THE  AMERICAN 
AUGUST,  1898. 
JOURNAL  OF  PHARMACY 
JUL?  01898 
VALUATION  OF  CRUDE  CARBOLIC  ACID. 
By  Cakx  E.  Smith. 
(Report  from  Research  Committee  D,  Section  II.,  Committee  of  Revision  of 
the  U.S.P.) 
The  U.S.P.  of  1890  characterizes  crude  carbolic  acid  as  "a  liquid 
consisting  of  various  constituents  of  coal-tar,  chiefly  cresol  and 
phenol,  obtained  by  fractional  distillation."  A  test  for  presence  of 
alkali  is  given,  and  another,  designed  to  exclude  more  than  10  per 
cent,  of  the  less  soluble  constituents  of  coal-tar. 
As  might  be  expected,  the  commercial  supplies  of  this  substance 
vary  considerably  in  composition  and  strength,  the  relative  propor- 
tions of  phenol  and  the  cresols,  the  percentages  of  so-called  tar-oils 
and  of  water  being  particularly  subject  to  variation.  Since  the  cre- 
sols have  been  shown  to  be  about  three  times  more  powerful  as 
antiseptics  than  phenol,  it  is  not  a  matter  of  indifference  to  the  con- 
sumer whether  a  product  consists  chiefly  of  one  or  of  the  others. 
The  non-phenolic  constituents  of  crude  carbolic  acid,  to  which  the 
collective  name  of  "tar-oils"  has  been  given,  may  include  hydro- 
carbons, as  naphthalene,  anthracene,  phenathrene,  diphenyl,  etc., 
such  bases  as  pyridine,  quinoline,  aniline,  etc.,  and  other  substances 
still  undetermined.  Some  of  these  compounds  mentioned  have 
undoubted  antiseptic  value,  while  others  are  inert.  Water  is  always 
found,  and,  if  present  in  larger  quantity  than  5  per  cent.,  might  be 
looked  upon  as  an  adulteration.  With  ordinary  care  in  the  distil- 
lation it  will  not  exceed  a  fraction  of  1  per  cent.,  according  to  the 
experience  of  at  least  one  manufacturing  firm  within  the  writer's 
knowledge. 
(369) 
