340 
On  Monobromated  Camphor. 
f  Am.  Jour.  Pharm, 
\    Aug.  1,  1872. 
crystals  as  first  formed  have  been  drained  in  a  funnel,  they  may  be 
obtained  nearly  pure  simply  by  washing  them  with  gasoline,  and  re- 
quire then  one  crystallization  from  alcohol  or  petroleum  benzine,  to 
be  entirely  pure  and  unaltered  in  the  light.  The  monobromated 
camphor  dissolved  by  the  gasoline,  may  be  recovered  by  evaporating 
most  of  the  solvent  spontaneously,  washing  the  crystals  with  a  little 
gasoline  and  recrystallizing.  The  remaining  mother  liquors,  if  not 
used  as  solvents  in  subsequent  operations,  may  be  worked  up  with  the 
oil  left  by  the  first  crystallization. 
While  experimenting  with  bromide  of  camphor,  W.  EL  Perkin,*  in 
1865,  obtained  monobromated  camphor  by  treating  the  oily  matter 
obtained  from  the  action  of  bromine  and  camphor  with  hot  solution 
of  potassa,  and  subsequently  heating  the  product  in  a  retort,  collect- 
ing that  portion  of  the  distillate  separately,  which  comes  over  above 
364°  C.  (508°  F.) 
Th.  Swarts,f  however,  prefers  the  process  suggested  by  him  to  that 
of  Perkin,  regarding  the  former  as  more  satisfactory ;  he  also  states 
that  when  moist  monobromated  camphor  is  distilled,  or  it  is  left  in 
contact  with  hot  water,  bromine  and  hydrobromic  acid  are  evolved, 
and  camphor  free  from  bromine  is  separated.  The  regeneration  of 
camphor  under  these  circumstances  has  never  been  observed  by  me ; 
onlthe  contrary,  when  the  monobromated  compound  is  boiled  in  a  re- 
tort with  water,  a  white  crystalline  sublimate  resembling  snow-flakes 
is  slowly  formed  in  the  neck  of  the  retort,  and  these  crystals  contain 
bromine,  and  have  all  the  behavior  of  monobromated  camphor. 
Perkin  observed  that  monobromated  camphor,  treated  with  alco- 
holic ammonia  in  a  sealed  tube,  at  180°  C.  (356°  F.),  undergoes  a 
slight  decomposition,  with  the  formation  of  an  organic  base  and  of 
ammonium-bromide.  Fearing  that  the  prolonged  action  of  hot  pot- 
assa solution  upon  the  oil  which  already  contains  monobromated  cam- 
phor might  induce  its  decomposition,  and  my  time  not  permitting  to 
investigate  it,  I  had  resort  to  carbonate  of  lime  (white  marble),  which, 
as  previously  observed,  was  found  to  answer  the  purpose  well,  as  far 
as  the  removal  of  hydrobromic  acid  was  concerned.  On  heating  the 
remaining  oily  matter  gradually,  it  was  found  to  turn  black  when 
nearing  150°  C.  (300°  F.),  the  color  became  darker  as  the  tem- 
*  Journal  of  the  Chemical  Society,  new  series,  iii,  92;  Annalen  d.  Chem.  a. 
Pharm.  Suppl.  iv,  124,  and  Will's  Jahresbericht,  1865,  570. 
f  L'Institut,  1866,  287.    Will's  Jahresbericht,  1866,  622. 
