346  Monobromated  Camphor.  {Xm^Z'^m' 
ON  THE  PREPARATION  OF  MONOBROMATED  CAMPHOR. 
BY  T.  C.  LINTHICUM,  PH.G. 
[From  an  Inaugural  Essay.) 
The  author  has  compared  three  different  processes,  which  have  been 
recently  recommended  for  the  successful  preparation  of  monobromated 
camphor,  namely,  those  of  J.  M.  Maisch  ("  Am.  Jour.  Pharm.," 
1872,  p.  337),  J.  U.  Lloyd  (Ibid,  1875,  p.  165)  and  of  Ed.  Dubois 
(u  Proc.  Am.  Phar.  Assoc.,"  1875,  p.  328).  The  latter  process  is 
similar  to  that  of  Gault  ("Am.  Jour.  Pharm.,"  1874,  p.  587),  from 
which  it  differs  mainly  in  the  treatment  of  the  crude  article  with 
carbonate  of  sodium,  and  in  the  asserted  almost  complete  absence  of 
any  by-products.  According  to  Dubois,  75  grams  of  camphor  are 
introduced  into  a  retort,  and  80  grams  of  bromine  at  once  added. 
The  two  substances  unite  with  a  slight  elevation  of  temperature 
and  become  liquid.  After  standing  for  two  or  three  hours  the  mix- 
ture is  heated  by  means  of  a  water  bath,  to  100°  C,  and  when  the 
reaction  is  completed  the  contents  of  the  retort  are  treated  with  a 
warm  solution  of  carbonate  of  sodium,  then  dissolved  in  boiling 
alcohol,  filtered  and  allowed  to  crystallize. 
Having  carefully  manipulated  according  to  each  of  the  three  pro- 
cesses, I  feel  justified  in  submitting  the  following  results.  My  first 
experiment,  made  with  the  process  of  Prof.  Maisch,  confirms  the 
result  obtained  by  him  in  1872.  By  the  process  of  Mr.  Dubois  I 
was  unable  to  obtain  crystals  of  monobromated  camphor.  But,  upon 
heating  the  resulting  mass  to  1320  C.  and  treating  with  hot  benzin,  I 
succeeded  in  obtaining  handsome,  large,  needle-shaped  crystals.  In 
making  the  experiment  according  to  Mr.  Lloyd,  who  directs  a  little 
over  one  atom  of  bromine  to  one  molecule  of  camphor,  I  used  an 
apparatus  constructed  upon  the  same  plan  as  that  employed  in  the  first 
process,  and  found  that  the  alkaline  carbonate  in  the  receiving  vessel 
was  but  slightly  affected,  owing  to  the  small  amount  of  hydrobromic 
acid  which  was  liberated.  After  many  fruitless  attempts  to  crystallize 
the  brownish,  oily  mass  resulting  from  this  operation,  either  from 
warm  alcohol  or  benzin,  I  transferred  it  to  a  retort,  and,  after  heating 
it  to  1520  C,  crystalized  the  contents  from  hot  benzin,  when  crystals 
of  monobromated  camphor  were  obtained,  and  a  large  amount  of  an 
oily  product. 
The  experiments  made  have  satisfied  me  that  two  atoms  of  bromine 
are  required  for  one  molecule  of  camphor,  and  that  monobromated 
camphor  is  best  formed  at  a  temperature  not  below  1320  C. 
