﻿Drushel 
  and 
  Felty 
  — 
  Preparation 
  of 
  Acids. 
  57 
  

  

  Art. 
  VI. 
  — 
  On 
  the 
  Preparation 
  and 
  Ionization 
  of 
  the 
  

   Dialkylphosphoric 
  and 
  Benzenedisidphonic 
  Acids; 
  by 
  

   W. 
  A. 
  Drushel 
  and 
  A. 
  II. 
  Felty. 
  

  

  [Contributions 
  from 
  the 
  Kent 
  Chemical 
  Laboratory 
  of 
  Yale 
  Univ. 
  — 
  cclxxxv.] 
  

  

  The 
  acids 
  studied 
  in 
  this 
  investigation 
  are 
  the 
  lower 
  

   dialkylphosphoric 
  acids 
  of 
  the 
  general 
  type 
  R 
  2 
  HP0 
  4 
  , 
  simple 
  

   monobasic 
  acids, 
  and 
  the 
  three 
  unsubstituted, 
  dibasic, 
  isomeric 
  

   benzenedisulphonic 
  acids 
  of 
  the 
  formula 
  C 
  6 
  M 
  4 
  (S0 
  3 
  H) 
  2 
  . 
  Ioniza- 
  

   tion 
  measurements 
  of 
  only 
  one 
  of 
  the 
  dialkylphosphoric 
  acids 
  

   have 
  been 
  reported 
  in 
  the 
  literature.* 
  

  

  Preparation 
  of 
  materials. 
  — 
  (a) 
  The 
  dialkylphosphoric 
  acids 
  

   and 
  their 
  alkali 
  salts. 
  For 
  making 
  conductivity 
  measurements 
  

   the 
  free 
  dialkylphosphoric 
  acids 
  and 
  their 
  sodium 
  salts 
  were 
  

   used. 
  The 
  trialkyl 
  phosphatesf 
  w 
  T 
  ere 
  prepared 
  by 
  the 
  action 
  

   of 
  the 
  proper 
  sodium 
  alcoholate 
  upon 
  phosphorus 
  oxychloride 
  

   in 
  the 
  presence 
  of 
  ether 
  according 
  to 
  the 
  equation 
  : 
  3RONa 
  

   + 
  POCI3 
  == 
  R 
  3 
  P0 
  4 
  + 
  3NaCl. 
  The 
  precipitated 
  sodium 
  chloride 
  

   was 
  filtered 
  off 
  and 
  washed 
  with 
  ether. 
  The 
  ether 
  was 
  dis- 
  

   tilled 
  off 
  from 
  the 
  filtrate 
  and 
  the 
  trialkyl 
  phosphate 
  was 
  

   recovered 
  from 
  the 
  residue 
  and 
  purified 
  by 
  fractional 
  distilla- 
  

   tion, 
  using 
  diminished 
  pressure 
  for 
  the 
  tripropyl 
  phosphate. 
  

   The 
  trialkyl 
  phosphates 
  were 
  decomposed 
  by 
  concentrated 
  

   aqueous 
  barium 
  hydroxide 
  and 
  the 
  barium 
  tetra-alkyl 
  phos- 
  

   phates 
  were 
  purified 
  by 
  crystallization 
  from 
  water. 
  The 
  

   anhydrous 
  barium 
  salts 
  dried 
  to 
  constant 
  weight 
  were 
  decom- 
  

   posed 
  by 
  the 
  theoretical 
  amount 
  of 
  sulphuric 
  acid, 
  taking 
  care 
  

   to 
  avoid 
  an 
  excess, 
  and 
  the 
  aqueous 
  acid 
  solutions 
  were 
  exactly 
  

   neutralized 
  with 
  pure 
  sodium 
  hydroxide. 
  The 
  aqueous 
  

   solutions 
  of 
  the 
  three 
  dialkyl 
  sodium 
  phosphates 
  were 
  evap- 
  

   orated 
  in 
  platinum. 
  The 
  sodium 
  salt 
  of 
  dimethylphosphoric 
  

   acid 
  was 
  recrystallized 
  and 
  dried 
  to 
  constant 
  weight 
  at 
  110-120°. 
  

   The 
  sodium 
  salts 
  of 
  the 
  diethyl- 
  and 
  dipropyl 
  phosphoric 
  acids 
  

   could 
  not 
  be 
  recrystallized 
  but 
  were 
  prepared 
  by 
  evaporating 
  

   their 
  aqueous 
  solutions 
  in 
  platinum 
  and 
  drying 
  to 
  constant 
  

   weight 
  at 
  140-150°. 
  These 
  two 
  salts 
  are 
  hygroscopic 
  and 
  must 
  

   be 
  weighed 
  from 
  weighing 
  bottles. 
  The 
  three 
  sodium 
  dialkyl 
  

   phosphates 
  were 
  made 
  up 
  in 
  N/8 
  solutions 
  for 
  conductivity 
  

   work. 
  

  

  The 
  dimethyl-, 
  diethyl- 
  and 
  dipropylphosphoric 
  acids 
  were 
  

   prepared 
  for 
  conductivity 
  work 
  by 
  treating 
  weighed 
  amounts 
  

   of 
  the 
  pure 
  barium 
  salts 
  with 
  the 
  theoretical 
  quantities 
  of 
  

   sulphuric 
  acid 
  and 
  making 
  up 
  the 
  solutions 
  to 
  the 
  proper 
  

   normality, 
  verifying 
  the 
  normality 
  of 
  each 
  solution 
  by 
  titration 
  

  

  *Van 
  Hove, 
  Bull. 
  Acad. 
  Eoy. 
  Belg., 
  1909, 
  282-294. 
  

   •f 
  Limpricht, 
  Ann. 
  d. 
  Chem., 
  cxxxiv, 
  347, 
  1865. 
  

  

  