Liquid-liquid extraction of sulfuric acid using tri-n-dodecylamine/kerosene

Abstract

The extraction of sulfuric acid has been investigated by tri-n-dodecylamine (\overline TDA ) in kerosene in the presence of octanol-1 as modifier. The effect of octanol-1 has been studied on the equilibrium constant of (TDAH)₂SO₄ and TDAHHSO₄ formation in the concentration range from 5 to 25% v/v and within the temperature range from 25 to 50 ^o C. The equilibrium constants (K₁ and K₂, at 25 ^o C), the enthalpy (&Delta ;H^o₁, Δ H^o₂) and the entropy (Δ S^o ₁, Δ S ^o₂) changes were calculated for two extraction reactions of sulfuric acid by tri-n-dodecylamine containing 10% octanol-1 and they were found to be 10^9.642 l⁴/mol⁴, 10^-0.899 l/mol, -99.11, -22.17 kJ/mol, -0.149, -0.063 kJ/mol.K, respectively. The two reactions are: 2 \overline TDA + 2 H⁺+SO₄^2- \rightleftarrows K₁ \overline (TDAH)₂ SO₄ and \overline (TDAH)₂ SO₄ H^+ + HSO₄^- \rightleftarrows K₂ 2 \overline TDAHHSO₄ .