bluuebunny/crossref_metadata_2025 huggingface dataset:
Diarylmethane derivatives VI: The occurrence of the bis‐(4‐methoxyphenyl)‐methyl radical
Authors: Nauta W. Th. , Mulder D.
Published: September 2010

When 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

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

The 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

Further 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

2‐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.
Colorimetric determination of tocopherol (vitamin E). IV. The quantitative determination of tocopherol in oils after saponification
Authors: Emmerie A.
Published: September 2010

This investigation has been carried out to determine the conditions under which an oil must be saponified for a reliable quantitative estimation of its tocopherol content.
La Détermination du Chlore, du Brome et de L'iode dans les Composés Organiques par Hydrogénation
Authors: Slooff A.
Published: September 2010

Nous 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 Heslinga

H. 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

L'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

Octadecachloroquaterphenyl (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

By 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

Es 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

Thirty 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

The 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

1,4‐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.
Sur les Acides Iridium‐III‐Dipyridino‐Tétrachlorhydriques [IrPy2Cl4]H
Authors: Delépine M. Marcel
Published: September 2010

On peut préparer les deux acides, cis et trans, à l'état cristallisé. Ce sont des acides forts.
Determination of non‐fermentable reducing substances in sugar cane molasses
Authors: Geerligs H. C. Prinsen
Published: September 2010

Cane 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

If 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.
Elaidinization
Authors: Bertram S. H.
Published: September 2010

A new hypothesis explaining the mechanism of elaidinization is given. Elaidinization is caused by addition followed by elimination of unstable hydrogen compounds. The hypothesis is in accordance with the known facts and it explains the fact that it must be an equilibrium reaction. Confirmation is found that elaidic acid will be the cis form.
Investigations in the purine series. I. The synthesis of 1:3:7‐triethylxanthine
Authors: Ruttink J.
Published: September 2010

This paper deals with the synthesis of 1:3:7‐triethylxanthine in one step and its importance for the recognition of lower ethylxanthines.
Note on consecutive reactions
Authors: Bruins E. M.
Published: September 2010

The consecutive reaction A + B → AB, AB + C → AC + B is a soluble problem of chemical dynamics if the concentration of B remains constant. The solution of this special problem is given.
The equilibrium of the system TiO2‐SO3‐H2O at 25° C
Authors: Reinders W. , Kies H. L.
Published: September 2010

The 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

Starting 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

The 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

The 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

Methods 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

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

Description 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

Le 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

Beim 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

Es 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

Für 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

The 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

Upon 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.
The determination of aneurin and aneurinphosphates in yeast
Authors: Westenbrink H. G. K. , van Dorp D. A. , Gruber M.
Published: September 2010

Many difficulties are encountered in the determination of aneurin and its phosphoric acid esters in yeast. Most of them arise from the presence, especially in top yeasts, of a powerful phosphatase, converting aneurinphosphates into aneurin, when no precautions are taken to inhibit its action. Moreover, aneurinpyrophosphate appeared to be converted into aneurinorthophosphate already by boiling for some minutes with 0.1 n hydrochloric acid. Besides that a yeast was found, to which it was impossible to apply the thiochrome method A (in which the thiochromephosphates are determined by measuring the fluorescence of the water‐layer), as it contains a substance with a strong blue fluorescence in alkaline solution, non‐extractable with isobutanol and very sensitive to oxidation with potassiumferricyanide. This sensitivity is so great that this substance cannot be a thiochromephosphate.

Generally applicable procedures, avoiding the errors, originating from these difficulties, were worked out for the determination of free aneurin (thiochrome method), total aneurin (thiochrome method), aneurinpyrophosphate (manometric method) and the sum of aneurinpyrophosphate and aneurinorthophosphate (thiochrome method).

All yeasts investigated appeared to contain free aneurin. With the exception of one yeast, which had been dried on a hot rotating drum, they all contained amounts of aneurinpyrophosphate, exceeding the amounts of free aneurin.

