A  AuJg°usrt)i898!'m-}     Valuation  of  Crude  Carbolic  Acid. 
375 
SAMPLE  II. 
Fraction. 
95°-i95° 
I95°-I97'5C 
I97*5°-2oo° 
20O°-2O5° 
Residue 
Distillate,  per  cent. 
./Water,  2'8p.  c. 
3  0  \  Phenols,  etc.,  *8  p.c. 
I 
25 
14 
6 
C.c.  _  Bromine  Solution  required  by  o'oi  gramme. 
10 
5'i5 
4-8 
4'5 
3'8 
The  sample  was  labelled  "  crude  cresol "  and  had  a  dark  red- 
brown  color.  It  required  4-68  c.c.  of  decinormal  bromine  solution? 
for  001  gramme,  which  is  equivalent  to  85  per  cent,  of  cresols, 
applying  the  factor  for  cresols  also  to  other  phenols  which  may  be 
present  in  small  amount.  The  ether  extract  was  4  65  per  cent,  and 
the  water  separated  by  distillation  2-8  per  cent.,  making  a  total  of 
92-5  per  cent.    The  remainder  is  unaccounted  for. 
A  third  sample  required  473  c.c.  of  the  bromine  solution  for  001 
gramme,  corresponding  to  about  85  per  cent,  of  cresols,  etc.  Dis- 
tillation separated  4  per  cent,  of  water  and  4-2  per  cent,  was 
extracted  from  the  alkaline  mixture  with  ether.  As  only  1*5  per 
cent,  of  phenols  passed  over  below  1900  in  distilling  the  water,  it 
was  concluded  that  the  sample  contained  little  or  no  phenol,  as  the 
latter  boils  at  1820,  and  the  cresols  between  1900  and  2000.  This 
sample  also  contains  7  per  cent,  of  constituents,  that  are  left  unde- 
termined for  the  present. 
It  was  at  first  suspected  that  these  discrepancies  might  have  been 
caused  by  an  error  in  the  strength  of  the  bromine  solution.  It  was 
therefore  re-standardized  and  found  correct.  After  titration  against 
carefully  purified  sodium  thiosulphate,  the  solution  was  used  in  an 
assay  of  the  purest  phenol  obtainable,  indicating  98-9,  99-3  and  98*5 
per  cent,  of  phenol.  The  sample  melted  at  40*5°,  the  melting-point 
required  for  absolute  phenol  being  42-5°,  and  the  result  of  assay 
thus  being  corroborated.  Titration  of  the  crude  acids  being  per- 
formed under  the  same  conditions,  as  nearly  possible,  insured  accu- 
racy of  the  results. 
While  it  is  not  yet  practicable  to  accurately  determine  the  quan- 
tities of  phenol  and  cresol  in  the  complex  mixtures  containing 
them  by  the  bromine  method,  this  method  is,  nevertheless,  in  the 
