^une^ml^}     Methyl  Alcohol  in  Wood  Spirit  279 
The  principal  impurity  of  methyl  alcohol,  aside  from  adulterations, 
is  aceton.  The  latter,  if  absolutely  pure,  when  acted  upon  by  the 
biniodide  of  phosphorus  produces  no  substance  similar  to  methyl 
iodide ;  at  the  temperature  of  100p  C.  a  few  drops  of  a  distillate  is 
formed,  which  on  shaking  with  water  almost  entirely  dissolves.  Ace- 
ton does  not  exert  any  perceptible  influence  on  the  yield  of  methyl 
iodide,  as  may  be  proved  by  experiment. 
It  acts  differently  with  another  very  common  impurity  of  wood 
spirit,  methylacetic  ether.  With  biniodide  of  phosphorus  this  sub- 
stance also  produces  some  methyl  iodide,  and  the  results  of  the  expe- 
riments show  that  the  methyl  of  the  methylacetic  ether  is  also  con- 
verted into  methyl  iodide.  This  ether,  when  pure,  on  being  treated, 
as  proposed,  with  biniodide  of  phosphorus,  yields  at  100°  C.  a  distil- 
late, about  half  of  which  is  soluble  in  water;  the  insoluble  portion  of 
the  distillate  is  methyl  iodide.  This  method  of  testing  is,  of  course, 
influenced  by  this,  but  when  we  consider  that,  in  using  wood  spirit 
for  methylating  anilin,  the  methylacetic  ether  also  aids  in  the  action 
just  in  proportion  as  it  contains  methyl,  we  may  disregard  the  error 
which  this  causes  when  testing  for  most  practical  purposes. 
There  is  also  a  very  simple  method  of  determining  the  quantity  of 
methylacetic  ether  in  wood  spirits,  by  adding  a  measured  quantity  of 
normal  soda  solution,  warming  slightly  and  titrating  with  normal 
hydrochloric  acid.  The  difference  in  the  amount  of  acid  required 
from  that  indicated  by  the  soda  added  furnishes  the  means  of  calcu- 
lating the  quantity  of  ether  present. 
The  other  impurities  in  wood  spirit  are  mostly  unstudied  hydro- 
carbons, and  are  present  only  in  inconsiderable  quantities.  They 
produce,  with  biniodide  of  phosphorus,  resinous  bodies  that  yield  no 
distillate  at  100°  C.  Hence  there  is  no  danger  of  the  methyl  iodide 
being  contaminated  by  their  products,  and  experiments  prove  it. 
The  tests  with  wood  spirits  are  conducted  as  follows  : 
In  a  glass  flask  of  about  100  grams  capacity  are  placed  30  grams 
of  dry  biniodide  of  phosphorus,  PI2,  and  the  flask  closed  with  a 
double  bored  stopper,  preferably  of  glass.  Through  one  of  these  open- 
ings is  inserted  a  small  dropping  tube  holding  five  c.  c.  ;  through  the 
other  is  a  tube  bent  at  an  obtuse  angle — the  latter,  when  surrounded 
with  a  good  cooler,  to  condense  and  return  the  vapors,  and  afterward, 
by  inclining  the  flask,  for  distilling  it  off. 
Exactly  five  c.  c.  of  the  wood  spirit  to  be  tested  are  placed  in  the 
