Studies of the system sulphuric acid-water-tributyl phosphate-carbon tetrachloride

The extraction of sulphuric acid and water into dilute solutions of tributyl phosphate (TBP) in CCl4 has been studied, and the nature and stability of the extracted species have been determined. For TBP concentrations up to 10 per cent by volume in CCl4 and for organic-phase sulphuric acid concentration 0·001–0·025 M the predominant species is 2 TBP·H+· y H2O…HSO4−, with an average aggregation number of 1·7. The values of y are 0·11, 0·14 and 0·28 for 5, 7 and 10 per cent by volume of TBP, respectively. The equilibrium constants of the reaction 2 TBP(org.) + H + ( aq. )+ HSO 4 − ( aq. )+y( H 2 O ) aq = 1 1·67 [2 TBP·H + ·y H 2 O … HSO 4 − ] 1.67 ( org ) at 25° have been determined for TBP concentrations up to 10 per cent by volume in CCl4.