374 
Valuation  of  Crude  Carbolic  Acid.  {K^i^li^mm' 
6  7  c.c.  of  decinormal  bromine  solution  for  o-i  gramme  of  oil,  and 
in  the  other  6-4  c.c,  which  is  approximately  one-tenth  as  much 
bromine  as  is  required  by  the  same  quantity  of  pure  phenol.  One 
of  the  samples  yielded  four  times  as  much  to  ether  as  the  other,  and 
also  in  other  respects  showed  great  difference  in  composition ;  it 
therefore  seems  remarkable  that  there  was  no  greater  difference  in 
the  bromine  absorption  of  the  two  ether  extracts.  It  is,  however, 
subject  to  too  much  variation  to  permit  the  adoption  of  a  constant 
correction  factor. 
Two  samples  of  crude  carbolic  acid  were  distilled  and  different 
fractions  of  the  distillate  examined  separately.  The  results  are 
given  in  the  following  tables  : 
SAMPLE  I. 
Fraction. 
Distillate,  per  cent. 
C.c.  —  Bromine  Solution  required  bv  o'oi  gramme, 
to 
98°-i8o° 
f  Water,  0*5  p.  c. 
X  Phenol,  etc.,  0  5  p.  c. 
l8o°-i8-,° 
(mostly  i83°-i84°) 
34 
5  75  white,  bulk}-  precipitate. 
1850-190° 
46 
56  " 
I90°-I95° 
13 
5-35  brown-3'ellow,  compact  precipitate. 
i95°-20o° 
4 
5*i5 
Residue 
2 
4-65 
The  crude  acid  itself  required  5  46  c.c.  of  decinormal  bromine 
solution  for  001  gramme  of  sample.  Assuming  the  proportions  of 
phenol  and  cresols  to  be  about  equal,  as  indicated  by  the  boiling 
points,  this  would  be  equivalent  to  approximately  93  per  cent,  of 
total  phenols.  The  hydrocarbons,  bases,  etc.,  extracted  with  ether, 
amounted  to  1*05  per  cent.,  and  water,  separated  by  distillation,  0  5 
per  cent.  This  still  leaves  5-5  per  cent,  unaccounted  for.  Partial 
loss  of  the  ether  extract  through  volatilization  does  not  explain  this 
great  discrepancy,  but  it  seems  probable  that  crude  carbolic  acid 
may  contain  a  considerable  quantity  of  other  acids,  which  ether 
would  not  extract  from  an  alkaline  solution.  Similar,  and  even 
greater,  discrepancies  were  noticed  in  the  examination  of  two  other 
less  pure  samples. 
