摘要:

AbstractThe compound N‐(2,4‐dinitrophenyl)‐N′‐methylnitro‐urea is easily prepared, and as a reagent for the identification of alcohols it combines many of the advantages of the substances used until now, while it lacks most of their di

ISSN:0165-0513    

DOI:10.1002/recl.19420610302

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

摘要:

AbstractIt is emphasized that on the basis of modern insight a scientific investigation of the plasticity of rubber should be carried out with the help of plastometers in which the test pieces are subjected as far as possible to a simple shear e.g. in cylindrical rotation plastometers. A true interpretation of the results asD‐τ relations is possible in that case only. Since, however, no rotation‐plastometer was at our disposal, while up to the present plasticity measurements have been carried out by means of plane parallel plate plastometers, an attempt was made to find out whether any preliminary impression of theD‐τ relations of rubber could be obtained from these results, using the theory of Scott.Measurements were carried out on raw and normally masticated rubber at increasing temperatures with the help of the balance plastometer of Hoekstra and of another plane parallel plate plastometer. The latter apparatus was used with varying weights of 5 and 10 kg. and with and without platform of 1 cm2. The results were recalculated toD‐τ relations.These only have a lim

ISSN:0165-0513    

DOI:10.1002/recl.19420610303

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

摘要:

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; unbe

ISSN:0165-0513    

DOI:10.1002/recl.19420610304

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

摘要:

AbstractEs wurde für Systeme der Type AgJ‐Elektrolyt ein Bild der Phasengrenzstruktur entwickelt, wobei die speziellen Eigenschaften der beiden in Kontakt stehenden Phasen in Rechnung gestellt wurden.Die in früheren Abhandlungen beschriebenen charakteristischen Eigenschaften dieser Type von Systemen passen ganz zu dem hier ausgearbeiteten Bi

ISSN:0165-0513    

DOI:10.1002/recl.19420610305

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

摘要:

AbstractIn the solid state N,N′‐diethylindigo forms dark blue needles with a metallic lustre. Its solutions in different solvents are an intense malachite green in colour.Depending on the method of crystallization N,N′‐dibenzylindigo forms dark green to nearly black needles. Its solutions however are the same colour as those of N,N′‐di

ISSN:0165-0513    

DOI:10.1002/recl.19420610306

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

摘要:

AbstractWhen trigonelline is heated with alkali, methylamine is split off and the remaining dialdehyde, formed by ring opening, is conjugated to aniline in acid medium.A yellow colour appears almost instantly, suitable for colorimetric determination.No turbidities occur, the colour is sufficiently stable in full daylight and 10 γ per ml can be determined with an accuracy of about 5%

ISSN:0165-0513    

DOI:10.1002/recl.19420610307

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19420610309

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

摘要:

AbstractThe velocity of the reaction between malonic acid and chromic acid has been measured in mixtures of sulphuric acid and water containing from 10 to 96.55% sulph. ac. at temperatures between 273.0° and 353.0° K. The formula for a bimolecular reaction does not hold, but the initial velocity is approximately proportional to the concentration of both reactants.In this case also the initial velocity has an optimum between 70 and 96% sulph. ac. Proportionality between acidity (measured colorimetrically) and velocity does not exist, in contrast to the case of the oxidation of formic acid.The temperature coefficients are largely dependent on the composition of the solvent. For most of the solvents used the formula of Arrhenius does not hold, in accordance with what was found for all substances investigated until now (exception in this case: 10 and 20% sulph. ac.).The temperature cofficients and both the parameters of the equation of Arrhenius show a minimum at about 60% sulph. ac., corresponding to what was found with other substances. Between the parameters a close correlation exists.It is supposed that the large changes in the temperature coefficient, which accompany relatively slight changes in the composition of the solvent, are to be ascribed to the presence of solution components whose concentration is dependent on the temperature and does not increase continuously with the increase of the sulph. ac. content of the solvent. These might be the hydrates SO35 aq. and SO33 aq. or an intermediate compound of CrO3, malonic acid and perhaps hydrates. This supposition could also explain the deviations from the equation of Arrheniu

ISSN:0165-0513    

DOI:10.1002/recl.19420610310

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

摘要:

AbstractThe unknown cyclohexylnitramine was prepared by the reaction of 2 moles of cyclohexylamine with 1 mole of oxalic acid diethyl ester, nitration of the N,N′‐dicyclohexyloxamide formed and saponification of the N,N′‐dinitro‐N,N′‐dicyclohexyloxamide with NH3. Several salts of cyclohexylnitramine are also described. By allowing only 1 mole of cyclohexylamine to react with 1 mole of diethyloxalate the ethyl ester of cyclohexyloxamic acid is formed in which the OC2H5group was replaced by other radicals. Several of the compounds obtained were nitrated to give the correspondi

ISSN:0165-0513    

DOI:10.1002/recl.19420610311

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19420610301

出版商:WILEY‐VCH Verlag    

年代:1942

数据来源: WILEY