740 
Purification  of  Crude  Cocaine, 
Am.  Jour.  Pharra 
October,  1920. 
is  filtered  while  warm.  On  cooling  it  deposits  an  oily-resinous  body 
which  soon  becomes  a  semi-crystalline  mass.  Ammonium  car- 
bonate is  added  until  the  solution  becomes  cloudy,  then  solution 
of  ammonia,  which  produces  a  beautiful  white  precipitate.  This  is 
extracted  with  ether  and  the  pure  cocaine  crystallizes  out  from  the 
ethereal  solution.  The  /3-naphthalene-sulphonic  acid  may  also 
be  recovered  by  concentrating  the  mother  liquors  and  precipitating 
with  hydrochloric  acid. 
Another  process  recommended  by  the  author  consists  in  dis- 
solving lo  grams  of  crude  cocaine  in  boiling  water  containing  acetic 
acid.  On  cooling,  the  solution  is  precipitated  by  the  addition  of 
ammonium  carbonate,  which  yields  a  resinous,  yellowish  precipi- 
tate, lighter  than  water.  The  solution  is  filtered  and  solution  of  am- 
monia added  in  excess,  the  almost  chemically  pure  cocaine  which  is 
precipitated  is  extracted  with  ether,  from  which  it  crystallizes  spon- 
taneously. This  method  also  yields  79  to  8 1  per  cent,  of  chemically 
pure  cocaine.  In  addition  to  separating  the  cocaine  from  the  crude 
product,  the  author  also  dealt  with  the  question  of  utilizing  the  resi- 
due {i.  e.,  the  resinous  precipitate  first  thrown  down)  obtained  in 
the  course  of  precipitating  the  pure  alkaloid,  particularly  the  possi- 
bility of  transforming  the  ecgonine  present  in  this  residue  into 
cocaine.  This  residue  is  purified  by  crystallization  from  alcohol, 
and  pure  ecgonine  is  precipitated  afterwards  by  means  of  carbonate 
of  sodium.  The  pure  ecgonine  thus  obtained  is  then  dissolved  in 
methyl  alcohol,  and  the  solution  treated  with  anhydrous  hydro- 
chloric acid,  yielding  methyl-ecgonine  hydrochloride;  the  unaltered 
ecgonine  is  then  extracted  with  ether.  Of  the  methyl-ecgonine  thus 
obtained,  20  grams  is  heated  on  a  water  bath  with  benzoyl  chloride 
20  grams,  until  no  more  hydrochloric  acid  is  evolved.  The  solu- 
tion is  now  added  to  cold  water,  whereby  benzoic  acid  is  precipi- 
tated; this  is  filtered  out  and  the  filtrate  concentrated.  The  syn- 
thetic cocaine  (termed  coca-ethyline  in  the  German  patent  47,713) 
is  then  precipitated  from  the  filtrate  by  the  addition  of  solution  of 
ammonia.  By  this  method  of  treating  the  residue  a  further  yield 
of  5  to  10  per  cent,  of  cocaine  is  obtainable. 
