bluuebunny/crossref_metadata_2025_split huggingface dataset:
Über den Einfluss Kathodischer und Anodischer Polarisation auf die Lösungsgeschwindigkeit der Metalle
Authors: Boonstra B. 
Published: September 2010

Obgleich mit der Theorie der Lokalelemente die elektrochemische Natur der Korrosionsvorgänge wohl allgemein anerkannt wurde, liegen systematische Untersuchungen über den Einfluss äusserlicher elektrischer Ströme kaum vor.Im folgenden wird gezeigt, wie man bei einem in Säure sich lösenden Metall, durch kathodische Polarisation mit bestimmten Stromdichten einen Einblick gewinnt in das Verhältnis der Grösse der wirksamen Lokalkathodenoberfläche zur Grösse der messbaren Gesamtoberfläche, und wie man mittels anodischer und kathodischer Polarisation die den Lösungsvorgang beherrschenden Stromdichte‐Potentialkurven ermitteln kann.
Zur Kenntnis der Metallketyle; die Umsetzung mit Carbonylgruppen
Authors: Oppenauer R. 
Published: September 2010

Es wurde gefunden, dass sich Pinakolate, die in Lösung in die sog. Metallketyle dissoziert sind, mit Aldehyden und Ketonen mehr oder weniger leicht auf folgende Weise umsetzen:magnified imageDie Reaktion kann als Anlagerung der Ketyle an die Carbonyldoppelbindung aufgefasst werden.
A study on the preparation and the physical constants of a number of alkanes andcycloalkanes
Authors: Wibaut J. P. , Hoog H. , Langedijk S. L. , Overhoff J. , Smittenberg J. 
Published: September 2010

AbstractThe following hydrocarbons have been prepared in a very high degree of purity:n‐pentane, 2‐methylbutane,n‐hexane, 2‐methylpentane, 3‐methylpentane, 2,2‐dimethylbutane. 2,3‐dimethylbutane, 2‐methylhexane, 2, 2‐dimethylpentane, 2,3‐dimethylpentane, 2,4‐dimethylpentane, 3,3‐dimethylpentane, 2,2,3‐trimethylbutane,n‐octane, 3‐methylheptane, 2,3‐dimethylhexane, 3,4‐dimethylhexane, 3‐methyl‐3‐ethylpentane, 2,2,3‐trimethylpentane,n‐nonane,n‐hexadecane, ethylcyclobutane,cyclopentane, methylcyclopentane,cyclohexane, methylcyclohexane, isopropylcyclohexane. The methods described are suitable for preparing the pure compounds in quantities of 1 kg or more. For each of the hydrocarbons and also forn‐heptane and 2,2,4‐trimethylpentane we have determined accurate values for the boiling point, melting point, densities at 15° and 20° or at 20° and 25°, refractive indices and molecular refractions at the same temperatures for the wave lengths 6563, 5876, 4861, 4341 Å. We have also recorded accurate values for the surface tension at 20° and for the parachor. The critical solution temperatures with aniline have also been determined.
Connection between taste and constitution of carboxylic acid hydrazides and their derivatives
Authors: Blanksma J. J. , Bakels H. A. 
Published: September 2010

AbstractThis investigationPart of dissertation by H. A. Bakels, Leiden, 1938.
deals with the hydrazides of malonic, succinic and citric acids, all three of which are sweet substances, and their derivatives, obtained by condensation with aldehydes and ketones, which are, in general, bitter when they are soluble in water.Esters of phthalic acid, isophthalic acid and terephthalic acid also have been treated with hydrazine hydrate, and the hydrazides obtained and their condensation products with aldehydes and ketones examined as regards their taste. The action of hydrazines on phthalic anhydride has also been investigated.We have also examined the hydrazides of some 2‐hydroxymethylbenzoic acids, prepared by opening the lactone ring in phthalide, nitrophthalide and aminophthalide with hydrazine. Finally, we opened the ring in meconine, nitromeconine and aminomeconine, these compounds being derivatives of phthalide containing two methoxy groups. Bitter substances were obtained by condensing these substances with aldehydes and ketones.
Über die Einwirkung von Salpeter‐Schwefelsäure auf 3,6‐Dinitro‐5‐Brompseudocumen: (3 Mitteilung)
Authors: Rinkes I. J. 
Published: September 2010

