Anocfober  1908^'}  American  Pharmaceutical  Association.  485 
satisfactory.  Thus  in  a  prepared  mixture  containing  7.14  per 
cent,  of  crystallized  phenol,  assaying  96  per  cent,  by  the  U.  S.  P. 
method,  7.00  per  cent.,  7.01  per  cent.,  6.9  per  cent.,  7.09  per  cent, 
and  7.15  per  cent,  of  the  phenol  was  found. 
In  trying  to  confirm  the  results  obtained  by  extraction  with 
chloroform  an  entirely  different  method  was  suggested,  namely,  that 
of  distillation  in  a  current  of  steam.  Results  obtained  by  this 
method  at  first  seemed  to  agree  with  and  to  confirm  the  accuracy 
of  the  chloroform  extraction  method,  but  it  was  soon  found  that 
on  some  of  the  tablets  results  considerably  higher  were  obtained, 
while  on  the  other  hand  two  specimens  gave  results  much  lower. 
In  some  of  these  experiments  the  distillate  assumed  a  yellow  color, 
the  tribromphenol  did  not  separate  well,  and  in  the  final  titration 
the  end  point  was  not  sharp. 
The  authors  after  careful  investigation  found  the  cause  of  these 
untoward  results  and  have  obtained  satisfactory  results  with  the 
following  method :  The  substance  containing  the  phenol  was  placed 
in  a  round-bottomed  distilling  flask  and  water  sufficient  to  cover 
it  was  added.  The  flask  was  connected  by  means  of  a  double 
perforated  rubber  stopper,  on  the  one  hand,  with  a  Liebig  condenser, 
and  on  the  other  with  a  tin  reservoir  containing  water.  A  current 
of  carbon  dioxide  was  then  passed  from  a  Kipp  generator  through 
the  reservoir  and  distilling  flask  for  fifteen  minutes  or  more.  (In 
the  case  of  the  known  mixtures  of  phenol  and  potassium  hydrox- 
ide V.  S.,  phenolphthalein  was  added  and  carbon  dioxide  passed 
until  colorless,  about  five  minutes  being  sufficient.)  The  water 
was  then  heated  to  boiling  and  the  distillation  continued,  a  brisk 
current  of  carbon  dioxide  *  passing  through  the  apparatus  con- 
tinually until  250  Cc.f  of  distillate  was  obtained.    Of  this  distillate 
*  Simple  saturation  with  carbon  dioxide  will  not  liberate  all  the  phenol, 
but  a  stream  of  the  gas  must  be  passed  during  the  distillation ;  when  in  an 
experiment  the  supply  of  carbon  dioxide  was  cut  off  as  soon  as  the  satura- 
tion was  complete,  and  then  the  distillation  continued,  only  88.64  per  cent, 
of  the  phenol  was  recovered  in  one  case,  90.48  per  cent,  in  another,  and 
86.68  per  cent,  in  a  third. 
f  If  250  Cc.  of  distillate  is  collected,  as  shown  in  an  experiment  with  pure 
phenol,  the  first  100  Cc.  of  distillate  in  one  case  contained  96.48  per  cent, 
of  the  phenol  taken  and  in  another  97.22  per  cent. ;  with  a  mixture  of  phenol, 
opium,  bismuth  subnitrate,  and  aromatic  powder,  and  containing  7.21  per 
cent,  phenol,  the  first  100  Cc.  distillate  contained  98.61  per  cent,  of  the  phenol 
present. 
