, dann 1 bis 2 . 10−5 Gr‐Ion Br' und schliesslich 3 bis 4 . 10−5 Gr‐Ion H. im Liter. Das Sol erwies sich als ein starkes Elektrolyt, da fast alle Wasserstoffionen (von 90 bis 100%), elektrometrisch wirksam sind. Die in der beschriebenen Weise hergestellten Sole sind gründlich und vielseitig untersucht worden. Man hat nämlich folgende Grössen gemessen: Dichte, Konzentration der dispersen Phase. Bromionen‐ und Wasserstoffionenaktivität im Sol und im Zentrifugat, totale Wasserstoffionenkonzentration im Sol, Teilchengrösse, mechanische und thermische Empfindlichkeit, Einfluss der Verdünnung von Zentrifugat bzw. KBr‐Lösung u.s.w. Auf Grund der potentiometrischen und konduktometrischen Messungen wurden die Rückschlüsse über den Charakter des Sols gezogen.
Condensation de la Benzile avec les Acides Oxy‐, Thio‐ et Sélénodiacétiques
Authors: Backer H. J. , Stevens W. 
Published: September 2010

AbstractLa condensation de la benzile avec les esters des acides oxy‐, thio‐ et sélénodiacétiques donne naissance à des dérivés de furane, de thiophène et de sélénophène. La dernière synthèse est nouvelle.On obtient des acides dibasiques ou monobasiques et parfois des esters. Le chauffage des acides dicarboxyliques conduit aux dérivés diphényliques de furane, de thiophène et de sélénophène. Plusieurs acides ont été caractérisés sous forme de leurs esters de méthyle et d'éthyle.Comme la décomposition de la benzile en milieu alcalin peut donner lieu à la formation de l'aldéhyde benzoïque, qui pourrait troubler les résultats, les auteurs ont étudié séparément la condensation de cette aldéhyde avec les acides mentionnés ci‐dessus. Les produits obtenus diffèrent complètement de ceux que donne la benzile.
The reactions between aminoguanidine and phenylglyoxal
Authors: Ekeley John B. , Carlson Raymond E. , Ronzio Anthony R. 
Published: September 2010

Abstract
A guanylhydrazone of phenylglyoxal has been prepared.
Two isomeric phenyl aminotriazines, their hydrochlorides and acetyl derivatives have been prepared and their structures determined.
The imino tautomer of one of the triazines has been prepared.
Absorption spectra curves for the four compounds from aminoguanidine and phenylglyoxal have been reported.
Journal citations in the “Recueil”, 1937‐1939
Authors: Patterson Austin M. 
Published: September 2010

AbstractVolumes 56, 57 and 58 of the Recueil contain 408 articles which make 4.457 citations to 287 different journals. An analysis shows that, next to the Recueil itself, the ten most cited journals are, in order: Berichte, Journal of the American Chemical Society, Journal of the Chemical Society (London), Zeitschrift für physikalische Chemie, Annalen (Liebigs), Journal für praktische Chemie, Bulletin de la Société Chimique de France, Comptes rendus (French Academy of Sciences), Chemisch Weekblad, and Helvetica Chimica Acta. About 38 % of the articles cited are of German origin, the Netherlands, United States, Great Britain, and France following with 22 %, 13 %, 12 % and 6 % respectively. Articles are mentioned most often within a year or two of their publication but continue to be cited with diminishing frequency over a long period; over 2 % of the citations are to papers 60 tot 100 years old.
Contribution à la „Normalisation”︁ des Feuilles D'orthosiphon Stamineus (Koemis Koetjin)
Authors: de Graaff W. C. 
Published: September 2010

AbstractDans le présent travail, on a essayé de normaliser la drogue “Koemis Koetjin” des Indes Néerlandaises. Il s'agit de stipuler les exigences auxquelles doit satisfaire la “première qualité” de ce produit.
Solvent and dissociating power of chlorinated hydrocarbons: I. Theoretical Part
Authors: van Braam Houckgeest J. P. W. A. 
Published: September 2010

