'\.m  Jour.  Pharm>  ) 
Sept.,  1880.  I 
^inic  Acid^  ^inone^  etc. 
459 
the  same  acid  by  fusing  piperinic  acid  with  caustic  potash,  and  named 
it  pyrocatechuic  acid,  and  to  him  is  improperly  ascribed  the  discovery 
of  this  acid. 
The  author  has  repeated  his  former  experiments,  and  this  time  on  a 
large  quantity  of  pyrocatechuic  acid,  which  had  been  prepared  as  before 
by  the  action  of  bromine  on  quinic  acid,  and  he  now  finds  that  hydro- 
quinia  is  not  produced,  as  he  had  previously  assumed.  When  opera- 
tmg  with  a  large  quantity  of  pyrocatechuic  acid  the  decomposition  does 
not  proceed  very  smoothly  ;  a  carbonaceous  mass  is  formed  whilst 
phenol  and  pyrocatechin  distil  over. 
In  addition  to  pyrocatechuic  acid  another  acid  is  produced  by  the 
action  of  bromine  on  quinic  acid.  It  can  be  obtained  by  evaporating 
the  product  of  the  reaction  to  a  syrup,  agitating  it  with  ether,  then  treat- 
ing the  ether  residue  with  lukewarm  water  in  which  the  new  acid  is 
insoluble,  but  which  dissolves  the  pyrocatechuic  acid.  It  can  be  puri- 
fied by  recrystallization  from  boiling  water.  It  crystallizes  in  colorless 
laminae  or  in  needles,  which  dissolve  with  some  difficulty  in  boiling 
water  and  are  almost  insoluble  in  cold  water,  but  easily  dissolve  in  ether. 
It  carbonizes  when  heated,  giving  pungent  fumes  and  a  brown  colored 
distillate  which  solidifies  to  a  radiated  crystalline  mass  and,  like  the 
original  substance,  gives  no  coloration  with  ferric  chloride.  Its  hot 
saturated  solution  gives  no  precipitate  with  lead  acetate  but  a  consider- 
able quantity  of  a  yellowish  white  precipitate  with  basic  lead  acetate. 
The  composition  of  this  substance  has  not  yet  been  ascertained,  but  it 
is  said  to  be  a  bromine  derivative. 
Action  of  Concentrated  Hydrochloric  Acid  on  Quinic  Acid. — Warm  con- 
centrated hydrochloric  acid  quickly  dissolves  quinic  acid,  but  without 
decomposition  ;  but  when  heated  with  it  at  140  to  150°  in  a  sealed  tube 
it  is  converted  into  hydroquinone  and  paraoxybenzoic  acid. 
■  Graebe  obtained  pyrocatechuic  acid  by  che  action  of  potassium 
hydrate  on  quinic  acid,  and  the  author  states  that  a  similar  result  ensues 
by  using  sodium  hydrate,  and  that  neither  oxysalicylic  acid  nor  hydro- 
quinone carbonic  acid  is  produced. 
^inone. — As  an  addendum  to  his  former  remarks  on  this  substance 
the  author  states  that  it  is  somewhat  readilysoluble  in  boiling  petroleum 
ether,  but  very  readily  so  in  boiling  ligroin  (j/V),  and  as  the  greater  part 
of  the  quinone  recrystallizes  out  on  cooling  in  beautiful  yellow  prisms,, 
these  solvents  serve  as  a  ready  means  of  purifying  this  substance. 
The^author  is  unable  to  confirm  the  statement  of  Sarauw,  that  diace- 
