82 
Bromoform. 
/ Am.  Jour.  Pharni. 
(.        Feb.,  1891. 
Gmelin  (Cavendish  edition,  vol.  VII,  p.  339)  gives  several  of  the 
methods  used  for  preparing  bromoform.  Lb  wig  first  prepared  it  in 
1832  by  distilling  bromal  (tri-brome  acetaldehyde)  with  excess  of 
solution  of  potassium  hydrate.  The  watery  distillate  was  decanted 
from  the  bromoform,  and  the  latter  dehydrated  by  sulphuric  acid. 
His  product  is  reported  as  having  a  specific  gravity  of  2- 13,  and 
must  have  been  impure. 
Dumas  is  stated  to  have  first  obtained  it  pure  and  recognized  its 
composition,  by  distilling  alcohol  or  acetone  with  excess  of  aqueous 
bromide  of  lime.  The  bromoform  was  shaken  with  sulphuric  acid, 
separated  and  then  treated  with  calcium  chloride.  This  is  the 
process,  it  is  believed,  that  is  generally  followed  in  preparing  the 
commercial  article. 
Lefort  obtained  it  by  gradually  adding  bromine  to  a  solution  of 
one  part  of  potassium  hydrate  and  one  part  of  wood  spirit,  kept 
cool,  until  the  liquid  became  colored.  The  bromoform  which  goes 
to  the  bottom  is  purified  over  calcium  chloride  which  retains  the 
undecomposed  wood  spirit.  L.  Reuter  {Ph.  Zeit.,  1890,  p.  5,  see  Amer. 
Journ.  of  Pharmacy,  1890,  p.  89)  made  use  of  the  same  process  and 
reports  the  product  as  a  colorless  liquid,  sp.  gr.  2-8,  boiling  point 
150°  C.  It  seems  almost  superfluous  to  state  here  that  absolutely 
pure  methylalcohol  yields  neither  chloroform,  bromoform  nor  iodo- 
form, and  that  the  amount  of  bromoform  produced  by  this  method  is 
but  a  measure  of  the  acetone  or  other  ketones  existing  as  impurities 
in  the  alcohol  used.  In  confirmation  of  this  statement,  see  Watt, 
Chem.  Diction.,  Supplement  II,  p.  324,  also  Archiv  der  Pharmacie, 
1887,  p.  376. 
More  recently  Fritz  Giinther  has  proposed  the  following  process : 
Acetone  is  mixed  with  10  parts  by  weight  of  20  per  cent,  soda  solu- 
tion in  a  flask  connected  with  a  reversed  condenser.  Bromine  is 
gradually  added  in  very  small  quantities,  through  a  funnel  tube  until 
bromoform  ceases  to  be  formed,  the  temperature  being  maintained 
during  the  operation  by  means  of  a  water-bath  at  500  C.  1-9  grm. 
acetone  was  said  to  yield  6-7  grm.  bromoform,  about  81  per  cent,  of 
the  theoretical  yield  {Archiv  der  Pharmacie,  1887,  378). 
No  mention  is  here  made  as  to  the  character  or  purity  of  the  pro- 
duct. In  my  hands  satisfactory  results  were  not  obtained  with  this 
process.  Pure  acetone  will  not  mix  with  20  per  cent,  soda  solution, 
and  on  agitation  therewith,  even  at  as  low  a  temperature  as  500  C. 
