48 Dr. A. W. Hofmann on Aromatic Monamines. [Dec. 5, 



inquiry, I will limit myself for the present to a brief statement of the 

 principal results obtained. 



Leaving secondary reactions out of consideration, the transformation 

 of the trimethylated phenylammonium iodide is represented by the 

 following equations : — 



Transformation of quartary into tertiary compound. 

 C 6 H 5 . CH 3 . CH 3 . CH 3 . NI=(C 6 H 4 . CH 3 ) CH 3 . CH 3 N . HI. 



Transformation of tertiary into secondary compound. 

 (C 6 H 4 . CH 3 ) CH 3 . CH 3 . N . HT= [C 8 H 3 (CH 3 )J CH 3 . HN . HI. 



Transformation of secondary into primary compound. 

 [0, H 3 (CH 3 )J CH, . HN . HI=[C 6 H 2 (CH 3 ) 3 ] HHN . HI. 



Accordingly trimethylated phenylammonium iodide, when submitted 

 to the action of heat, is transformed, in the first place, into iodhydrate of 

 dimethylated methylophenylamine or dimethyltoluidine ; this, hi a second 

 phase of the reaction, becomes iodhydrate of monomethylated dime- 

 thylophenylamine or methyl xylidine, which in its turn is ultimately con- 

 verted into iodhydrate of trimethylophenylamine, i. e. of cumidine. The 

 essential character of the reaction is thus seen to be an intramolecular 

 change in the position of the methyl groups. According to the duration 

 of the process, there are incorporated in the benzol nucleus, first the methyl 

 group of the alcohol iodide, and then successively the two methylic 

 groups which are stationed in the ammonia fragment. The action of 

 heat on the quartary ammonium compound thus places at our disposal a 

 simple means of rising from the benzol series itself to the toluol, xylol, 

 and cumol series, or, generally (for the reaction may probably be utilized in 

 many other cases), of passing from a less carbonated to a more carbonated 

 series of compounds. 



In carrying out the researches, the general results of which are sketched 

 in the preceding paragraphs, rather considerable quantities of trimethy- 

 lated phenylammonium iodide were consumed. This I obtained partly 

 by methylating pure aniline with methyl iodide, partly by starting from 

 commercial dimethylaniline, which was most liberally supplied to me by 

 my friends Drs. Martius and Mendelssohn Bartholdy, having been spe- 

 cially purified for this purpose by Mr. Gr. Krell, by fractional distillation 

 in the laboratory of the factory. This purified material was found to boil 

 between 192° and 200° ; and only few rectifications were necessary in order 

 to obtain from it dimethyaniline in a state of perfect purity, identical in 

 every respect with the base prepared by submitting trimethylated phenyl- 

 ammonium hydrate to distillation. Pure dimethylaniline is a liquid of 

 0*9553 volume weight, sohdifying to a crystalline mass at + o, 5, and boiling 