No indications were obtained that yeast, whether fresh or dried, ever contains aneurinorthophosphate. Hence we believe that for routine analyses aneurinpyrophosphate determinations by the manometric method may be omitted and the sum of the aneurinphosphates found by the thiochrome method may be equalised to the amount of aneurinpyrophosphate present.

The fact that free aneurin is found and no aneurinorthophosphate proves that the aneurin is orginally present in the yeast and is not formed from aneurinpyrophosphate during drying and extraction.
The density and sorptive capacity of some samples of cotton, silk and wool: Part II. determinations on silk
Authors: Heertjes P. M.
Published: September 2010

In this paper the dyeing process of silk with an acid dye is explained by means of density measurements.

The adsorption of hydrogen by silk has been measured and found to be in correspondence with the explanation of the dyeing process. From the sorption measurements in air, it can be deduced that the sorption of air by silk is principally a chemo‐sorption.

From the density of silk in helium the number of possibilities found in the literature for the lattice of Bombyx‐Mori silk can be reduced to a single one.

By comparing degummed and raw silk, it was found that the sericins are low molecular proteins, which sorb neither hydrogen nor air.

The relation is discussed between chain‐length, relative positions of the chains, on the one hand, and the sorption properties, density etc. on the other hand.

The densities of silk cited in the literature are criticised and compared with the author's observations.
Über einige besonderen Eigenschaften des Isanoöls
Authors: Steger Alph. , van Loon J.
Published: September 2010

Im Gegensatz zu den in der Literatur erwähnten Angaben muss das Isanoöl nicht zu den trocknenden, sondern zu den nicht‐trocknenden Ölen gerechnet werden. Es ist als Leinölersatz ungeeignet. Infolge der im Öle vorkommenden Vinylverbindungen polymerisiert es sich sehr leicht, sowohl beim Erhitzen als auch bei der Belichtung. Die anfangs hellgelbe Farbe des Öles wird dadurch tiefrot.
Dilatation of ammonium nitrate between −70° and −40° C
Authors: Meerman P. G.
Published: September 2010

By means of the static dilatometric method the cubical expansion of ammonium nitrate was measured between −72.2° and −40.2° C. Since no abnormality could be detected either in this experiment or in the determination of heating curves, the existence of a transition region as stated by Crenshaw and Ritter could not be ascertained. Nevertheless a sluggishness in the establishment of volume‐temperature equilibrium was probably due to the same cause as that of the low temperature transitions in other ammonium salts.
Une Nouvelle Réaction Conduisant à la Formation de Spirans
Authors: Backer H. J. , Wiggerink G. L.
Published: September 2010

La condensation de la 1, 3‐dichloracétone et du monothioglycol donne naissance à un spiran. En faisant agir, au lieu du monothioglycol, son dérivé monosodique, on obtient le même produit, dont on peut ainsi déterminer la structure et le mode de formation. Afin de savoir si cette formation de spirans présente une synthèse générale, les auteurs ont remplacé les deux réactifs par des composés analogues, d'abord le monothioglycol par le dithioglycol et le glycol, puis la dichloracétone par la 2, 6‐dibromocyclohexanone, ainsi que par le chlorure de chloracétyle et le phosgène.

Comme le dithioglycol s'est révélé très propre à la formation de spirans, on l'a également remplacé par un autre 1, 2‐dimercaptan, le 1, 2‐dimercaptobenzène, et par deux 1, 3‐dimercaptans, le 1, 3‐dimercapto‐2, 2‐diméthylpropane et le 1, 3‐dimercapto‐2, 2‐pentaméthylènepropane. Ces deux 1, 3‐dimercaptans ont donné des spirans avec des anneaux de sept atomes.

