296 
Detection  of  Phenol  in  Creasote. 
/Am.  Jour.  Pharm. 
X      June,  1885. 
DETECTION  OF  PHENOL  IN  CREASOTE.^ 
By  Peter  MacEwan. 
In  the  "Chemical  News/'  of  May  2, 188  4,  there  appeared  the  follow- 
ing note  among  the  weekly  "Chemical  Notices  from  Foreign  Sources/' 
the  source  in  this  instance  being  "Zeitschrift  fiir  analytische  Chemie 
^'A  Sensitive  Reaction  of  Phenol  (J.  F.  Eykman). — A  very  dilute 
solution  of  phenol  mixed  with  a  few  drops  of  nitrous  ether,  and  the 
same  volume  of  undiluted  sulphuric  acid,  takes  a  red  color.  If  the  acid 
is  allowed  to  run  down  the  side  of  the  glass  so  as  to  form  a  layer  below 
the  phenol  solution,  there  appears  a  narrow  red  band  where  the  liquids 
meet.    This  reaction  indicates  one  in  two  millions." 
On  trying  the  test  with  a  5  per  cent,  solution  of  pure  nitrous  ether, 
and  i  per  cent,  and  1  per  mille  solutions  of  phenol,  I  obtained  a  triple 
ring,  the  intermedial  stratum  being  brown,  the  lower  a  bright  emerald 
green,  and  the  upper  pink.  This  not  being  satisfactory  I  referred  to 
the  "  foreign  source  "  and  found  that  Eykman's  paper  had  appeared  in 
New  Remedies  and  that  spirit  of  nitrous  ether  was  to  be  used  in  the 
test.  With  the  spirit  the  emerald  green  color  is  not  produced ;  the 
ring  is  at  first  brown  with  a  red  shade,  but  after  standing  for  a  short 
time  the  brown  color  disappears,  leaving  a  fine  pink  stratum,  and  the 
strong  acid  has  also  a  pink  shade.  On  mixing  the  two  liquids  an 
opaque  solution  of  a  red  shade  (approaching  magenta)  is  produced. 
The  pure  nitrous  ether  solution  is  quite  clear  and  of  a  darker  red 
color.  The  red  color  is  due  to  reaction  between  phenol-sul phonic  acid 
and  the  aldehyde  contained  in  the  sweet  spirit  of  nitre. ^  The  reaction 
as  a  mere  test-tube  experiment  is  pretty  and  interesting,  particularly 
when  a  solution  of  pure  nitrous  ether  is  used,  the  immediate  bright 
green  color,  and  the  gradual  development  of  the  red  owing  to  the  slow 
formation  of  aldehyde,  are  very  interesting.  Apart  from  this  it  struck 
me  that  the  reaction  might  be  practically  useful  in  the  detection  of 
phenol  in  creasote,  and  I  put  the  matter  on  trial. 
An  aqueous  solution  of  creasote  (1  in  500)  on  the  addition  of  spirit 
of  nitrous  ether  becomes  cloudy  and  colored  (phenol  solution  remains 
transparent  and  colorless),  and  when  the  sulphuric  acid  is  added  a 
'  Read  at  a  meeting  of  the  Edinburgh  Chemists'  Assistants  and  Appren- 
ti-^es'  Association,  January,  28. 
^  See  paper  by  Mr.  Dunstau,  "Pharm.  Journ.,"  [3],  xiv,  837. 
