Am.  Jour  Pharm. 
Oct.,  1887. 
Ethyl  Nitrite. 
485 
tion  of  caustic  potassa  on  ethyl  nitrite  (Liebig's  Annalen,  vol.  77, 
p.  331). 
It  is  prepared  by  adding  copper  turnings  to  a  mixture  of  equal 
parts  of  nitric  acid  and  alcohol  contained  in  a  retort  connected  to  a 
cooling  apparatus ;  the  action  which  starts  up  is  sufficient  to  cause  the 
ether  to  pass  over  without  the  application  of  external  heat.  It  may 
now  be  either  washed  and  dried  or  proceed  as  Kopp  directs,  viz,  pass 
the  ether  in  the  state  of  vapor  through  a  wash-bottle  containing 
water,  which  in  turn  is  connected  to  a  calcium  chloride  drying-tube, 
and  this  latter  to  a  cooling  apparatus,  and  the  pure  ether  collected. 
3.  United  States  Pharmacopoeia  Process.  A  mixture  of  alcohol, 
sulphuric  acid  and  nitric  acid  is  distilled,  and  the  distillate  washed 
with  water. 
4.  Method  of  M.  Carey  Lea.  Is  similar  to  the  preceding  one, 
with  the  exception  that  ferrous  sulphate  is  employed  in  place  of  the 
sulphuric  acid. 
5.  Grosourdy  uses  a  mixture  of  either  nitrite  or  nitrate  of  potassium, 
alcohol  and  sulphuric  acid ;  this  he  heats  gently  for  forty- eight  to  seven- 
ty-two hours,  when  the  ether  distills  over. 
6.  Feldhaus  claims  the  following  method  to  be  the  best  after  having 
tried  others ;  it  is,  a  mixture  of  potassium  nitrite,  water  and  alcohol 
is  poured  gradually  into  a  cold  mixture  of  alcohol,  water  and  sulphu- 
ric acid,  contained  in  a  distillatory  apparatus,  heat  enough  is  pro- 
duced in  the  reaction  to  carry  it  through,  and  the  ether  distills  off. 
In  methods  3  and  4  some  ordinary  ether  is  produced. 
In  5  a  large  amount  of  aldehyde  is  formed.  In  all  the  processes 
undecomposed  alcohol  passes  over ;  this  is  particularly  so  in  5  and  3. 
In  1  and  2,  as  Watts  (Gmelin's  Handbook)  suspected,  and  as 
Schmidt  and  Duflos  have  proved,  a  small  amount  of  ethyl  chloride  is 
produced  when  calcium  chloride  is  used  as  a  drying  agent. 
The  following  general  method  was  used  in  purifying  the  products 
of  the  several  methods,  viz : 
The  distillate  was  shaken  with  one  third  its  volume  of  ice-water 
vigorously,  three  successive  times.  After  the  third  washing,  the  ether 
was  separated  as  much  as  possible  by  means  of  a  separately  funnel, 
and  the  washed  ether  shaken  occasionally  in  half  hour  with  pure  re- 
cently ignited  potassium  carbonate,  allowed  to  settle,  decanted  into  a 
dry  flask,  and  distilled.  During  this  treatment  No.  5  alone  browned 
the  potassium  carbonate  used. 
