152 
Manufacture  of  Acetone. 
j  Am.  Jour.  Phui  uj. 
\     March,  18*5. 
to  a  still  larger  number  of  uses,  and  is  perhaps  better  adapted  to  the  manu- 
facture of  chloroform. 
The  product  of  this  first  rectification  was  then  digested  with  about  10  p.  c.  of 
dry  calcium  chloride.  This  abstracted  most  of  the  water  and  settled  in  dense 
solution  at  the  bottom  of  the  bright  yellowish  acetone.  This  latter  was  separ- 
ated and  distilled,  and  again  digested  for  several  days  with  io  p.  c.  of  fresh 
calcium  chloride,  being  frequently  well  shaken.  Again  twice  separated  and 
distilled  from  fresh  portions  of  calcium  chloride,  in  a  capacious  flask  with  a 
good  Hempel  tube  filled  with  small  glass  marbles,  and  the  whole  apparatus 
filled  with  well-dried  air,  and  distilled  directly  into  specific  gravity  bottles,  such 
as  are  described  in  the  Bphemeris,  Vol.  IV.,  p.  1448 — it  gave  six  fractions,  four 
of  which  had  the  specific  gravities  at  if  °  C,  as  follows  :  First,  o  79662;  second, 
079704;  third,  079712;  sixth,  079793.  The  irregularities  of  these  differences 
are  doubtless  due  to  differences  in  rate  of  boiling,  yet  they  demonstrate  con- 
clusively that  the  first  fraction  can  not  be  anhydrous. 
Authorities  differ  much  as  to  the  s.  g.  of  acetone.  The  lowest  noticed  is 
given  by  W.  H.  Perkins,  Ph.D.,  F.R.S.,  in  the  Journal  of  the  Chemical  Society 
of  London,  1884,  Vol.  XI/V,  p.  478.  He  gives  the  s.  g.  at  \%°0  as  079652,  and 
at  If  0  as  078669 — and  says  this  is  lower  than  that  usually  observed,  but  agrees 
pretty  closely  with  that  of  Linnemann,  who  obtained  if°  =  07975.  Thorpe's 
number,  calculated  for  this  temperature,  gave  \f°0  =  0*80244.  Judging 
from  the  circumstance  that  the  writer's  fractions  did  not  agree,  and  that  there- 
fore there  was  no  constant  boiling  point  to  his  distillate,  and  hence  no  part 
anhydrous — his  and  Perkin's  results  are  both  too  high. 
Notwithstanding  this,  the  writer  accepts,  for  the  present  at  least,  his  own 
result  as  a  basis  for  the  following  specific  gravities  of  dilutions.  His  best 
results  as  obtained  by  the  use  of  his  above-mentioned  specific  gravity  bottles, 
and  a  sensitive  thermometer  in  tenths  of  a  degree,  recently  compared  with  a 
standard,  are  as  follows: 
At  fo  C.  0-808157.    At  ifg  C.  0796620.    At  |f°  C.  0.786988. 
It  was  first  desirable  to  know  whether  dilutions  of  acetone  with  water  were 
mixtures,  or  whether,  as  in  the  case  of  alcohol,  there  was  molecular  com- 
bination with  contraction  and  elevation  of  temperature.  It  was  found  that 
when  40  Cc.  of  acetone  of  about  90  p.  c.  was  mixed  with  40  Cc.  of  water  there 
was  a  contraction  of  3*2  Cc,  and  an  increase  of  temperature  of  5*6°  C,  with  an 
effervescence  of  gas  as  in  alcohol. 
The  proportion  of  10  Gm.  of  recently  boiled  distilled  water  added  to  90  Gm. 
of  this  distillate,  mixed  by  connecting  two  flasks  with  the  weighed  quantities, 
and  passing  the  liquids  back  and  forth  without  exposure  to  external  air  or  loss 
of  vapor,  gave  the  following  specific  gravities  : 
Acetone  at  |°  C.  0-8371.  f|°  C.  0*8260.  f|°  C.  o"8i68  for  10  p.  c.  of  water  or 
90  p.  c.  acetone. 
This  method  of  dilution  by  weighing  the  acetone  and  water  separately  in 
flasks  and  then  connecting  the  flasks  for  mixing  without  loss  of  vapor  or  outer 
air  contact  was  adopted  for  the  basis  of  an  acetone  table.  The  lines  of  the 
table  that  are  given  in  heavy-faced  type  are  given  from  actual  observation, 
and  the  remainder  by  interpolation. 
Acetone  =  C3H60,  or  Dimethyl  Ketone  =  CH3COCH3  is  a  transparent,  color- 
less, mobile,  light,  inflammable  liquid  of  an  agreeable  spirituous  or  ethereal 
