PRODUCTION  AND  SEPARATION   OF  METHYL  AMINE.  347 
in  quantity,  becomes  very  soon  crystalline  ;  indeed  this  change 
takes  place  so  rapidly  that  the  fluid  stage  may  easily  pass  un- 
noticed. More  oxalate  of  methylamine  remains  in  the  mother 
liquid  and  separates  on  further  evaporation. 
After  the  fluid  has  crystallized,  the  resulting  pearly  white 
laminas  are  purified  by  boiling  with  absolute  alcohol,  or  with  a 
mixture  of  equal  parts  of  alcohol  of  42°  B.  and  ether,  and  this 
is  repeated  three  or  four  times,  allowing  a  thorough  cooling  to 
take  place  between  each  operation.  The  oxalate  of  methylamine 
finally  crystallizes  out  quite  pure,  and  methylamine  may  be  ob- 
tained from  it  directly  by  distillation  with  caustic  alkali.  But  the 
distillation  is  extremely  unpleasant,  exhibiting  the  phenomenon 
of  percussive  ebullition  to  such  a  degree  as  to  endanger  the  whole 
apparatus,  and  to  drive  the  liquid  out  of  the  Woulfe's  bottle  in 
strong  jets  through  the  safety  tube.  It  is  therefore  advisable  to 
treat  the  oxalate  with  nitrate  of  baryta  or  chloride  of  barium, 
leaving  them  in  contact  for  a  day,  to  evaporate  the  filtrate  and 
then  distill.  I  give  the  preference  to  the  nitrate  of  baryta,  be- 
cause the  nitrates  of  the  ammonias  distill  more  quietly  than  any 
of  the  others  of  these  salts. 
The  methylamine  thus  obtained  was  converted  into  chloro- 
platinate  and  analyzed.* 
1-0105  grms.  gave  of  Pt,       .       .  .4216 
This  corresponds  to,  per  cent,    .  41-72 
Theory  requires  for  C^H^ 
►  NCI,  Pt012,  41-62 
H  ! 
H 
H 
The  residue,  after  the  greater  part  of  the  oxalate  of  methyl- 
amine had  crystallized  out,  was  evaporated,  exhausted  with  ab- 
solute alcohol,  treated  with  nitrate  of  baryta,  distilled  with  caus- 
tic soda  and  neutralized  with  picric  acid.  From  this  solution 
there  crystallized  out  beautiful  amber-colored  bevelled  prisms 
and  hexagonal  plates  greatly  resembling  the  picrate  of  ethyl- 
*  It  is  scarcely  necessary  to  observe  that  if  platinum  salts  are  recrystai- 
lized,  the  result  of  their  analysis  cannot  be  taken  as  a  proof  of  the  accuracy 
of  the  mode  of  separation  used.  In  the  analyses  here  published  care  was 
taken  to  use  in  all  cases  an  excess  of  bichloride  of  platinum,  and  to  include 
the  whole  precipitate  in  the  analyses. 
