14°  Gleanings  from  the  German  Journals.  {AmMX",?894.rm' 
GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
By  Frank  X.  Moerk,  Ph.G. 
The  manufacture  of  ethyl  ether  and  its  homologues  by  the  interven- 
tion of  aromatic  sulphonic  acids  and  based  upon  extensive  research 
is  announced  by  Professor  Krafft.  The  alkyl  esters  of  sulphonic 
acid,  like  the  alkyl  sulphuric  acids,  possess  the  property  of  forming 
ethers  when  heated  with  alcohols ;  these  reactions  are  expressed  as 
follows  : 
HO  S02OC2H5  -f  C2H5OH  =  HO  S02-OH  +  C2H5-O  C2H5 
C6H5-S02-OC2H5  -|-  C2H5OH  =  C6H5-S02-OH  +  C2H5  O  C2H5 
Sulphuric  acid,  as  is  well  known,  readily  gives  up  oxygen  to  oxidizable 
substances,  to  which  class  alcohol  belongs.  In  the  sulphonic  acids 
like  C6H5-S02-OH  the  hydroxyl  group  of  the  sulphuric  acid,  which 
does  not  take  part  in  the  etherification  of  the  alcohol,  is  replaced 
by  strong  radicals  like  pheynl,  naphthyl,  etc.,  which  are  strongly 
united  with  the  sulphonic  group,  in  consequence  of  which  these 
sulphonic  acids  show  a  marked  stability  towards  the  alcohols 
towards  which  they  do  not  act  as  oxidizing  agents  but  simply  as 
etherifying  agents.  Sulphuric  acid  upon  heating  only  reluctantly 
gives  up  water  and  the  gradual  taking  up  of  more  water  in  the 
manufacture  of  ether  finally  prevents  the  etherification  of  the  alcohol  >' 
the  disadvantage  is  notably  reduced  by  the  use  of  the  sulphonic 
acids  which  give  up  the  water  much  more  readily  than  does  the 
sulphuric  acid.  In  the  preparation  of  ether  and  its  homologues  the 
sulphonic  acid  is  heated  to  the  proper  temperature  and  the  alcohol 
allowed  to  run  in ;  the  distillate  consists  of  ether,  water  and 
unchanged  alcohol ;  the  sulphonic  acid  is  always  regenerated  and 
can  be  used  for  unlimited  periods.  The  process  is  illustrated  by 
the  reactions : 
C6H5S02OH  +  C2H5OH  =  C6H5S02OC2H5  +  H20 
C6H5S02OC2H5  +  C2H5OH  ^  C6H5S02OH  +  C2H50C2H5 
Experiments  have  proven  that  benzene-sulphonic,  benzene-disul- 
phonic,  /-toluene-sulphonic,  /9-naphthalene  sulphonic  acids  or  their 
esters  are  suitable  for  the  manufacture  of  ethers.  Benzene  sul- 
phonic acid  has,  without  loss  of  its  activity,  been  used  in  converting 
one  hundred  times  its  weight  of  alcohol  into  ether  ;  under  favorable 
