bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diarylmethane derivatives VI: The occurrence of the bis‐(4‐methoxyphenyl)‐methyl radical
Authors: Nauta W. Th. , Mulder D. 
Published: September 2010

AbstractWhen a solution of bis‐(4‐methoxyphenyl)‐chloromethane is treated in an indifferent atmosphere with molecular silver, a transient red colour is produced in the solution.At the end of the reaction the solution is colourless and symm. tetra‐(4‐methoxyphenyl)‐ethane can be isolated in a quantitative yield.When the removal of halogen is carried out in an atmosphere of oxygen, a red coloration occurs initially but at the end of the reaction the colour is orange yellow to pale brown.4. 4′‐Dimethoxybenzophenone and anisaldehyde can be isolated from the reaction mixture and 1‐hydroxy‐4‐methoxybenzene is probably present also.Nitric oxide can also remove the bis‐(4‐methoxyphenyl)‐methyl radicals initially produced. In this case, only 4. 4′‐dimethoxybenzophenone could be isolated along with some symm. tetra‐(4‐methoxyphenyl)‐ethane.
Researches on pyrimidines, CLXIV: The synthesis from uracil of pyrimidines related structurally to thiamine
Authors: Riehl Doris , Johnson Treat B. 
Published: September 2010

Abstract
Hydroxymethyl‐benzamide and hydroxymethylphthalimide interact with uracil in the presence of concentrated sulfuric acid. Substitution takes place in the 5‐position of the uracil molecule giving derivatives of thymine namely: benzoylthyminylamine and 5‐phthalimidomethyluracil respectively.
These two derivatives of thymine undergo hydrolysis with regeneration of uracil by digestion with acids.
Neither of these two acylderivatives of thyminylamine can be recommended as practical intermediates for the synthesis of reduced pyrimidine derivatives related to thiamine (I).
The exact measurement of the specific heats of solid substances at high temperatures: XII. The specific heats of iron‐nickel‐alloys of various compositions between 100° and 1400° C
Authors: Zuithoff A. J. 
Published: September 2010

AbstractThe specific heats of iron‐nickel‐alloys with about 10%, 20%, 30%, 40%, 50%, 70% and 80% nickel have been determined. The so‐called “reversible” alloys (with 40% nickel and more) prove to show an evident conformity of their cp‐t‐curves. On the other hand, the “irreversible” alloys (with 0—30% nickel) exhibit a deviating course of their cp‐t‐curves. An appreciable discontinuity was observed in the curves of alloys with 10% and 20% nickel at the γ → α‐transformation; the alloy with 30% nickel, moreover, shows a strong retardation at its transformation point. The influence of cooling in liquid air was studied: the γ → α‐transformation is only completed at a rather low temperature.The true specific heats cp were deduced from the values of c̄p obtained and their values considered in connection with the compositions of the different alloys.The heat‐content and the specific heat show a minimum value at about 30% nickel, which fact is in agreement with the occurrence of a minimum thermal expansion in the case of invar (35% nickel). The additive law of Neumann and Kopp was once more checked and proved again only to have an approximate validity, even in this case of solid solutions.The microscopic structures of the different alloys were finally compared with each other.
Electrolysis of solid solutions of oxygen in metallic zirconium
Authors: de Boer J. H. , Fast J. D. 
Published: September 2010

AbstractFurther particulars are given regarding the solubility of oxygen in zirconium (table I). It is shown that the oxygen atoms are present in the interstices of the zirconium lattice and that at high temperatures they have a great mobility in the lattice. Under the influence of an electric field it is found that under suitable conditions of temperature and potential drop the oxygen moves through the metal lattice as a negative ion, causing the oxygen concentration (and with it the electrical resistance) to increase at the anode end and to decrease at the cathode end (fig. 2).
On the reactivity of bromine atoms in brominated pyridines. The formation of 2‐hydroxy‐6‐bromopyridine by the acid hydrolysis of 2,6‐dibromopyridine: (46th communication on derivatives of pyridine and quinoline)
Authors: Wibaut J. P. , Haayman P. W. , van Dijk J. 
Published: September 2010

Abstract2‐Hydroxy‐6‐bromopyridine is formed by the action of concentrated aqueous solutions of sulphuric acid, phosphoric acid, acetic acid or formic acid on 2,6‐dibromopyridine at 160°.The use of phosphoric acid affords a method for the preparation of 2‐hydroxy‐6‐bromopyridine from 2,6‐dibromopyridine.
La Détermination du Chlore, du Brome et de L'iode dans les Composés Organiques par Hydrogénation
Authors: Slooff A. 
Published: September 2010

