Alj"a^uaryPi9i8m'  )     Manufacture  of  Anthraquinone.  39 
will  be  distilled  in  India  by  modern  methods,  and  not  exported  for 
distillation  abroad."  In  regard  to  palmarosa  oil,  which  was  dealt 
with  in  the  C.  &  D.  of  July  14,  1916  (p.  787),  recent  investigations 
have  shown  that  improvements  in  distillation  can  be  effected  by 
employing  a  modern  type  of  steam  still,  and  that  by  distilling  the 
grass  with  steam  20  per  cent,  more  oil  can  be  obtained.  In  regard 
to  wintergreen  oil,  Mr.  Puran  Singh,  chemical  adviser  at  the  Forest 
Research  Institute,  is  believed  to  have  been  the  first  to  show  that 
the  oil  can  be  distilled  at  a  profit  in  India  from  the  leaves  of  Gaul- 
theria  fragrantissima  collected  in  Assam  during  the  winter,  the 
fresh  leaves  giving  as  much  as  0.65  per  cent,  of  oil,  or  1.2  per  cent, 
calculated  on  the  dry  material.  Naturally  Mr.  Troup  gives  a  de- 
tailed account  of  the  Indian  pine-resin  industry,  to  which  much 
attention  has  been  devoted  of  late  years,  and,  judging  from  his 
remarks,  there  is  no  doubt  that  eventually  India  will  be  able  to 
supply  the  greater  part  of  her  own  markets  with  rosin  and  turpen- 
tine oil. 
THE  MANUFACTURE  OF  ANTHRAQUINONE.1 
There  is  a  growing  feeling  that  our  American  color  industry 
should  promptly  enter  upon  the  manufacture  of  alizarin  and  the  other 
important  dyes  derived  from  anthraquinone.  In  this  connection  we 
reproduce  from  La  Revue  Produits  Chimiques  a  full  account  of  the 
current  process,  now  employed  in  Europe,  for  transforming  the 
hydrocarbon  anthracene  into  anthraquinone : 
By  oxidation  anthracene  yields  anthraquinone  according  to  the 
equation : 
C14H10  +  30  =  C14Hs02  +  H20. 
As  this  oxidation  is  effected  industrially  by  means  of  chromic 
acid  it  may  be  formulated  as  follows : 
C14H10  +  Na2Cr207  +  4H2S04  =  C14H802  +  Cr2(S04)3 
+  Na2S04  +  5H20. 
It  is  performed  in  large  wooden  vats,  lined  with  lead,  holding  10  to 
12  cubic  meters.  The  vats  are  heated  with  direct  steam  and  fur- 
nished with  agitators.  A  vat  is  charged  wtih  sublimed  anthracene, 
still  in  form  of  paste.    The  charge  is  150  kilos  of  anthracene  to 
1  Reprinted  from  The  Chemical  Engineer. 
c 
