DERIVATIVES OF IMIDOPYROPHOSPHORIC ACIDS AS EXTRACTANTS .1. THE PREPARATION AND FUNDAMENTAL CONSTANTS OF TETRAALKYLIMIDOPYROPHOSPHORIC ACIDS

Improved methods for the preparation of imidotetraalkyl-pyrophosphates are reported. The dissociation constant of the water soluble tetraethyl analogue was determined by potentiometric titration. The values for the partition constant and aggregation constant of the tetradodecyl analogue were determined by two phase EMF potentiometric titration of which the data were processed through a sophisticated general optimization technique. The application of this method also made it possible to obtain a species distribution curve of the organic phase in terms of variation of pH in the aqueous phase.