Le phosgène, agissant sur les 1, 2‐dimercaptans, ne donne pas de spiran, mais des dithiocarbonates. La réaction du 1, 2‐dithioglycol s'accomplit beaucoup plus rapidement que celle de l'o.dimercaptobenzène, fait que l'on peut attribuer à la souplesse des valences aliphatiques.
Properties of suspensions, especially in non‐aqueous media
Authors: Verwey E. J. W.
Published: September 2010

The properties of suspensions of finely ground materials in various dispersion media, as a function of their degree of colloid chemical stability, are discussed. Special attention is given to unstable suspensions showing a phenomenon similar to coacervation (found with lyophilic colloids), and to stable suspensions with dilatant sediments.
Untersuchungen über Pyrrolderivate: 6. Mitteilung
Authors: Rinkes I. J.
Published: September 2010

Man kann die Leichtigkeit, mit der Atome und Gruppen aus dem Pyrrolkern vertrieben werden, dadurch vergleichen, dass man sie zwei an zwei an α‐Stellen in Pyrrolderivaten anbringt und feststellt, welche Gruppe am leichtesten durch die Nitrogruppe verdrängt wird. Es zeigt sich, dass die untersuchten Gruppen mit abnehmender Verdrängbarkeit in folgende Reihenfolge geordnet werden müssen: COOH, COCH3, J, COC6H5.
Le Principe Toxique du Gluta Renghas Linn
Authors: Backer H. J. , Haack N. H.
Published: September 2010

Les fruits du Gluta Renghas Linn. renferment dans leurs noix un latex à propriétés vésicantes. Le principe toxique, le glutarenghol, est un dérivé du pyrocatéchol. Le produit hydrogéné est identique au 2, 3‐dihydroxy‐n‐heptadécylbenzène, que nous avons préparé par synthèse. Le glutarenghol renferme une double liaison dans la chaîne latérale.
La structure de l'Acide Pélandjauïque
Authors: Backer H. J. , Haack N. H.
Published: September 2010

Le latex du Pentaspadon Motleyi renferme l'acide pélandjauïque, dont la décarboxylation conduit au pélandjauphénol. En préparant par synthèse le tétrahydropelandjauphénol, les auteurs ont prouvé que le pélandjauphénol est le m‐hydroxy‐n‐heptadécanediénylbenzène. En oxydant le dérivé diméthylé de l'acide pélandjauïque, ils ont établi la structure de cet acide, qui est l'acide 2‐hydroxy‐6‐heptadécanediénylbenzoïque.
On the preparation of mellitic acid from hexa‐methylbenzene and on the hexachloride of mellitic acid
Authors: Wibaut J. P. , Overhoff J. , Jonker E. W. , Gratama K.
Published: September 2010

Mellitic acid may be prepared by oxidation of hexamethylbenzene by means of concentrated nitric acid at 120‐160°; this method has the advantage that the crude reaction product already consists of rather pure mellitic acid; the yield of the pure product is about 35% of the theoretical.

The hexachloride of mellitic acid has been prepared in the pure state. We investigated the directions of Maumené‐Lecuir, for preparing the potassium salt of mellitic acid by thermal decomposition of the potassium salt of tartaric acid; we obtained only very low yields of mellitic acid by this method.
Derivatives of 1‐chlor‐2‐nitro‐4‐cyanbenzene
Authors: Blanksma J. J. , Witte C. H. D.
Published: September 2010

The mobile chlorine atom in 1‐chlor‐2‐nitro‐4‐cyanbenzene was replaced by amines, oxyethylamine, ethylenediamine, hydrazine and methylhydrazine.
Quantitative investigation of the ozonization of ortho‐xylene and of 1,2,4‐trimethyl benzene; a chemical proof of the equivalence of the six cc bonds in the benzene ring
Authors: Haaijman P. W. , Wibaut J. P.
Published: September 2010

The qualitative results of Levine and Cole on the formation of glyoxal, methyl glyoxal and dimethyl glyoxal in the ozonization of o‐xylene are confirmed. However, we obtained much greater yields of these oxidation products, namely 20‐26% of the theoretical yield.

A method has been worked out for determining these aldehydes and ketones in the form of the oximes. The mixture of oximes obtained in the ozonization of o‐xylene consists of 21.0% dimethylglyoxime, 34.2% methylglyoxime and 43.9% glyoxime (averages of 5 experiments).

