Influence of Solute Polarity on Diffusion Coefficient in Supercritical Carbon Dioxide by Chromatographic Impulse Response Method

Abstract

Infinite dilution binary diffusion coefficients D₁₂ were measured for various compounds such as o-, m-, and p-xylenes, C1 to C3 mono-alcohols, acetone, phenol, and naphthalene in supercritical carbon dioxide at 313.21 K and pressures from 7.4 to 25 MPa by the chromatographic impulse response method using a poly(ethylene glycol) coated diffusion column. The D₁₂ values for xylenes decrease with increasing the dipole moment. The D₁₂ values were roughly correlated with the solute molecular weight under the fixed conditions, and the values were also secondarily affected by the solute polarity.