AbstractNous basant sur les données de la littérature, nous avons déterminé la position des équilibres de dissociation des hydracides halogénés gazeux et calculé les vitesses avec lesquelles ces équilibres s'établissent à des températures différentes et avec des excès différents d'hydrogène dans le mélange gazeux. Ces calculs ont été effectués dans le but de découvrir les conditions dans lesquelles il est possible de déterminer quantitativement les halogènes, dans les composés organiques, par hydrogénation. Enfin, nous donnons, pour le dosage des halogènes dans les composés organiques, une méthode dans laquelle l'hydrogène est utilisé seul pour l'hydrogénation et qui doit, par conséquent, être considérée comme une modification de la méthode de Ter Meulen et HeslingaH. zer Meulen et J. Heslinga, Rec. trav. chim. 42, 1093 (1923); H. ter Meulen, Rec. trav. chim. 47, 698 (1928).
, qui emploient, pour l'hydrogénation, un mélange d'hydrogène et d'ammoniaque.
L'association de L'alcool Étudiée par L'effet Raman
Authors: Brüll L. , Errera J. , Sack H. 
Published: September 2010

AbstractL'effet Raman de l'alcool pur, de l'hexane pur et de solutions d'alcool dans l'hexane à 20% et 5% a été étudié. On observe une raie “monomoléculaire” à 3640 cm−1 qui garde à peu près son intensité en passant de 5 à 100% d'alcool, et une large bande “polymoléculaire” vers 3370 cm−1 dont l'intensité augmente fortement avec la concentration en alcool. Ces resultats sont tout à fait analogues à ceux obtenus dans l'infrarouge proche.
Octadecachloroquaterphenyl (perchloroquaterphenyl) and a facile method for the preparation of decachlorobiphenyl (perchlorobiphenyl)
Authors: Wibaut J. P. , Overhoff J. , Gratama K. 
Published: September 2010

AbstractOctadecachloroquaterphenyl (perchloroquaterphenyl), C24Cl18, is prepared by heating quaterphenyl with an excess of antimony pentachloride; it is a colorless, crystalline compound, which melts at 364‐365° and can be sublimed in a vacuum without decomposition.Decachlorobiphenyl is prepared by chlorinating pentachlorobiphenyl, which can be obtained commercially.
The peculiar behaviour of the sodium‐uranyl triple acetates
Authors: Schoorl N. 
Published: September 2010

AbstractBy a determination of the water of crystallization in the triple acetates of Na, Mg and UO2 (Blanchetière) or Na, Zn and UO2 (Barber and Kolthoff), it has been found that six molecules of water of crystallization are taken up with an unmeasurably small vapour‐pressure and that these 6 H2O are present as “facultative water of crystallization”. In addition yet a 7th molecule of water is taken up as a “zeolithic increment”. Consequently the weight of the triple acetates in the air‐dried state can still fluctuate by about 0.25%.Kahane's triple acetate was found to contain not 8 H2O but about 5 H2O and in addition about 1.5 mol. ethylalcohol. It is stable in air up to 110° and shows a very small zeolithic increment.The alcohol content of the liquid can vary in the precipitation between 30 and 60%, without the content of “volatile matter” (sum of water and alcohol) in the crystals varying more than 0.2%.Into the anhydrous sodium magnesium uranyl triple acetate 4 molecules of ethyl alcohol can be introduced artificially; they are taken up without any noticeable vapour‐pressure but are readily replaced by H2O.
Präparative Studien mit Monomolekularen Filmen II: Zur Problemstellung. Physikalische Hilfsmethoden zur Untersuchung der verwendeten Filme
Authors: Kögl F. , Havinga E. 
Published: September 2010

AbstractEs werden die Faktoren besprochen, welche den in monomolekularen kondensierten Filmen verlaufenden Reaktionen gegenüber jenen in dreidimensionalen Systemen einen besonderen Charakter verleihen können. Um über den Bau der verwendeten Filme näheren Aufschluss zu erhalten, wurden ausser der Bestimmung der molekularen Oberfläche auch noch die ultra‐mikroskopische Untersuchung und die Beugung von Elektronenstrahlen als physikalische Hilfsmethoden herangezogen.
ρ‐Iodobenzazide as a reagent for the identification of phenols
Authors: Sah Peter P. T. , Young Ping‐Te 
Published: September 2010

