152  Separation  of  Oxymethylanthraquinones.  { Am*Ap?S1 
Jour.  Pharm. 
1915. 
Sodium  Carbonate  Fraction.-— The  amount  of  color  removed  at 
this  point  was  small.  The  general  test  for  oxymethylanthraquinones 
was  positive  and  characteristic.  The  color  test  gave  reactions  as 
follows : 
Residue  +  H2S04  =  red,  brownish ;  +  HNOs  =  yellow ;  +  H20  = 
yellow  solution. 
The  intense  pink  color  with  sulphuric  acid  characteristic  of  this 
fraction  in  the  cases  of  buckthorn,  rhubarb,  and  senna  was  lacking. 
This  peculiarity  was  encountered  with  both  varieties  of  aloes  and 
also  with  the  fluidextract. 
Sodium  Hydroxide  Fraction. — The  greater  part  of  the  color  in 
the  benzol  was  removed  at  this  point,  and  a  copious  ether  residue 
was  obtained.  It  was  of  the  characteristic  golden-yellow  color ; 
gave  the  general  test  for  oxymethylanthraquinones,  and  by  the  color 
test,  the  characteristic  behavior  observed  for  chrysophanic  acid  as 
obtained  from  other  sources  in  previous  experiments.  In  case  of 
Socotrine  aloes  the  residue  fused  at  185 0  and  liquefied  at  189  0  to 
1920.  With  Barbadoes  aloes  fusion  took  place  at  above  1800,  with 
liquefaction  at  about  1980. 
Discussion. 
The  melting-points  of  chrysophanic  acid  as  obtained  from  differ- 
ent drugs  shows  considerable  variation.  It  is  obviously  not  a  pure 
product,  the  nature  of  the  impurity  depending  upon  the  source  from 
which  it  is  derived.  The  melting-points  for  this  substance  recorded 
in  the  literature  show  also  wide  variations,  figures  from  1620  to 
191 0  being  given.14 
The  melting-points  obtained  for  emodin  are  in  closer  agreement 
among  themselves,  and  in  reasonable  accord  with  those  given  in  the 
literature,  about  2500.  Tschirch  and  Oesterle  15  find  for  alo-emodin 
a  melting-point  of  2160. 
For  the  purposes  of  this  investigation,  however,  melting-points 
have  been  regarded  rather  as  broadly  differentiating  between  the 
substances  separated  than  as  precise  observations  intending  to  in- 
dicate states  of  purity. 
The  procedure  followed  in  the  experiments  described  furnishes 
11  See  Allen,  "  Commer.  Organ.  Anal.,"  4th  ed.,  vol.  5,  p.  227.  Beilstein, 
"  Handb.  d.  Organ.  Chem.,"  vol.  3,  p.  452.  Mulliken,  "  The  Identification  of 
Pure  Organic  Compounds,"  vol.  1,  p.  208. 
35  Ber.  d.  Pharm.  Ges.,  8,  174. 
