546 
Oleates  and  Oleo-Palmitates. 
(  Am.  Jour.  Pharnk. 
1       Nov.,  1881. 
such  is  the  case  with  pure  oleic  acid,  it  certainly  is  much  more  so  with 
the  oleic  acids  found  in  the  market,  of  which  the  greater  portion  i& 
the  oleo-stearic  acid  of  the  candlemakers,  deprived  of  its  coloring^ 
matter,  while  others  are  oleo-palmitic  acids  derived  from  either  pre- 
cipitating olive-oil  or  almond-oil  soaps.  Either  of  them  soon  gives 
rise  to  heavy  precipitates,  as  the  oleic  acid  itself  has  a  tendency  to 
take  up  the  oxygen  of  the  oxide  and  reduce  it  to  the  metallic  state. 
Oleic  acid,  if  pure  and  freshly  made,  will  keep  considerable  of  the 
oxides  in  solution,  but  the  very  excess  of  oleic  acid  present  is  the 
cause  of  its  gradual  change  and  deterioration,  and  though  the  appear- 
ances of  the  preparation  may  be  saved  by  repeated  filtration,  the  result 
is  very  soon  that  of  an  oleate  containing  no  metallic  salt  in  solution. 
Actuated  by  the  desire  to  prepare  true  oleates,  and  to  obtain  them 
by  a  cheaper  method  than  the  retrograde  j^rocess  of  first  making  acid 
from  a  true  oleate  and  then  making  a  series  of  oleic  solutions,  led  me  to- 
experiments  of  which  I  already  spoke  in  one  of  our  last  yearns  meet- 
ings. 
I  have  already  mentioned  the  fact  in  my  former  paper  on  this  sub- 
ject, that  petroleum  benzin  was  a  ready  solvent  for  oleates,  while  it 
appeared  to  be  a  non-solvent,  or  at  least  a  very  limited  one  at  ordinary 
temperature,  of  palmitates  and  stearates.  I  had  utilized  this  to  sepa- 
rate the  lead  oleate  from  the  lead  palmitate  in  making  oleic  acid. 
That  chemically  true  oleates  could  be  made  in  the  same  way  as  the 
lead  oleate  in  that  process  was  an  inference  which  could  be  readily 
drawn,  but  which  proved  practically  of  not  much  success.  As  soaps^ 
however,  could  be  readily  decomposed  by  metallic  salts  into  sodium  or 
potassium  salts  and  oleo-stearates  or  oleo-palmitates  of  the  metal& 
there  was  no  difficulty  in  obtaining  the  joint  salts  which  could  be  sep- 
arated in  turn  by  the  use  of  benzin.  After  conducting  experiments 
on  that  subject,  I  found  that  this  method  of  preparing  oleo-stearates 
had  been  proposed  in  an  article^ — translated  from  a  French  journal — in 
the  "  Medical  Times,"  and  reprinted  in  the American  Journal  of 
Pharmacy,"  January,  1874,  page  28. 
In  order  to  obtain  true  oleates,  I  saponified  pure  oleic  acid,  prepared 
according  to  my  method,  as  published  in  my  former  article,  with 
caustic  soda  until  saponification  was  complete,  dissolved  the  sodium 
oleates  so  obtained  in  water  and  precipitated  with  metallic  salts  with 
the  results  of  obtaining  oleates  that  were  stable  and  definite  in  char- 
acter, possessing  besides  therapeutic  properties  of  which  I  satisfied 
