摘要:

AbstractWith the aid of an improved and automatically working bromination apparatus, we have closely examined the bromination of bromobenzene, chlorobenzene and fluorobenzene in the gas phase.All the three halogenobenzenes investigated, show a change from theortho‐para‐to themeta‐substitution type at about 400‐450° in brominations with artificial graphite as contact substance. With bromobenzene the relative quantities ofOrtho‐, meta‐andpara‐dibromobenzenes obtained were accurately determined at various reaction temperatures. The effect of temperature on the ratio in which the isomers are produced cannot be explained by the existing theories of substitution.The reaction took a completely different course in brominations with ferric bromide as a catalyst. Under these conditions, the reaction velocity is so high that the reaction can be investigated from 200°. With all three halogenobenzenes, thepara‐ortho‐substitution type persists throughout the whole region of 200‐500°. Similar results were obtained with copper bromide as a catalyst. The theoretical views of Scheffer on the relationship between the reaction temperature and the ratio of the isomers so obtained, in substitutions in the benzene nucleus, which so far has only been tested experimentally over relatively small ranges of temperature, could now be tested over the range of 200‐450° with the data obtained in the bromination of bromobenzene with iron bromide as a catalyst. In this catalytic bromination, the agreement between the values found experimentally and those calculated from Scheffer's formula was excellent.According to the investigations of Holleman and his co‐workers the type of a disubstitution reaction (ortho‐paraormetasubstitution) is determined by the nature of the substituent already present. From our investigations it appears that in the case of Cl, Br or F atoms, which have so far been considered as typicalortho‐paradirecting atoms, the nature of the atom already in the benzene nucleus is not the sole factor determining the type of substitution. It depends on the temperature at which the reaction is carried out and the nature of the catalyst used, whether the reaction belongs to t

ISSN:0165-0513    

DOI:10.1002/recl.19370560902

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

摘要:

AbstractBei der Durchsicht der Literatur fällt auf, dass die Dampfspannungen von gesättigten wässerigen Lösungen sowohl von anorganischen Salzen als auch von organischen Stoffen meistens nur über einen kleinen Temperaturbereich hin gemessen worden sind. Nur für die Systeme H2O‐AgNO31) und H2O‐NH4NO32) wurde diep‐T‐Linie der gesättigten Lösungen bis an den Schmelzpunkt der Salze bestimmt. Hier werden jetzt die Resultate von, nach einer statischen Methode ausgeführten, Dampfspannungsmessungen von gesättigten wässerigen Lösungen von Resorcinol, von Pyrocatechol und von Chinol gegeben, von 15° C an und für die beiden ersteren Stoffe bis zum Schmelzpunkt des gelösten Stoffes.Ebenfalls wurden die Dampfspannungen von wässerigen Lösungen, gesättigt an einem dieser Stoffe, von 15° C an bis zu der eutektischen Temperatur der beiden gelösten Stoffe gemessen. Diese Eutektika wurden erneut bestimmt und für das System Pyrocatechol‐Resorcinol auch die gesamte Schmelzlinie. Dabei wurden bedeutende Unterschiede gegenüber den in der LiteraturH. W. Bakhuis Roozeboom, Verslag. Akad. Wetenschappen Amsterdam 10, 350 (1901)E. Jänecke und E. Rahlfs, Z. a

ISSN:0165-0513    

DOI:10.1002/recl.19370560903

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

摘要:

AbstractOn a amélioré la manière de préparer l'acide 1‐naphtylacétique, substance acrivant la croissance des végétaux. Pour le composé à l'état pur, on a déterminé un point de fusion de 135°‐135°.5, tandis qu'on trouve dans la littérature des chiffres vari

ISSN:0165-0513    

DOI:10.1002/recl.19370560904

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

摘要:

AbstractEn général les hydrocarbures saturés n'ont pas de moment diélectrique. II était cependant possible que cet équilibre électrique n'existât plus dans les dérivés monosubstitués des cyclanes. Len‐propylcyclopropane préparé dans ce but montrait en effet un petit moment diélectrique. L'hydrocarbure a été obtenu comme suit: CH2(COOC2H5)2→nC3H7CH(COOC2H5)2→. →nC3H7CH(CH2OH)2→

