AmMJai-ch,f908.rm'}       Alcohol  in  Concentrated  Nitrous  Ether.  105 
No. 
Date 
Ale.  Sol. 
Chromic  acid 
mixture 
Per  cent,  of 
Standard  alcohol 
Alkali  required       in  original 
I. 
December  24  . 
.  20  c.c. 
20  C.C. 
7 '4  c.c.  normal  16*5 
2  . 
24  . 
.  20  c.c. 
20  C.C. 
Bottle  broken  in  steam-bath 
3- 
24  . 
.  20  C.C. 
15  c.c. 
7'5  c.c.  normal  16*7 
4- 
24  • 
.  15  C.C. 
20  c.c. 
5'5  c.c.      "  16-4 
5- 
24. 
.  10  c.c. 
12  C.C. 
37  c.c.      "  16-5 
6. 
"  24. 
.  10  c.c. 
13  c.c. 
'    37  c.c.     "  16-5 
7- 
26  . 
.  20  c.c. 
23  c.c. 
7*2  c.c.      "  i6#o 
8. 
26  . 
.  20  c.c. 
23  c.c. 
7'35  c.c.    "  16-3 
9- 
:' [  j>  "     26  . 
.  15  c.c. 
18  c.c. 
55- 1  c.c.      "    tenth  i6"4 
10. 
26 . 
.  15  c.c. 
18  c.c. 
54-4  c.c.      "       "  i6"2 
 '  i6'44 
A  4-8376  gramme  sample  of  the  original  nitrous  ether  was 
weighed  in  a  cold  100  c.c.  flask,  diluted  at  once  to  100  c  c.  with 
alcohol,  and  tested  in  nitrometer  for  absolute  ethyl  nitrite. 
No. 
1.  5  c.c.  of  this  solution  liberated  65  c.c.    of  nitric  oxide 
2.  5  c.c.  "    "         "  "        65*2  c.c.  "     "  " 
Average  65*1  c.c. 
65-1  c.c.  of  nitric  oxide  represents  82  63  per  cent,  of  absolute  ethyl 
nitrite  in  sample.  The  indicated  composition  of  this  sample  is, 
therefore:  alcohol,  16*44  Per  cent.,  ethyl  nitrite,  82-63  Per  cent. 
SUMMARY. 
Alcohol  can  be  estimated  in  concentrated  nitrous  ether  by  the 
method  of  Dupre,  using  certain  modifications,  as  outlined.  The  ex- 
perimental error  is  large,  unless  exceptional  care  is  taken  at  every 
step,  because  the  final  error  is  magnified  by  multiplication  in  com- 
putation. Aldehydes,  if  they  be  present,  will  be  estimated  along 
with  alcohol,  and  some  of  the  methods  for  estimating  aldehydes 
must  be  used  for  this  correction.  In  the  samples  above  examined 
no  aldehyde  was  detected  by  addition  of  ammonia  or  solution  of 
sodium  bisulphite.  Reduction  tests  for  aldehydes,  of  course,  are 
useless  in  the  presence  of  ethyl  nitrite. 
Any  ethyl  nitrite  left  dissolved  in  the  water  along  with  the  alcohol 
is  also  changed  into  acetic  acid.  This  error  is  so  slight  that  it  may, 
in  most  cases,  be  ignored.  A  correction  may  be  subtracted  for  this 
error  by  estimating  the  amount  of  ethyl  nitrite  in  the  water  by 
means  of  a  nitrometer. 
From  Research  Laboratory  of 
Smith,  Kline  &  French  Company. 
