Halide-free deep eutectic solvents with low viscosity and corrosion for efficient SO ₂ capture and conversion under environmental conditions

Eight halogen-free deep eutectic solvents (DESs) with low viscosity were synthesized for the capture and subsequent catalytic conversion of SO₂. The resulting DESs exhibit excellent SO₂ solubility (up to 1.2514 g g^-1 at 20 °C and 1 bar) and high catalytic activity in the cycloaddition between SO₂ and epoxides. Spectroscopic and theoretical investigations elucidate the mechanisms of SO₂ capture and conversion, revealing a synergistic effect between hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs).