Molecular state of hydrochloric acid in its tributyl phosphate extracts

Using IR spectroscopy we have shown that at digerent equilibrium concentrations of HCl in aqueous phases, its tributyl phosphate @acts contain: 1) at C_Hcl^a < 2.3 M, micelle-like associates H₅O₂⁺(H₂O)_n–2(TBP)_mCl^–·(H₂0·TBP)₂ (n 26 and m 13), the structure of micelles is discussed 2) at 2.3 M < C_HCl^a < 5.6 M, dimer associates [H₅O₂⁺(H₂O)₂Cl^–(H₂O·TBP)₂]₂; 3) at 5.6 M < C_HCl^a < 8.5 M, H-bonded molecular fragments H₅O₂⁺(TBP)_2/3Cl^–(A); and 4) at C_HCl^a > 8.5 M, considerable amounts of the H₃O⁺ tisolvate start to form in molecular fragments H₃O⁺(TBP)_1/3Cl^–(B) H-bonded with the nearest neighbors. At C_Hcl^a > 5.6 M, almost no free TBP molecules occur in the extracts and a structured liquid forms from the A fragments; and at C_Hcl^a > 8.5 M, from the B fragments.Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturmoi Khimii, Vol. 34, No. 5, pp. 72–79, September–October, 1993.Translated by K. Shaposhnikova