Nachdem ich in der zweiten MitteilungI. J. Rinkes, Rec. trav. chim. 58, 218 (1939).
über dieses Thema meinen Befund berichtet hatte, dass die Säure aus dem Nitrat von Huender aus zwei isomeren Säuren besteht, ist es mir jetzt gelungen, das 2,5‐Dimethyl‐3,6‐dinitro‐4‐brombenzylnitrat und das 2,4‐Dimethyl‐3,6‐dinitro‐5‐brombenzylnitrat, ausgehend von Para‐ und Metaxylen, zu synthetisieren und ihre Eigenschaften mit dem Nitrat von Huender zu vergleichen.
Investigation of the volatile constituents of raspberry juice (Rubus idaeus L.)
Authors: Coppens A. , Hoejenbos L. 
Published: September 2010

AbstractAn investigation has been made of the volatile constituents of raspberry juice, i. e. of the substances contributing to the aroma of the fruit.Several substances have been identified; besides so called fruit ethers viz. ethyl acetate and perhaps caproic esters, other constituents, mainly aromatic, responsible for the heavy part of the raspberry flavour, were found, viz. benzyl alcohol, phenylethyl alcohol, coumarin. Other substances were also identified.
The chlorination of pyridine: Investigations on pyridine and quinoline derivatives 41st. Communication
Authors: Wibaut J. P. , Nicolay J. R. 
Published: September 2010

AbstractOn chlorinating pyridine in the gas phase at 270° a good yield of 2‐chloropyridine is obtained together with a small quantity of 2:6‐dicloropyridine. At 400° the main product is 2:6‐dichloropyridine.It is shown that among the products produced in the chlorination at 270°, a small amount of a pyridylpyridinium compound must be present, for 2‐aminopyridine is obtained on hydrolysis of the reation product.Chlorination in the gas phase takes place very slowly at about 200° at this temperature 3:5‐dichloropyridine is obtained together with 3:4:5‐trichloropyridine.On chlorinating fused pyridine hydrochloride at about 170° a considerable yield of 3:5‐dichloropyridine is produced along with a small amount of 3:4:5‐trichloropyridine and pentachloropyridine.Thus in the chlorination of pyridine a specific temperature effect on the type of substitution is observed as in the bromination of pyridine. In the chlorination, the temperature limits for both types of substitution lie near together.2‐Aminopyridine is obtained on heating 2‐chloropyridine with aqueous ammonia and copper sulphate. 2‐Amino‐6chloropyridine is obtaines on heating 2:6‐dichloropyridine with aqueous ammonia.
The influence of an alternating electric field on the rate of coagulation. I. Negative Silver Iodide Sols
Authors: Hermans J. J. 
Published: September 2010

AbstractSilver iodide sols are coagulated by potassium nitrate. The coagulation is studied by plotting the turbidity of the sol versus the time. The initial slope si of the curves obtained is called rate of coagulation.§ 1. The properties of the sol and the principal features of the method as described in a previous paper are reviewed briefly.§ 2. Description of the apparatus.§ 3. The change of the initial slope si with the concentration c of the sol is studied in more detail than before. At high electrolytic concentration x the coagulation rate si is proportional to c2. At lower concentrations of the KNO3, si becomes almost proportional to c. It is shown that the value of p in Paine's relation: si = AxP is necessarily dependent of the solconcentration c.§ 4. The increase in coagulation rate in the presence of an electric field is shown to be very similar to that in the presence of a sonic field.§ 5. The influence of the field strength F is proportional to Fn, where n is very nearly 4. Changing the frequency from 50 to 400 sec−1 has no appreciable effect.§ 6. Comparing the influence of the sonic field with that of the electric field, it seems probable that the distortion of the double layer plays an important part in the phenomena described. This further leads to suggest that the influence of a sonic field of energy E is proportional to E2.
Diarylmethane derivatives VII: Properties of the diphenylmethyl radical
Authors: Nauta W. Th. , Mulder D. 
Published: September 2010

