Am.  Jour.  Pharm.  ") 
March  1, 1871.  J 
Chloral, 
113 
CHLORAL: 
Hydrate — Alcoholate — Tests — Therapeutical   Value — Pharmaceutical 
Preparations. 
By  Alfred  H.  Mason. 
Read  at  a  a  meeting  of  the  Liverpool  Chemists'  Association,  held  December 
22d,  1870. 
The  principal  object  of  this  paper  is  to  show  that  the  hydrate  of 
chloral  of  commerce  is  not  all  pure  hydrate  of  chloral,  but  that  other 
compounds  have  been  put  upon  the  market.  I  have  examined  sam- 
ples, obtained  from  different  sources,  varying  veiy  seriously  in  the 
proportion  of  chloroform  they  produce  upon  decomposition  with  alka- 
line reagents,  and  I  feel  it  a  moral  duty  to  pharmaceutists  to  advise 
them  of  these  facts.  When  it  is  considered  that  one  agent  alone  in 
London  has  disposed  of  twenty-two  thousand  pounds'  weight"^  during 
the  past  twelve  months,  it  is  certainly  high  time  for  us  to  be  alive  to 
the. necessity  of  dispensing  a  guaranteed  article. 
Chloral,  C2Ci3H05  is  formed  by  the  prolonged  action  of  chlorine 
upon  absolute  alcohol. f  To  prepare  it,  the  current  of  chlorine  must 
be  kept  up  as  long  as  the  hydrochloric  acid  gas  continues  to  escape, 
and  the  product  is  to  be  agitated  with  three  times  its  volume  of  con- 
centrated sulphuric,  acid.  On  gently  warming  this  mixture  in  a  water- 
bath,  the  impure  chloral  separates  as  an  oily  liquid,  which  floats  on 
the  surface  of  the  acid  ;  it  is  purified  by  distillation  from  fresh  sul- 
phuric acid,  and  afterwards  from  a  small  quantity  of  quicklime,  which 
must  be  kept  completely  covered  by  the  liquid  until  the  end  of  the 
operation.  The  chemical  reactions  which  take  place  in  its  formation 
were  described  in  a  valuable  paper  by  Mr.  Henry  Sugden  Evans,  of 
London,  last  session. 
Chloral  is  a  thin,  oily,  colorless  liquid,  of  peculiar  and  penetrating 
odor,  which  excites  tears,  and  it  has  but  little  taste. 
Liebreich  says, J  if  chloral  be  left  in  contact  with  concentrated  sul- 
phuric acid,  it  is  transformed  into  polymeric  insoluble  chloral ;  this 
body  is  more  easily  purified,  since  it  is  not  soluble  in  alkalies  or  acids, 
and  it  may  be  treated  a  long  time  with  these  substances  without 
decomposing.  Warm  this  insoluble  chloral,  and  it  converts  itself  into 
*  Tkis  includes  both  kinds  of  hydrate  of  chloral,  as  distinguished  now  by  the 
agents  themselves, — guaranteed  and  unguaranteed, 
t  Fownes'  "  Manual  of  Chemistry,"  p.  813.  1868. 
X  "  L'Hydrate  de  Chloral,"  0.  Liebreich,  1870,  p.  15. 
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