358 
Decomposition  of  Chloroform. 
A.m.  Jour.  Pharm. 
July.  1893. 
We  have  not  hitherto  observed  the  formation  of  a  straw-colored 
supernatant  liquid  in  the  decomposition  of  chloroform,  as  described 
by  Mr.  Brown  in  his  paper. 
As  is  now  well  known,  the  decomposition  of  chloroform  is  pre- 
vented by  an  addition  of  alcohol,  and  not  only  does  such  an  addi- 
tion stop  decomposition  that  has  already  commenced,  but  it  will, 
with  sufficient  shaking,  remove  the  free  chlorine  that  has  been 
eliminated,  as  well  as  the  carbon  oxychloride  formed.  The  amount  of 
alcohol  requisite  for  that  purpose  depends  upon  the  extent  to  which 
decomposition  has  advanced,  and  hence  it  will  be  seen  that  the 
length  of  time  during  which  alcohol  will  protect  chloroform  will 
always  be  proportionate  to  the  amount  of  alcohol  added.  So  soon 
as  the  alcohol  is  consumed,  by  the  joint  action  of  the  free  chlorine 
and  the  carbon  oxychloride  directly  resulting  from  decomposition 
of  chloroform,  the  products  of  the  change  that  has  gone  on  up  to 
that  point  without  injurious  consequences  become  all  at  once  recog- 
nizable, just  as  if  the  alteration  had  suddenly  commenced.  At  that 
point  the  presence  of  free  chlorine  and  carbon  oxychloride — the  initial 
products  of  the  decomposition — can  be  detected.  Moreover,  since 
hydrochloric  acid  will  also  have  been  formed  by  the  subsequent 
reaction  of  the  free  chlorine  with  alcohol,  that  acid  will  also 
become  recognizable  as  soon  as  the  last  trace  of  alcohol  dis- 
appears, though  it  will  at  first  be  dissolved  by  the  alcohol  present. 
These  successive  changes  afford  an  explanation  of  the  fact  that 
alcoholic  chloroform  will  in  the  first  instance  evolve  hydrochloric 
acid,  originating  indirectly  from  the  reaction  of  chlorine  with 
alcohol,  and  soon  afterwards  free  chlorine  and  carbon  oxychloride 
originating  directly  from  the  decomposition  of  chloroform.  The 
decomposition  of  pure  chloroform,  on  the  contrary,  commences  by 
giving  rise  at  once  to  the  products  shown  in  the  equation  given  by 
Mr.  Brown,  which  coincides  exactly  with  the  one  that  was  given 
by  ourselves  in  the  paper  above  referred  to. 
According  to  our  own  experience  an  addition  of  alcohol, 
amounting  to  one  part  in  four  hundred  of  chloroform  (0-25  per 
cent.),  is  sufficient  to  prevent  recognizable  decomposition  for  one 
month  or  longer,  with  double  that  amount  (05  per  cent.),  decom- 
position is  prevented  for  nearly  a  year,  and  with  one  per  cent,  for 
many  years.  These,  however,  are  only  average  statements,  liable 
to  variation  in  both  directions,  according  to  the  effects  produced 
