Am.  Jour.  Pharm. ) 
Oct.,  1882.  1 
DichloroGmnphor. 
511 
DICHLOEOCAMPHOR. 
By  p.  Cazeneuve  and  Didelot. 
Camphor  is  dissolved  in  absolute  alcohol,  and  treated  with  a  current 
of  dry  chlorine  for  several  hours  at  80  to  90°.  Heat  is  developed  and 
hydrochloric  acid  is  given  off  in  large  quantity.  The  product  is  repeat- 
edly treated  with  water,  and  heated  then  to  remove  chloral  and  hydro- 
chloric acid.  On  cooling,  it  solidifies  to  a  crystalline  mass,  which  may 
be  purified  by  crystallization  from  alcohol.  The  dichlorocamphor, 
CiqHj^C120,  thus  obtained  forms  large  white  oblique  prisms,  slightly 
soluble  in  cold,  but  very  soluble  in  hot  alcohol ;  soluble  in  ether,  in 
the  vapor  of  which  it  liquefies,  but  insoluble  in  water.  It  softens  at 
89°,  and  melts  at  93°,  at  which  temperature  it  gradually  volatilizes 
without  decomposition.  Above  150°  it  blackens  and  decomposes  with 
evolution  of  hydrochloric  acid.  On  continued  heating,  the  tempera- 
ture rises  to  263°,  at  which  point  it  remains  constant,  and  a  colorless 
liquid  distils  over. 
The  formation  of  the  dichlorocamphor  is  probably  preceded  by  that 
of  the  monochloro-derivative.  No  higher  derivative  is  obtained  by 
the  prolonged  action  of  chlorine  at  the  temperature  of  the  experiment. 
Dichlorocamphor  is  insoluble  in  water,  but  imparts  to  it  its 
peculiar  odor.  When  placed  on  the  surface  of  Avater,  it  exhibits 
gyratory  movements,  similar  to  those  of  camphor.  It  is  insoluble  in 
cold,  but  readily  soluble  in  hot  alcohol,  in  chloroform,  carbon  bisul- 
phide, and  ether.  The  ethereal  solution  crystallizes  with  difficulty, 
and  the  ether  appears  to  form  a  molecular  combination  with  the 
dichlorocamphor.  The  latter,  unlike  camphor,  is  insoluble  in  acetic 
acid.  It  combines  with  aldehyde  in  aqueous  solution,  forming  a  liquid 
heavier  than  water,  but  does  not  liquefy  ^yl^en  triturated  with  chloral 
hydrate.  Its  sp.  gr.  is  4*2;  it  melts  at  96°,  and  solidifies  at  95°,  but 
remains  soft  and  pasty  below  70°.  The  monochloro-camphor  described 
by  Wheeler  melts  at  95°  The  rotatory  power  of  dichlorocamphor  for 
=  -\~  57*3°,  and  is  constant  in  both  alcohol  and  chloroform. 
Dichlorocamphor  crystallizes  well  only  from  alcohol,  in  right  rhombic 
prisms,  with  brachydiagonal  domes,  and  with  difficult  cleavage  in  two 
directions  parallel  with  the  faces  of  the  prism.  When  the  crystals 
form  rapidly,  the  faces  of  the  prism  are  nnich  elongated,  and  the 
crystals  are  long  friable  needles ;  when,  on  the  other  hand,  they  form 
very  slowly,  the  j)rismatic  faces  are  l)ut  little  devel()])ed,  and  the 
crystals  have  an  octohedral  appearance. — Jour.  (  Item.  Hoc,  July,  Aug., 
1882,  i'voml(hmpt.  reiul,  vol.  94. 
