Effect of alkyl and halide moieties on the absorption and stratification of SO2 in tetrabutylammonium halide aqueous solutions

Abstract

Stratification occurs after a reaction between SO₂ and tetraalkylammonium halide aqueous solution. To explore the interactions between SO₂ and tetraalkylammonium halide, the effects of temperature, concentration, length of alkyl chain, and halide anion on the solubility of SO₂ in tetraalkylammonium halide aqueous solutions were investigated. To determine the mechanism of absorption of SO₂ by aqueous tetrabutylammonium bromide solution, the composition and concentrations of each component in the upper and lower liquid phase were measured from 283.15 K to 303.15 K. The solubility of SO₂ in aqueous tetraalkylammonium halide solutions increased with a corresponding increase in the alkyl chain length and a decrease in temperature. When SO₂ was added into the solution by bubbling, SO₂ molecules diffused into the clathrate compound of tetrabutylammonium bromide⋯nH₂O (TBAB⋯nH₂O) hydrate and formed a more stable clathrate inclusion complex.