AbstractIn studying the solvent and dissociating power of chlorinated hydrocarbons, chiefly derivatives of ethane, certain peculiarities have been found, the explanation of which is attempted below. Taking a definite model for the solvatation phenomena as a starting point the changes in thermodynamic potential, due to dissociation of an electrolyte into ions and the forming of a solution of this electrolyte are calculated. It is possible in this way to derive equations for the dissociation equilibrium and the solubility of the electrolyte.
The Fittig‐reaction with α.ω‐dibromoparaffins
Authors: van Alphen J. 
Published: September 2010

Abstractα. ω‐Diphenylparaffins, with the exception of 1 : 2‐diphenylethane, can be obtained in good yield by the Fittig reaction between bromobenzene, sodium and the corresponding α. ω‐dibromoparaffin. With 1 : 10‐dibromodecane higher diphenylparaffins are also formed.
Tentative investigation into the influence of tetra‐ethyl‐lead on the flame velocity in hydrocarbon ‐ air mixtures, ignited by electric sparks
Authors: Smittenberg J. , Kooijman P. L. 
Published: September 2010

AbstractA simple “ballistic impulse‐meter” was constructed, the deflection of which could be used as an arbitrary measure for the flame velocity in hydrocarbon‐air mixtures ignited by an electric spark.The explosion impulses of iso‐octane‐air mixtures were not influenced perceptibly by the addition of T.E.L.‐vapour at temperatures varying from roomtemperature to 500° C.The same was the case for n‐butane‐air mixtures at temperatures up to 300° C. Above this temperature the explosion impulses of the mixtures were strongly diminished by the slow oxidation reaction of the n‐butane during the waiting period before the spark ignition. This slow oxidation reaction was strongly suppressed by the addition of T.E.L.‐vapour.As a result of this tentative investigation it may be concluded that the antiknock effect of T.E.L. in sparkignition engines must not be ascribed to a diminishing effect of T.E.L. on the flame velocity.
Atomic distances in small graphite crystals and the nature of the bond
Authors: de Boer J. H. 
Published: September 2010

AbstractIt is pointed out that the decrease of the carbon‐carbon distance within the atomic layers of graphite crystals, and the increase of the distance between the layers, found by Hofmann and Wilm for extremely small graphite particles in comparison with normal graphite, are both a direct consequence of the nature of the two types of binding forces involved here (homopolar bonds, and van der Waals‐London attraction forces, respectively).
Über die Stabilität der beiden Glycerolphosphorsäuren und diejenige ihrer Salze
Authors: Verkade P. E. , Stoppelenburg J. C. , Cohen W. D. 
Published: September 2010

AbstractSalze der beiden Glycerolphosphorsäuren erweisen sich beim Kochen in stark alkalischer Lösung oder beim Erhitzen mit Pyridin als sehr stabil.Beim Erhitzen in stark saurer Lösung gehen die beiden genannten Säuren wechselseitig leicht ineinander über; es stellt sich ein Gleichgewicht zwischen beiden Isomeren ein. Bei pH = 0.9 waren im Gleichgewichtszustande die α‐ und die β‐Säure in einem Verhältnis von etwa 87 : 13 vorhanden. Es wird eine Vorschrift zur Herstellung des α‐Dinatriumsalzes ausgehend von dem im Handel erhältlichen β‐Salz gegeben.Ferner werden einige Angaben über die Hydrolyse der beiden Glycerolphosphorsäuren gemacht. Die Hydrolysegeschwindigkeiten erreichen in der Nähe von pH = 3 ein Maximum.
A new method for the comparison of the extinquishing action of various finely‐divided solid substances on explosive gas mixtures
Authors: Jorissen W. P. , Snijders H. G. , Vink H. J. 
Published: September 2010

AbstractDescription of a method for the comparison of the concentrations in which solid substances in the form of dust clouds are able to prevent an explosion in explosive gas mixtures. Several results obtained by the method.
Reaktionen und Salzbildung des Phenanthrenchinonmonoxims. XIII. Mitt. Systematischer Ausbau der Atomgruppen in der Analytischen Cbemie
Authors: Keuning K. J. , Dubský J. V. 
Published: September 2010

AbstractDie Autoren kontrollieren die Arbeit von Pavolini und stellen fest, dass Phenanthrenchinonmonoxim auch mit den dreiwertigen Metallionen reagiert. Auch die Kobaltverbindung ist ein Kobaltisalz. Die Verbindungen sind innere Komplexsalze, die sehr leicht gewisse Mengen des Oxims adsorbieren.
Synthesis of compounds related to antihemorrhagic vitamin K. II: β‐Naphthol and β‐naphthylamine as starting materials for the synthesis of 2‐methyl‐ and 2‐ethyl‐1,4‐naphthoquinones
Authors: Sah Peter P. T. 
Published: September 2010

