( 264 ) 



was determined by titration. For this purpose Ü.1 gram of the 

 nitration mixture was dissolved in water and titrated with N,10 

 alkali; when using phenolphthaleine as indicator this titration is 

 accurate within one drop. 0.1 gram is about 0.5 millimol of chloro- 

 and 0.4 millimol of bromonitrobenzoic acid which require 5 and 4 cc. 

 of N 10 alkali respectively. One drop (0.05 cc.) corresponds therefore, 

 with 1% of the molecular weight of the chloro- or 0.8% of the 

 bromo-acid. II* now the molecular weighl lies between 201.5 + 2 or 

 246 + 2, respectively the substance may he taken to be pure nitro- 

 acid. True it might be possible that, accidentally, a mixture had 

 formed consisting of unattacked acid, mononitro- and dinitro-acid, 

 which apparently possesses the molecular weight of the pure inono- 

 nitro-acid but apart from the improbability that this should have 

 formed, the possibility was also excluded, because the nitration 

 mixture of w-bromobenzoie acid was again treated with absolute 

 nitric-acid, which caused no serious alteration in the molecular 

 weight. Mol. weight first 245; on repeated treatment 247. 



Mr. De Lkki w obtained the following results in the analysis of 

 the nitration products prepared b\ himself. 



I. Nitration of tfi-chlorobenzoic acid at 0°; 5 grams treated with 

 lit) grams of absolute nitric acid. 

 Mol. weight of the product 203.2. 



1. Weighed 381.9 mgrs. of nitration product; shaken with about 

 100 mgrs. of byeproduct {COJIJ'LXO., = 1,3,2) and 100 grams of 

 water at 25°.0. 



Pipetted oil' 36.256 grains of solution which required 15.10 cc. 

 of 0.0432 normal potassium hydroxide for neutralisation. 

 Main product 92.4°,,; byeproduct 7.6%,. 



2. Weighed 364.1 mgrs. of nitration product: shaken with about 

 100 mgrs. of byeproduct and 100 grams of water at 25°. 0. 



Pipetted off 69.464 grams which required 27.85 cc. of the said 

 alkali for neutralisation. 



Main product 92.8%; byeproduct 7.2%. 



II. Nitration of m-chlorobenzoic acid at — 30°; 5 grams treated 

 with 30 grams of absolute nitric acid. 



Molecular weight of the nitration product 200.4. 



1. Weighed 351.7 mgrs. of the product; shaken with about 

 100 mgrs. of byeproduct and 100 grams of water at 25°. Pipetted 

 off 34.538 grams of solution which required 13.5 cc. of the above 

 alkali for neutralisation. 



Main product 93.5%; byeproduct <>5 „ 



