AmMSch,]89irm'}  Gleanings  from  the  German  Journals.  133 
weight  of  crude  nitric  acid,  an  equal  volume  of  water  is  then  added 
and  the  mixture  supersaturated  with  ammonia ;  if  the  liquid  be 
now  poured  off  from  the  separated  wax  it  should,  if  the  wax  was 
pure,  have  only  a  yellow  color  ;  but  if  the  wax  contained  as  little  as 
one  per  cent,  of  resin,  the  liquid  will  be  of  a  red-brown  color,  due 
to  the  formUion  of  nitro-derivatives  of  the  resin-constituents. — Dr. 
H.  Rbttger,  Chemiker  Ztg.,  1 891 ,  45. 
The  red  coloration  of  carbolic  acid  has  been  the  subject  of  a  very 
elaborate  investigation  by  E.  Fabini,  the  results  of  which  are  that 
the  coloration  is  due  to  the  action  of  hydrogen  peroxide  upon 
metal  containing  carbolic  acid  in  presence  of  ammonia  ;  H202, 
metal  and  NH3  must  be  present  to  produce  the  color.  The  quantity 
of  metal  necessary  is  very  small,  one  part  of  Cu  or  Fe  in  180,000  is 
sufficient  for  the  red  coloration,  while  one  part  of  Cu  or  Fe  in 
300,000  or  one  part  Pb  in  65,000  is  sufficient  to  show  change  in  the 
acid  ;  of  NH3  one  part  in  10,000  will  be  quite  sufficient.  The 
appearance  of  the  color  is  explained  by  the  formation  of  ammonium 
phenylate  (by  absorption  of  NH3  from  the  air),  which,  with  the 
metallic  salt  present  in  the  carbolic  acid,  forms  a  metal-phenylate, 
which  in  turn  is  acted  upon  by  H202  producing  the  coloring  prin- 
ciple and  liberating  the  metal.  Copper  sulphate  with  ammonium 
phenylate  gives  a  green  precipitate  of  cupric  phenylate  ;  the  latter, 
upon  the  addition  of  H202,  produces  at  once  (with  effervescence) 
the  red  coloring  matter.  This  is  soluble  in  alcohol  reprecipitated 
upon  addition  of  water,  upon  drying  forming  a  black,  brittle  sub- 
stance which  has  the  property  of  coloring  carbolic  acid  ;  1  :  300,000 
will  still  impart  a  faint  red  color.  The  coloring  matter  is  entirely 
organic,  being  absolutely  free  from  metal,  is  volatile,  and  colored 
blue  by  concentrated  H2SOr 
The  action  of  metals  upon  the  formation  of  the  red  color  can  be 
illustrated  by  the  following  experiment  :  10  cc.  liquefied  carbolic 
acid  are  placed  in  a  test  tube,  y2  drop  ammonia,  a  few  drops  H202 
solution  added  and  the  mixture  gently  warmed.  If  the  acid  is  free 
from  metals,  no  coloration  is  produced ;  if  now  a  bright  knife  blade 
be  introduced  into  the  mixture,  blood-red  streaks  will  flow  from  it 
after  a  very  short  time. 
The  occasionally  noticeable,  sudden  coloration  of  carbolic  acid  is 
ascribed  to  elevated  temperatures — this  favoring  the  action  previ- 
ously explained. — Pharm.  Post,  1891,  2,  25,  41  and  61. 
I 