AbstractThirty crystalline p‐iodophenyl‐urethanes were prepared by the condensation of p‐iodobenzazide, a new reagent, with various types of phenols in boiling ligroin solution. None of these derivatives, which are suitable for the identification of phenols, have been described in the literature.
Second pressure limits in gaseous explosion regions: II. Experimental data on explosions of CO and CH4 with oxygen and air
Authors: Dijksman A. J. , van den Brandhof C. 
Published: September 2010

AbstractThe authors investigated the explosion limit as a function of the pressure (below about 120 cm Hg). With CH4‐O2, CH4‐air, CO‐O2 and CO‐ air mixtures no shapes of explosion regions were found which were reminiscent of the lowpressure‐inflammation regions of these mixtures at higher temperatures. Though at the upper limit of mixtures with CO a “second pressure limit” was found, this was not at all comparable with the shape of the explosion region observed with H2‐O2 mixtures1). The “second pressure limit” of CH4‐air mixtures found by Lavrov and Bestchastny cannot have been an explosion limit, but must be attributed to secondary effects.
Quinones as reagents for the dehydrogenation of cholesteryl acetate to pro‐vitamin D
Authors: Sah Peter P. T. 
Published: September 2010

Abstract1,4‐Quinones, when heated with cholesteryl acetate in sealed tubes at 120 to 135° for 6 to 8 hours, were found to partially dehydrogenate the sterol ester to a pro‐vitamin D (probably 7‐dehydro‐cholesteryl acetate). The crude products, after the removal of hydroquinones, quinhydrones and unreacted quinones, were irradiated for 4 hours with ultraviolet light produced by a quartz‐mercury lamp and were found to acquire antirachitic properties. 1,2‐Quinones, when used in the above reaction, gave doubtful results. Aliphatic and aromatic di‐ketones, such as diacetyl, benzil, anthraquinone and phenanthroquinone, were not able to dehydrogenate the sterol ester to pro‐vitamin D, since their products, after irradiation, acquired no antirachitic properties.
Determination of non‐fermentable reducing substances in sugar cane molasses
Authors: Geerligs H. C. Prinsen 
Published: September 2010

AbstractCane molasses contains a variable amount of non‐fermentable reducing matter which, in routine commercial analysis, is erroneously incorporated in the figure for total sugar, which determines the price to be paid for the article.Since this fact is detrimental for the purchasers' interest and a direct method of determination is not available a good one for the fixing of the “spirit yield” is suggested here.
Osmotic iso‐pc‐complexes with one invariant and two variable liquids; all substances diffuse
Authors: Schreinemakers F. A. H. , Werre J. P. 
Published: September 2010

AbstractIf two variable liquids, which are in osmotic contact with an invariant liquid, have the same composition at the beginning of the osmosis and, of course, also the same composition at the end of the osmosis (viz. that of the inv. liq.), they will get, however, a different composition at every moment of the osmosis.
The equilibrium of the system TiO2‐SO3‐H2O at 25° C
Authors: Reinders W. , Kies H. L. 
Published: September 2010

AbstractThe solubility of TiO2nH2O and of TiO2SO32H2O in mixtures of sulphuric acid and water at 25° C was determined. There is a triple point at 38.1% of sulphuric acid and 3.5% of TiO2, the saturated solutions of the sulphate being stable only with higher sulphuric acid concentrations. The solubility of the sulphate in pure water is extremely high; the solution is however metastable with respect to the dioxide. In sulphuric acid of 50 to 65% the solubility of the sulphate is very low, no more than about 0.05%, increasing again in more concentrated acid.
The action of anti‐knock dopes
Authors: Oosterhoff L. J. 
Published: September 2010

AbstractStarting from the assumption that the knock suppressing action of some metalcompounds is due to the removal of peroxide molecules by a metal‐or metaloxide cloud, it is shown that the observed effect can be explained if the radius of the particles in the cloud does not surpass a length of the order of magnitude of 100 Å.
Theoretical considerations on the relation between explosion and inflammation regions
Authors: Dijksman A. J. 
Published: September 2010

