COLORATION OF ANILINE: II. 421 



It has been shown 7 that dimethylaniline adds on oxygen to form the 

 compound C B H 5 -N=(CH 3 ),. This tendency seems to be a peculiarity of the group 

 II 





 C 6 H 5 .N : X3. It thus seems probable that while the fixation of the lahile hydrogen 



atoms of aniline will destroy the sensibility of the compound to the action of 

 light in the absence of oxygen, in the presence of oxygen the dimethyl compound 

 may undergo chemical change. 



The absorption spectrum of aniline has been studied by various in- 

 vestigators. 



Hartly and Huntington 8 found that in solutions the absorption extended in 

 the ultra-violet from about A=310 ftu on, and in thinner layers there appeared an 

 absorption band from about 285 to 274 fifi and complete absorption from 250 

 ixfi, on. By greater dilution the first band disappears and a second forms between 

 240 and 232 /x/x. Pauer 10 gives for one gram molecule in 20 liters in layers 

 of 1 centimeter thickness, absorption from 315 ftu on, and in greater dilution 

 an absorption band between 298 and 268 /x/i with, a transmission band between 

 268 and 258 fi/i. 



Purvis " studied the absorption spectra of the vapor, the liquid and alcoholic 

 solutions. The vapor showed considerable variation in the bands due to changes in 

 temperature and pressure. At 14 degrees and 763 millimeters pressure he measured 

 83 bands from A=297.8 /u/i to 271.7 n/i. The complete absorption began about 

 240 ftp. At 30 degrees and 807 millimeters there were 85 bands, at 45 degrees 

 and 833 millimeters, 36 bands, at 60 degrees and 863 millimeters 13 bands, at 

 75 degrees and 893 millimeters 6 bands and at 90 degrees and 923 millimeters 

 the bands had all disappeared and complete absorption began at about 307 /j./j~ 

 The absorption spectrum of liquid aniline shows no bands. The point at which 

 complete absorption begins depends upon the thickness of the layer and was 

 found to be 318.5 fxfx for a film of 0.050 millimeter thickness varying to 314 fifx, 

 with a film 0.001 millimeter thick. In alcoholic solutions this investigator's 

 results agree with the prior work of Hartley and Huntington, and Baly and 

 Collie. The absorption spectrum of the vapor has also been investigated by 

 Pauer and by Grebe. 12 The absorption in the visible and infra-red has been 

 investigated by Russell and Lapraik 13 and others." The former found bands 

 between 706 and 700, 653 and 647, 631 and 629 and 614 and 609 /*/*. The 

 transmission is evidently relatively complete between 609 and 315 fifi. 



Baly and Collie 15 have shown that the broad absorption band in the ultra- 

 violet is due to the basic nitrogen atom, and Baly and Marsden 16 state that the 



7 Bamberger and Rudolf, Ber. d. deutschen chem. Oes. (1908), 41, 3290. 



"Phil. Trans. (1879), 170, 271. 



9 Baly and Collie, Journ. Chem. Soc. London ( 1905 ) , 87, 1338 and 1346, repeated 

 the work with identical results. They state that there is a broad absorption band 

 heading about 288 h/j.. 



10 Ann. d. Phys. u. Chem. (Wiedermann), (1897), 61, 374. 



11 Journ. Chem. Soc. London (1910), 92, 1546. 



12 Chem. Centralol. (1906), 77, 341; Ztschr. f. wiss. Photograph., Photophys. u. 

 Photochem. (1905), 3, 376. 



13 Journ. Chem. Soc. London (1881), 39, 168. 



11 Hand 'buch d. Spectroscopic, Kayser. Leipzig (1905), 3, 476. 

 15 Journ. Chem. Soc. London (1905), 87, 1338. 

 u IUd. (1908), 93, 2108. 