AbstractA general method of synthesis of 2‐alkyl‐1,4‐naphthoquinones (with special references to 2‐methyl‐ and 2‐ethyl‐1,4‐naphthoquinones, recently proved to possess strong, anti‐hemorrhagic vitamin K activity), using β‐naphthol and β‐naphthylamine as starting materials, is described in this paper.
Synthesis of compounds related to antihemorrhagic vitamin K. III: 1,4‐naphthoquinone as a starting material for the preparation of 2‐methyl‐1,4‐naphtho‐hydroquinone and derivatives
Authors: Sah Peter P. T. 
Published: September 2010

AbstractA general method for the synthesis of 2‐alkyl‐1,4‐naphthoquinones and hydroquinones from 1,4‐naphthoquinone as the starting material is described in this paper, with special references to 2‐methyl‐1,4‐naphthoquinone, 2‐methyl‐1,4‐naphtho‐hydroquinone, the dimethyl ether, the diacetate, the dipropionate, and the dibenzoate of the synthetic 2‐methyl‐1,4‐naphtho‐hydroquinone, which have recently been shown to possess strong anti‐hemorrhagic vitamin K activity.
Über die Thermische Umsetzung von an Stickstoff Substituierten Pyrrolen, Insbesondere von N‐Phenylpyrrol
Authors: Gitsels H. P. L. , Wibaut J. P. 
Published: September 2010

AbstractDas C‐Phenylpyrrol, das bei der thermischen Umsetzung von N‐Phenylpyrrol bei 700° entsteht, wurde durch Reduktion in C‐Phenylpyrrolidin umgesetzt: Dieses C‐Phenylpyrrolidin erwies sich als ausschliesslich aus 2‐Phenylpyrrolidin bestehend. Bei der thermischen Umsetzung von N‐Phenylpyrrol bei 700° entsteht also ausschliesslich 2‐Phenylpyrrol. Im Laufe der Untersuchung wurden die folgenden bisher noch nicht beschriebenen Verbindungen durch Synthese bereitet:2‐Methyl‐3‐carbaethoxy‐4‐phenyl‐5‐formylpyrrol,3‐Carbaethoxy‐4‐phenyl‐2,5‐dicarbonsäurepyrrol,2,5‐Dimethyl‐3‐carbaethoxy‐4‐phenylpyrrol.
Diarylmethane derivatives VIII: Methyl Substitution Products of Tetraphenylethanes
Authors: Coops J. , Nauta W. Th. , Ernsting M. J. E. , Faber A. C. 
Published: September 2010

AbstractIn order to be able to study the influence of the position of substituents in the aromatic nuclei of compounds of the tetraphenylethane type on the possibility of dissociation, several of these substances were synthesized.It was found that the presence of four ortho‐methyl groups per diphenyl‐methyl in this series is an essential condition for the occurrence of dissociation upon heating in solvents like benzene, toluene, and naphthalene.
The oxidation of normal butane: I. Experimental Part
Authors: Schuit G. C. A. 
Published: September 2010

AbstractThe kinetic characteristics of the oxidation of normal butane were investigated in the temperature region of 220‐270° C. The reaction is autocatalytic, it is accelerated by increase of pressure, temperature and the concentration of butane, while oxygen retards the velocity of reaction. The Semenoff relation Δp = Ae φtis found to hold in the above‐mentioned temperature region.The state of the walls exerts great influence on the reaction velocity: a covering of KCl on the walls leads to a retardation of the reaction, mainly by a lowering of the value of φ. Indications were found that it is also possible to poison the walls in such a way that the value of A is also decreased.It is possible to increase A by the addition of small amounts of foreign substances. Very active among such substances are alkyl nitrites and nitrates, as well as diethyl ether and n‐butyl aldehyde.From the analysis of the reaction products it was found that at high concentrations of the combustible substance considerable reaction already occurs during the induction period. It was found that a sudden acceleration of the increase in pressure occurring at these concentrations could be correlated with the maximum of the peroxide concentration.