Am.  Jour.  Pharm 
Dec. 
i9i8?rm'}     Manufacture  of  Chloramine — T.  883 
dissolved  in  a  warm,  strongly  alkaline  solution  of  sodium  hypo- 
chlorite of  concentration  1.3  to  2.0  N,  a  large  crop  of  chloramine  is 
formed  on  cooling  and  the  remainder  can  easily  be  obtained  on 
evaporation.  It  is  very  important  to  have  a  decided  excess  of 
caustic  soda,  and  for  each  mol.  of  amide  we  usually  take  1.05  to  1.1 
mols.  of  hypochlorite  and  1  mol.  of  sodium  hydroxide.  The  prep- 
aration of  the  hypochlorite  is  of  course  straightforward.  Owing, 
however,  to  the  cost  of  acids  in  New  Zealand  and  to  there  being 
no  electrolytic  source  of  chlorine,  we  found  it  most  convenient  and 
cheapest  to  use  bleaching  powder  as  the  starting  point.  The  crude 
chloramine-T  obtained  in  this  way  is  contaminated  with  sodium 
chloride;  but  even  the  crude  crystals  on  drying  contain  92-95  per 
cent,  of  chloramine.  The  substance  can  be  easily  purified  by  re- 
crystallization  from  water.  If  dissolved  in  twice  its  weight  of  hot 
water,  a  large  proportion  can  be  obtained  in  the  pure  form  (over 
98  per  cent.)  on  cooling.  The  final  filtration  is  apt  to  be  trouble- 
some ;  the  crystals  do  not  pack  well  on  the  filter  and  it  is  therefore 
difficult  to  remove  the  mother  liquid  completely.  If,  however,  the 
cooling  is  carried  out  rapidly  without  stirring  a  different  shape 
of  crystal  is  obtained  which  filters  much  more  readily.  It  is  thus 
possible,  working  with  large  quantities,  to  get  a  product  of  over  99 
per  cent,  purity. 
Utilization  of  By-products. — In  the  sulphonation  as  described 
most  of  the  toluene  is  used,  but  half  the  sulphuric  acid  taken  is  con- 
tained in  the  mother  liquors  after  removal  of  the  toluene  by  super- 
Heated  steam.  At  first  it  was  hoped  that  it  would  be  possible  to 
recover  the  acid  in  the  pure  state  by  distillation  and  use  it  over  again : 
but  there  is  always  some  charring  and  the  impurities  remaining  make 
it  comparatively  useless.  It  contains  34  per  cent,  of  water.  In  the 
remaining  stages  of  preparing  the  sulphonate  the  by-products  are 
small  in  quantity  and  comparatively  valueless.  Some  lime  or  cal- 
cium carbonate  is  used  and  converted  into  sulphate,  but  the  quantity 
is  very  small.  In  the  preparation  of  the  sulphonic  chloride  the  by- 
products are  sodium  chloride  and  sodium  ortho-  and  meta-phos- 
phate.  It  would  probably  be  worth  while  to  utilize  the  latter  on  the 
large  scale  but  out  experiments  are  incomplete.  In  the  preparation 
of  the  sulphonamide  the  chief  by-products  are  ammonium  chloride 
and  excess  of  ammonia.  The  former  can  be  easily  recovered  and 
the  ammonia  could  be  made  use  of  with  suitable  apparatus. 
