( 260 ) 



temperature higher substituted nitro-products were readily formed. 

 It' the nitration is carried out ;ii -f- 60° a product is formed which 

 solidifies at - 9°,2, a temperature which is situated lower than the 

 eutectic one of mixtures of the two pure components. The sp. gr. 

 i- i.2i>2t>. No doubt considerable quantities of polyvalent nitro- 

 compounds arc formed at this high temperature of nitration. 



Amsterdam, Ore. chem. lalt. Univ. Aug. '08. 



Chemistry. " The quantitativi estimation of the products of 



nitration of m-chloro and m-bromobenzoic acid. By Prof. A. 



F. HOLLEMAN. 



The above investigation has occupied me more than once. l ) In 

 the nitration of each of these acids two nitrohalogen acids are 

 formed namely 1,6,3 = CO a H, NO,, CI (Brl as main product and 

 1,2,3 = ('< >,H, N( >,, CI (Br) as byeproduct ; the question arose in what 

 proportion these acids are present in the nitration mixture. 



The reasons which induced me to revert to this investigation 

 are twofold. Firstly, because the percentage of byeproduct in the 

 nitration mixture of m-chlorobenzoic acid was found 2.8 'higher in 

 the first investigation than in the second, when another method of 

 analysis was applied and this difference was not satisfactorily explained. 

 Secondly because n was found in the nitration of c-chloro- and 

 e-hromobenzoic acid and also in that of m-chlorobenzoic acid, that 

 more byeproduct is formed at 3 than at — 30, whereas in the 

 nitration of m-bromobenzoic acid the very opposite result was noticed. 



In the first investigation the quantity of main product was deter- 

 mined by extracting the nitration mixture with benzene and deter- 

 mining the sp. gr. of the benzene solution. In the second determination 

 the quantity of byeproduct was deduced from the solidifying point 

 of the mixture. A third modus operandi was followed for this renewed 

 investigation, namely, the extraction of the nitration mixture with 

 water and titration of the aqueous solution obtained. 



I do not intend giving any further details of these methods as I 

 described these repeatedly ou former occasions. 



Mssrs. J. J. Polak and H. L. de Leeuw, who have carried out these 

 investigations independently, started from chemically pure preparations 

 of m-chloro- and m-bromobenzoic acid, which were nitrated with absolute 

 nitric acid after which the nitration product was collected according 



>) R. 19 188, 1.1900] and R. 20, 223 [1908]. 



