bluuebunny/crossref_metadata_2025_split huggingface dataset:
The determination of aneurin and aneurinphosphates in yeast
Authors: Westenbrink H. G. K. , van Dorp D. A. , Gruber M. 
Published: September 2010

AbstractMany 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

AbstractIn 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

AbstractIm 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

AbstractBy 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

AbstractLa 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

AbstractThe 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

AbstractMan 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

AbstractLes 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

AbstractLe 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

AbstractMellitic 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractNach 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

AbstractNach 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.
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

AbstractM. J. StuurmanJ. 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 piècesProc. 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

AbstractEs 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

AbstractAt 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

AbstractNew 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

AbstractEs 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

AbstractThe 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

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

AbstractIn 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

AbstractIn 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

AbstractAn 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractA 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).