Controllable preparation of honeycomb supermacroporous core-shell SiO2 coated with cellulose-derivate and investigation of confinement effect on chiral separation performance.

The separation of enantiomers is of significant importance in pharmaceutical production and chemical synthesis. In this work, a novel kind of honeycomb supermacroporous core-shell SiO2 (HSC-SiO2) was controllably synthesized via an etching method. By precisely regulating the amounts of CTAB, ODA, and NH4F, a hierarchical pore structure composed of a mesoporous framework and supermacroporous channels was successfully constructed. The optimized material, denoted as HSC-SiO2-2, exhibited a specific surface area of 79.2 m2·g-1, an average pore size of 6.1 nm, and a maximum pore size of 136 nm. Chiral stationary phases (CSPs) were prepared by coating cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) onto the surface of aminofunctionalized HSC-SiO2. Evaluation of the separation performance for twelve racemic compounds demonstrated that CSP-2, fabricated from HSC-SiO2-2, possessed superior enantioselectivity, achieving baseline separation for eight analytes on a short 100 mm column. Specifically, it achieved an α of 2.75 and an Rs of 5.32 for metoprolol, an Rs of 3.04 for trans-stilbene oxide, and an Rs of 2.21 for benzoin. Comparative tests revealed that its resolution for trans-stilbene oxide was comparable to that of the commercial Chiralcel OD-H column (Rs = 3.01), while its Rs values for metoprolol and benzoin were markedly higher than those of the traditional fully porous silica-based CSP (Rs = 2.25 and 1.38, respectively). The performance enhancement is attributed to the hierarchical pore architecture with a favorable confinement effect, which provides a high surface area for sufficient chiral selector loading while enabling efficient mass transfer through the supermacroporous channels. This research offers a new design strategy for high-performance chiral separation supports, showing promising potential for applications in efficient enantiomer analysis and purification.