AF4raary^f"}     Volumetric  Estimation  of  Acetone.  67 
A.  Lieben,1  in  1870,  discovered  that  certain  organic  groups,  such 
as  CH3,  COC  — ,  CH3  CH(OH)C— ,  CH3CH2OH,  etc.,  when  treated 
with  iodine  in  the  presence  of  an  alkali,  yield  iodoform.  Iodoform 
itself,  however,  was  discovered  in  1822,  by  Serullas.2  With  some 
of  the  groups  the  application  of  heat  is  necessary  to  bring  about  the 
reaction.  Lieben  also  observed  that  methyl  alcohol  did  not  re- 
spond to  this  test,  and  suggested  at  the  same  time  that  this  fact 
might  be  of  service  in  establishing  the  purity  of  this  alcohol. 
Ten  years  later,  G.  Kramer3  devised  a  gravimetric  process,  based 
on  the  iodoform  reaction  for  estimating  acetone  in  wood  alcohol. 
The  results  obtained  by  this  method  were  rarely  concordant,  conse- 
quently it  was  unsatisfactory. 
From  1884  to  1888  much  interest  was  manifested  in  this  country 
concerning  the  manufacture  of  chloroform  from  acetone.  During 
this  period,  W.  R.  OrndorfT4  and  H.  Jessel  studied  the  action  of 
chlorinated  lime  on  acetone  in  the  manufacture  of  chloroform.  On  the 
results  of  this  investigation  J.  Messinger5  based  the  first  volumetric 
method  for  estimating  acetone  in  wood  alcohol.  The  method  has 
been  applied  with  success  to  all6  mixtures  in  which  acetone  gener- 
ally occurs. 
The  reactions7  involved  for  this  volumetric  process  are  as  fol- 
lows : 
I2  +  2KOH  =  KIO  +  KI  +  H20. 
CH3COCH3  +  6KIO  =  CH3COCI3  +  3KOH  +  3KI. 
CH3COCI3  +  KOH  =  CHI3  +  KC2H302. 
KIO  +  KI  +  2HCI  =  I2  +  2KCI  +  H20. 
KIO3  +  5KI  +  6HC1  =  3l2  +  6KC1  +  3H20. 
The  solutions  required  for  the  process  are  as  follows :  56 
grammes  of  potassium  hydroxide,  free  from  nitrite,  dissolved  in  dis- 
tilled water  and  made  up  to  1  litre. 
1 1876,  Ann.  (Liebig)  Supp.,  7,  218  and  377. 
2 1822,  Ann.  chem.  phys.,  30,  165. 
3 1880,  Ber.  d.  chem.  Ges.,  13,  1000;  Ztschr.  anal.  Chem.,  19,498. 
4  1888,  Am.  Chem.  J.,  10,  363. 
5 1888,  Ber.  d.  chem.  Ges.,  3366. 
6  See  literature  at  the  end  of  the  article. 
7  There  may  be  some  question  coucerniug  the  actual  reactions,  but  the  basis 
of  calculation  is  not  involved.  Kramer  expresses  it  in  a  single  equation  : 
CH3COCH3  +  61  +  4KOH  =  CHI3  +  3KI  +  KC2H30,  +  3H20. 
