346       PRODUCTION  AND  SEPARATION    OF  METHYLAMINE. 
liquid  is  then  distilled  with  caustic  alkali,  and  the  gaseous  pro- 
ducts are  conducted  into  water. 
In  the  solution  we  should  by  analogy  expect  to  find  ammo- 
nia, methyl  amine,  dimethylamine  and  trimethylamine,  and  it 
remains  to  separate  these  bases.  This  is  a  matter  of  extraordi- 
nary difficulty,  much  surpassing  that  of  the  separation  of  the 
ethyl  bases.  In  the  ethyl  series  the  bases  differ  from  each  other 
and  from  ammonia  by  C4H4,  whereas  in  the  methyl  series  the 
successive  terms  acquire  the  addition  of  C2H2  only.  Naturally, 
therefore,  we  must  look  for  greater  similarity  in  character  and 
corresponding  difficulty  in  separation.  Accordingly,  the  methods 
which  give  such  satisfactory  results  with  the  ethyl-ammonias, 
fail  entirely  with  the  methyl  bases.  Ammonia  cannot  be  sepa- 
rated from  them  by  a  difference  in  the  solubility  of  the  sulphates 
in  alcohol  :  when  the  mixed  solution  is  neutralized  with  sulphu- 
ric acid  and  exhausted  with  alcohol,  little  or  nothing  is  removed 
by  it.  Nor  can  the  separation  be  effected  by  means  of  picric 
acid,  although  that  substance  may  be  used  in  one  particular 
case  mentioned  below. 
This  problem  I  have  as  yet  been  able  to  resolve  only  in 
part.  Two  steps  I  have  accomplished  : — first,  the  complete  re- 
moval of  the  ammonia  from  the  mixed  methyl  bases,  and  second, 
the  isolation  of  the  methylamine  in  a  state  of  purity.  The 
separation  of  the  more  substituted  bases  still  remains  to  be  ac- 
complished. 
It  is,  however,  satisfactory  to  have  a  process  forobtaining  per- 
fectly pure  methylamine  without  resorting  to  the  troublesome 
reaction  of  the  cyanate  of  methyl,  and  that  much  has  been  ef- 
fected. After  the  compound  ether  has  been  completely  decom- 
posed by  the  ammonia,  the  contents  of  the  bottles  are  to  be  dis- 
tilled with  caustic  alkali  or  lime.  The  solution  of  the  mixed 
bases  and  of  ammonia  is  to  be  exactly  neutralized  with  oxalic 
acid  and  the  water  driven  off  as  far  as  possible  by  being  heated 
over  the  water-bath.  The  resulting  mass  is  transferred  to  a 
flask,  and  boiled  a  few  minues  with  a  large  quantity  of  alcohol 
of  density  42°  B.,  and  after  cooling  and  standing  some  hours,  it 
is  filtered.  The  whole  of  the  ammonia  remains  as  oxalate  upon 
the  filter.  The  filtrate  by  spontaneous  or  gentle  evaporation 
separates  into  two  layers.    The  lower,  which  is  much  the  least 