AbstractThe author emphatically distinguishes betweenexplosionandinflammation.The shape of the inflammation regions (with pressure and composition of the mixture as variables) is discussed for such gas mixtures as possess a “low pressure inflammation region” in addition to a thermal inflammation region at a higher pressure (e.g. H2‐O2, CO‐O2, CH4‐O2).From experiments on the influence of a spark on the shape of the inflammation region and of the temperature on the position of the explosion limits, the author derives a general shape of the explosion region (as determined at room temperature). It follows from this that indentations in the explosion region may sometimes be expected in the place where thermal and low pressure inflammation regions merge. The “second pressure limits” which then occur were actually found with H2‐O2and H2‐ air mixtures. The “second pressure limit” found by Lavrov and Bestchastny for CH4‐ air mixtures must have been due to secondary effects.The inflammation regions cannot be accounted for by one theory, although all the cases are instances of chain reactions. For, these reactions have in the thermal inflammation region a normal relationship between temperature and reaction rate, whereas this relationship is abnormal in the low pressure inflammation region. The various parts of the explosion regions can, therefore, not be accounted for by one theory either.Former attempts to explain the shape of explosion regions by either the thermal or the chain theory were wrong.A simple explanation of the association between explosion and inflammation is given.
On the relation between extinction limits of stationary flames and ternary explosion limits
Authors: Verbrugh A. J. 
Published: September 2010

AbstractThe extinction limits of flames of hydrogen, carbon monoxide and methane were determined in mixtures of oxygen with nitrogen, carbon dioxide or argon. Also varying amounts of the extinguishing gas were added to the combustible gas.In the same way the extinction limits of ammonia gas were determined. In the latter case only nitrogen and argon were employed as extinguishing gases.In addition similar investigations were carried out with so‐called “reversed flames”, in which oxygen‐nitrogen mixtures were burned in mixtures of hydrogen and nitrogen, etc.Since the explosion limits of the ternary systems H2‐O2‐N2, H2‐O2‐CO2, H2‐O2‐A and CO‐O2‐N2 were already known, only the following ternary explosion limits were determined for the sake of comparison with the extinction limits: CO‐O2‐CO2, CO‐O2‐A, CH4‐O2‐N2, CH4‐O2‐CO2, CH4‐O2‐A, NH3‐O2‐N2, NH3‐O2‐A.The extinction and explosion limits were compared. A method was found of constructing, from the explosion limit curves, curves representing the corresponding extinction limits.
Hydrazides as characteristic derivatives for the identification of esters, acids, salts, acid halides, acid anhydrides, acid amides, ureas and nitriles
Authors: Sah Peter P. T. 
Published: September 2010

AbstractMethods for the identification of esters, acids, salts, acid halides, acid anhydrides, acid amides, ureas, and nitriles by means of the formation of crystalline hydrazides are described in this paper.The Jamieson method was found to be most valuable for the rapid estimation of hydrazine nitrogen in hydrazides and their derivatives.
Unmixing in several binary systems of novocaine salts with water, in connection with complex coacervation of biocolloids
Authors: Holleman L. W. J. , de Jong H. G. Bungenberg 
Published: September 2010

Abstract
In the systems Novocaine bichromate + water, Novocaine perchlorate + water, Novocaine rhodanide + water and Novocaine iodide + water an unmixing region occurs.In the first three cases mentioned the unmixing is stable within a certain temperature range.
In the binary systems mentioned in 1. we encounter the case of a system consisting of a typical electrolyte and water in which equilibria are observed between two liquid phases, on the one hand of the type familiar in the case of two substances which give an unmixing area in the liquid state, and which on the other hand recall the phenomenon occurring upon mixing two oppositely charged biocolloid sols, which has been given the name complex coacervation.
Du Dosage des Halogènes dans les Composés Organiques, par Destruction avec du Nitrate de Sodium et de L'oxyde de Calcium en Tube Scellé
Authors: Weber A. Ph. 
Published: September 2010

AbstractDescription d'une nouvelle méthode de dosage du chlore, du brome et de l'iode dans les matières organiques, par combustion en tube scellé, avec un mélange de nitrate sodique et de chaux calcinée, le tube étant préalablement rempli d'anhydride carbonique. L'efficacité de la méthode se confirme par le résultat de l'analyse d'une vingtaine de substances.
Analyse Qualitative de Substances Organiques par Hydrogénation
Authors: Slooff A. , van Duyn D. 
Published: September 2010

AbstractLe décèlement d'azote, d'halogène et de soufre dans des substances organiques se fait le plus souvent par expériences isolées. En appliquant la méthode d'hydrogénation de ter Meulen, nous avons réussi à obtenir un mode opératoire qui permet de déceler ces éléments par une seule expérience.La dite méthode, que nous allons ici décrire, s'est en même temps révélée propre à contribuer à une analyse de substances organiques, qui soit intégrale.
Synthesen von Glyceriden mit Hilfe von Tritylverbindungen. IV: Ein‐ und zweisäurige αβ‐Diglyceride
Authors: Verkade P. E. , Cohen W. D. , Vroege A. K. 
Published: September 2010

