BENZENE DERIVATIVES CONTAINING NITROGEN. 383 



themselves distinguished by beautiful colors or may be converted 

 into numerous derivatives showing all the various shades of red, blue, 

 violet, green, etc. 



As an instance of the formation of an aniline dye may be men- 

 tioned that of rosaniline, which takes place thus : 



C 6 H 7 N + 2C 7 H 9 N + 30 : C 20 H 19 N 3 + 3H 2 O. 

 Aniline. Toluidine. Rosaniline. 



Experiment 60. To some of the aniline obtained by performing Experiment 

 59 add a little solution of bleaching powder : a beautiful purple color is ob- 

 tained. Treat another portion with sulphuric acid to which an aqueous solu- 

 tion of potassium dichromate has been added : a blue color is produced. A 

 third quantity treat with solution of cupric sulphate and potassium chlorate : 

 a dark color is the result. 



Diphenyl-amine, (0 6 H 5 ) 2 NH, is obtained by the destructive distillation of 

 triphenyl-rosaniline (aniline blue) as a grayish crystalline substance, slightly 

 soluble in water, more soluble in acids. A 0.2 per cent, solution in diluted 

 sulphuric acid (forming diphenyl-sulphonic acid) is colored intensely blue by 

 nitric acid ; also, temporarily by nitrous acid and, somewhat less intensely, 

 by hypochlorous, bromic, and iodic acids, and a number of other oxidizing 

 agents. 



Meta-phenylene-diamine, or Diamido-benzol, C 6 H 4 (NH 2 ) 2 , is obtained by 

 the reduction of meta-dinitrophenol as a grayish crystalline powder. It has 

 strongly basic properties, is somewhat soluble in water, readily soluble in alco- 

 hol or ether. It is a valuable reagent for nitrites, as it forms with even traces 

 of nitrous acid an intense yellow color. 



Sulphanilic acid, Aniline-para-sulphonic acid, C 4 H 6 .NH. 2 .S0 3 H. Obtained 

 by heating 1 part of pure aniline oil with 2 parts of fuming sulphuric acid, 

 and purifying the product by crystallization. 



C 6 H 5 .NH 2 + H 2 S0 4 = C 6 H 4 .NH 2 .SO 3 H + H 2 O. 



It is a colorless crystalline substance, soluble in 182 parts of cold water. 

 When sulphanilic acid is acted upon by nitrous acid, it is converted into diazo- 

 benzol-sulphonic acid, C 6 H 5 NNSO 4 H, which is of interest because it is used as a 

 reagent in Ehrlich's diazo-reaction in urinary analysis. 



Acetanilid, Antifebrine, C 8 H 9 NO or C 6 H 5 .NH.C 2 H 3 O (Phenyl- 

 acetamide). The term anilid is used for derivatives of aniline obtained 

 from this compound by replacement of the ammonia hydrogen (or 

 amido hydrogen) by radicals, and according to the introduction of an 

 alcohol radical or acid radical a distinction is made between " alcohol 

 anilids" and "acid anilids." 



If the radical used for replacing the hydrogen in aniline is acetyl, 

 C 2 H 3 O, the radical of acetic acid, the resulting compound is acetanilid,. 



