Am.  Jour.  Pharm. 
Dec,  1887. 
Terpenes. 
619 
the  C18H30O2  from  the  hexabromo-derivative ;  for  the  former,  he  pro- 
poses the  name  linolic  acid,  for  the  latter  linolenie  acid. 
If  linolic  acid,  prepared  from  the  tetrabroruo- derivative,  is  oxidized 
with  alkaline  potassium  permanganate,  it  yields  sativic  and  azelaic 
acids,  but  no  linusic  acid  ;  when  treated  with  bromine,  it  gives  tetra- 
bromolinolic  acia\  melting  at  114-115°. 
Linolenie  acid,  CISH30O2,  prepared  from  the  hexabromo-compound 
melting  at  177°,  has  an  "iodine  value"  of  245,  and  yields  on  oxida- 
tion no  solid  acid  but  linusic  acid  (m.  p.  20 1  °).  With  bromine,  noth- 
ing but  the  hexabromolinolenic  acid  is  formed. 
These  experiments  clearly  show  that  the  acids  from  drying  oils  con- 
tain both  linolic  acid,  C18H3202,  and  linolenie  acid  C18H30O2.  The  au- 
thor proposes  to  examine  the  acids  from  poppy  oil,  hemp-seed  oil,  and 
nut  oil,  which  give  only  sativic  acid  on  oxidation.  He  enunciates  the 
following  law  for  the  oxidation  of  the  unsaturated  fatty  acids :  these 
acids  when  oxidized  in  alkaline  solution  with  potassium  permanganate 
add  as  many  (OH)-groups  as  they  contain  free  valencies,  and  form 
saturated  acids  which  contain  the  same  number  of  carbon -atoms  in  the 
molecule.  On  this  law,  he  founds  an  exact  qualitative  method  for 
the  examination  of  fats  and  oils. 
TEEPEXES. 
By  0.  Wallach.1 
The  eight  isomeric  terpenes  may  be  distinguished  from  each  other 
by  comparing  the  properties  of  their  compounds  with  HC1,  HBr,  HI, 
etc.,  as  shown  in  the  following  table  : — 
Pinene. 
Camphene. 
Limonene. 
Dipentene. 
p      TT       |B,  Pt  
CioJ±i6  {  M  pt  
CioHi6,HCl  ■[  M-  gt  
CioHi6,HBr.  Ml  p  
CioHi6,2HC1.  "  
CioHl6,2HBr.  "   
CIOHi6,2HI.  "   
CioHi6Br4  "   
C10H16X2O3  "   
Color  with  acetic  anhydride  and 
cone.  H2SO4  
159—161° 
207—208° 
about  125° 
90° 
pink  or  yellow 
160—161° 
48-^9° 
decomposes 
yellowish 
175° 
[50]*  • 
[64,* 
[77  or  79°]* 
104—105 
red 
180—182° 
z 
50° 
64° 
77°  or  79° 
125° 
red 
1Annalen,  239, 1-54.  Reprinted  from  Jour.  Chem.  Soc,  October  1886,  p.  965. 
■^Identical  with  the  corresponding  dipentene  compounds. 
