ON  THE  OXYPHENIC  ACID  OF  WOOD-VINEGAR. 
343 
not  rendered  turbid  even  by  long  boiling  ;  and  besides,  the  de- 
posit which  they  may  sometimes  furnish-under  these  circum- 
stances, would  not  present  the  composition  above  indicated. 
The  author  adds,  that  by  this  simple  process,  potash  or  ammo- 
niacal  alum  may  be  quickly  detected  in  wines  containing  one 
one-thousandth,  one  two-thousandths,  or  even  one  three-thou- 
sandths of  these  salts. — Chem.  Gas.,  April  1,  from  Comptes 
Eendus,  Feb.  25,  1856,  p.  410. 
ON  THE  OXYPHENIC  ACID  OF  WOOD-VINEGAR. 
By  Max  Buchner. 
Pettenkofer  found  that  wood-vinegar  contains  an  acid,  which 
from  its  properties  might  be  taken  for  pyrogallic  acid.  At  his 
instigation  A.  Pauli  investigated  this  body,  and  found  that  it 
was  distinct  from  pyrogallic  acid.  The  author  has  continued 
this  investigation,  and  found  that  it  is  identical  with  phenic  acid, 
pyromoritannic  acid  of  "Wagner,  and  pyrocatechine  of  Reinsch 
and  Zwenger. 
Wood-vinegar  is  evaporated  to  the  consistence  of  a  syrup, 
and  the  residue  agitated  with  a  saturated  solution  of  chloride  of 
sodium,  in  order  to  separate  the  tarry  constituents.  The  benzoic 
acid  remains  in  the  solution,  and  is  extracted  therefrom  by  ether, 
which  is  shaken  with  the  solution.  The  etherial  stratum  is 
drawn  off,  and  the  ether  got  rid  of  by  distillation. 
The  residue  is  now  further  distilled,  whilst  a  current  of  car- 
bonic acid  is  passed  through  the  apparatus.  Various  distillates 
are  obtained.  The  first  still  contains  some  ether,  together  with 
acetic  acid  ;  it  is  nearly  colorless.  The  second  is  a  reddish- 
yellow,  rather  thinly  fluid-oil ;  it  contains  the  principal  part  of 
the  required  acid.  The  third  is  a  brown  oil,  in  which  there  is 
still  some  acid,  which  however  does  not  crystallize. 
The  second  distillate,  collected  until  the  brown  oil  begins  to 
pass  over,  sets  into  a  crystalline  jelly,  which  is  purified.  The 
crude  wood-vinegar  contains  from  0-1  to  0-2  per  cent,  of  this 
acid.  Its  amount  is  determined  by  adding  potash  to  the  wood- 
vinegar,  and  allowing  oxygen  to  be  absorbed  by  the  fluid.  10 
milligrms.  of  oxyphenic  acid  absorb  3.7  cub.  centims.  of  oxygen 
at  32p  F.,  and  with  a  barometric  pressure  of  760  millims. 
