176 
Neutral  Oleate  of  Mercury. 
J  Am.  Jour.  Pharm. 
(      April,  1885. 
NEUTRAL  OLEATE  OF  MERCURY.^ 
By  Charles  R.  C.  Tichborne,  L.L.D.,  F.I.C.,  Etc. 
Attempts  have  been  made  to  make  the  mercurial  oleates  by  double 
decomposition,  but  my  experience  is  that  it  is  not  attended  with  much 
success.  This  is  in  great  measure  owing  to  the  fact  that  when  the 
salts  (let  us  say  mercuric  chloride  and  oleate  of  sodium)  in  the  propor- 
tions to  form  the  neutral  oleate  are  brought  together,  very  little  of  the 
oleate  is  formed,  and  it  is  next  to  impossible  to  work  the  product 
properly.  If  we  double  or  halve  the  equivalent  of  oleic  acid  so  as  to 
get  an  acid  or  basic  salt  the  product  is  much  larger.  It  is  the  acid 
oleate  which  has  generally  been  formed  in  the  double  decomposition 
process. 
Assuming  that  oleic  acid  is  what  is  termed  a  monobasic  acid,  the 
neutral  mercuric  oleate  should  have  the  following  composition  : 
Hg2C„H3,0,. 
We  find  that  mercuric  oxide  (either  the  red  or  yellow  oxide)  dis- 
solves in  the  proportions  requisite  to  produce  a  neutral  salt  forming  a 
colorless  and  fairly  homogeneous  mass.  If  this  be  placed  under  the 
microscope,  however,  indications  of  the  separated  water  may  be  per- 
ceived. This  water,  which  is  produced  by  the  decomposition,  has,  I 
think,  frequently  been  lost  sight  of  in  considering  the  oleates.  The  re- 
action is  as  follows : 
HgO+2C,3H3A-Hg2C,3H330„H,0. 
If  we  allow  oleate  of  mercury  to  stand,  however,  some  considerable 
time,  this  water  seems  to  be  assimilated,  and  a  hydrate  is  formed.  The 
oleate  pectises,  and  the  colloid  oleate,  if  diluted  with  vaseline  and 
placed  under  the  microscope,  is  seen  in  jelly-like  masses  disseminated 
through  the  element.  It  is  mixed  with  some  little  difficulty.  If  the 
oleate  is  gradually  heated  upon  a  water-bath  to  100°  C,  the  water  is 
very  slowly  given  off,  and  long  before  the  theoretical  quantity  is  lost, 
the  oleate  begins  to  decompose.  The  acid  being  oxidized  and  metallic 
mercury  deposited,  if  this  reaction  be  pushed  to  its  ultimate  results,  a 
dark-colored  liquid  oil  is  produced  and  metallic  mercury.  The  fusing 
point  of  mercuric  oleate  is  two  or  three  degrees  above  the  boiling  point 
of  water. 
1  From  the  "  Medical  Press,"  September  24,  1884. 
