AmNTo"'iSifrm"}    Derivatives  of  Benzoic  Sulphinide.  553 
The  starting  point  for  their  preparation  was  paradiazotoluene- 
orthosulphonic  acid,  which  was  converted  into  parafluortolueneor- 
thosulphonic  acid  by  heating  with  concentrated  hydrofluoric  acid  in 
a  platinum  dish  until  the  decomposition  was  complete,  evaporating 
to  a  syrupy  consistence,  diluting  with  a  large  quantity  of  water,  and 
neutralizing  with  barium  carbonate  (the  calcium  salt  not  being 
easily  crystallizable).  From  the  barium  salt  the  potassium  com-* 
pound  was  obtained  by  treatment  with  potassium  carbonate.  This 
latter  salt  crystallizes  from  water  in  large  glistening  scales,  contain- 
ing two  molecules  of  water  of  crystallization.  The  corresponding 
chlorine  and  bromine  salts  were  prepared  in  a  similar  manner, 
potassium  chlortoluenesulphonate  crystallizing  in  light  yellow 
needles  containing  no  water,  and  the  bromtoluenesulphonate  in 
thin  lustrous  scales  containing  1  mol..  of  water  of  crystallization. 
For  the  preparation  of  the  iodo-salts  the  diazo  compound  was 
decomposed  by  hydriodic  acid  in  presence  of  alcohol,  the  flask 
being  kept  cool ;  after  the  evolution  of  nitrogen  had  ceased  the  con- 
tents were  warmed  and  the  alcohol  distilled  off.  The  residue  was 
diluted  with  a  large  quantity  of  water,  neutralized  with  lead  oxide 
and  filtered  hot.  The  lead  salt,  being  insoluble,  could  not  be  easily 
freed  from  the  excess  of  oxide,  and  was  converted  into  the  potas- 
sium salt,  which  crystallized  from  aqueous  solution  in  transparent 
"  whetstone-shaped  "  crystals  containing  1  mol.  of  water  and  corre- 
sponding to  the  potassium  salt  of  the  /9-iodotoluenesulphonic  acid 
described  by  Glassner  (Berichte,  viii,  561).  Accompanying  the 
insoluble  lead  salt  was  another  which  was  very  soluble  ;  it  was  not 
examined  as  such,  but  was  converted  into  the  potassium  salt,  and 
on  analysis  gave  figures  corresponding  to  potassium  toluenesul- 
phonate. 
From  these  four  potassium  salts,  the  corresponding  amides  were 
prepared  by  the  action  of  phosphorus  pentachloride,  followed  by 
aqueous  ammonia.  The  solutions  were  evaporated  to  dryness  on 
the  water-bath,  alcohol  added,  and  after  treatment  with  animal 
charcoal,  crystallized  out.  With  the  exception  of  the  iodo  salt,  all 
are  easily  soluble  in  hot  water  and  alcohol,  sparingly  soluble  in  cold 
water.  The  melting-point  of  the  fluorine  salt  is  1 5 5 °,  of  the  chlo- 
rine salt,  1450,  and  of  the  iodine  salt,  185-1870  (uncorrected). 
From  these  amides,  the  sulphinides  (sulphonic  imides)  were  pre- 
pared by  oxidation  with  alkaline  permanganate,  the  most  successful 
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