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Chemistry. — Professor A. P. N. FRANCHIMONT presents to the 
Jibrary of the Academy Dr. P. J. Monraenn’s dissertation, 
entitled “ The action of hydrogen nitrate upon the three 
tsomeric chloro-benzoic acids and some of their derivatives’. 
(Read January 27, 1900.) 
The contents of which he explains as follows: 
MONTAGNE’s work originated in experiments made by VAN 
RoMBURGH in 1885 and by Taverne in 1897 and 1898. Van 
RomBuRGH had treated benzamide and its two methyl derivatives 
with nitric acid at the ordinary temperature and had found that, 
to some extent, their behaviour differed from that of the aliphatic 
amides and methyl-amides under the same circumstances; this 
together with other facts was at first ascribed to the more pronounced 
negative properties of the aromatic atomic group. As, however, in 
the nitration of aromatic substances, this also takes place in the 
nucleus, the question first arose whether the change of the carboxyl 
group into the amide or methyl-amide group had any effect on the 
position taken up by the nitro-group. Experience regarding the 
nitration of aromatic substances teaches that the NO», group often 
takes up more than one position, the greater part into one and a 
smaller part into another, and that this depends, among other 
things, on the temperature at wich the reaction takes place ; 
when the temperature is lowered the formation of the bye-product 
sometimes diminishes or ceases. TAVERNE showed that the tempe- 
rature and the duration of the action of the nitric acid influenced 
the result. If, therefore, we want to follow the effect of an alteration 
in the side chain it is desirable to make the experiments at the 
same, preferably low, temperature. The negative properties of the 
benzene nucleus are however changed by the entrance of a nitro- 
group to a degree which varies with the position taken up by the 
nitro-group. Since the greater or smaller negativeness of this nucleus 
may influence the action of the acid on the side chain, it was of 
importance to investigate the effect of altering the negativeness of 
the benzene group in some other way. MonvraGNe chose the 
increase of the negativeness by the introduction of chlorine and 
therefore investigated the action of nitric acid at zero on the three 
isomeric chloro-benzoic acids and also on their methyl esters, amides, 
methyl- and dimethylamides. Then Taverne had found no difference 
in the nitration at zero of benzoic acid and of its methyl ester, 
but a difference existed in the case of the amide. HOLLEMAN has 
only recently demonstrated by means of more accurate experiments 