This ratio is in good accordance with the ratio calculated on the basis or the following assumptions:

that the six CC bonds in the benzene‐nucleus of o‐xylene are equivalent (the two Kékulé structures contributing each for 50% to the structure of o‐xylene);

that the addition of ozone is not affected by steric hindrance of the methyl groups.

The ozonization of 1,2,4‐trimethylbenzene has been investigated by means of the same methods. In this case the mixture of oximes consists of 17.9% dimethylglyoxime, 66.2% methylglyoxime and 14.2% glyoxime (average of two experiments). This ratio agrees very well with the ratio calculated on the basis of the assumptions: 1. that the six CC bounds in the benzenering of 1,2,4‐trimethylbenzene are equivalent, 2. that the addition of ozone is not affected by steric hindrance of the CH3‐groups.
Diarylmethane derivatives IX). The oxidation products of the diarylmethyl radicals
Authors: Nauta W. Th. , Ernsting M. J. E. , Faber Miss A. C.
Published: September 2010

The mixture of products containing oxygen which results when a diarylchlormethane reacts with molecular silver in the presence of oxygen was studied for a number of methyl‐substituted diarylchlormethanes.

The reaction products, which should be considered to have been formed by the decomposition of the primary product, a peroxide of the diarylmethyl radicals, are of the same nature as were found in the reactions described in the foregoing communications. In one. case, namely that of bis‐(3,5‐dimethylphenyl)‐methyl, the peroxide could be isolated in a pure form.

The oxidation products of bis‐(2,6‐dimethylphenyl)‐methyl, which was obtained in solution by thermal dissociation of the ethane, were found to correspond to those which are formed in the reaction of bis‐(2,6‐dimethylphenyl) ‐chlormethane with silver in the presence of oxygen.
Die Struktur der Phasengrenze bei Hydrophoben Kolloiden: I. Die elektrometrische Analyse der Phasengrenze bei kolloidalen Systemen
Authors: de Bruyn H.
Published: September 2010

Nach einem Hinweis darauf, wie wünschenswert eine genaue Analyse der Adsorptionsvorgänge von potentialbestimmenden Ionen ist, wurde die Methode beschrieben, mit welcher das hierzu erforderliche Tatsachenmaterial erlangt wurde.
Die Struktur der Phasengrenze bei Hydrophoben Kolloiden: II. Der Einfluss der Solkonzentration auf die Ladung kolloidaler Teilchen
Authors: de Bruyn H.
Published: September 2010

Nach Beschreibung einiger merkwürdiger Phänomene, die bei der Erforschung des Einflusses der Solkonzentration auf die Adsorption der potentialbestimmenden Ionen beobachtet wurden, wurde angegeben, in welcher Weise der bei der elektrometrischen Untersuchung von Solen störende Solkonzentrationseffekt experimentell eliminiert werden kann. Weiter wurde eine in erster Annäherung gültige mathematische Formulierung des Solkonzentrationseffektes abgeleitet, wonach eine theoretische Betrachtung über die beobachteten Erscheinungen gegeben wurde.
The size distribution of fat globules in milk
Authors: van Kreveld A.
Published: September 2010

An improved technique of counting fat globules in milk is described. Frequency curves are given for fresh and evaporated milk in different stages of homogenization. Evaluation of the fat balance yields roughly the correct amount of fat in fresh milk. In evaporated milk a shortage is found, owing to submicroscopic fat globules.
Regularity of the arrangement of fat globules in milk
Authors: van Kreveld A.
Published: September 2010

Countings of fat globules in milk carried out by various authors show a remarkable regularity of spatial arrangement. This is ascribed to repulsive forces between the globules, reaching up to 50μ. The conception is supported by experiments showing that the degree of order is lessened by dilution.
La Vitesse D'Oxydation de Cycloheptène, D'Heptène‐3 et de Nonène‐4 par de L'Acide Peracétique
Authors: Böeseken J. , Hanegraaff C. J. A.
Published: September 2010

