Am.  Jour.  Pharm. 
January,  1921. 
Thymol  and  Carvacrol  Problems. 
crucible  at  a  just  perceptible  red  heat.  The  carvacrol  carried  only 
about  o.o i  per  cent,  of  non- volatile  material. 
I.  8.775  Gms.  carvacrol  gave  0.0007  Gm.  non-volatile  residue.  - 
II.  8.675  Gms.  carvacrol  gave  0.0010  Gm.  non-volatile  residue. 
It  thus  becomes  apparent  that  from  a  solution  of  carvacrol  in 
five  per  cent,  sodium  hydroxide  the  free  phenol  alone  is  extracted 
by  ether. 
In  continuation  of  this  work  the  behavior  of  various  other  sol- 
vents toward  thymol  in  alkaline  solution  was  determined  on  a  some- 
what more  exact  basis  under  conditions  which  would  resemble  those 
actually  employed  in  the  extraction  of  thymol  from  oils  used  as  a 
source  of  the  phenol.  The  use  of  5  per  cent,  sodium  hydroxide  has 
been  recommended  for  the  assay  of  phenol-containing  oils  and  also 
for  extraction  in  preparation  of  the  phenols  and  for  analytical 
separations. 
An  alkaline  solution  was  prepared  from  sodium  hydroxide  made 
by  hydrating  the  metal  to  keep  the  product  free  from  carbonate. 
Sodium  was  placed  in  a  nickel  dish  covered  with  a  layer  of  paraffin 
oil  shout  5  cm.  deep  in  a  casserole  and  a  funnel  just  fitting  into  the 
casserole  but  over  the  dish  covered  the  whole.  A  dropping  funnel 
allowed  water  to  run  slowly  on  the  metal.  This  solution  was  made 
up  to  5  per  cent,  strength  and  standardized.  When,  however,  the 
alkaline  solution  of  thymol  was  prepared  by  adding  one  equivalent 
of  the  phenol,  expansion  took  place  almost  equivalent  to  1  Cc.  per 
Cm.  of  thymol. 
Vol.  of  alkali  solution    840  Cc.   
Equivalent  of  thymol    157  Gms. 
Vol.  of  solution  after    985  Cc.   
Increase   145  Cc. 
All  of  the  thymol  did  not  go  into  solution,  however,  and  after 
continued  shaking  it  was  filtered  and  the  residue  recovered.  The 
hydrolysis  of  the  thymol  sodium  compound  at  these  dilutions  would 
effect  also  the  amount  taken  into  solution,  as  thymol  itself  is  ex- 
tremely slightly  soluble  in  water.  In  view  of  this  fact  and  because 
of  the  ease  with  which  it  is  removed  by  ether  a  quantitative  estima- 
Xon-volatile  residue. 
I   
II   
Percentage. 
0.009 
0.012 
