Am.  Jour.  Pharm.  1 
Aug.  1, 1872.  | 
On  Monobromated  Camphor. 
343 
converted  into  hydrobromic  acid,  its  saving  is  a  matter  of  some  im- 
portance ;  it  may  be  collected  in  water,  or  combined  with  any  salifia- 
ble base  or  its  carbonate.  I  have  found  the  employment  of  white 
marble  very  convenient ;  the  resulting  solution  of  bromide  of  calcium 
is  nearly  pure  ;  traces  of  iron  present  are  removed  by  hydrosulphate 
of  ammonia,  after  which  the  solution  will,  on  evaporation,  yield  the 
pure  salt. 
The  retort  is  charged  with  13  oz.  of  camphor  broken  into  pieces  of 
•convenient  size,  with  which  the  neck  is  completely  filled,  while  the 
balance  is  given  into  the  retort.  For  this  quantity,  12  oz.  of  bromine 
are  used,  which  is  introduced  in  four  or  five  portions  in  quantities 
ranging  from  2  to  4  oz.  at  a  time,  the  larger  quantity  being  used  in 
the  beginning,  the  smaller  afterwards.  If  a  funnel  tube  is  used  for 
this  purpose,  and  the  last  drops  of  the  bromine  are  washed  down  with 
a  small  quantity  of  alcohol,  (about  J  drachm,)  the  reaction  usually 
commences  in  from  15  to  20  minutes,  or  it  may  be  brought  on  by  the 
careful  application  of  heat,  which  should  be  at  once  withdrawn  as  soon 
as  gas  bubbles  commence  to  rise  in  the  retort ;  the  reaction  will  then 
proceed  without  any  further  attention,  the  heat  increases,  some  bro- 
mine and  bromine  compounds  volatilize,  the  latter  being  mostly  con- 
densed in  the  upper  part  of  the  retort,  while  the  former  condenses  in 
the  neck,  forming  with  the  camphor  an  oily  liquid  which  returns  to 
the  retort.  The  next  addition  of  the  bromine  should  not  be  made  un- 
til the  contents  of  the  retort  have  cooled  down  almost  or  quite  to  the 
ordinary  temperature  ;  and  this  precaution  should  particularly  be 
observed,  if,  perhaps  in  consequence  of  too  violent  reaction,  all  the 
camphor  has  run  into  the  retort.  The  contents  of  the  latter  will 
usually  solidify  when  cooling,  after  such  a  reaction  ;  but  sometimes 
they  remain  quite  fluid,  and  congeal  on  the  subsequent  addition  of  the 
requisite  bromine.  If  the  bromine  is  added  in  too  large  quantities,  the 
heat  will  become  so  high,  and  the  reaction  so  violent,  that  a  large 
quantity  of  bromine  may  distil  over  uncondensed  ;  if  added  in  frac- 
tions, with  the  precautions  stated,  the  temperature  rises  generally  to 
from  60  to  65°  C,  (140  to  150°  F.,)  with  at  first  slow,  but  gradually 
brisk  extrication  of  hydrobromic  acid  gas.  It  follows  from  the  latter 
phenomenon,  that  the  mass  must  contain  some  monobromated  cam- 
phor, or  perhaps  combinations  of  it  with  hydrobromic  acid  and 
bromine. 
Up  to  this  stage  the  tubulure  of  the  retort  may  be  kept  closed  with 
