Am.  Jour.  Pharm. 
February,  1915. 
|     Camphor — Natural  and  Synthetic. 
55 
Pinus  maritima,  and  the  Russian  from  Pinus  sylvestris.  Russian 
turpentine  is  not  suitable  for  the  manufacture  of  camphor,  on  account 
of  its  low  content  of  pinene. 
The  turpentine  is  very  carefully  fractionally  distilled,  in  order  to 
obtain  anhydrous  pinene  (C10H16),  which  boils  at  about  1550  to 
1600  C,  and  which  should  constitute  90  per  cent,  of  a  good  sample 
of  oil  of  turpentine. 
Starting  out  from  pinene,  there  are  a  great  number  of  variations 
in  the  processes  for  the  preparation  of  camphor.  Hundreds  of 
patents  have  been  taken  out.10  Some  of  the  typical  processes  will 
be  mentioned  here. 
In  many  of  the  processes  the  pinene  is  thoroughly  cooled,  and 
is  then  saturated  with  dry  hydrochloric  acid  gas.  A  white  crystal- 
line mass  of  pinene  hydrochloride  is  thrown  out.  Pinene  hydro- 
chloride is  sometimes  called  "  Artificial  camphor  " — an  unfortunate 
name,  for  it  is  still  far  removed  from  the  true  synthetic  camphor,  and 
is  not  suited  to  the  purposes  for  which  true  camphor  is  used. 
The  next  step  is  to  split  off  hydrochloric  acid  from  the  pinene 
hydrochloride,  in  order  to  obtain  the  hydrocarbon  camphene  (C10- 
H16),  which  is  isomeric  with  the  pinene  from  which  the  process 
started. 
The  following  formulae  indicate  the  first  two  steps — the  addition 
of  hydrochloric  acid  to  pinene  in  the  position  1.2,  and  its  removal 
from  another  part  of  the  molecule,  viz.,  the  position  2.3 : 
CH, 
€H 
CH3-C-CH3 
I 
CH2  C- 
I 
-CH2 
CH3 
(X)  Pinene 
CH2- 
-CH- 
CH3— C— CH3 
CH2- 
-CH— 
-CI     CH2  CH  CH 
I  I 
I  CH3-C-CH3 
I  I 
-H     CH2  C  CH 
CH3 
(XI)  Pinene  hydrochloride 
CH3 
(XII)  Camphene 
The  conversion  of  pinene  hydrochloride  to  camphene  ,may  be  ac- 
complished in  a  great  variety  of  ways,  among  which  may  be  men- 
tioned : 
1.  Heating  with  ammonia  or  with  organic  bases,  such  as  methyl- 
amine,  pyridine,  quinoline,  piperidine,  or  piperazine. 
10  Cf.  O.  Kausch,  Kunststoffe  4,  1-4,  24-5.  F.  Rochussen,  Chem.  Zeitung 
(1909),  33,  704. 