M. J. Stuurman

J. Stuurman, “Meting van de snelheid van oxydatie van enkele groepen alkenen door perazijnzuur”, Thèse Delft 1936.

a calculé les valeurs de K, E et B de l'équation d'Arrhenius‐Scheffer: log K = – E/2.303 RT + B, outre la vitesse de réaction de l'acide peracétique sur un nombre d'alkènes a chaine ouverte et de cyclènes. Les valeurs du cyclohexène concordaient parfaitement avec ceux de l'hexène‐3, alors que des différences notables se sont révélées entre, d'une part ceux du cyclopentène et du cyclobuténe, d'autre part ceux du pentène‐2, resp. du butène asymètrique. Nous en avons conclu que le cyclohexène n'a pas de tension annulaire, alors que doivent être tendus les anneaux à cinq et à quatre pièces

Proc. Akad. Wetenschappen Amsterdam 39, 2‐9 (1936).

.

Ces observations, nous les avons complètées par l'examen, exposé cidessous, du cycloheptène et de quelques alkènes à chaine ouverte: nous avons constaté que l'anneau à sept pièces se range à cǒté du cyclohexène, tant qu'il n'y a pas indication de tension dans cet anneau.
Zur Analytischen Chemie des Zirkons: I. Die Bestimmung des Zirkons als Phosphat unter Berücksichtigung eines Hafniumgehaltes
Authors: Claassen A. , Visser J.
Published: September 2010

Es wird gezeigt, dass die Bestimmung des Zirkons als Phosphat durch Fällung mit Ammoniumphosphat in 10 vol.‐%iger Schwefelsäure sehr genaue Resultate liefert. Die Bestimmung kann sowohl nach der von Lundell und Knowles angegebenen als auch nach einer in dieser Arbeit vorgeschlagenen schnelleren Methode erfolgen.

Aus Versuchen an Lösungen mit bekanntem Hafniumgehalt wurde der Umrechnungsfaktor innerhalb 0.1 % gleich dem theoretischen, dem Hafniumgehalt entsprechenden Wert gefunden. Zur Erhaltung eines weissen Glühproduktes muss das Phosphat 1 bis 3 Std. im elektrischen Ofen auf 1150° erhitzt werden. Die zur Fällung verwendete Ammoniumphosphatmenge soll das 50 bis 100‐fache der theoretisch aur Bildung von ZrP2O4 erforderlichen Menge betragen.

Ausser in schwefelsaurer Lösung kann die Bestimmung mit gleicher Genauigkeit in salzsaurer Lösung erfolgen. Gegenwart von Weinsäure stört die Bestimmung nicht.

Das Verfahren liefert eine scharfe Trennung des Zirkons von Aluminium, Kupfer, Cadmium, Wismut, Nickel, Kobalt, Mangan, Zink, Magnesium. Erdalkalien und Alkalien, Wolfram, Vanadium, Molybdän und Uran. Die Trennung von dreiwertigem Eisen gelingt nur, wenn dieses in kleinen Mengen vorhanden ist; zur Trennung von grösseren Eisenmengen muss dieses in die zweiwertige Form übergeführt werden. Die Trennung von Titan in wasserstoffperoxydhaltiger Lösung liefert nur bei nicht zu grossen Niederschlagsmengen genaue Ergebnisse. Eine Trennung von Zinn ist nicht möglich.
On the formation of benzonitrile in the thermal decomposition of N‐alkylanilines
Authors: Wibaut J. P. , Speekman B. W.
Published: September 2010

At 500‐560° N‐alkylanilines undergo a thermal decomposition in which benzonitrile is formed among other products. The reaction was investigated in the cases of N‐methylaniline, N‐ethylaniline, N‐(n‐propyl)‐aniline and N‐(n‐butyl)‐aniline. The yield of benzonitrile was greatest with N‐ethylaniline.
On the reconstitution of carboxylase: (Preliminary note)
Authors: Westenbrink H. G. K. , Parvé Elizabeth P. Steyn
Published: September 2010

New experiments on the carboxylase system have shown that nondissociated holocarboxylase is formed, when aneurinpyrophosphate and Mg are added to alkaline washed dried yeast. Of increasing amounts of added aneurinpyrophosphate an always diminishing percentage is bound, and so the impression is created that one has to do with a dissociated enzyme. Hence there is no longer any reason to assume the existence of a dissociated carboxylase.
Die Struktur der Phasengrenze bei Hydrophoben Kolloiden. IV. Die Aktivität der Gegenionen
Authors: de Bruyn H.
Published: September 2010

Es wurde untersucht, ob die Grenzschichtverunreinigungen eines Sols die Aktivität der Gegenionen beeinflussen.

