Am  Jour.  Pharm. ") 
March,  1886.  J 
Terpenes. 
145 
TERPENES. 
By  0.  Wallach. 
Pare  borneol,  prepared  by  the  action  of  sodium  on  camphor,  melts 
at  206-207°,  not  at  198°  as  generally  stated.  This  compound  be- 
haves like  a  saturated  secondary  alcohol,  but  it  has  the  property  of 
uniting  with  bromine  and  hydrogen  bromide,  etc.,  to  form  unstable 
additive  products.  For  example,  when  bromine  is  added  to  a  solu- 
tion of  borneol  in  light  petroleum,  a  crystalline  precipitate  is  de- 
posited, which  consists  chiefly  of  borneol  bromide,  C10H18OBr2,  mixed 
with  a  small  quantity  of  (C10H18O)2Br2.  Cineol,  like  borneol,  unites 
with  bromine  in  two  different  proportions,  forming  compounds  which 
have  the  same  composition  as  the  borneol  bromides.  When  borneol 
bromide  is  covered  with  light  petroleum  and  left  for  some  time  in  a 
closed  vessel,  decomposition  ensues  resulting  in  the  formation  of 
borneol  and  borneol  hydrobromide,  (C10H18O)2,HBr.  The  same  com- 
pound is  obtained  as  a  white,  crystalline  powder  by  the  action  of  hy- 
drogen bromide  on  a  solution  of  borneol  in  light  petroleum.  It  is 
decomposed  by  water  and  alcohol. 
The  hydriodide,  (C10H18O)2,  HI,  is  a  white,  crystalline  compound, 
which  decomposes  spontaneously. 
Bornyl  chloride,  C10H17C1,  is  easily  prepared  by  adding  borneol  to  a 
mixture  of  phosphorus  pentachloride  and  light  petroleum.  The 
action  is  finished  in  half  an  hour.  The  crude  product  is  poured  into 
water,  and  repeatedly  washed.  Bornyl  chloride  is  not  identical  with 
pinene  hydrochloride.  It  is  readily  converted  into  camphene  by 
heating  with  aniline.  Camphene  is  decomposed  by  dehydrating 
agents,  such  as  zinc  chloride  and  strong  sulphuric  acid,  or  by  the 
action  of  heat  alone.  In  each  case  the  decomposition  products  are 
liquid.  Monobromocamphene  is  obtained  as  an  oily  liquid  when 
bromine  is  added  to  a  solution  of  camphene  in  alcohol  and  ether. 
Camphene  is  formed  by  the  action  of  dehydrating  agents  on  borneol, 
but  the  hydrocarbon  cannot  be  isolated  (except  when  potassium 
pyrosulphate  is  the  dehydrating  agent)  as  it  is  decomposed  by  zinc 
chloride  or  phosphoric  anhydride  or  strong  sulphuric  acid. 
The  so-called  hydrocarbon  "  borneen,"  which  Pelouze  (Annalen,  xl, 
327),  Kachler  (ibid.,  clxiv,  78),  and  Oppenheim  (Jour.  Chem.  Soc, 
1874,  891)  obtained  by  the  action  of  phosphoric  anhydride  on  borneol, 
is  a  mixture  of  the  decomposition  products  of  camphene. 
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