434       Recent  Literature  Relating  to  Pharmacy.  {As™ptJembeJbim 
RECENT  LITERATURE  RELATING  TO  PHARMACY. 
THE  TESTING  OF  ACETONE. 
Crude  acetone  may  contain  a  number  of  undesirable  ketones 
which  occasionally  find  their  way  into  the  purified  article,  and  our 
present  analytical  methods  are  generally  deficient  for  making"  proper 
deductions.  Most  of  the  methods  not  only  estimate  the  acetone, 
but  also  include  other  homologous  ketones  and  associated  bodies. 
A  good  acetone  should  mix  clear  with  distilled  water  and  when 
evaporated  at  100°  C.  should  not  leave  any  residue.  Its  specific 
gravity  should  not  exceed  0  800  at  15*5°  C.  and  four-fifths  of  the 
quantity  taken,  by  volume,  must  distil  at  a  temperature  not  exceed- 
ing 590  C.  The  acetone  should  not  contain  more  than  0-005  per 
cent,  of  acid,  calculated  as  acetic  acid,  which  is  estimated  by  dilut- 
ing 50  c.c.  of  the  acetone  with  an  equal  volume  of  distilled  water, 
adding  2  c.c.  of  phenolphtalein  solution,  and  titrating  with  N/100 
sodium  hydrate.  On  adding  1  c.c.  of  a  y1^  per  cent,  solution  of 
potassium  permanganate  to  100  c.c.  of  the  acetone,  a  distinctive 
color  must  be  retained  for  at  least  thirty  minutes. — Mr.  James  T. 
Conroy,  J.  Sac.  Chem.  Ind.y  1899,  ig,  206.  L.  F.  Kebler. 
THE  IODINE  VALUE  OF  OILS. 
Literature  is  teeming  with  results  on  the  iodine  value  of  oils,  yet 
the  exact  nature  of  the  reactions  of  the  various  methods  proposed 
is  obscure.  Wijs'  proposition  (Ber.  deut.  chem.  Gesel.,  1898,  31, 
750)  to  employ  a  solution  of  iodine  monochloride  in  acetic  acid  in 
place  of  Hiibl's  solution  marks  a  distinct  advance  in  the  practical 
execution  of  such  determinations.  Wijs'  solution  is  rapid  in  reac- 
tion, nearly  permanent,  and  Lewkowitsch  has  shown  (Analyst,  1809, 
257)  that  it  gives  the  same  iodine  values  as  Hubl's  solution. 
Ephraim  {Ztsch.  angew.  Chem.,  1895,  254)  thought  and  even 
Wijs  himself  {Ztsch.  anal.  Chem.,  1898,  277)  was  of  the  opinion 
that  with  Hiibl's  solution  the  iodine  monochloride  was  added 
directly  to  the  unsaturated  acid  radical.  Wijs  now  thinks  that  the 
iodine  chloride  reacts  with  water  as  follows:  IC1  +  H20  =  HIO 
-f-  HC1 ;  the  hypoiodous  acid  formed  is  then  added  to  the  unsatu- 
rated radical;  C17H33C02H  +  HIO  =  HIOC17H33C02H,  which 
addition  product  subsequently  reacts  with  the  hydrochloric  acid, 
