n6 
Crude  Carbolic  Acid. 
/Am. Jour  Pharm. 
{     March,  1894. 
oil  was  treated  with  three  equal  portions  of  weak  caustic  soda  solu- 
tion, the  last  portion  extracting  the  oil  completely. 
Each  solution  was  neutralized  with  sulphuric  acid,  and  the  result- 
ing acids  distilled.  In  order  to  show  their  composition  more  clearly 
the  result  is  calculated  after  deducting  the  water  present. 
Acid  from  : 
First  Second  Third 
Portion.  Portion.  Portion. 
Per  Cent.      Per  Cent.     Per  Cent. 
To  180,   6  —  — 
"  185,   30  -  - 
"  190,   74  1  — 
"  195,   86  41  2 
v  200,   91  71  16 
"  205,   94  83  54 
"  210   —  87  74 
"  215   —  91  84 
"  220,   —  —  88 
"  225,   —  —  92 
The  first  portion  is  equal  to  a  6o°  acid,  and  contains  a  large 
amount  of  phenol;  the  third  portion,  none  at  all.  To  prepare 
crystal  acid  from  these  crude  materials,  they  are  carefully  rectified 
in  large  iron  stills,  the  watery  portions  separated,  and  the  fractions 
from  (say)  1800  to  1900  cooled,  the  phenol  crystallizes  and  is 
drained  from  the  liquid  portions.  The  crude  crystals  thus 
obtained  are  then  carefully  refined.  As  the  crystal  carbolic  acid  has 
a  much  higher  value  than  the  other  acids,  it  is  in  the  interest  of  the 
manufacturer  to  remove  it  as  completely  as  possible.  The  remain- 
ing liquid  acids  are  sold  as  "  crude  carbolic  acid  100  per  cent.,"  as 
they  are  entirely  soluble  in  caustic  soda  solution,  excepting  traces  of 
naphthaline  and  other  impurities. 
The  lowest  grades  of  crude  acids  known  as  10,  15,  20  and  25  per 
cent.,  are  simply  unextracted  portions  of  the  heavy  oil,  containing 
this  amount  of  tar  acids.  The  higher  grades,  50,  60  and  70  per 
cent.,  are  prepared  by  adding  100  per  cent,  to  the  lower  grades. 
As  the  heavy  oils  used  in  mixing  these  acids  contain  a  large  num- 
ber of  bodies,  these  are  of  course  present  in  the  commercial  acids. 
The  most  important  of  these  are  the  pyridine  bases  and  naphtha- 
line. The  former  gives  to  certain  acids  a  rank,  disagreeable  smell. 
The  latter  is  generally  present  in  large  amounts,  some  oils  consist- 
ing of  more  than  half  crude  naphthaline.  In  cold  weather  this 
anphthaline  is  deposited,  and  as  the  liquid  portions  are  drawn  off,  it 
