582 
The  Acids  of  Butter . 
Am.  Jour.  Pharm. 
Nov.,  1892. 
RESEARCH  ON  THE  ACIDS  OF  BUTTER.1 
By  Emil  Koefoed. 
785  grammes  of  a  butter  fat  giving  15-1  cc.  Reichert  figure  (by 
Nilson's  modification,  Z.  fur  Anal.  Ckemie,  28,  175),  were  saponified 
with  200  grammes  caustic  soda  in  500  cc.  of  water  ;  the  soap  was 
decomposed  by  300  grammes  of  sulphuric  acid  diluted  with  500  cc. 
of  water,  and  the  liquid  boiled  under,  an  inverted  condenser  till  the 
soap  was  all  decomposed,  a  current  of  carbon  dioxide  being  passed 
through  the  flask.  The  fatty  acids  (720  grammes)  were  filtered, 
and  the  aqueous  filtrate  shaken  three  times  with  ether,  which,  on 
distillation,  left  6  grammes  of  acids  smelling  like  butyric.  This 
extraction  with  ether  was  proved  to  have  removed  the  whole  of  the 
organic  acids.    The  6  grammes  constituted  Portion  I. 
The  720  grammes  of  acids  left  on  the  filter  were  distilled  under  30 
mm.  pressure.  The  acids  distilling  between  93 0  and  200°  weighed 
54  grammes,  and  constituted  Portion  II. 
The  remaining  acids  were  dissolved  in  500  grammes  of  alcohol 
of  950  Tralles,  and  were  several  times  crystallized  from  this  medium  ; 
100  grammes  were  thus  obtained. 
The  whole  of  the  alcoholic  filtrates  (about  4  litres)  were,  after  the 
addition  of  30  gm.  of  acetic  acid,  treated  with  an  alcoholic  solution 
of  600  grammes  of  crystallized  lead  acetate.  The  precipitate  was 
collected  after  24  hours  on  a  filter,  washed  with  alcohol,  and  air 
dried.  The  acids  were  then  set  at  liberty  by  boiling  with  hydro- 
chloric acid,  and  weighed  314  grammes,  which,  with  the  100 
grammes  obtained  by  crystallization,  formed  Portion  III. 
The  filtrate  was  made  faintly  alkaline  with  ammonia,  and  a  small 
quantity  of  a  semi-fluid  lead  salt  separated,  probably  Gottlieb's 
oxyoleate  of  lead.  This  was  boiled  with  hydrochloric  acid,  and  the 
acid  thus  obtained  dissolved  in  ammonia,  and  its  barium  salt  pre- 
cipitated by  barium  chloride.    This  formed  Portion  IV. 
From  the  filtrate  the  alcohol  was  removed  by  distillation,  and  the 
fatty  acids  transformed  into  barium  salts  as  above.  These  consti- 
tuted Portion  V. 
The  Portions  were  then  examined. 
Portion  V.  The  barium  salts  were  boiled  successively  with 
acetic  ether  and  chloroform.    From  the  acetic  ether  solution,  oleate 
1  Bulletin  de  /' Academie  Roy  ale  Danoise,  1891  ;    The  Analyst,  1892,  p.  130. 
