Am.  Jour.Pharrn.  \ 
March,  1895.  j 
Manufacture  of  Acetone. 
Now,  upon  cooling  and  opening  the  still,  samples  taken  from  various  parts 
of  the  contents  were  all  found  to  be  barium  carbonate  and  free  from  acetic 
acid. 
During  the  progress  of  these  distillations  from  pumice  stone,  from  carbon- 
ates and  from  the  empty  stills  alike,  whenever  the  supply  of  acid  vapor  was  cut 
off  the  distillation  almost  instantly  ceased,  showing  that  there  was  then  noth- 
ing in  the  still  to  decompose. 
This,  then,  is  the  improved,  continuous  process  for  the  production  of  acetone 
directly  from  the  acetic  acid,  which  avoids  and  saves  the  intermediate  steps  of 
forming  and  decomposing  acetates. 
The  formation  of  acetates  in  the  still  was  repeatedly  tried  with  both  barium 
and  calcium  carbonates,  but  always  failed  until  the  temperature  was  reduced 
to  about  the  boiling  point  of  water,  or  the  condensing  point  of  watery  vapor, 
and  then  the  acetates  formed,  cohered  and  adhered  to  the  ribs  and  shell  of  the 
still,  and  no  longer  moved  until  again  decomposed  by  a  higher  heat. 
Corresponding  trials  were  made  with  calcium  carbonate  and  with  calcium 
acetate  decomposed  to  carbonate,  with  results  very  similar  to  those  above  given, 
but  the  barium  carbonate  seemed  to  answer  best,  possibly  because  it  yields  a 
heavier  powder  that  occupies  less  space  and  moves  better. 
When  commercial  acetate  of  lime  was  used  tarry  matters  obstructed  the  exit 
tubes  and  contaminated  the  distillates.  The  portion  of  these  tarry  matters 
that  was  reduced  to  charcoal  in  the  still,  and  there  mixed  with  the  carbonate, 
seemed  to  be  rather  beneficial  than  obstructive.  But  on  the  whole  the  process 
appeared  to  do  better  with  carbonates  reduced  from  acetates  that  wTere  made 
for  the  purpose  from  good  materials.  As  the  process  seems  to  be  rather  a 
mechanical  or  physical  one  of  surface  contact,  it  would  be  reasonable  to  expect 
better  results  from  reduced  carbonates  than  from  precipitated  carbonates.  And 
it  is  still  an  open  question  whether,  on  the  large  manufacturing  scale,  with 
better  control  of  the  essentials,  heat  and  motion,  pumice  or  bone  black,  or 
some  other  such  substance,  will  not  be  better  than  the  carbonates.  Of  one 
thing  the  writer  is  convinced,  and  that  is  that  the  close  regulation  of  the  heat- 
ing within  narrow  limits  of  variation,  is  far  the  most  important  element  in 
the  process.  Within  very  narrow  limits,  too  little  heat  gives  undecomposed 
acid,  while  too  much  gives  inflammable  gases  in  place  of  acetone.  But  on  the 
large  scale  this  element  will  be  under  much  better  control,  whilst  a  proportion- 
ately longer  still  will  give  the  acid  vapor  farther  to  go  and  a  prolonged 
exposure  to  the  limited  heating  and  contact. 
There  are  no  patents  sought  for  on  this  process. or  apparatus. 
The  dilute  acetone  from  this  process  is  fairly  good  and  clean,  and  is  colorless 
except  for  the  action  of  the  free  acid  contained  on  the  iron  tubing.  With  the 
free  acid  the  s.  g.  by  hydrometer  varies  between  0*93  and  C97.  No  part  of  the 
distillate  has  more  than  a  thin  film  of  oil  on  the  surface  too  small  to  be  meas- 
ured, and  this  oily  surface  is  only  in  the  first  flask  with  the  acid  water.  On 
further  dilution  of  the  ice-bath  distillate  it  is  rendered  opalescent  for  a  minute 
or  two  and  then  becomes  again  transparent. 
This  distillate  (undiluted)  is  a  good  solvent  for  many  substances,  and  is  prob- 
ably pure  enough  for  the  manufacture  of  chloroform. 
When  allowed  to  stand  some  days  upon  caustic  lime  and  then  poured  off  and 
rectified,  it  is  much  improved  in  character  and  strength,  and  is  then  adapted 
