Synthesis Of Chiral Covalent Organic Framework Core-shell Composites Based On Silica Gel Microspheres As Stationary Phase For High Performance Liquid Chromatography

Chiral covalent organic frameworks（CCOFs）are a class of crystalline functional materials with large specific surface area,good stability,adjustable pore size,and structural modification.They have broad application prospects in the field of enantiomeric separation.However,due to the characteristics of light weight,low density,irregular morphology,uneven particles,and wide particle size distribution,conventional CCOFs directly used as stationary phases for enantiomeric separation in high performance liquid chromatography（HPLC）have shortcomings such as difficulty in column preparation,low column efficiency,undesirable peak shape,and high column back pressure,which limit their application in the field of liquid chromatography.Synthesis of CCOFs@SiO₂core-shell composite materials through in-situ growth strategies can well overcome these shortcomings,thereby broadening their application in HPLC.In this thesis,CCOFs@SiO₂were prepared by in-situ growth of CCOFs on the surface of SiO₂microspheres and used as a chromatographic stationary phase to prepare chiral columns.Their chiral recognition performance in HPLC were studied.The main contents of this paper are as follows:In chapter 1,briefly introduces the basic concepts of chirality,chiral compounds,and the concept and significance of chiral resolution;HPLC and type of chiral stationary phases;Classification and synthesis methods of CCOFs and core-shell composites,and their applications in chromatographic separation.In chapter 2,a novel chiral covalent triazine skeleton core-shell composite material CC-DMP CCTF@SiO₂was synthesized by in-situ growth strategy using activated silica gel as the core and chiral covalent triazine skeleton（CCTF）CC-DMP CCTF as the shell.The CC-DMP CCTF@SiO₂was used as a chiral stationary phase for the separation of chiral compounds by HPLC,and the effects of injection volume and column temperature on separation performance and the reproducibility of chiral column were investigated.The experimental results show that there are 17 chiral compounds were well separated on the CC-DMP CCTF@SiO₂column,indicating that the chiral column has good chiral resolution performance.In chapter 3,a uniform spherical COF（TPB-Dva SCOF）with controllable size was synthesized by adjusting the concentration and amount of acetic acid as catalyst at room temperature,and its core-shell composite material TPB-Dva SCOF@SiO₂was prepared by immobilizing it on the surface of SiO₂.Synthesis of chiral core-shell composite material CTPB-Dva SCOF@SiO₂by introducing chiral source D-cysteine in the TPB-Dva SCOF@SiO₂with the help of thiol-ene click chemistry.The CTPB-Dva SCOF@SiO₂ was applied as a HPLC chiral stationary phase for the separation of enantiomers and positional isomers,and the effects of injection volume,column temperature,and other factors on chromatographic separation were discussed.In chapter 4,the CCOF（Λ）-TpPa-Py with keto configuration was synthesized using 2-methylpyrrolidine as chiral inducer,and the（Λ）-TpPa-Py@SiO₂core-shell composite material was synthesized using CCOF（Λ）-TpPa-Py as shell and spherical amino silica gel as core by in-situ growth method.The（Λ）-TpPa-Py@SiO₂core-shell composite was used as a chiral stationary phase for the resolution of racemates in HPLC.The effects of injection amount and temperature on the resolution results were investigated.