AbstractWhen oxygen is excluded, the interaction of molecular silver on diphenylchloromethane dissolved in benzene gives a quantitative yield of symm.‐tetraphenylethane.If this reaction is carried out with shaking in an atmosphere of oxygen only traces of the ethane can be isolated from the reaction mixture.The diphenylmethyl radicals, initially formed by dehalogenation, are removed by the oxygen.The reaction products obtained in this case, namely, di‐(diphenylmethyl) ether, benzophenone and diphenylmethanol, may be considered as the decomposition products of a peroxide formed initially.No coloration is observed in the reaction leading to symm.‐tetraphenylethane. On the other hand, during the oxidation the reaction mixture assumes a permanent pale yellow colour.Various reactions of diphenylmethyl compounds described in the literature as taking unexpected courses, may be readily explained by the occurrence of the diphenylmethyl radical.
The reactivity of the bromine atoms in brominated pyridines; the formation of 1‐methyl‐6‐bromo‐2‐pyridone from 1‐methyl‐2.6‐dibromopyridinium salts
Authors: Wibaut J. P. , Speekman B. W. , van Wagtendonk H. M. 
Published: September 2010

Abstract2,6‐Dibromopyridine and dimethyl sulphate react to give 1‐methyl‐2,6‐dibromopyridinium methosulphate, which has only been obtained as an aqueous solution. 1‐Methyl‐2,6‐dibromopyridinium iodide has been obtained as a microcrystalline solid. These 1‐methylpyridinium compounds react with dilute alkali at room‐temperature to give 1‐methyl‐6‐bromo‐2‐pyridone.The constitution of this compound follows from its transformation into 2,6‐dibromopyridine by the action of phosphorus bromide.
The action of immiscible organic liquids on aqueous dispersions
Authors: Bolam T. R. , Bowden G. 
Published: September 2010

AbstractThe distribution of finely‐divided gold or silver iodide between water and an immiscible organic liquid depends upon the nature and concentration of the electrolytes present. A reasonable interpretation of the observed effects may be given in terms of the influence of the electrical double layer upon the adsorption of non‐electrolytes.
Nachweis von Barium und Sulfat durch Tüpfelreaktionen
Authors: Feigl F. , Aufricht W. 
Published: September 2010

AbstractIn Gegenwart von viel KMnO4 gefälltes BaSO4 enthält stets Permanganat und ist dadurch violett gefärbt. Das durch Adsorption oder Gittereinlagerung im Sulfat befindliche Permanganat ist gegenüber Reduktionsmittel weitgehend resistent. Dieser Effekt kann zum Nachweis von Barium und Sulfat in Form von Tropfenreaktionen verwendet werden.
The gradual decomposition by oxidation of fatty acids into their next lower homologues
Authors: Mendel H. , Coops J. 
Published: September 2010

AbstractA method for the gradual decomposition by oxidation of fatty acids into their next lower homologues is described and tried on palmitic and stearic acids.The new method comprises the following steps: bromination of the original fatty acid in α‐position, conversion into α‐hydroxy‐fatty acid, oxidation of the latter to aldehyde with lead tetra‐acetate and subsequent immediate oxidation of the aldehyde to the desired lower fatty acid with air and an excess of lead tetra‐acetate.The various steps of the first reactions are executed in such a manner, that nearly quantitative yields are obtained. The decomposition of the α‐hydroxy‐fatty acid to the lower fatty acid gives a yield of 88 to 89%. The total yield of lower homologues was approximately 84%.
The influence of liver‐extract on the oxygen consumption of mammalian erythrocytes. IV. On the mechanism of the reaction. B. Yellow enzymes
Authors: Overbeek G. A. 
Published: September 2010

Abstract
It is probable that the “original” yellow enzyme system of Warburg is responsible for a part of the Michaelis Salomon reaction.
There are strong arguments against the functioning of amino‐acid oxidase and xanthine oxidase.
On aliphatic polyamines X
Authors: van Alphen J. 
Published: September 2010

