Am.  Jour.  Pharm. 
May,  1910. 
} 
Quinine  Salts. 
221 
melts  with  decomposition.  It  thus  follows  that  no  distinct  melting- 
point  can  be  given  for  this  salt. 
This  acid  requires  475  parts  of  water  at  25 0  C.  for  solution. 
The  test  adopted  by  the  U.  S.  Pharmacopoeia  for  the  determina- 
tion of  the  presence  of  acetanilide  cannot  be  used  in  its  present 
form,  as  even  the  purest  acetphenetidin  will  not  give  a  clear  solution. 
If,  however,  the  method  is  modified  in  the  following  way,  very 
small  quantities  of  acetanilide  can  be  detected : 
A  quantity  of  0.1  Gm.  of  acetphenetidin  is  mixed  in  a  test-tube 
with  2  c.c.  of  a  solution  of  potassium  hydroxide,  1  to  2,  and 
the  test-tube  put  in  boiling  water  for  two  minutes,  shaking  it 
during  this  time.  The  contents  of  the  tube  are  now  diluted 
with  4  c.c.  of  cold  water,  the  mixture  cooled  and  filtered  through 
a  small  pellet  of  glass  wool.  To  the  resulting  clear  liquid  5  c.c. 
of  solution  of  chlorinated  soda  are  added.  If  the  acetphenetidin 
is  pure  a  clear  yellowish  solution  is  produced ;  if  acetanilide  is 
present  the  liquid  will  assume  at  once  a  slight  to  a  dark  purplish- 
brown  color,  according  to  the  quantity  of  acetanilide  present,  the 
color  changing  gradually  to  yellow  when  allowed  to  stand  for 
some  time. 
This  test  will  show  the  presence  of  even  less  than  2  per  cent, 
of  acetanilide. 
A  list  of  official  chemicals  is  appended  for  which  the  sulphuric 
acid  test  has  been  adopted.  It  is  very  important  to  have  this  test 
carried  out  in  distinct  proportions  of  the  substance  and  concentrated 
sulphuric  acid  to  get  uniform  results  in  the  hands  of  different 
chemists.  From  practical  experience  I  have  found  the  proportions 
given  in  this  list  to  be  perfectly  satisfactory. 
Solubility  in  water  at  25 0  C 
Solubility  in  water  at  80 0  C 
Solubility  in  alcohol  at  25 0  C 
i:45 
1:9 
1  :  105 
SALICYLIC  ACID. 
ACETPHENETIDIN. 