Es wurde gefunden, dass selbst bei sehr reinen Solen (Verunreinigungen nur 1%) noch ein Aktivitätskoeffizient f = 0.6 auftritt.

Diese hohe Aktivität ist auf Grund des Sternschen Phasengrenzenmodells unverständlich.

Es wird darauf hingewiesen, dass die von Rabinovitch und Kargin geäusserte Kritik der Ansicht von Pallmann, wonach der „Suspensionseffekt”︁ von der Aktivität der Gegenionen beherrscht wird; unbegründet ist.
The crystal structure of hexabromoethane C2Br6
Authors: Snaauw G. J. , Wiebenga E. H.
Published: September 2010

The crystal structure of the orthorhombic modification of C2Br6 has been investigated by X‐ray analysis. Rotation and Weissenberg diagrams give

.

The cell contains 4 molecules. The space group is Pnma (D162h).

By trial and error, followed by Fourier syntheses of the a and c‐axis projections, the positions of the Br‐atoms have been determined. The contour lines indicate vaguely the positions of the C‐atoms. The molecules are found to be in the “trans” configuration (fig. 5). This result is discussed in connection with the results of recent Raman investigations of other substituted ethanes.

Assuming 1.52 Å for the C‐C distance, the C‐Br distance becomes 1.93 Å, in agreement with the value for this bond length in other aliphatic compounds. The valency angles are 113° and 108°. The intermolecular Br‐Br distance is 3.7‐3.8 Å.

The cell dimensions and the space group are in agreement with the results of an incomplete analysis by Miss Yardley in 1927.

The present investigation also confirms her conclusion that the molecule possesses a centre of symmetry and a plane of symmetry.
De L'Action du BF3. C2H5OC2H5 sur le Méthylchavicol, sur les Oximes des Acides γ‐p.Méthoxybenzoyl‐n. Butyrique et γ‐p.Éthoxybenzoyl‐n. Butyrique et sur L'Oxime de Benzophénone
Authors: van Der Zanden J. M. , de Vries M. M. G. , Dijkstra R. H.
Published: September 2010

Nous avons fait les recherches ci‐dessous pour savoir si le BF3. C2H5OC2H5 peut catalyser la polymérisation du méthylchavicol, et provoquer la transposition, selon Beckmann, de l'oxime de l'acide γ‐p‐méthoxybenzoyl‐n‐butyrique.

Cette transposition nous a donné des résultats importants pour l'élucidation de la structure d'un dimère du méthylchavicol

J. M. v. d. Zanden, Rec. trav. chim. 57, 233/47 (1938).

).
Colorimetric determination of tocopherol VI): (Vitamin E)
Authors: Emmerie A.
Published: September 2010

In this paper a slightly modified method for the extraction of tocopherol from serum is given.

According to acetylation experiments no substances are present in our purified serum extracts which interfere with our method for the determination of tocopherol.
On the bromination of phenol in the gas phase at temperatures between 200° and 500°)
Authors: Speekman B. W. , Wibaut J. P.
Published: September 2010

In the bromination of phenol at temperatures between 200° and 500° monobromophenol and more highly brominated products are formed. By means of a special method of analysis the ratio is determined in which ortho, meta and para‐bromophenol occur in the reaction mixture. Meta‐bromophenol is formed to a very small degree at all temperatures; the ratio of ortho to para‐bromophenol becomes larger with increasing temperature.
Energetische Angaben über die Kohlenstoff‐Kohlenstoffbindung II. Die Aktivierungsenergie der Dissoziation von sym. Tetra‐(2,6‐dimethylphenyl)äthan in den Lösungsmitteln ortho‐, meta‐ und para‐Xylen
Authors: Coops J. , Nauta W. Th. , van Duuren L.
Published: September 2010

