The study on cholesteryl chloroformate liquid crystal for separation of isomers and determination of its surface properties

ABSTRACT

The ability to separate isomer series and the surface properties of cholesteryl chloroformate (CC) liquid crystal were investigated by inverse gas chromatography (IGC). The retention diagrams of the selected solvents were plotted between 308.2 and 333.2 K using the IGC technique. The selectivity coefficients, α, of the structural isomers were determined for the CC liquid crystal in the infinite dilution. Besides, the dispersive energy, ${\gamma }_S^D$, the Gibbs specific energy, $\mathrm{\Delta }{G}_A^S$, the adsorption enthalpy, $\mathrm{\Delta }{H}_A^S$, the adsorption entropy, $\mathrm{\Delta }{S}_A^S$, of the selected solvents were also determined. The $\mathrm{\Delta }{H}_A^S$ values were associated with the number of acidic and basic group to calculate the acidity constant ($K_A$) and the basicity constant ($K_D$). When the $\mathrm{\Delta }{H}_A^S$ values calculated in experimental studies were examined, it was seen that the adsorption takes place exothermically. According to $K_A$ and $K_D$ constants, CC surface was found to be basic character ($K_D/K_A\cong 3.11)$.

KEYWORDS:

• Isomer separation
• liquid crystal
• surface properties
• inverse gas chromatography

Acknowledgements

This research has been supported by Yildiz Technical University Scientific Research Projects Coordination Department. Project Number: FBA-2019-3498.

Declaration of interest statement

The authors declare that they have no conflict of interest.