Solubility and Thermodynamic Parameters of HS/CH in Ionic Liquids Determined by H NMR.

Natural gas remains an important global source of energy. Usually, sour gas from the well or refinery stream contains HS among other contaminants that should be removed to fulfill permissible standards of use. Despite the use of different gas-liquid sour gas upgrading technologies, ionic liquids (ILs) have been recognized as promising materials to remove HS from sour gas. However, data concerned with thermodynamic solution functions of HS in ILs have scarcely been reported in the literature. In this work, solution H NMR spectroscopy was employed for quantifying HS soluble in [BMIM][Cl] and for gaining a better understanding of the HS-IL interaction. Experiments were carried out in a Young-Tap NMR tube containing a saturated solution of HS/CH/[BMIM][Cl] and recording spectra from 298 to 333 K. The thermodynamic solution functions, determined from the Van't Hoff equation, showed that solubility of the HS in the [BMIM][Cl] is an exothermic gas-liquid physisorption process (Δ = -66.13 kJmol) with a negative entropy change (Δ = -168.19 JK mol). H NMR spectra of the HS/[BMIM][Cl] solution show a feature of strong solute-solvent interactions. However, solubility enthalpy is a fifth of the H-S bond energy value. Results from H NMR spectroscopy also agree with those from the bench dynamic experiments.