542  Cause  of  Coloration  of  Phenol.       {AmNovr/im rui 
that  this  test  did  not  appear  to  be  very  definite,  as  "  of  five  samples 
tested  three  (pimpinella)  gave  a  blue  color ;  one  (illicium)  gave  a  pink  ; 
one  (illicium)  gave  a  yellow  color,"  while  the  result  of  more  recent 
experiments  confirms  the  observation  that  with  "  pimpinella  "  oil  the 
color  given  is  a  rich  blue,  changing  into  a  more  or  less  brownish- 
red.  Star  anise  oils  give  a  yellow  or  brownish-yellow  color,  usually 
but  not  always,  changing  to  a  rich  red.  The  test  therefore  depends 
not  upon  the  difference  between  a  pink  and  a  yellowish. brown  color, 
but  upon  the  production  or  non-production  of  a  deep  blue  color,  on 
addition  of  the  reagent,  wrhich  is  best  used  in  considerable  excess. 
I  would  venture  to  suggest  that  the  different  results  obtained  by 
Mr.  Umney  wrere  due  to  the  use  of  an  alcohol  not  sufficiently  satu- 
rated with  hydrochloric  acid.  The  reagent  used  above  had  a  sp.  gr. 
of -970  and  contained  2/ per  cent,  by  weight  of  hydrochloric  acid 
gas.  With  an  acid  of  half  that  strength,  the  characteristic  blue 
color  is  not  produced. 
THE  CAUSE  OF  THE  RED  COLORATION  OF  PHENOL.1 
By  Charles  A.  Kohn,  Ph.D.,  B.Sc, 
Lecturer  on  Organic  Chemistry,  University  College,  Liverpool. 
Since  alkalis  (especially  ammonia),  metallic  salts,  and  oxidizing 
agents  play  an  important  part  in  the  turning  red  of  phenol,  their 
separate  and  combined  actions  on  specially  purified  phenol,  has  been 
investigated.  The  purest  commercial  phenol,  known  as  "  absolute 
phenol,"  was  used  in  a  portion  of  the  experiments  ;  in  the  remainder, 
a  specially  purified  sample,  kindly  prepared  by  C.  Lowe,  Esq.,  of 
Manchester. 
This  phenol  was  first  purified  by  repeated  distillation  from  glass 
vessels,  the  first  and  last  portions  of  each  distillate  being  rejected. 
The  distilled  product  was  then  tested  with  hydrogen  peroxide, 
ammonia,  caustic  potash,  iron  and  copper  salts,  after  one,  six,  nine 
and  fifteen  distillations,  respectively. 
The  tests  were  carried  out  by  placing  2-3  cc.  of  the  melted 
phenol  in  a  test-tube  and  adding  one  or  two  drops  of  the  reagent  or 
mixtures  of  the  reagents.  The  reagents  were  employed  in  various 
strengths. 
1  Abstract  of  a  paper  read  before  the  British  Association  (  Section  B),  Notting- 
ham Meeting,  1893,  through  Chem.  News,  1893,  p.  163. 