AbstractThe reaction between 1 : 2‐diaminoethane hydrate and 1 :6‐dibromohexane furnishes polyamines containing straight chains of dimethylene and hexamethylene groups separated by nitrogen atoms. A small quantity of a cyclic amine, 1‐(2′‐aminoethyl)‐1‐aza‐cyclo‐heptane, is also formed and the yield of the latter is relatively increased when very dilute solutions of the reaction components are used.A survey is made of the reaction between an excess of 1 : 2‐diaminoethane hydrate and the various αω‐dibromo‐paraffins.
Quelques Acides Arsonocarboxyliques non Saturés
Authors: Backer H. J. , van Oosten R. P. 
Published: September 2010

AbstractLe mémoire décrit trois représentants simples des acides arsonocarboxyliques non saturés: les acides α‐arsonacrylique, α‐arsonocrotonique et β‐arsonocrotonique. L'action de l'arsénite de potassium sur les acides α‐bromocrotonique et α‐bromoisocrotonique conduit au même acide α‐arsonocrotonique: les acides β‐chlorocrotonique et β‐chloroisocrotonique donnent également le même acide β‐arsonocrotonique.La fonction arsonique ‐AsO3H2 donne lieu à la formation d'ortho‐esters avec les 1,2‐diols.La formation des acides arsonocarboxyliques aux dépens d'arsénite et d'acides chlorocarboxyliques apparaît, dans certaines conditions, comme une réaction bimoléculaire.Les acides arsonocarboxyliques sont tribasiques; leurs trois constantes de dissociation ont été déterminées par titrage électrométrique.
On the mechanism of water adsorption in gelatine gel
Authors: Weidinger A. , Pelser H. 
Published: September 2010

AbstractAn attempt is made to bring into a closer correlation the conceptions of “bound” and “intramicellar” water. For this purpose we made use of gelatine gels containing cobaltous chloride, observed the colour, typical for different amounts of adsorbed water (an indication for “free” or “bound” water) and found by means of X‐ray spectrography the magnitude of the “side chain spacing” (measure for intramicellar water) in dependance on the amount of adsorbed water. The results obtained for gels of low cobaltous chloride content are valid for pure gelatine gels.
The essential oils from Litsea Cubeba Pers
Authors: van Hulssen C. J. , Koolhaas D. R. 
Published: September 2010

AbstractA research has been carried out with regard to the composition of the essential oils distilled from the leaves of Litsea cubeba Pers. Two types of oil were found to be present, namely, Litsea oil with a relatively high content of the aldehydes citronellal and citral and Krangean oil with a small content of aldehydes, but with a high content of cineol. The constituents of both oils were isolated and identified and the quantitative composition was determined.
On the influence of the solvent and the temperature on the speed of oxidation of some organic substances by chromic acid. II
Authors: Snethlage H. C. S. 
Published: September 2010

AbstractThe velocity (v) of the reaction between oxalic acid (1) and chromic acid (2) has been measured in mixtures of sulph. ac. and water, containing from 0 to 95.8% sulph. ac. at 303.0° K and 323.0° K. The most appropriate method to investigate the influence of the solvent was to calculate n1 and n2 from v = k × c1n1 × c2n2.n1 was found to vary between 1 and 2, n2 between 1 and 1.51. In consequence, the effect of the composition of the solvent varies with the concentration of the reactants. The addition of sulph. ac. to water decreases the velocity of the reaction until a minimum is reached, at ± 70% sulph. ac. an optimum exists. The initial stage of the reaction shows, in solvents which contain more than 60% sulph. ac. abnormal (too low) velocities, a phenomenon which is not caused by the effect of any product of the reaction, nor by any reaction between the solvent and the reactants. It is supposed to be the consequence of the slow formation of a compound between the reactants, prior to the actual decomposition.The temperature coefficients are largely dependent on the composition of the solvent, they vary between 4.32 (water) and 8.8 (70% sulph. ac.) for 20° (303.0‐323.0° K). An optimum is found at 70%, a minimum at 80% sulph. ac. In water and diluted sulph. ac. no complete oxidation can be obtained as part of the oxalic acid is bound by the reduction product of the chromic acid. Taking this into consideration the initial stage of the reaction in water may be represented by the formula for a termolecular reaction, which can also be applied to solutions in 13.4% sulph. ac., where complete oxidation is obtained.
o‐Nitrobenzazide as a reagent for the identification of phenols
Authors: Sah Peter P. T. , Yin Wen‐Hou 
Published: September 2010

