Am.  jour.  Pharm.  i      Preparation  of  Dichloramin  T.  I7 
January,  1918.    it  J  1/ 
layer  of  toluol  has  disappeared  the  sulphonation  mixture  is  poured 
into  water  and  neutralized  with  lime.  After  filtering,  the  solution 
of  the  ortho  and  para  calcium  sulphonates  is  treated  with  sodium 
carbonate  and  boiled  to'  form  the  sodium  salts  and  precipitate  calcium 
carbonate.  The  filtered  solution  is  evaporated  to  dryness  and  care- 
fully dried. 
2.  Preparation  of  the  Sulpho-Chlorides. 
The  powdered  sodium  sulphonates  are  treated  with  an  equal 
weight  of  phosphorus  pentachloride.  After  the  pentachloride  has 
disappeared  the  semifluid  mass  is  heated  on  the  water  bath  to  com- 
plete the  reaction  and  then  poured  on  ice.  The  para  sulpho-chloride 
crystallizes  after  a  time  while  the  ortho  derivative  is  a  liquid.  They 
are  separated  by  centrifuging. 
3.  Preparation  of  the  Sulphon-Amide. 
The  para  sulpho-chloride  is  melted  on  the  water  bath  and  treated 
with  an  excess  of  ammonium  carbonate.  The  odor  of  sulpho- 
chloride  should  no  longer  be  observable.  The  mixture  of  ammonium 
carbonate  and  sulphon-amide  is  extracted  with  water  and  dried. 
If  the  sulphon-amide  is  not  pure  white  it  should  be  recrystallized 
from  hot  water. 
4.  Preparation  of  the  Dichloramide. 
The  toluol  para  sulphon-amide  is  dissolved  in  ten  parts  of  1 : 10 
caustic  soda  (390  Be.)  and  diluted  with  twenty  parts  of  water.  The 
solution  is  filtered  through  glass  wool  and  then  through  double  filter 
paper.  This  removes  iron  hydroxid  from  the  strongly  caustic  solu- 
tion. 
Chlorine  gas  from  a  cylinder  is  then  passed  through  the  solution, 
cooled  externally  by  ice,  until  a  voluminous  white  precipitate  of 
toluol  p.  sulphon-dichloramide  is  formed.  This  is  filtered  off,  thor- 
oughly washed  twice  with  5-8  parts  of  water  and  finally  with  enough 
10  per  cent,  alcohol  to  make  a  thin  paste.  The  dilute  alcohol  wash- 
ing should  be  done  very  quickly  and  the  substance  filtered  off  with 
aid  of  a  vacuum  filter.  It  is  then  dried  at  a  temperature  not  ex- 
ceeding 550  C.  in  a  vacuum  dryer. 
The  method  has  the  advantage  that  it  is  very  rapid  and  avoids 
