Thermodynamic Parameters of a New Synthesized Tricationic Ionic Liquid Stationary Phase by Inverse Gas Chromatography

A new tricationic ionic liquid [benz(2NPTim)(3)](NTf2)(3) with three N-naphthyl imidazolium cations has been synthesized and used as a stationary phase in gas chromatography. The stationary phase was characterized using the inverse gas chromatography technique. The McReynolds constants, Abraham solvation parameters, the activity coeficients (y(infinity)), selectivities (S-ij(infinity)), and capacities (k(j)(infinity)) at infinite dilution were determined accordingly. The TGA analysis showed that the stationary phase had high thermal stability up to 673 K. On the basis of the obtained data from the McReynolds constants, the stationary phase had an average polarity of 1153 and polarity number equal to 130, which indicates its highly polar nature. The Abraham solvation parameters were compared to that of other stationary phases and revealed stronger H-bond basicity, dipole dipole, and dispersive interactions with the solutes. The Kovats retention indexes obtained for polyaromatic compounds suggest that the stationary phase has strong interactions with these compounds.