Separation of taurine and Na2SO4via the in situ formation of deep eutectic solvents: experiments and computational simulation

Abstract

As an important and free amino acid, taurine (Tau) has extensive applications in pharmaceuticals. The coexistence of inorganic salts during the production process affects the purity and quality of Tau. The present study firstly describes a novel method to separate Tau and Na₂SO₄ by forming deep eutectic solvents (DESs) in situ. Ethanolamine (MEA) was chosen as the optimal hydrogen bond donor to pair with Tau. After the removal of Na₂SO₄, taurine was stripped out from the DES using n-propanol as a reverse solvent, yielding 98% of Tau and trace impurities (Na₂SO₄ and NaCl contents of less than 13.70 mg g⁻¹ and 12.93 mg g⁻¹, respectively). Under optimized parameters, the Tau purification and separation processes were further elucidated using quantum chemical calculations and molecular dynamics simulations. Results showed an interaction energy of 116.1 kJ mol⁻¹ between MEA and Tau, confirming the superiority of the Tau purification process using DESs in situ.