432 
ACTION  OF  CHLORIDE  OF  ZINC  ON  FATS. 
still  better,  with  water  acidulated  by  hydrochloric  acid,  a  fatty 
body  is  obtained,  which,  when  distilled,  furnishes  the  correspond- 
ing fatty  acids  with  an  insignificant  production  of  acroleine. 
The  washing-waters  carry  off  nearly  all  the  chloride  of  zinc  em- 
ployed, which  can  be  again  prepared  for  use  by  evaporation. 
The  fatty  acids  are  thus  produced  in  as  great  quantity  as  by  the 
ordinary  methods  ;  they  have  the  same  aspect,  qualities  and 
melting-point  as  those  produced  in  manufactories  where  the  dis- 
tillation is  effected  after  the  sulphuric  saponification.  To  operate 
well  and  quickly,  the  mixture  of  the  neutral  fatty  body  and 
chloride  of  zinc  must  be  heated  rapidly  until  the  moment  when, 
in  consequence  of  the  violent  reaction  of  the  two  bodies  upon 
each  other,  aqueous  vapors  are  evolved  in  abundance. 
The  washing  with  acidulated  water  after  saponification  may 
be  avoided,  but  then  the  products  of  the  distillation  are  softer. 
If  the  distillation  be  hastened  by  means  of  a  current  of  super- 
heated steam,  this  defect  may  be  corrected  in  a  great  degree. 
In  all  cases  steam  allows  harder  and  less  colored  products  to  be 
obtained  with  rapidity.  The  quantity  of  chloride  of  zinc  neces- 
sary for  a  good  saponification  varies  from  8  to  12  per  cent,  of 
the  weight  of  the  neutral  fatty  body. 
The  following  are  some  of  the  authors'  experiments  : — 
Tallow. — Experiment  1.  300  parts  of  tallow,  fusible  at  100e 
F.  After  saponification  and  washing  284  ;  loss  by  saponifica- 
tion, 5  per  cent.  After  distillation  with  steam,  250  parts  of 
substance  fusible  at  113°  F.  ;  loss  by  distillation,  13  per  cent. 
Experiment  2.  2000  parts  of  fat  fusible  at  100°  F.,  and  240 
parts,  or  12  per  cent,  of  chloride  of  zinc.  After  saponification 
the  fusing-point  was  107°6  F. ;  and  after  distillation,  without 
steam,  113°  F.    Chloride  of  zinc  recovered  215  parts. 
Palm-oil. — Experiment  1.  2160  parts  of  palm-butter  fusible 
at  75Q  F.,  and  12  per  cent.,  or  260  parts  of  chloride  of  zinc. 
The  product  of  saponification  was  fusible  at  95°  F.,  and  that  of 
distillation  (without  steam)  at  113°  F.  Chloride  of  zinc  re- 
covered, 211. 
Experiment  2.  Palm-butter.  195  of  saponified  product  gave 
175  of  fatty  body,  fusible  at  122°  F. 
Experiment  3.   300  of  palm-oil ;  after  saponification,  290  ; 
