摘要:

AbstractThe behaviour of membranes in contact with electrolyte solutions has been studied as regards both electrical potential differences between the two sides of the membranes and the movement of dissolved substances as well as solvent (water) through the membrane. This first communication deals with potential measurements on “cellophane” membranes through which KCl and NaCl solutions diffused towards solutions of ten times smaller concentrations of the same salt. The pH was maintained the same on both sides of the membrane. It was found that pH had a great influence on the measured membrane diffusion potential (MP) (table III).The difference Δ between MP and the liquid junction potential (LJP) was the same in KCl and in NaCl experiments. Δ increases with the pH according to a curve (fig. 1) which is very similar to the dissociation curve of a monobasic acid. There is apparently a close correlation between MP (or Δ) and the dissociation of acid groups in the membrane sub

ISSN:0165-0513    

DOI:10.1002/recl.19510700702

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractBy heating 3‐bromopyridine‐N‐oxide hydrochloride with sulphuryl chloride at 120°, 3‐bromo‐4‐chloropyridine is formed together with 3‐bromo‐2‐chloropyridine and some 3‐br

ISSN:0165-0513    

DOI:10.1002/recl.19510700703

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractIt is shown that the nitro‐group in 4‐nitropyridine‐N‐oxide can be readily replaced by negative ions and that the N‐oxides thus obtained, can be reduced quantitatively to the corresponding pyridine derivatives.This fact reveals an excellent method for the preparation of several 4‐substituted pyridine‐N‐oxides and pyridines. It is all the more useful, since the synthesis of 4‐nitropyridine‐N‐oxide has been simplified.The preparation of 4‐bromo‐, 4‐chloro‐ and 4‐ethoxypyridine

ISSN:0165-0513    

DOI:10.1002/recl.19510700704

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe nitration of some mono‐substituted derivatives of pyridine‐N‐oxide containing a bromine atom, an ethoxy‐ or a methyl‐group in positions 2 or 3, has been investigated.When these compounds are heated With a mixture of fuming nitric acid and sulphuric acid, a nitro‐group is introduced into the 4‐position. It appears that the course of the nitration is not influenced by the presence of the bromine atom, the ethoxy‐ or methyl‐group in the nucleus. A 4‐nitro‐compound is obtained even from 2‐ethoxypyridine‐N‐oxide, the nitro‐group entering themeta‐position with respect to the stronglyor

ISSN:0165-0513    

DOI:10.1002/recl.19510700705

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractSome time ago1) we described the formation of cinnamaldehyde by the action of boron fluoride ether on benzaldehyde. We suggested a possible mechanism of reaction: benzaldehyde gives benzyl alcohol by a Canizzaro reaction. The latter then reacts with boron fluoride ether with the formation of benzyl ethyl ether and ethyl alcohol. Dismutation of ethyl alcohol with benzaldehyde then gives acetaldehyde, which condenses with benzaldehyde to form cinnamaldehyde.In order to obtain support for the above suggestion we have made attempts to detect the presence of benzyl ethyl ether in the reaction mixture.

ISSN:0165-0513    

DOI:10.1002/recl.19510700706

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe experiments ofBuchnerandMeylinkon the effect of ions of divalent metals on the melting point of the gelatin gel have been extended to the bromides and iodides of some of these metals. Since similar results were not observed, the chlorides were re‐examined. The relation found byBuchnerandMeylinkcould not be confirmed. A relation between the concentrations of salt necessary to lower the melting point to a definite temperature and the equivalent conductance of the cations could be deduced, however. With the aid of these equations it was possible to calculate the depression of the melting point for 0.5nsolutions, which agreed with the experimental data.The maxima occurring in the melting curves are explained by the presence in the solution of insoluble hydroxides, produced as a result of hydrolysis. This was confirmed by an investigation with aluminium chloride and lanthanum chloride and some hydroxides. A connection has been found to exist between the heights of the maxima and the degrees of hydrolysis of the salts.The abnormal course of the melting curves with beryllium chloride, aluminium chloride and lanthanum chloride are discussed in more detai

ISSN:0165-0513    

DOI:10.1002/recl.19510700707

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe method outlined in part I *) is applied to solutions of cellulose nitrate in acetone. It is found that the non‐Newtonian character of the flow is strongly dependent on the polymer concentrations, but does not persist at the limit of infinite dilution. In other words, the non‐Newtonian character of the flow is not an intrinsic property of the polymer molecule but results from molecular interactions.The concentrations were varied between 0.05 and 0.2 g/100 ml. In one series we went up to 0.8 g/100 ml. The highest gradient attained was about 5.104se

ISSN:0165-0513    

DOI:10.1002/recl.19510700708

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractEn faisant réagir des amines aliphatiques et aromatiques sur le trichloracétonitrile, les auteurs ont préparé plusieurs trichloracétamidines. L'addition de guanidines et d'amidines à ce nitrile conduit à des dérivés moins simples de la trichloracétamidine.Trois nouveaux composés, soumis à l'examen bactériologique, ont présenté une activité bactériostatique. Cependant leur activité est inférieure à celle du sulfanilamide et leur toxicité en

ISSN:0165-0513    

DOI:10.1002/recl.19510700709

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

摘要:

AbstractThe action of 43 % sulphuric acid on methylchavicol\documentclass{article}\pagestyle{empty}\begin{document}\[{\rm CH}_3 {\rm O}{\rm .C}_6 {\rm H}_1 .{\rm CH}_2 - {\rm CH = CH}_{\rm 2} \left({\rm I} \right)\]\end{document}has afforded metanethole, m.p. 135°, along with a mixture of substances, which can be shown to contain in all probability isoanethole and from which two products melting at 76.5° and 94°, respectively, could be isolated. The structures of these two products has been determin

ISSN:0165-0513    

DOI:10.1002/recl.19510700710

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19510700701

出版商:WILEY‐VCH Verlag    

年代:1951

数据来源: WILEY