Am\p?iT*i9i5arm" }  Separation  of  Oxymethylant hraquinones.  153 
a  satisfactory  qualitative  separation  of  the  chief  color  principles  in 
the  drugs  examined,  and  it  is  also  believed  that  the  separation  can, 
within  reasonable  limits,  be  made  quantitative. 
The  reaction  utilized  to  identify  chrysophanic  acid  in  the  presence 
of  phenolphthalein 16  serves  also  as  a  test  for  oxymethylanthra- 
quinones  generally,  and  is  much  more  specific  for  this  group  than 
the  Borntrager  reaction. 
By  the  color  test  described  emodin  and  chrysophanic  acid  give 
characteristic  reactions.  The  distinguishing  features  are  that  emodin 
gives  an  intense  pink  color  immediately  on  addition  of  concentrated 
sulphuric  acid,  and  a  pink  solution,  or  one  with  a  decided  pink  tinge, 
on  final  dilution  with  water;  chrysophanic  acid  gives  an  orange-red 
color  with  sulphuric  acid,  and,  on  final  dilution,  gives  a  yellow 
solution  and  a  yellow  precipitate.  The  sodium  carbonate  soluble 
color  fraction  derived  from  aloes  is  an  exception  to  the  behavior  of 
emodin  as  derived  from  buckthorn,  rhubarb,  and  senna.  The  un- 
identified oxymethylanthraquinone,  or  mixture,  obtained  in  the  am- 
monium carbonate  fraction  is  characterized  by  an  intense  purple  or 
violet  color  with  concentrated  sulphuric  acid.  These  reactions  may 
be  summarized  as  follows : 
Emodin,  as  derived  from  buckthorn,  rhubarb,  and  senna : 
With  cone.  H2S04  —  pink;  +  HNQ3  =  yellow;  +  H20  =  pink 
solution. 
As  derived  from  aloes  (sodium  carbonate  soluble)  : 
With  cone.  H2S04  =  red,  brownish ;  +  HNOs  =  yellow ;  +  H20  = 
yellow  solution. 
Chrysophanic  acid,  as  derived  from  all  sources : 
With  cone.  H2S04  ==  orange  red ;  +  HN03  =  yellow ;  +  H20  = 
yellow  solution  and  precipitate. 
Unidentified  oxymethylanthraquinones  (ammonium  carbonate 
soluble)  : 
With  cone.  H2S04  =  purple  or  violet ;  +  HNOs  =  yellow ;  +  H20 
==  yellow  solution. 
A  relatively  large  amount  of  chrysophanic  acid  was  present  in 
the  aloes  examined.  The  color  removed  by  sodium  hydroxide  was 
greatly  in  excess  of  that  removed  by  sodium  carbonate. 
/.  Ind.  Eng.  Chem.,  6,  4,  320. 
