486 
Notes  on  Benzoin. 
f  Am.  Jour.  P  harm.. 
\     Nov.  1, 1872. 
2d.  Known  portions  of  Nos.  2,  3,  4  and  5  were  subjected  to  sub- 
limation at  a  gentle  heat,  the  vessel  removed  from  time  to  time,  al- 
lowed to  cool  and  the  contents  stirred.  The  product  of  the  sublima- 
tion of  each  sample  was  very  small,  and  the  weight  was  not  taken. 
Each  product,  both  by  precipitation  and  sublimation,  gave  the  char- 
acteristic tests  for  cinnamic  acid. 
3d.  Sample  No.  1  was  a  splendid  specimen  obtained  through  the 
kindness  of  Prof.  Maisch.  It  was  treated  by  precipitation,  the  same 
as  in  the  first  series  of  experiments,  with  no  result. 
Another  portion  was  then  treated  by  the  same  process,  only  using 
more  water,  boiling  longer,  and  evaporating  to  three  fluid-drachms  be- 
fore adding  the  muriatic  acid.  The  result  was  a  yield  of  six  per  cent, 
of  an  amorphous  white  precipitate. 
4th.  A  portion  of  sample  1  was  then  sublimed,  yielding  nineteen 
per  cent,  of  crystals.  These  and  the  amorphous  precipitate  giving 
no  evidence  of  cinnamic  acid,  it  w,as  concluded  that  this  sample  con- 
tained benzoic  acid  only. 
5th.  Some  pure  cinnamic  acid  in  an  amorphous  state  was  sublimed 
with  a  gentle  heat.  The  amount  of  crystals  obtained  was  comparatively 
insignificant. 
6th.  A  known  quantity  of  seven  of  the  samples  was  treated  with  alco- 
hol. The  undissolved  residue,  dried  and  weighed,  gave  an  average  of 
twenty-one  per  cent,  of  insoluble  matter.* 
These  investigations  lead  to  the  conclusions — 1.  That  the  results 
of  experiments  1  and  2  were  cinnamic  acid,  which,  being  less  soluble 
in  water  than  benzoic,  would  be  thrown  down  from  solution  of  cinni- 
mate  of  lime  upon  the  addition  of  muriatic  acid. 
2d.  That  considerable  cinnamic  acid  is  found  in  much  of  the  benzoin 
in  our  market.  Cinnamic  acid  can  be  obtained,  fr.ee  from  benzoic 
acid,  for  all  practical  purposes,  by  boiling  the  benzoin  with  double  its 
bulk  of  lime  in  forty  times  its  own  weight  of  water  for  fifteen  or 
twenty  minutes,  filtering,  cooling,  acidulating  strongly  with  muriatic 
acid,  washing  the  precipitate,  and  recrystallizing  from  water  acidu- 
lated with  muriatic  acid. 
3d.  That  benzoic  acid  is  best  obtained  by  sublimation,  and  when 
procured  in  that  way  is  almost  free  from  cinnamic  acid. 
*  It  is  to  be  regretted  that  the  author  did  not  give  in  detail  the  results  of  this, 
series  of  experiments ;  one  or  two  of  the  samples  were  very  pure,  dissolving, 
without  almost  any  residue. — Editor. 
