274     Chemical  Examination  of  Ipomcea  Purpurea.  {Am'j,unUer"i908arm' 
talline  mass.  By  recrystallizing  this  salt  four  times  from  water  it 
was  obtained  perfectly  white,  and  then  melted  at  185-1900  C* 
From  the  sodium  compound  the  acid  was  liberated  by  means  of 
acetic  acid.  On  heating  the  acidified  liquid  the  solid  acid  melted, 
then  dissolved,  and,  on  allowing  the  solution  to  cool,  it  separated  in 
long,  thin,  interlaced  needles  which  melted  at  100-1010  C.  It  can 
also  readily  be  purified  by  crystallization  from  warm  chloroform. 
On  heating  the  acid  at  100-1050  C.  there  was  no  loss  of  weight, 
and  it  is  therefore  anhydrous.  When  dissolved  in  absolute  alcohol 
it  was  found  to  be  devoid  of  optical  activity.  It  was  analyzed  with 
the  following  result : 
00686  gave  0-1618  C02  and  0-0674  H20.     0  =  64-3;  H  =  10*9 
C14H2804  requires  C  =  64-6 ;   H  =  io-8  per  cent. 
The  sodium  salt  gave,  on  analysis,  the  following  results : 
0*2212  of  the  air-dried  salt,  on  heating  at  1 10°  C,  lost  0*0106  H20. 
H20  =  4-8 
0-2 106  of  the  anhydrous  salt  gave,  on  ignition,  0-0400  Na20O3. 
Na  =  8-2 
014H27O4  Na,  H20  requires  H20  =  6  0  per  cent. 
C14H2704  Na  requires  Na  —  8-2  per  cent. 
The  somewhat  low  percentage  of  water  found  in  this  salt  indicates 
that  some  efflorescence  had  occurred. 
From  the  sodium  salt  a  silver  salt  was  prepared,  which  also  was 
crystalline,  and  melted  at  1600  C.  Oa.  analysis  it  gave  the  follow- 
ing results  : 
0-1430  gave  0-2382  COo,  0-0940  H20,  and  0  0428  Ag. 
C=45'4I  H  =  7-3;  Ag  =  29-9 
0-1304  gave  on  ignition  00390  Ag.    Ag  —  29-9 
C14H2704  Ag  requires  C  =  45-8;   H  —  7-4 ;   Ag  —  29-4  per  cent. 
A  copper  salt  was  likewise  prepared  from  the  sodium  salt  by  pre- 
cipitation with  a  solution  of  copper  sulphate.  This  was  obtained 
in  the  form  of  a  pale  blue,  amorphous  powder,  but  on  analysis  was 
found  to  be  highly  basic  and  ot  indefinite  composition. 
The  preceding  results  prove  that  the  above  described  substance 
is  a  monocarboxylic  acid,  having  the  empirical  formula,  C14H2804. 
As  it  is  not  identical  with  any  acid  hitherto  described,  it  is  proposed 
to  designate  it  ipurolic  acid. 
