Am.  Jour.  Pharm.  \ 
March,  1895.  j 
Manufacture  of  Acetone. 
145 
recharged  with  fresh  acetate,  making  an  interrupted  process  of  repeated  charg- 
ing and  discharging  and  heating  and  cooling.  This  process  is  very  old;  but 
two  patents  have  been  taken  out  in  this  country  on  some  details  of  the  process 
and  apparatus. 
The  writer  proposed  to  himself  to  make  acetone  directly  from  acetic  acid  by 
a  continuous  process,  and  has  accomplished  that  object. 
In  Gmelin's  Hand  Book  of  Chemistry,  Cavendish  Society  edition,  1853,  Vo1- 
VIII,  at  page  291,  under  the  head  of  decomposition  of  acetic  acid  by  heat, 
much  work  is  given  where  the  vapor  of  acetic  acid  was  passed  through  heated 
tubes,  acetone  being  one  of  the  products;  and,  on  this  line  of  investigation,  the 
writer's  work  was  taken  up. 
It  was  not  difficult  to  see  that  the  discrepant  results  reached  by  the  authori- 
ties were  due  to  differing  physical  conditions,  and  different  degrees  of  heating, 
since  it  was  mechanically  quite  certain  that  a  current  of  vapor  passing  through 
a  stationary  tube,  heated  from  below,  whether  empty  or  filled,  could  not  be 
heated  to  the  same  degree  in  all  parts  of  the  tube,  and  therefore  could  not  give 
the  same  decomposition  in  all  parts. 
The  work  undertaken  was  commenced  in  very  long-necked,  glass  bulbs,  held 
in  a  horizontal  position  so  that  they  might  be  stationary  or  be  revolved  by 
hand,  and  these  were  heated  by  a  bath  of  Wood's  metal — the  acid  being  passed 
in,  and  the  products  coming  out  through  horizontal  tubes  in  the  long  necks. 
Experiences  with  these  bulbs  led  to  much  better  mechanical  devices.  A 
small  flask  was  arranged  as  a  still,  and  from  this,  by  a  gas  burner,  a  constant 
current  of  acetic  acid  vapor  could  be  produced  at  any. desired  rate.  The  rate 
was  regulated  by  the  rate  of  supply  of  liquid  acid  from  an  elevated  graduated 
supply  vessel,  the  supply  going  to  the  still  through  a  glass  tube,  in  which  the 
rate  of  dropping  was  seen  and  controlled  by  stop-cock.  Then,  by  varying  the 
acid  supply  and  the  heat  from  the  burner,  the  boiling  liquid  in  the  still  could 
be  kept  at  about  a  constant  level,  and  with  a  controllable  known  rate  of  vapor 
supply. 
At  some  distance  from  this  end  of  this  apparatus  the  condensing  apparatus 
was  arranged  to  receive  the  distillates.  The  products  of  distillation  were  first 
received  in  a  flask  where  most  of  the  watery  vapor  and  undecomposed  acid  was 
condensed,  but  where  the  temperature  continued  so  high  that  but  a  mere  trace 
of  acetone  was  arrested  there.  From  the  neck  of  this  flask  the  remaining 
gases  and  vapors  passed  through  a  good  condenser  which  delivered  the  re- 
mainder of  the  water  and  undecomposed  acid  and  the  acetone  into  a  flask 
immersed  in  an  ice  bath.  Here  almost  all  the  condensible  vapors  were  con- 
densed. The  gases  and  uncondensed  vapors  were  taken  from  the  neck  of  this 
flask  to  a  small  wash  bottle  supplied  with  water,  by  which  the  current  of  gases 
was  washed.  Here  waste  acetone  enough  was  caught  to  increase  the  volume  of 
contents  to  a  point  at  which  all  went  off  together  in  the  current  of  gases,  and 
the  level  remained  constant.  Next  was  a  wash  bottle  containing  a  strong 
solution  of  sodium  hydrate.  Through  this  the  residual  gases  were  passed  in 
order  that  most  of  the  carbon  dioxide  might  be  combined.  Finally  the  gases 
were  passed  through  another  small  wash  bottle  containing  water.  At  the 
small  exit  tube  of  this  bottle  the  gases  were  tested  for  inflammability,  and  the 
proportion  of  methane  and  carbon  monoxide  was  estimated  by  the  absence  or 
the  degree  of  inflammability.  Except  at  the  times  of  testing,  this  exit  tube  was 
