"""^  jln";8^8o""  }  .       Nicotin  and  Nicotinic  Acid,  31 
washed  with  ether,  is  dissolved  in  water  and  again  decomposed  with 
potash  as  above.  The  product  is  finally  heated  to  iio°C.  for  six  hours 
by  a  paraffin-bath,  and  a  slow  stream  of  dry  hydrogen  passed  through 
!t  to  remove  ammonia,  ether  and  water.  The  temperature  is  then 
gradually  raised  to  2io°C.  to  complete  the  removal  of  the  water,  and  on 
fractionally  distilling  the  residue,  pure  nicotin  comes  over  between  240 
and  242°C.  It  must  be  preserved  in  sealed  tubes.  One  centner  of 
tobacco  thus  treated  yielded  600  grams  of  pure  nicotin  (=1 J  per  cent.), 
besides  impure  base. 
Nicotin  is  not  decomposed  into  well-defined  simpler  bodies  by  heat- 
ing with  hydrochloric  acid  at  280  and  300°C.  No  addition  product"  is 
formed  by  the  action  of  nascent  hydrogen  on  the  brominated  hydro- 
bromide,  CioHi3N2Br5. 
Nicotin  is  readily  oxidized  by  potassium  permanganate  in  the  cold, 
but  only  when  the  salt  is  added  to  its  solution  as  long  as  it  is  decolor- 
ized is  it  possible  to  obtain  crystalline  oxidation-products.  By  employ- 
ing a  suitable  process,  which  is  fully  described,  potassium  carbonate  and 
nicotinate  are  the  sole  products  found.  The  nicotinate  is  dissolved  out 
by  absolute  alcohol,  and  converted  into  silver  salt'  by  precipitation. 
Nicotinic  acid  may  be  obtained  from  this  by  decomposing  it  with 
hydrogen  sulphide. 
Nicotinic  acid  was  first  obtained  by  Huber,  by  oxidizing  nicotin  with 
chromic  mixture,  and  was  subsequently  recognized  by  him  as  carhopyri- 
denic  acid,  C^H.N.COOH  ("Ber.,"  3,  849).  Weidel  also  (''Annalen," 
165,  328),  by  acting  on  nicotin  with  nitric  acid,  obtained  an  acid  which  he 
identified  with  Ruber's  and  which  the  author,  by  a  crystallographic 
comparison  of  salts,  proves  to  be  identical  with  his  own  \  he,  however, 
assigned  to  it  the  formula  CjQHgN203.  By  analyses  of  the  acid  and  a 
variety  of  its  salts  (silver,  calcium,  potassium)  and  other  compounds 
with  hydrochloric  acid  and  auric  and  platinic  chlorides,  the  author 
decides  in  favor  of  Huber's  formula.  He  also  shows  that  when  nico- 
tinic acid  is  distilled  with  soda-lime,  it  yields  a  quantity  of  pyridene 
nearly  equal  to  that  which  might  be  expected  from  a  carbopyridenit 
acid.  Moreover,  nicotin  yields  carbopyridenic  acid  in  almost  molecular 
proportion. 
Nicotinic  acid  forms  crystalline  compounds  with  hydrochloric  and 
hydrobromic  acids,  of  the  formula  C6H5NO2.HCI  and  C^H^NO^HBr. 
