504  Furification  of  ConDnerclal  Alcohol.  {'''"^ioCiss^''^' 
compound  as  a  white  amorphous  mass,  with  a  taste  even  more  bitter 
than  that  of  quassiin ;  this  compound  dissolved  in  alkalies  with  an 
intense  yellow  color^  distinctly  produced  by  the  smallest  traces,  and  at 
the  same  time  lost  its  bitter  taste  almost  completely. 
An  experiment  made  to  test  statements  as  to  the  occurrence  of  an 
essential  oil  in  quassia  wood  gave  negative  results,  a  small  quantity  of 
solid  white  substance  that  collected  on  the  surface  of  the  aqueous  distil- 
late proving  to  consist  of  free  fatty  acid. — Fhar.  Jour,  and  Trmw., 
August  19,  1882,  from  Archh.,  xx,  481. 
THE  PURIFICATION  OF  COMMERCIAL  ALCOHOL. 
By  a.  Riche. 
It  is  known  that  in  fermentation  sugar  does  not  split  up  exclusively 
into  alcohol  and  carbonic  anhydride,  according  to  the  equation  of  Gray- 
Lussac,  and  Pasteur  has  shown  that  glycerin  and  succinic  acid  are 
constantly  formed  during  the  alcoholic  fermentation.  Many  others 
besides  these  four  products  make  their  appearance  at  the  same  time, 
several  of  which  are  not  yet  defined,  but  mention  may  be  made  of 
most  of  the  alcohols  and  acids  of  the  fatty  series  ;  the  aldehydes,  their 
isomers  and  various  derivatives ;  and  isopropylic  acid. 
Alcohol  is  now  manufactured  from  the  most  varied  materials ;  fresh 
and  dried  grapes ;  beetroot  and  beetroot  molasses ;  various  grains, 
such  as  barley,  rye,  maize  and  rice;  saccharine  fruits,  as  figs,  dates, 
plums,  and  mulberries  ;  and  several  starches.  Some  of  the_  bodies 
contaminating  commercial  alcohol  are  derived  from  the  material  used 
as  the  source  of  the  alcohol,  and  are  only  met  with  if  the  alcohol  is 
derived  from  a  particular  material. 
The  temperature  to  which  the  fermented  liquor  is  subjected  in  the 
distillatory  columns  also  determines  the  formation  of  contaminating 
products,  and  notably  of  substances  possessing  a  disagreeable  odor  and 
taste ;  so  that  the  number  of  compounds  affecting  the  purity  of  alcohol 
is  very  large  and  very  diverse  in  nature.  In  weight  they  only  repre- 
sent a  very  small  portion  of  the  alcohol,  but  this  quantity  is  neverthe- 
less sufficient  not  only  to  give  the  alcohol  a  special  flavor,  but  also  to 
render  it  more  injurious  for  consumption  than  pure  vinic  alcohol. 
It  is,  therefore,  very  important  to  free  the  alcohol  from  these  impu- 
rities. At  first  it  was  hoped  that  this  could  be  done  by  several  rectifi- 
cations, and  M.  Pierre  effected  it  by  frequently  repeated  operations 
