Am.  Jour.  Pharm.  ) 
Febmary,  1909.  j 
Estimation  of  Alcohol. 
7* 
determine  the  specific  gravity  and  compute  the  percentage  of 
glycerin  from  the  published  tables.13 
To  100  c.c.  of  a  glycerin-alcohol-water  mixture  (which  assayed 
23.89  per  cent,  alcohol),  3.85  grammes  of  acetanilid  were  added,  the 
mixture  made  up  to  no  c.c.  and  the  original  volume  (100  c.c.) 
distilled  by  the  usual  method.  Specific  gravity  of  distillate,  0.97212  ; 
alcohol,  23.89  per  cent.  It  is  seen  that  the  addition  of  acetanilid  did 
not  influence  the  determination  of  alcohol.  Fifty  c.c.  of  the  dis- 
tillate, when  evaporated  on  the  water-bath  to  about  1  c.c.  and  the 
evaporation  continued  over  sulphuric  acid  gave  0.0013  gramme 
residue.  The  residue  gave  the  isonitril  reaction,  indicating  the 
presence  of  acetanilid. 
A  mixture  of  alcohol  and  water  was  assayed  for  alcohol :  specific 
gravity,  0.97236;  alcohol,  23.65  per  cent.  An  equal  volume  of  the 
same  mixture  was  treated  in  the  same  way  after  adding  about  3  per 
cent,  acetanilid :  specific  gravity,  0.97220 ;  alcohol,  23.80  per  cent. ; 
gain,  0.15  per  cent.  One-half  of  this  last  distillate  was  shaken  out 
three  times  with  chloroform,  filtered  and  evaporated  and  the  residue 
dried  over  sulphuric  acid  :  residue,  0.0053  gramme ;  proportion  dis- 
tilling over,  0.706  per  cent.  The  residue  gave  the  isonitril  reaction 
and  a  precipitate  of  tribrom  acetanilid  with  bromine  water. 
From  the  results  of  these  experiments  with  acetanilid  it  is  seen 
that  this  substance  volatilizes  somewhat  in  the  vapors  of  boiling 
water  (or  in  hydro-alcoholic  vapors),  but  that  the  quantities  dis- 
tilling over  in  carrying  out  the  determination  for  alcohol  are  not 
sufficient  to  appreciably  vitiate  the  alcoholic  values.  In  addition  to 
these  experiments,  another  series  was  conducted  in  each  of  which 
300  c.c.  of  41.509  per  cent,  alcohol  were  taken.  Glycerin,  acetanilid, 
and  antipyrin  were  respectively  added  to  different  samples  and  each 
diluted  to  500  c.c.  Duplicate  alcohol  determinations  were  then  made 
from  each  sample  by  each  worker  and  the  results  compared  with  the 
calculated  values.  Aliquots  of  each  distillate  were  evaporated  and 
weighed.  A  mixture  containing  alcohol,  water,  glycerin,  acetanilid, 
antipyrin,  caffeine  and  the  bromides  of  potassium  and  sodium  was 
prepared  and  the  alcohol  and  the  solids  in  the  distillate  determined. 
Lastly,  a  similar  mixture,  but  containing  sugar  in  addition,  was 
subjected  to  the  same  treatment.    The  results  are  given  in  the  sub- 
13Nicol,  W.  W.  J.;  Pharm.  Jour.  Tr.  [3],  18,  302  (1887). 
