94 REPORTS ON THE STATE OP SCIENCE. 



(2) The shallow absorption bands which appear in the near ultra- 

 violet region at wave-lengths from 3000 to 4200 in the case of sub- 

 stances such as acetone are almost without influence on the optical 

 properties of these substances in the visible region. 



(3) The dominant absorption may, however, be brought nearer to 

 the visible region by introducing an ethenoid linkage, as in allyl alcohol, 

 or a benzenoid nucleus as in phenyl ethyl carbinol ; but in none of the 

 simple compounds of which the magnetic rotatory dispersion has been 

 determined does the dominant absorption fall within the region usually 

 photographed in the study of absorption spectra. 



The Transformation of Aromatic Nitroamines and Allied Substances, 

 and its Relation to Substitution in Benzene Derivatives. — Report of 

 the Committee, consisting of Professor F. S. Kipping (Chairman), 

 Professor K. J. P. Orton (Secretary), Dr. S. Kuhemann, Dr. A. 

 Lapworth, and Dr. J. T. Hewitt. 



Transformations of Chloro- and Bromo-amines into Halogenanilides . 

 In last year's Report the following conclusions were reached: — 



1. The chlorination and bromination of anilides is a direct process, 

 and does not take place by way of the chloro- or bromo-amines. These 

 substances ai*e by-products. 



2. The conversion of a chloroamine into the isomeric chloroanilide 

 can only take place in the presence of hydrogen chloride. This acid 

 and the chloroamine react reversibly : — 



ArNCl-Ac+HCl ^ ArNHAc + Cl,. 



The anilide and chlorine can then react directly, forming chloroanilide. 



Hydrogen bromide (and hydrogen iodide) react similarly, for 

 example, in a suitable medium: — 



Ar NClAc + HBr ^ BrCl + ArNH Ac. 



Bromination of the anilide and not chlorination now ensues. 



3. When chlorine reacts with an anilide, two very rapid changes 

 occur side by side, (a) the formation of a chloroamine, Ar'NCTAc, and 

 hydrogen chloride, N-chlorination ; (b) the formation of a chloroanilide, 

 ClArNHAc, and hydrogen chloride, C-chlorination. 



4. The existence of a complex, Ar"NHAcCl 2 , as an intermediary 

 in these reactions was discussed. Its relations are shown in the 

 scheme : — 



^ArNClAc + HCl 

 Cl 2 + Ar-NH Ac ^Ar-NH AcCl 2 - 



^^ ClArNHAc + HC1. 



Although its existence is not excluded by the results, it was shown 

 that such a complex must have very different properties in the case of 

 different anilides ; as the composition of the medium is changed, the 



