Measurements of binary diffusion coefficients and retention factors for dibenzo-24-crown-8 and 15-crown-5 in supercritical carbon dioxide by chromatographic impulse response technique

Binary diffusion coefficients D12 and retention factors k for dibenzo-24-crown-8 and 15-crown-5 ethers at 308.18 and 313.20 K, and vitamin K1 at 313.20 K were measured in supercritical carbon dioxide by the chromatographic impulse response technique, and the effects of molecular shapes on the D12 values were studied. At 313.2 K and 11.0 MPa the D12 value of 15-crown-5 was higher than that predicted from the D12 correlation with molecular weight MW over the range from 32 of methanol to 1138 of trinervonin reported in our previous studies, while the D12 value of dibenzo-24-crown-8, disk shape molecule with MW = 448.5, was almost in agreement with that of vitamin K1, long chain molecule with MW = 450.7, and with those predicted from the correlation.