BENZENE SERIES. AROMATIC COMPOUNDS. 565 



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

 tioned that of roaaniline, which takes place thus: 



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

 Aniline. Toluidine. Rosaniline. 



Experiment 70. To some of the aniline obtained by performing Experiment 

 69 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. 



Acetanilide, Acetanilidum, C 6 H 5 .NH.(CH 3 CO) 134.09, (Anti- 

 febrine, Phcnylacdamide). The term anilide is used for derivatives 

 of aniline obtained from this compound by replacement of the am- 

 monia hydrogen (or amino hydrogen) by acid radicals. If the radical 

 introduced is acetyl, C 2 H 3 O, the resulting compound is acetanilide, 



C* TT 



the constitution of which is represented in the formula NH^p 6 TT 5 r\ 



It is obtained by boiling together for one or two days equal weights 

 of pure aniline and glacial acetic acid, distilling and collecting the por- 

 tion which passes over at a temperature of about 295 C. (563 F.). 

 The distillate solidifies on cooling and may be purified by recrystalliza- 

 tion from solution in water. The chemical change taking place is this : 



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



Pure acetanilide forms white odorless crystals of a silky lustre and a greasy 

 feeling to the touch. It fuses at 113 C. (235 F.) and boils at 295 C. (563 F.) ; 

 it is but slightly soluble in cold, much more soluble in hot water, readily solu- 

 ble in alcohol and ether ; the solutions have a neutral reaction and are not 

 colored by either concentrated sulphuric acid or by ferric chloride. 



Analytical reactions: 



1 . When 0.1 gramme of acetanilide is boiled for several minutes with 

 2 c.c. of hydrochloric acid, and to this solution are added 3 c.c. of an 

 aqueous solution of phenol (1 in 20) and 5 c.c. of a filtered, saturated 

 solution of bleaching powder, a brownish-red liquid is obtained which 

 turns deep blue upon supersaturation with ammonia water. 



2. On heating 0.1 gramme of acetanilide with a few c.c. of concen- 

 trated solution (1 in 4) of potassium hydroxide, the odor of aniline 

 becomes noticeable ; on now adding chloroform, and again heating, 

 the disagreeable odor of the poisonous phenyl-isocyanide, C 6 H 5 NC, is 

 evolved (distinction from antipyrine). 



3. A mixture of equal parts of acetanilide and sodium nitrite 



