652  Chemistry  of  Gossypol.  {Am'slptr'i9iirm' 
by  petroleum  ether  does  not  remove  gossypol,  the  residue  after 
extraction  by  petroleum  ether  or  gasoline  would  contain  about  0.9 
per  cent,  gossypol. 
Preparation. — The  methods  which  have  been  used  to  isolate  gos- 
sypol from  cottonseed  are  much  simpler  than  the  tedious  process 
by  which  Marchlewski  secured  it  from  the  "  foots  "  of  cottonseed- 
oil  purification.  A  crystalline  product  of  high  purity  is  secured 
directly. 
Method  1. — It  has  been  found  most  convenient  to  use  decorti- 
cated cottonseed  kernels  or  "  meats "  which  have  been  passed 
through  rollers  to  crush  the  kernels  before  they  are  cooked  in  the 
oil  mill.  The  kernels  are  flattened  out  and  in  this  condition  are 
easily  broken  up  by  sifting  into  smaller  particles.  The  material  is 
passed  through  a  coarse  sieve  to  remove  the  greater  part  of  the  lint 
and  hulls,  and  then  is  extracted  with  petroleum  ether  or  gasoline. 
For  preparation  of  considerable  amounts  of  gossypol  the  kernels 
may  be  simply  percolated  with  gasoline  to  remove  the  greater  part 
of  the  oil.  The  resulting  material  is  dried  and  extracted  with  ethyl 
ether.  The  extract  amounts  to  2  to  6  per  cent,  of  the  weight  of 
material  extracted  according  to  the  thoroughness  of  previous  ex- 
traction. The  concentrated  extract  is  of  a  dark  cherry-red  color 
if  fresh  kernels  have  been  used  or  almost  black  if  from  older  seeds. 
These  "gossypol  extracts"  contain  about  17  per  cent,  to  50  per 
cent,  gossypol.  In  one  case  where  very  fresh  kernels  were  used  a 
considerable  part  of  the  gossypol  separated  out  of  the  "  gossypol 
extract "  on  standing  as  a  red  crystalline  powder.  The  gossypol 
may  be  precipitated  in  brown  amorphous  flocks  by  adding  petroleum 
ether,  but  better  yields,  practically  quantitative,  are  secured  by  treat- 
ing the  gossypol  extract  with  one  half  to  one  third  its  volume  of 
glacial  acetic  acid.  On  standing  several  hours  or  days,  or  ■  more 
quickly  by  warming  in  the  water  bath,  most  of  the  gossypol  sepa- 
rates as  the  well-crystallized  gossypol  "acetate"  containing  10. 1 
per  cent,  acetic  acid  of  composition.  The  crystalline  paste  is  then 
sucked  off  and  washed  with  small  amounts  of  glacial  acetic  acid, 
and  then  with  petroleum  ether.  For  further  purification  the  gos- 
sypol acetate  thus  secured  is  dissolved  in  ether  and  glacial  acetic 
acid — about  10  parts  to  1  part  of  gossypol — is  added.  The  ether  is 
then  in  part  distilled  until  the  gossypol  begins  to  separate  readily. 
By  this  method  the  fatty  and  colored  impurities  are  retained  by  the 
solvent,  which  is  not  so  much  the  case  when  Marchlewski's  method 
