146 
Manufacture  of  Acetone. 
Am.  Jour.  Pbarm. 
March,  1895. 
connected  to  a  Sprengel  water  pump,  and  a  minus  pressure  of  1  to  6  Cm.  of 
mercury  was  maintained  on  the  entire  apparatus.  This  served  to  relieve  all 
joints  and  connections  and  caused  all  the  leakages  to  be  inward,  whilst  a  mer- 
cury gauge  at  each  end  gave  due  notice  of  obstruction  or  irregularities. 
These  two  ends  of  the  apparatus  remaining  constant,  the  intervening  space 
was  occupied  by  the  varying  form  of  distilling  or  decomposing  apparatus.  An 
earthenware  drain  pipe  with  movable  tile  ends  served  as  a  furnace.  This  drain 
pipe,  supported  in  a  horizontal  position,  had  6  holes  drilled  above  and  below. 
Each  lower  hole  was  large  enough  to  admit  a  Bunsen  burner  with  limited  air 
space  around  it,  while  the  holes  on  top,  to  give  exit  to  the  products  of  the  com- 
bustion, were  smaller.  The  decomposing  tubes  or  stills  of  wrought  iron,  with 
cast-iron  ends,  occupied  this  drain  pipe  furnace,  being  connected  with  the 
vapor  supply  apparatus  at  one  end  and  the  condenser  at  the  other. 
Much  preliminary  work  was  necessary  in  getting  the  apparatus  in  good  work- 
ing order  and  in  following  up  tangential  points;  but  these  are  passed  over,  and 
only  the  important  work  given — and  that  not  always  in  the  order  in  which  it 
was  done,  but  in  an  order  which  brings  the  results  into  a  more  logical  sequence 
more  easily  understood. 
Two  strengths  of  acetic  acid  were  used.  First,  an  acid  containing  36  p.  c.  of 
absolute  acid.  But  as  this  gave  distillates  unnecessarily  dilute,  it  was  gener- 
ally given  up  in  favor  of  a  60  p.  c.  acid,  although  the  reactions  were  not  notice- 
ably different  in  the  use  of  the  two  strengths.  Hence,  with  two  exceptions,  the 
results  given  are  from  a  60  p.  c.  acetic  acid. 
Reducing  the  work  from  the  disorderly  way  in  which  it  was  done  to  a  natural 
order,  and  rejecting  what  was  not  trustworthy,  it  is  best  to  begin  with  some 
repetitions  of  work  already  long  on  record.  (See  Gmelin's  Hand  Book,  and 
other  authorities.) 
A  tube  of  wrought  iron  about  36  Cm.  (14  inches)  in  length  by  6 '5  Cm.  (2*5 
inches)  internal  diameter,  reduced  at  each  end  to  tubing  of  about  o*6  Cm.  ('25 
inch),  was  held  stationary  in  the  centre  of  the  furnace,  and  connected  at  one 
end  with  the  acid  vapor  supply,  and  at  the  other  with  the  condensers.  This 
tube  could  be  heated  by  the  gas  burners  to  any  desired  degree  up  to  a  dull  red 
heat.  The  trials  were  made  under  as  nearly  the  same  conditions  as  practicable, 
the  running  time  being  about  3-5  hours,  and  under  close  observation.  The 
amount  of  60  p.  c.  acetic  acid  which  could  be  passed  in  in  vapor  during  this  time, 
varied  much — generally  250  to  350  Cc.  The  quantities  used  were  always  re- 
duced to  absolute  acid  (HC2H302  =  59*86),  and  the  results  are  given  in  the  same 
acid,  but  a  high  degree  of  accuracy  was  impracticable,  and  therefore  not 
aimed  at. 
(1)  With  the  tube  empt}-  and  heated  nearly  to  redness  at  first,  and  finally  to 
dull  red  heat,  290  Cc.  of  60  p.  c.  acid  ==  174  Gm.  absolute  acid,  was  passed  in  in  3  -5 
hours.  About  11 1  Gm.  of  this  acid  passed  through  unchanged,  and  63  Gm.  was 
decomposed.  That  is,  about  63-8  p.  c.  came  through  unchanged,  and  36*2  p.  c. 
was  decomposed.  In  the  first  receiving  flask,  kept  hot  by  the  vapor,  there  was 
no  acetone,  but  only  132  Cc.  of  a  53  p.  c.  acid.  In  the  second  flask,  in  the  ice- 
bath,  there  was  115  Cc.  of  a  36  p.  c.  acid;  and  this  liquid,  roughly  estimated  by 
the  iodoform  test,  contained  10  to  12  p.  c.  of  acetone.  From  the  final  wash 
bottle  came  a  stream  of  inflammable  gas — probably  methane  and  carbon  mon- 
oxide— that  would  burn  almost  continuously. 
