摘要:

AbstractL'action du glycérol, de l'érythritol et de quelques hexanehexols sur la conductibilité électrique de l'acide borique a été examinée pour vérifier l'hypothèse de la répulsion mutuelle des groupes hydroxyle1). Il était à prévoir que l'accroissement du nombre des groupes hydroxyle voisins dans les polyols saturés augmenterait leur influence sur la conductibilité électrique de l'acide borique, puisque la position de deux groupes hydroxyle voisins doit devenir, sous l'action répulsive des autres groupes, de plus en plus avantageuse pour la formation d'un borocomplexe. Les recherches qui viennent d'être rappelées ont confirmé cette prévision.Entre l'érythritol et les hexols manquait cependant l'examen des polyols à cinq groupes hydroxyle voisins. Dans ce qui suit, nous avons comblé cette lacune et le résultat de nos recherches a été celui que nous attendions: les augmentations de conductibilité exercées par les pentols (xylitol, arabitol et adonitol) sont situées nettement entre celles du tétrol d'un cǒté et celles des hexols de l'autre.En outre, nous avons trouvé que les différences entre elles des augmentations de conductibilité produites par ces pentols sont assez grandes; pour une conc. de 0.25 mol. du polyol dans une sol. demimol. d'acide borique, l'augmentation est de 54.5 × 10−6mhos dans le cas de l'adonitol, de 194.2 × 10−6mhos dans celui de l'arabitol et de 418.0 × 10−6mhos dans celui du xylitol.Ce fait intéressant peut être interprêté par le même raisonnement que celui qui a permis d'expliquer d'une fačon satisfaisante les différences entre les augmentations observées chez les acides tartrique et antitartrique ou leurs éthers alkyliques2) et chez les hydrobenzoines3).En admettant que la répulsion mutuelle des groupes CH2OH ou CHOH. CH2OH est plus grande que celle des groupes OH, on peut montrer que la chance de formation d'un borocomplexe augmente lorsqu'on passe de l'adonitol à l'arabitol et de celui‐ci au xylitol.L'hypothèse générale que les molécules sont mobiles et que les groupes exécutent des mouvements oscillatoires par rapport à des états d'équilibre détermi

ISSN:0165-0513    

DOI:10.1002/recl.19400590202

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

摘要:

AbstractA research has been carried out with regard to the composition of the essential oils distilled from the leaves ofLitsea cubebaPers. 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.

ISSN:0165-0513    

DOI:10.1002/recl.19400590203

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

摘要:

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 n1and n2from v = k × c1n1× c2n2.n1was found to vary between 1 and 2, n2between 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

ISSN:0165-0513    

DOI:10.1002/recl.19400590204

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

摘要:

AbstractThe specific heats of iron‐nickel‐alloys with about 10%, 20%, 30%, 40%, 50%, 70% and 80% nickel have been determined. The so‐called “reversible” alloys (with 40% nickel and more) prove to show an evident conformity of their cp‐t‐curves. On the other hand, the “irreversible” alloys (with 0—30% nickel) exhibit a deviating course of their cp‐t‐curves. An appreciable discontinuity was observed in the curves of alloys with 10% and 20% nickel at the γ → α‐transformation; the alloy with 30% nickel, moreover, shows a strong retardation at its transformation point. The influence of cooling in liquid air was studied: the γ → α‐transformation is only completed at a rather low temperature.The true specific heats cpwere deduced from the values of c̄pobtained 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 ofinvar(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

ISSN:0165-0513    

DOI:10.1002/recl.19400590205

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

摘要:

AbstractFurther particulars are given regarding the solubility of oxygen in zirconium (table I). It is shown that the oxygen atoms are present in the interstices of the zirconium lattice and that at high temperatures they have a great mobility in the lattice. Under the influence of an electric field it is found that under suitable conditions of temperature and potential drop the oxygen moves through the metal lattice as a negative ion, causing the oxygen concentration (and with it the electrical resistance) to increase at the anode end and to decrease at the cathode end (fig. 2).

ISSN:0165-0513    

DOI:10.1002/recl.19400590206

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

摘要:

AbstractVerschiedene Forscher berichten über die Eigenschaften und die Zusammensetzung des “Canari‐Öls”. Ihre Angaben stimmen aber nicht überein. Hier wird gezeigt, dass das Öl nur aus Glyceriden der Palmitin‐, der Stearin‐, der Öl‐, der Linol‐ und der Linolensäure

ISSN:0165-0513    

DOI:10.1002/recl.19400590207

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

摘要:

AbstractDie bisherigen Methoden zur Darstellung und Spaltung des razemischen 1,2‐Diphenyl‐1,2‐diaminoäthans (Stilbendiamins) werden kurz besprochen. Eine neue Darstellungsmethode, die erlaubt, grosse Mengen des reinen Diamins mit wesentlich geringerem Kostenaufwand zu bereiten, wird angegeben. Die Eigenschaften der reinen Base und einiger ihrer Derivate werden mitgeteilt und endlich eine neue, bequeme Spaltungsmethode besch

ISSN:0165-0513    

DOI:10.1002/recl.19400590208

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

摘要:

AbstractI. In a previous publicationThis journal58, 111 (1939).the dipole moments of a number of heterocyclic parent nuclei were measured.II. The most probable structure of these molecules is calculated according to a simple principle of minimum energy described in this publication.III. The object of this publication is to investigate in how far dipole moments of heterocyclic molecules agree to those of the corresponding open‐chain molecules. It was found that the bond moments calculated from cyclic molecules are always greater than those which can be calculated for the corresponding open‐chain molecules. The bond moments calculated from open‐chains molecules are therefore inapplicable for the calculation of the valency angles in heterocyclic molecules from their dipole moments.IV. Description of the re

ISSN:0165-0513    

DOI:10.1002/recl.19400590209

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

摘要:

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

ISSN:0165-0513    

DOI:10.1002/recl.19400590210

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19400590201

出版商:WILEY‐VCH Verlag    

年代:1940

数据来源: WILEY