Am.  .Tour.  Pharm. 
Dec,  1881 , 
Chemical  Notes. 
609 
bleach ing-powder  is  obtained  at  from  40°  to  45°C. — Chem.  Industrie, 
Sept.,  1881,  p.  296. 
Organic  Chemistry. — On  a  Neiv  Synthesis  of  Urea  from  Benzene, 
Ammonia  and  Air  by  the  Action  of  Heated,  Platinum. — E.  F.  Herronn, 
by  drawing  a  current  of  air  through  wash-bottles  containing  ammonia 
and  benzene,  and  tlien  passing  it  over  a  coil  of  platinum  wire  heated 
to  bright  redness,  has  succeeded  in  forming,  along  with  ammonium 
carbonate,  nitrite  and  nitrate,  a  crystallized  substance  easily  recognized 
as  urea.  Enoagh  was  prepared  to  analyze,  and  salts  were  made  from  it. 
Heated  spongy  platinum  and  platinized  asbestos  were  tried  as  sub- 
stitutes for  the  platinum  wire,  but  they  apparently  produced  too  much 
oxidation,  forming  more  ammonium  carbonate  and  less  urea  than  in 
the  case  of  the  wire. 
Olefiant  gas  was  also  employed,  but,  while  large  quantities  of  ammo- 
nium carbonate  were  produced,  no  urea  was  formed. 
Acetylene,  however,  was  found  to  be  a  good  substitute  for  benzene, 
very  considerable  amounts  of  urea  being  formed  in  the  case  of  its  use. 
— Jour.  Eng.  Chem.  8oc.,  Oct.,  1881,  p.  471. 
Reactions  of  Thymol. — Hamraersten  and  Robbert  have  studied  the 
reactions  of  thymol  as  compared  with  those  of  phenol.  With  ferric 
chloride  thymol  gives  no  reaction ;  with  sodium  hypochlorite,  on 
addition  of  anilin,  the  same  blue  coloration  ensues  as  is  obtained  with 
phenol ;  on  the  contrary,  sodium  hypochlorite  and  ammonia  yield  not 
a  blue  color,  as  with  phenol,  but  a  green  color,  w^hich  after  some  time 
passes  into  a  bluish-green,  and  after  4  or  5  days  into  a  red  color.  This 
reaction  is  recognizable  even  with  a  dilution  of  1  in  3,000.  With 
Millon's  reagent  a  faint  reddish-violet  color  is  produced,  which  disap- 
pears on  boiling,  whereas  w^ith  phenol  the  color  remains.  Bromine 
water  with  thymol  yields  no  crystalline  precipitate  as  in  the  case  of 
phenol,  but  a  milky  turbidity  only.  Ferric  chloride  and  bromine  are 
therefore  the  reagents  best  adapted  to  show  the  presence  of  phenol  in 
thymol.  The  most  delicate  reaction  for  thymol  is,  however,  that  with 
glacial  acetic  acid  and  concentrated  sulphuric  acid,  which  can  be  recog- 
nized with  a  dilution  of  1  in  1,000,000. 
For  this  purpose  the  solution  to  be  tested  is  mixed  with  one-half  its 
volume  of  glacial  acetic  acid  and  at  least  an  equal  volume  of  sulphu- 
ric acid,  and  is  then  heated,  when  a  beautiful  reddish-violet  color 
ensues,  which  is  not  destroyed  by  excess  of  acid  or  by  boiling.  In 
connection  with  the  separation  of  thymol  from  mixtures  may  be  noted 
39 
