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2 Polish Journal of Chemistry

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Isothermal Gas Chromatographic Partion Coefficients of n-Alkanes, Benzene, Methylbenzenes and Chlobenzenes on Two Opposite Polarity Stationary Phases

Perez-Parajon J., Santiuste J.

Polish Journal of Chemistry

2005

Vol. 79 / nr 5

883-896

Partition coefficients of benzene, its twelve methylbenzenes and its twelve chlorobenzenes have been estimated on two fused silica capillary columns coated with the stationary phases HP-5 and ZB-WAX at 100-180_C range. These retention data are compared to evaluate the column temperature effect, the dependence of the substituent number and the influence of the stationary phase polarity. The partition coefficient decreases with increasing column temperature in all cases, but, on the contrary, it increases with the number of methyl radicals and chlorine atoms at each stationary phase at each temperature, and it increases for the polar stationary phase. The partition coefficients of the isomers (1,2-), (1,2,3-) and (1,2,3,4-) are larger than those of the other diisomers (1,3-) and (1,4-), triisomers (1,2,4-) and (1,3,5-), and tetraisomers (1,2,3,5-) and (1,2,4,5-). Discussion in terms of physicochemical properties of these isomers is forwarded.

Gas-Liquid Chromatographic Interactions for Twelve benzene-Derived Chemical Functions on Twelve Polar Stationary Phases

Santiuste J.

Polish Journal of Chemistry

2000

Vol. 74, nr 2

257-263

Linear solvation energy relationship (LSER) was used to describe the solute-solvent interactions of benzene and twelve derivatives on 12 stationary phases taken from literature. The hydrogen-bond interactions between the basic solute and the acid solvent were negligible, the more relevant interactions being cavity-formation/dispersion and the dipolar interactions. The effect of the polarity of both the stationary phase (solvent) and the solute (chemical function) on interactions has been investigated. The dipolar interaction increases for each solute with increasing phase polarity and for each phase with increasing solute polarity, whereas the cavity-formation/dispersion interaction decreases with increasing stationary phase polarity. The plots of the cavity-foration/dispersion and of dipolar interaction increments between chemical functions and parent benzene molecule versus stationary phase polarity confir the above trends.