Am.  Jour.  Pharm. 
Alay,  1879. 
Bromide  of  Ethyl. 
De  Vrij's  process/  which  depends  upon  the  decomposition  of  potas- 
sium bromide  by  sulphuric  acid  in  the  presence  of  alcohol,  was  again 
looked  to  as  a  basis  for  a  working;  formula,  and  the  process  recom- 
mended by  Dr.  E.  R.  Squibbb^  for  preparing  hydrobromic  acid  by  dis- 
tilling from  a  mixture  of  potassium  bromide,  sulphuric  acid  and  water, 
suggested  a  plan  by  which  the  contamination  of  ordinary  ether  could 
be  avoided,  and  this  process  was  subsequently  recommended  by  Dr. 
Greene.^ 
In  a  series  of  experiments  intended  to  ascertain  practically  the  pro- 
cess which  could  be  adopted  if  it  be  deemed  advisable  to  introduce  the 
new  agent  into  the  U.  S.  Pharmacopaeia,  the  following  is  selected  as 
the  best  (cut  of  the  apparatus  will  appear  in  the  next  number)  : 
Potassium  bromide  (not  powdered),         .  .  .58  parts. 
Sulphuric  acid,  sp.  gr.,  1838,  .  .  ;  4+  " 
Alcohol  (clean)  95  per  cent.,  .  .  .       44  " 
Water,  .  .  .  .  .  28  " 
Pour  the  water  into  a  flask  having  double  the  capacity  of  the 
liquid  ingredients  above,  and  gradually  add  the  acid;  when  the  liquid 
has  become  cool  add  the  potassium  bromide,  and  having  placed  the 
flask  in  a  sand-bath,  adjust  a  thermomeier,  and  with  a  bent  glass  tlibe 
connect  the  flask  with  a  well  cooled  condenser,  insert  a  narrow  glass 
tube  in  the  cork  of  the  flask,  and  by  means  of  a  short  rubber  tube  con- 
nect it  with  a  narrow  glass  tube  which  is  terminated  by  a  syphon  ;  the 
shorter  limb  of  this  syphon  is  inserted  in  the  bottle  containing  the 
alcohol,  which  is  elevated  three  feet  or  more  above  the  flask.  Heat 
the  contents  of  the  flask  to  ii6°C.,  and  having  attached  a  screw 
pinch  cock  to  the  short  rubber  tube  of  the  syphon,  allow  the  alcohol  to 
<irop  or  flow  in  a  sm.all  stream  into  the  flask,  carefully  regulating  the 
rate  of  flow  so  that  the  temperature  should  not  fall  below  100°C.,  nor 
rise  above  ii6°C.  When  all  the  alcohol  has  passed  into  the  flask 
continue  the  distillation  until  the  temperature  rises  to  ii6°C.,  and  then 
disconnect  the  receiving  flask.  Agitate  the  distillate  with  an  equal 
bulk  of  distilled  water,  to  which  has  been  added  five  parts  of  solution 
of  soda  (or  suflicient  to  render  the  liquid  slightly  alkaline),  and  when 
the  mixture  has  clearly  separated  into  two  layers,  pour  off"  the  upper- 
^ Watts'  "Dictionary  of  Chemistry,"  vol.  ii,  p.  528. 
^"American  Journal  of  Pharmacy,"  March,  1878,  p.  ij6. 
'"American  Journal  of  Pharmacy,'''  June,  1879. 
