74 
Terpin  Hydrate. 
( Am.  Jour.  Pharm. 
1    February,  1897. 
o-8$6,  and  a  boiling  point  of  from  1540  to  1570  C,  was  obtained, 
and  this  product  was  used  in  all  my  experiments. 
The  first  method  tried  was  one  suggested  by  Carl  Hempel  (An- 
nalen  der  Ckemie,  153,  71),  using  the  following  quantities: 
(1)  Oil  of  turpentine  120  c.c. 
(2)  Alcohol  (sp.  gr.,  0-816)  30  " 
(3)  Nitric  acid  (sp.  gr.,  1-35)  30  " 
These  liquids  were  mixed  in  a  flask  in  the  order  indicated  by  the 
numbers,  and  allowed  to  stand  three  days,  shaking  occasionally. 
The  mixture  separated  into  two  layers,  the  lower  one  becoming 
quite  dark  in  color.  On  the  third  day  it  was  poured  into  a  flat  dish 
and  15  c.c.  of  alcohol  added,  and  allowed  to  stand  in  a  room  having 
a  temperature  of  about  180  C. 
Crystals  began  to  form  within  five  days,  and  at  the  end  of  two 
weeks  they  had  separated  from  the  mother  liquor.  About  13 
grammes  of  crystals  were  thus  obtained.  This  product  was  puri- 
fied by  recrystallization  in  a  solution  of  boiling  alcohol,  and  yielded 
8  grammes  of  terpin  hydrate,  which  was  found  to  answer  all  the 
U.S. P.  requirements. 
The  mother  liquor  was  allowed  to  stand  for  a  short  time,  and 
another  crop  of  crystals  was  obtained  ;  but  these,  when  tested  with 
sulphuric  acid,  did  not  give  the  characteristic  deep  orange  color, 
but  a  light,  pinkish  one,  which  quickly  faded. 
The  next  method  tried  was  one  suggested  by  Wm.  A.  Tilden 
{Jour.  Chem.  Soc.  Lond.,  33,  247),  the  following  being  the  propor- 
tions of  liquids  used  : 
Oil  of  turpentine   60  c.c. 
Alcohol   30  " 
Nitric  acid  (sp.  gr.,  140)   60  " 
In  this  method  and  all  others  suggested  by  Tilden,  nitric  acid 
having  the  specific  gravity  of  1-40  was  employed,  but  the  writer's 
experience  with  acid  of  this  strength  was  that  a  thick  resinous-like 
mass  was  obtained,  which  showed  no  signs  of  crystallization. 
A  method  was  also  given  by  F.  Flawitzky  (Jour.  Chem.  Soc.  Lond., 
38,  264),  in  which  he  used  sulphuric  instead  of  nitric  acid,  and 
obtained  a  compound  having  the  formula  C10H18O. 
As  ethyl  alcohol  commands  a  comparatively  high  price  at  the 
present  time,  methyl  alcohol  was  substituted  for  it,  and  the  follow- 
ing formula  was  found  to  be  very  satisfactory  : 
