Thermodynamic and separation properties of 4-(octyloxy) benzoic acid liquid crystals by inverse gas chromatography (IGC)

Abstract

The thermodynamic properties of 4-(octyloxy) benzoic acid (OBA) liquid crystal (LC) were investigated at infinite dilution by inverse gas chromatography (IGC). The phase transition temperatures of OBA LC were determined by differential scanning calorimetry (DSC) and IGC. The thermodynamic region was determined to be between 160 and 170 °C. Specific retention volumes were calculated using IGC measurements to prepare retention diagrams. The results from the diagrams were used to characterize the thermodynamic properties of the OBA LCs. Based upon these properties, the solvents used in this study were determined to be unsuitable for OBA LCs. The separation of structural isomer series (butyl acetate, butyl alcohol, and amyl alcohol series) was studied by an OBA LC coated Chromosorb W stationary phase in the thermodynamic region. This system was able to distinguish the isomers according to the determined selectivity coefficients.

Keywords:

• Inverse gas chromatography (IGC)
• isomer separation
• 4-(octyloxy) benzoic acid liquid crystal
• phase transition temperatures
• thermodynamic properties

Disclosure statement

No potential conflicts of interest are reported by the authors.

Additional information

Funding

This work was supported by the Yildiz Technical University Scientific Research Projects Coordination Department, Project No. FDK-2020-4071.