Am.  Jour.  Pharm. 
Jan.,  1890. 
The  Purification  of  Benzin. 
7 
0*670  to  0'675,  admits  of  but  a  very  small  portion  of  the  distillate, 
corresponding  to  a  commercial  benzin  of  78°B.  being  used.  It  is  safe 
to  say  that  none  of  the  commercial  so-called  deodorized  benzins,  and 
but  very  little  of  the  petroleum  ether  sold  for  chemical  purposes, 
answer  the  pharmacopoeial  requirements.  What  is  generally  supplied 
the  pharmacist,  when  he  orders  benzin,  is  a  distillate  of  65°B.  (sp.  gr. 
0*717)  or,  frequently,  even  as  high  a  gravity  as  62°B.  (sp.  gr.  0*729) 
is  supplied.  If  he  is  somewhat  particular,  he  may  procure  75°  B.  (sp. 
gr.  0*680),  but  benzins  from  75°B.  to  90°B.  are  generally  supplied  as 
gasoline.  Every  sample  of  commercial  deodorized  benzin  that  I  have 
been  able  to  procure,  has  been  so  contaminated  with  pyrogenous  and 
sulphurous  impurities  as  to  be  totally  unfit  for  pharmaceutical  pur- 
poses, and  the  petroleum  ethers,  while  cheap  enough  to  be  used  as  sol- 
vents in  chemical  analysis  are  too  expensive  for  pharmaceutical  use. 
The  solvent  properties  of  benzin  render  it  a  valuable  agent  in  the 
laboratory  and  I  have  no  doubt  that,  in  the  near  future,  it  will  be  used 
in  many  of  the  processes  of  pharmacy,  such  as  the  preparation  of  plas- 
ters, the  extraction  of  fats  and  oils  from  certain  drugs  before  percola- 
tion, such  as  nux  vomica,  ergot  and  strophanthus,  or  of  caoutchouc- 
like substances  from  others  such  as  lactucarium. 
A  process  by  which  the  pharmacist  can  easily,  safely  and  cheaply 
purify  benzin  seems  to  me  to  be  a  desirderatum.  It  was  surmised  that 
the  sulphur  compounds  could  be  removed  by  oxidation  with  potassium 
permanganate.  As  the  result  of  experiments  the  following  process  was 
devised.  t 
Take  of  Potassium  permanganate  one  ounce  avoir. 
Sulphuric  acid  a  half  pint. 
Water  three  and  a  half  pints. 
Mix  the  acid  and  water  and  when  the  mixture  has  become  cold, 
pour  it  into  a  two-gallon  bottle.  Add  the  permanganate  and  agitate 
until  it  is  dissolved.    Then  add 
Benzin  one  gallon. 
and  thoroughly  agitate.  Allow  the  liquid  to  remain  in  contact  for  24 
hours,  frequently  agitating  the  mixture.  Separate  the  benzin  and  wash 
in  a  similar  bottle  with  a  mixture  of 
Potassium  permanganate  \oz  avoir. 
Soda      £oz.  avoir. 
Water  2  pints. 
Agitate  the  mixture  frequently  during  several  hours.  Then  separate 
the  benzin  and  wash  it  thoroughly  with  water. 