AbstractBeim Schütteln von ein‐ oder zweisäurigen αβ‐Diacyl‐y‐tritylglycerolen in absolut alkoholischer Lösung oder Suspension bei etwas erhöhter Temperatur (45‐50°) mit Wasserstoff in Gegenwart von Palladium‐Kohle und von etwas fein verteiltem Calciumcarbonat werden die Tritylgruppen leicht abgespalten. Die dabei neben Triphenylmethan entstandenen einsäurigen bezw. zweisäurigen αβ‐Diglyceride lassen sich leicht rein und mit sehr guter Ausbeute isolieren.
Apparatur zur Messung des Polarisationszustands von Ramanlinien
Authors: Nijveld W. J. , Gerding H. 
Published: September 2010

AbstractEs wird eine Vorrichtung zur genauen Bestimmung des Polarisationszustands von Ramanlinien beschrieben, die sich der Hauptsache nach an die von Reitz benutzte Apparatur anschliesst. Ausserdem wird eine einfache Apparatur angegeben (modifizierte Placzek‐van Wijk Methode), die es gestattet in viel kürzerer Zeit als bei der obengenannten Apparatur, jedoch weniger genau, den Depolarisationsgrad der Ramanlinien zu finden. Das Anbringen einer Korrektur für die Konvergenzfehler ist notwendig. Schliesslich wird eine übersicht über die für CCl4 und SO3 nach beiden Methoden bestimmten Q‐Werte gegeben.
Über die Struktur und die Disproportionierung von 2‐Phenylpyrrolidin
Authors: Gitsels H. P. L. , Wibaut J. P. 
Published: September 2010

AbstractFür das 2‐Phenylpyrrolidin, das Gitsels und Wibaut durch Reduktion von 2‐Phenylpyrrol mit Zinkstaub und Salzsäure erhielten, wird die Struktur von 2‐Phenyl‐Δ4‐dihydropyrrol annehmbar gemacht.Dieses 2‐Phenylpyrrolidin unterliegt im reinen Zustand und bei Abwesenheit eines Katalysators bei gewöhnlicher Temperatur einer langsamen Veränderung, wobei durch Disproportionierung 2‐Phenylpyrrol neben 2‐Phenylpyrrolidin entsteht; diese Reaktion wird durch Platinschwarz beschleunigt.
Solvent and dissociating power of chlorinated hydrocarbons: II. Calculations
Authors: van Braam Houckgeest J. P. W. A. 
Published: September 2010

AbstractThe equations which have been derived J. P. W. A. van Braam Houckgeest, Thesis, Leiden 1939.
J. P. W. A. van Braam Houckgeest, Rec. trav. chim. 59, 560 (1940).
for the dissociation equilibrium and the solubility of an electrolyte contain a series of energy quantities, the values of which must be known in order to enable comparison between theory and experiment. In this article the evaluation of these energy terms is given.
Deacylation in alcoholic medium with platinum as catalyst
Authors: Verkade P. E. , van Dijk C. P. , Veld F. A. In 'T 
Published: September 2010

AbstractUpon shaking αβ‐diacyl‐γ‐tritylglycerols in alcoholic solution with hydrogen in the presence of palladium on active carbon as a catalyst, hydrogen is taken up and the corresponding αβ‐diglycerides together with triphenylmethane are formed. However, when platinum oxide is used as a catalyst, no hydrogenation takes place, but deacylation. For example, αβ‐dibenzoyl‐γ‐tritylglycerol can be converted quantitatively into ethyl benzoate and α‐monotritylglycerol.The same contrast between the two catalysts was observed in the case of the β‐acyl‐αγ‐benzylideneglycerols. Upon shaking these compounds in alcoholic solution with hydrogen in the presence of palladium on active carbon, hydrogen is taken up and the corresponding β‐monoglycerides are formed in addition to toluene. When platinum oxide is used as a catalyst, however, a quantitative deacylation takes place; β‐stearyl‐αγ‐benzylideneglycerol, for example, can be converted into ethyl stearate and αγ‐benzylideneglycerol.This new method of deacylation is discussed in detail. The reaction takes place at least as smoothly when the substance, in alcoholic solution, is shaken in air with platinum oxide which has been previously reduced with hydrogen.