Tracer diffusion coefficients of benzene in dense CO2 at 313.2 K and 8.5–30 MPa

Binary diffusion coefficients D12 of benzene at infinite dilution in carbon dioxide were measured at 313.2 K in the pressure range from 8.5 to 30 MPa by the Taylor dispersion method. At 313.2 K, the measured values in this study were slightly higher than those of Swaid and Schneider, 1979, and lower than those of Sassiat et al., 1987. It was found that the D12 values measured with the coiled diffusion column installed vertically were lower than those when it was installed horizontally. The correlation of D12 with solvent viscosity was effective for the D12 of benzene, both in dense CO2 and in the liquid solvents: hexane, cyclohexane and dodecane. In addition, the measured D12 decreased smoothly with increasing pressure, and there was no evidence of the anomalous decrease in D12 at 313.2 K in the pressure range from 8.5 to 30 MPa.