Degree of polymerization of di(2-ethylhexyl) phosphoric acid and sodium di(2-ethylhexyl) phosphate in wet benzene by differential vapour-pressure measurements

Differential vapour-pressure measurements at 20°C on wet benzene solutions of di(2-ethylhexyl)phosphoric acid, sodium di(2-ethylhexyl)phosphate, and mixtures of these indicate polymerization increasing with increasing sodium salt content from the dimer of the acid form (0·06–0·5 M) to ∼13 (at 0·1 M) and ∼50 (at ∼0·25 M) monomers per average polymer for the sodium salt form.