AbstractTwenty‐eight crystalline o‐nitrophenyl‐urethanes were prepared by the action of o‐nitrobenzazide on various phenols in boiling ligroin solution. In the cases of ortho‐substituted phenols, the condensation took place in the presence of dimethylaniline as catalyst. These urethanes possess excellent properties and are suitable derivatives for the identification of phenols.
Die Elektrochemische Kohlenwasserstoffsynthese mit Aromatischen Säuren
Authors: Fichter Fr. 
Published: September 2010

AbstractNach einer Besprechung der verschiedenen Gründe, die bei der Benzoesäure das Zustandekommen einer Kolbe'schen Elektrosynthese besonders erschweren, wird eine Elektrolysemethode unter Verwendung von Pyridin allein oder mit Methylalkohol zusammen als Lösungsmittel ausgearbeitet, mit Hilfe deren verschiedene aromatische Säuren, deren Carboxyl nicht unmittelbar am Benzenkern sitzt, die Kohlenwasserstoffsynthese mit brauchbarer Ausbeute durchzuführen gestatten.Schliesslich wird eine halb mit Diäthylamin neutralisierte Lösung von Benzoesäure in unvermischtem Pyridin elektrolysiert, mit dem Ergebnis, dass bei dieser solange widerstrebenden Säure nicht nur die Synthese des Biphenyls glückt, sondern dass die genaue Untersuchung der Produkte den Beweis der intermediären Bildung von Di‐benzoyl‐peroxyd erbringt, womit die seit mehr als zwanzig Jahren verfochtene PeroxydtheorieF. Fichter und E. Krummenacher, Helv. Chim. Acta 1, 146 (1918).
;) der Kolbe'schen Elektrosynthese eine neue und besondere überzeugende experimentelle Stütze erhält.
La Composition D'extraits Aqueux de la Semence de Beta Saccharifera
Authors: Gillis J. 
Published: September 2010

AbstractLes expériences de Fröschel ayant révélé une action retardatrice sur la germination de certaines graines, produite sous l'influence d'extraits aqueux de certaines semences, la question s'est posée de connaître la composition de ces extraits aqueux en vue de rechercher s'il existe une ou plusieurs substances responsables de l'effet retardateur en question.L'analyse a porté en premier lieu sur le dosage des constituants ionisés de quelques extraits aqueux d'akènes de Beta saccharifera, notamment des cations: Na, K, Mg, Ca et des anions: Cl, NO3, SO4, C2O4.Grâce aux données de ces dosages, il a été possible de réaliser une première expérience marquant nettement l'action inhibitrice des ions oxaliques sur la germination des graines de Lepidium sativum. d'autres expériences devront être entreprises pour reconnaître si les ions oxaliques sont les seuls responsables de l'effet retardateur de la germination de certaines graines ou bien pour savoir s'il existe encore d'autres substances capables de “freiner” la germination.
Vitamin‐C in tea leaf
Authors: Deijs W. B. 
Published: September 2010

AbstractAn investigation has been carried out on the content of vitamin‐C in fresh and manufactured tea (both green and black teas). Three methods of determining ascorbic acid have been mutually compared. At the same time we have investigated how the contents of ascorbic and dehydroascorbic acids alter during the various stages of tea manufacture.An examination has been made of how green tea can be prepared so that the final product is still rich in vitamin‐C.An enzyme preparation has been obtained from tea leaf, which possesses in a high degree the properties of an ascorbic acid‐oxidase.Finally we have examined the effect of ascorbic acid and ascorbic acid‐oxidase on the fermentation of tea. Investigations on the chemistry of the fermentation of tea are being continued.
Bis repetita desiderantur. Wer hat zum ersten Mal ein Gas verflüssigt?
Authors: Cohen Ernst , Cohen‐de Meester W. A. T. 
Published: September 2010

