Synthesis Of Two Polarizable Polyphenyl Grafted Polysiloxane Stationary Phases Containing Trifluoromethyl Groups And Their Chromatographic Performance Evalution

In recent years,with the improvement of gas chromatographic separation requirements,a large number of gas chromatography stationary phases with different separation performance have emerged.These stationary phases have been widely used to expand the application of gas chromatography in the field of medicine,food,environment,pesticides.In order to improve the performance of this type of stationary phase,the polar groups of trifluoromethyl and fluorine were introduced into polyphenyl side chain which could increase the polarizability of the stationary phase and enhance the interaction between the stationary phase with solute molecules to improve the selectivity of the stationary phase.The work of this thesis mainly includes:(1)The types and characteristics of the existing stationary phases will be elaborated from three aspects,such as universal GC stationary phase,specially selected stationary phase and new stationary phase.(2)Synthesis of two novel gas chromatographic stationary phases containing trifluoromethyl groups:Synthesis of 3,4-bis(2-trifluoromethylphenyl)-2,5-diphenyl-cyclopentadienone and 3,4-bis(2-fluoro-5-trifluoromethylphenyl)-2,5-diphenylcyclo-pentadienone were using the principle of benzoin condensation and oxidation(Cu2+),combination with methyl vinyl polysiloxane(Silicon gum),and the gas chromatography stationary phase of OFMP and FFMP were prepared by using the reaction principle of Diels-Alder with methyl vinyl polysiloxane(silica gel).In addition,the structures of OFMP and FFMP were characterized by nuclear magnetic resonance,mass spectrometry,and gel permeation chromatography.(3)Two kinds of gas chromatographic columns OFMP and FFMP were prepared by static method.The chromatographic performances of the two columns were characterized by the analysis of column efficiency test specimens,Grob mixture,McReynolds mixture,Abraham system model and pyrolysis ethylene mixture.The results showed that the efficiency of the two stationary phases of OFMP and FFMP were higher,and the best column efficiencies were 3806 and 3763 plates/m,respectively.As two kinds of medium polarity gas chromatography stationary phases,the interaction between OFMP and FFMP with solute molecules were dominated by dipole-induced dipole interaction,followed by the interaction of hydrogen bonding and dispersion.(4)The separation performance of two gas chromatographic columns,OFMP and FFMP,was further evaluated by analyzing the actual sample mixture.Due to the presence of polyphenyl groups containing large π-bonds,the two stationary phases had good separation selectivity for monocyclic aromatic hydrocarbons and aromatic hydrocarbons such as polycyclic aromatic hydrocarbons by the interaction of strongπ-π conjugation.In addition,the OFMP stationary phase could be used for the separation analysis of fatty acid esters and substituted aromatic aldehydes,the FFMP stationary phase could be used for the separation and analysis of fatty alcohol mixtures.Since N and O in the mixture of nitrogen-containing heterocycles and ethers all had lone electron pairs,it was easy to form strong p-π conjugates with polyphenyl groups in the stationary phase of OFMP and FFMP.Therefore,the OFMP and FFMP stationary phases had excellent separation selectivity for the mixtures of nitrogen-containing heterocycles and ethers,respectively.