In guter Übereinstimmung mit dem früher für die Aktivierungsenergie der Dissoziation des sym. Tetra(2,6‐dimethylphenyl)äthan in ortho‐Dichlorbenzen gemessenen Wert von 22.5 kcal wurde in den Lösungsmitteln ortho‐, meta‐ und para‐Xylen 22.9 bzw. 23.0 bzw. 23.4 kcal gefunden.
Attempts to prepare N,N′‐ethene indigo. (On indigo VIII)
Authors: van Alphen J.
Published: September 2010

An attempt was made tot prepare N,N′‐ethene indigo, the derivative of cis‐indigo in which the nitrogen atoms are joined by an ethene link.

A compound was however obtained whose probable formula is that of N,N′‐ethene indigo with a molecule of water added at the double bond between the two indol nuclei. It was found impossible to split off the water from this compound without further decomposition.
The raman spectra of 1,2‐dichloro‐ and 1,2‐dibromoethane at different temperatures
Authors: Gerding H. , Meerman P. G.
Published: September 2010

The intensity ratio of the Raman lines corresponding to the vibrations ω2 and ω′2 of cis‐ and trans‐1,2‐dibromoethane and 1,2‐dichloro‐ethane has been determined in the liquid at temperatures ranging from 15°‐120° Celsius. The difference in energy between cis and trans has been derived from these data assuming ideal thermodynamic behaviour of the undiluted liquid. The results show that this condition was apparently not fulfilled.

The phase integral ratio for cis and trans in the gaseous phase has been estimated for both substances and the dipole moment of the cis‐form calculated herewith from the polarization data of Zahn and Linke.
The Raman spectrum and the molecular structure of pyrosulphuryl chloride
Authors: Gerding H. , v. d. Linden A. C.
Published: September 2010

The preparation of pure pyrosulphuryl chloride S2O5Cl2 is described. The Raman spectrum of the liquid has been determined and polarization measurements have been effected. For the molecule the structure ClO2S‐O‐SO2Cl has been deduced. Each sulphur atom is tetrahedrally surrounded by the four atoms attached to it. The spatial configuration is such that two vertical planes of symmetry and a twofold axis are present in the molecule (symmetry C2v). An assignment of the frequency shifts found to the normal vibrations of the molecule of the symmetry C2v has been given. Some remarks are made about the molecular structure of pyrosulphuric acid.
New aspects on the cohesion of simple compounds. V
Authors: Stevels J. M.
Published: September 2010

The Debye and Keesom contributions to the boiling points of methane, ethane, propane and ethene derivatives are studied, and several remarkable numerical relationships between them are found. These relationships can be explained theoretically. Moreover, they permit the calculation of the Debye and Keesom contributions to the boiling points of the propane derivatives, which hitherto could not be estimated empirically.

A method is developed, according to which it is possible to calculate theoretically the values k in the formulae for the London contribution to the boiling points of the methane, ethane and propane derivatives. The agreement with the empirical values is satisfactory.

Some minor questions, left open for further discussion in earlier papers, are treated.
Method for measuring the whiteness of substances in powder form
Authors: Straub J. , Simons W.
Published: September 2010

A description is given of the construction (fig. 1) and theory of an apparatus with which the reflection factor of surfaces can be measured visually. The measurement takes place on the inside surface of a cavity covered with the substance to be investigated. It is shown that the accuracy increases rapidly with the reflection factor, so that the method is especially suitable for the investigation of substances with a high reflection factor (measurement of whiteness and of saturated colours). An accuracy is attained which is eight or more times as great as that attained by direct measurement. Results are given for wheat flour bleached in different ways (table I), for wheat flour of different milling grades (fig. 3) and quality (table II), for zinc‐white and titanium‐white (table III, fig. 4). A method is indicated for measuring the absolute reflection factor with this apparatus (tables IV and V).