„……während die Erfahrung aller Zeiten uns belehrt, wie schwierig es selbst für geübte Intelligenzen ist, Begriffe aufzugeben, welche sie seit langer Zeit als Wahrheiten betrachteten, obwohl deutlich nachgewiesen war, dass ihre Begriffe unbegründet waren.„Im holländischen Original: „……terwijl de ondervinding van alle tijden geleerd heeft, hoe bezwaarlijk geoeffende verstanden zelven zodanige begrippen kunnen laaten vaaren, welken zy zederd eenen geruimen tijd voor waarheid hebben aangenomen, of schoon het ongegronde hunner begrippen duidelyk is aangetoond.”︁
Präparative Studien mit monomolekularen Filmen III. Lactonbildung in monomolekularen Schichten
Authors: Kögl F. , Havinga E. 
Published: September 2010

AbstractWie sich in der vorliegenden Arbeit gezeigt hat, findet die Lactonisierung von ω‐Oxyaethyl‐stearyl‐malonsäure bei pH 3 bis 6 in monomolekularer Schicht mit einer Geschwindigkeit statt, welche 103 bis 104 mal grösser ist als jene in einer gewöhnlichen Lösung von gleicher Wasserstoffionenkonzentration.
Experiments on a synthesis of dl‐pelletierine. I
Authors: Wibaut J. P. , Beets M. G. J. 
Published: September 2010

Abstractβ‐(2‐Pyridyl)‐propionaldehyde‐acetal has been prepared from bromoacetal and α‐picolyl lithium.The preparation of this compound forms the first step in a synthesis of dl‐pelletierine.
The ceric hydroxide sol
Authors: Kruyt H. R. , Meilink N. , Hintzer H. M. R. 
Published: September 2010

AbstractInvestigations have been made to prepare a pure and stable ceric oxide sol by hydrolysis of ceric ammonium nitrate in an electro‐dialyser. The problem cannot be solved completely in consequence of the conflicting requirements with regard to pH and the removal of the cerous nitrate.
The potentiometric titration of calcium. II
Authors: Tendeloo H. J. C. , Heeres H. 
Published: September 2010

AbstractThe reversible electrode of the third order, lead amalgam ‐ lead oxalate ‐ calcium oxalate, is useful for the potentiometric titration of calcium ions with ammonium oxalate. The titration is however disturbed when magnesium and chlorine ions are present in too great a concentration.
Quelques Remarques sur le Pouvoir Réducteur du gaz à L'eau
Authors: Meyer G. , Scheffer F. E. C. 
Published: September 2010

AbstractL'équilibre entre un métal et son oxyde exige, à une température donnée, une valeur déterminée de la tension d'oxygène. Si on chauffe donc un mélange du métal et de son oxyde dans un gaz quelconque, la tension d'oxygène de ce dernier détermine le sens de la transformation dans la masse solide. Nous avons calculé ces tensions d'oxygène dans le gaz à l'eau, préparé par l'action de la vapeur d'eau sous la pression d'une atmosphère sur le carbone à des températures différentes.
The dipole moment of pentachlorobenzene and of 1.2.3 vic. trichlorobenzene
Authors: Ketelaar J. A. A. 
Published: September 2010

AbstractThe dipole moments of monochlorobenzene, 1.2.3 vic. trichlorobenzene and pentachlorobenzene, using benzene as a solvent, were determined as 1.545 D, 2.31 D and 0.87 D respectively.
Chemischer Beitrag zur Kenntnis Xanthomatöser Geschwülste
Authors: Veer W. L. C. , Beekman E. M. , Boer P. W. 
Published: September 2010

AbstractChemische Lipoidanalyse einer xanthomatösen Knochengeschwulst. Bestimmt wurden Neutralfette, Cholesterin, Cholesterinester, Glycerinphosphatide (Lecithin, Kephalin), Diaminophosphatide (Sphingomyelin). Cerebroside konnten nicht nachgewiesen werden.Die erhaltenen Lipoidwerte werden verglichen mit denjenigen anderer Cholesterin enthaltenden Geschwülste und mit normaler Haut. In der xanthomatösen Geschwulst sind nicht nur Cholesterin, sondern auch die Phosphorlipoide, insbesondere das Lecithin, in höherer Konzentration erhalten als in normaler Haut.