280 
Santoninic  Acid. 
(  Am.  Jour.  Phakm. 
\    June  1, 1874. 
dropping  tube  at  a  temperature  of  15°  C,  and  allowed  to  drop  slowly 
upon  the  iodide,  about  ten  drops  per  minute.  When  all  the  wood 
spirit  has  been  admitted,  the  flask  is  warmed  for  five  minutes,  in  boil- 
ing water,  the  cooler  being  placed  upright.  The  apparatus  is  then 
inclined  in  such  a  way  that  the  distillate  will  run  out,  and  the  mixture 
distilled  on  a  water  bath  as  long  as  anything  goes  over.  Toward  the 
end  of  the  experiment  the  whole  flask  must  be  immersed  in  the  boil- 
ing water.  The  distillate  is  caught  in  a  glass  receiver,  or,  better,  in 
a  graduated  glass  tube,  narrow  at  the  bottom,  so  that  the  narrow  por- 
tion may  be  very  accurately  graduated.  The  receiver  should  hold 
25  c.c,  and,  after  the  distillation,  is  filled  up  to  the  25  c.c.  mark 
with  water,  a  part  of  the  water  being  used  to  rinse  out  the  condenser. 
If  transparent  crystals  of  iodide  of  phosphonium  are  deposited  in  the 
cooler,  the  water  must  be  added  carefully,  drop  by  drop.  The  methyl 
iodide  collected  in  the  receiver  is  shaken  with  water  and  its  volume 
read  off  at  15°  C.  Five  cubic  centimeters  of  absolute,  chemically 
pure  methyl  alcohol,  prepared  from  methylbenzoic  ether,  gave  7*19  c.c- 
methyl  iodide,  which  quantity  corresponds  very  nearly  with  the  theo- 
retical yield.  By  comparison  with  the  quantity  of  iodide  of  methyl 
obtained  from  the  specimens  tested,  the  quantity  of  methyl  alcohol 
can  be  calculated  by  simple  proportion ;  or,  if  the  space  of  7*19  c.  c. 
in  the  receiver  be  divided  in  100  equal  parts,  the  percentage  may  be 
read  off  directly. — Journ.  of  Applied  Chem.,  May,  1874. 
SANTONINIC  ACID. 
By  0.  Hesse. 
Santonin  is  the  anhydride  of  an  acid,  of  which  hitherto  only  the 
salts  have  been  known.  The  free  santoninic  acid  is  obtained  by  add- 
ing an  excess  of  dilute  hydrochloric  acid  to  a  cold  aqueous  solution 
of  the  sodium  salt,  and  shaking  at  once  the  milky  liquid  with  ether. 
From  the  ethereal  solution  granular  crystals  soon  separate  out,  which 
are  recrystallized  from  alcohol. 
Santoninic  acid,  C15H20O4,  forms  white,  rhombic  crystals,  which  are 
not  colored  yellow  by  exposure  to  light.  It  is  sparingly  soluble  in 
cold  water,  more  freely  in  boiling  water,  and  readily  in  alcohol,  but 
not  very  freely  in  ether.  Its  aqueous  solution  has  a  strongly  acid 
reaction,  and,  when  hot,  decomposes  the  carbonates  of  sodium  and 
calcium.    The  santonates  have  an  alkaline  reaction,  and  are  not  col- 
