Am.  Tour.  Pharm.  \ 
Sept.,  191S.  > 
Chemistry  of  Gossypol. 
653 
using  alcohol  and  aqueous  acetic  acid  is  followed.  The  crystalline 
product  in  this  case  contains  uniformly  10. 1  per  cent,  acetic  acid, 
while  by  Marchlewski's  method  it  tended  to  vary  from  8.5  to  9.6 
per  cent. 
For  the  preparation  of  crystalline  gossypol  from  the  "  acetate  " 
the  latter  is  dissolved  in  ether  and  water  ,  is  added.  The  ether  is 
distilled,  leaving  the  gossypol  as  crusts  floating  on  the  water  which 
contains  all  the  acetic  acid.  The  free  gossypol  may  then  be  crystal- 
lized from  alcohol  or  other  suitable  solvent. 
Method  ia. — In  this  method  the  kernels  are  not  previously  ex- 
tracted with  petroleum  ether,  but  with  ethyl  ether  only.  The  evapo- 
rated ether  extract  is  treated  with  acetic  acid  and  allowed  to  stand 
until  the  gossypol  "  acetate  "  separates  out.  This  requires  a  much 
longer  time  than  in  Method  1.  The  use  of  80  per  cent,  and  90  per 
cent,  acetic  acid  is  more  advantageous  than  the  use  of  the  glacial 
acid.  It  was  found  that  7  parts  of  80  per  cent,  acetic  acid  per  100 
of  extract  gave  larger  yields  than  did  90  per  cent,  or  100  per  cent, 
acetic  acid.  Acid  weaker  than  80  per  cent,  tends  to  form  a  separate 
layer  with  the  extract.  By  adding  7  parts  per  100,  heating  to  ioo° 
to  1 1 50  and  then  setting  aside,  the  separation  of  the  gossypol  "ace- 
tate "  is  hastened.  Nevertheless,  this  is  very  slowly  formed,  re- 
quiring one  to  three  weeks.  The  yields  are  poorer  on  account  of 
the  large  mass  of  oil  present  but  from  50  to  80  per  cent,  of  the  gos- 
sypol may  be  obtained  if  sufficient  time  is  given. 
Method  2. — The  basis  of  this  method  is  the  insolubility  in  oil 
of  the  salts  of  gossypol.  This  principle  is  applied  commercially  in 
removing  the  gossypol  and  other  coloring  matters  from  crude  cot- 
tonseed oil.  The  extracts  (cf.  Method  1)  of  cottonseed  kernels 
are  shaken  with  a  slight  excess  of  strong  aqueous  caustic  soda.  The 
sodium  salt  of  gossypol  and  sodium  salts  of  the  free  fatty  acids  are 
formed  and  pass  into  the  aqueous  layer,  while  the  clear  yellow  oil 
rises  to  the  top.  The  alkaline  liquor  is  neutralized  with  acid  which 
causes  the  fatty  acids  and  gossypol  to  separate  as  a  pasty  .mass. 
This  mass  may  be  treated  with  hot  acetic  acid  to  cause  separation 
of  the  gossypol.  This  method  is  not  satisfactory  and  is  almost  use- 
less where  much  free  fatty  acid  is  present  in  the  oil,  when  a 
"break"  into  oily  and  aqueous  layers  is  greatly  retarded.  Gossy- 
pol quickly  oxidizes  in  alkaline  solutions  exposed  to  air.  This  oxi- 
dation, however,  may  be  retarded  by  adding  sodium  hyposulphite 
("hydrosulphite")  Na2S204. 
