Gas chromatographic study of limiting activity coefficients of organic solutes in squalane

Abstract

The specific retention volumes of 20 solutes in squalane coated on a silanized diatomite have been measured at 25 and 50 OC by varying the sample size for each packed column of different liquid loadings. The values for the limiting specific retention volumes extrapolated to zero sample size are slightly dependent upon the liquid loading ratio, which is attributed to the solute-solvent coadsorption on the solid surface. Polar solutes such as alcohols, acetonitrile, ketones, acetates, and ether indicate gas-liquid interface adsorption in the region of small sample size; the extrapolation to zero sample size has been carried out from the solution dominating region of large sample size. The activity coefficients in bulk-liquid squalane have been calculated from the intercepts of the plots of the limiting specific retention volume against the reciprocal liquid loadlng ratio. The experimental activity coefficients are compared with the predictions of the UNIFAC and the ASOG methods.

Characterization of the Solvent Properties of Glycerol Using Inverse Gas Chromatography and Solubility Parameters

“…The specific retention times and the retention volume data for the glycerol-alcohol systems as a function of temperature is given in Table 1. The determined specific retention volumes for the alcoholic solutes in glycerol over the different column loadings noted previously were in excellent agreement with each other, indicating that a negligible influence of the gas-liquid adsorption effect [25] for the n-alcohols on the glycerol loadings used in this study. The mole fraction and the weight fraction activity coefficients calculated using Eqs.…”

“…The experimental procedure followed in the study is similar to that described previously [24,25]. A column containing a specific weight fraction of glycerol was placed in a HP 5890 (Agilent Technologies, Santa Clara, CA, USA) Series II gas chromatograph equipped with a HP 7673 auto sampler and a flame ionization detector (FID).…”

Probe dependency of segmental interaction parameters in copolymers by inverse gas chromatography

“…It might happen because ethanol had surface adsorption on nonpolar solvents. 28 When different loading was used for different copolymers in chromatographic packings the variation of surface-to-volume ratio might cause a change in the specific Figure 4 The plot of ln K m vs. the volume fraction of PDPS for n-heptane, acetone, and benzene, in PDMS-PDPS system at 100 C. Solid lines are correlation based on eq. (5).…”

Infinite-dilution activity for alkanals, alkanoates, alkanes, and alkanones in 4-methyl-2-pentanone

“…All retention times for peaks with skews outside the range of 0.8-1.2 were corrected to the peak maximum retention. This and surface effects, as discussed elsewhere (2, 3,7,8), may add additional error. Table VI is a comparison of measured activity coefficients of this work with predictions by group contribution methods.…”