470 
Inulin. 
Am.  Jour.  Pharm.. 
Sept.,  1881. 
tubes^  with  formation  of  bromoform  and  carbonic  and  oxalic  acids 
the  hydrobromic  acid  formed  in  the  reactin  converts  the  unchanged 
inulin  into  levulin.    This  latter,  by  the  farther  action  of  bromine^, 
gives  the  same  jDroducts  as  inulin.    By  heating  the  brominated  liquid 
with  silver  oxide,  some  of  the  unchanged  levulose  is  converted  into 
glycollic  acid.    As  this  acid  is  formed  by  the  direct  action  of  bromine 
and  silver  oxide,  it  is  possible  that  the  inulin  is  converted  by  the  bro- 
mine into  levulose,  which  is  then  oxidized  by  the  silver  oxide  into 
glycollic  acid  ;  for  comparison  the  author  has  studied  the  action  of 
bromine  and  silver  oxide  on  dextrose,  and  finds  that  no  oxalic,  but 
only  gluconic  acid  is  formed,  according  to  the  equation  CgH^2^6+^— 
Qffi^fi^.   Glycollic  acid  is  formed  as  a  secondary  product  of  the  action 
of  silver  oxide  on  the  gluconic  acid.    By  distillation  of  inulin  with 
hydriodic  acid,  a  small  quantity  of  an  oil  containing  iodine  is  obtained,, 
but  its  constitution  could  not  be  ascertained,  as  it  readily  decomposed. 
By  the  action  of  nascent  hydrogen  on  inulin  (sodium  amalgam  and 
water)  neither  mannitol  nor  mannitan  is  formed.    Pure  inulin  reduces 
ammoniacal  silver  solution  and  gold  chloride,  but  not  Fehling's  solu- 
tion nor  gold  nor  platinic  chloride. 
When  inulin  is  heated  with  baryta  water  it  is  partly  converted  into 
fermentation  lactic  acid.  By  inversion,  inulin  is  not  converted  at  ordi- 
nary temperatures  nor  at  40°C.  into  levulose  (Barth,  "  Ber./'  11,  474;. 
1878,  591).    It  appears  from  these  properties  that  inulin  stands  in 
near  chemical  relation  to  levulose,  and  is  probably  its  anhydride.  This 
is  sliown  by  the  readiness  with  which  it  takes  up  water  in  many  reac- 
tions, being  converted  into  levulose.  It,  however,  differs  from  levulose 
by  not  reducing  Fehling's  solution,  and  not  undergoing  fermentation 
with  yeast,  and  not  forming  an  additive  compound  with  hydrogen.. 
Levulose,  the  hydrate  of  inulin,  differs  from  dextrose  in  its  oxidation 
products  with  nitric  acid  and  bromine  water ;  the  former  gives  glycol- 
lic and  oxalic,  the  latter  gluconic  acid.    This  difference  may  be  sim- 
ply explained  by  supposing  dextrose  to  be  the  aldehyd  whilst  levulose 
is  the  ketone  of  mannitoL— Jour.  Chem.  Soc,  May,  1881 ;  Annalen^ 
205,  145-190. 
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