ISSN:0165-0513    

DOI:10.1002/recl.19370560905

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

摘要:

AbstractThis communication deals with a continuation of work described in the previous paper on this topic2). Some halogenonitro‐derivatives of 1:2‐bis‐(phenylamino)‐ethane with the halogen atom in themeta‐position are first described along with their nitration to explosive nitramines. The bromination and chlorination of 1:2‐bis‐(phenylamino)‐ethane and some of its derivatives are then discussed. The nitration of the acetyl compounds of 1:2‐bis‐(phenylamino) ‐ethane and its derivatives leads to the formulation of some rules on substitution. Finally, the nitration of N.N'diphenylpiperazine and its derivatives is dealt with, the occurrence of ring opening pointing to a striking analogy with van Romburgh's nitrati

ISSN:0165-0513    

DOI:10.1002/recl.19370560906

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

摘要:

AbstractThe initial speed of oxidation of succinic, glutaric and adipic acid by chromic acid has been measured at temperatures varying from 25°‐99° and at sulphuric acid concentrations from 60‐100%.The curves which represent the relation between the concentration of the sulphuric acid and the speed of oxidation are very similar for these three substances, though at one and the same concentration they are oxidised at rather different rates.A maximum, shifting from the side of higher acid concentrations to that of lower concentrations with decrease of the temperature, is found between 78.2% and 75.5% sulphuric acid, and a minimum, which shifts in the opposite direction, at about 99.5%. At still higher concentrations a very considerable increase of the speed of oxidation is found.The constants of Arrhenius' formula are calcu

ISSN:0165-0513    

DOI:10.1002/recl.19370560907

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

摘要:

AbstractIt is shown that in computing the cohesive energy of a mixture it is possible to allow for the different sizes and shapes of the molecules by introducing an interaction constant. This constant is calculated for some molecules from the work of Hirobe; the calculation gives constant values for molecules of small polarity; for strongly polar molecules the theory will be given in a later paper.

ISSN:0165-0513    

DOI:10.1002/recl.19370560908

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

摘要:

AbstractThe values ofEand log.AinkT=Ae ‐E/RT. which have been published for the oxidation of succinic acid with chromic acid in sulphuric acid of varying strength, allow one to calculatekTfor any temperature. The maximum which was found in thekT‐acid concentration curve must show a shift to lower sulphuric acid concentrations with decrease of the temperature. At −40° it is found very near to the composition SO33 aq. This, and the fact that the speed of oxidation increases rapidly with the acid concentration as soon as the composition SO35 aq. has been reached, leads to the conclusion that SO33 aq. is one of the active components of the system. Comparison of the speed of decomposition of chromic acid, the speed of oxidation of organic substances and the speed of decomposition of organic substances by sulphuric acid, leads to the conclusion that a second hydrate, probably 2 SO31 aq. is active too. It is known that reactions which are dependent on the concentration of this substance have an abnormally high temperature coefficient. The superposition of the effects caused by these two hydrates explains the behaviour of solutions of sulphuric acid in water at different temperatures in a number of

ISSN:0165-0513    

DOI:10.1002/recl.19370560909

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

摘要:

AbstractFrom kinetic measurements of the reactions of Me, Et, Prβand Buγ, phenyl ethers, acetates, alcohols (with hydrogen bromide) and bromides (with aqueous alcohol) Buγcompounds are found to react very much more rapidly than the others. The suggestion is made that in primary and secondary aliphatic compounds. AlkX, X is bound partially by α‐hydrogen. This would support theories of Polanyi and others to explain the Walden Inversion as shown by the relative reactivities of the corresponding alkyl halides with a

ISSN:0165-0513    

DOI:10.1002/recl.19370560910

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19370560911

出版商:WILEY‐VCH Verlag    

年代:1937

数据来源: WILEY