Facile Synthesis and Chiral Separation of Chiral Mesoporous Silica Microspheres

Mesoporous silica microspheres were synthesized by an acid-catalyzed sol-gel method using tetraethoxysilane (TEOS) as a precursor. The hydrochloric acid was used as a catalyzer to induce the hydrolysis of TEOS, while the cyclohexane acted as a stabilizer of the sol. The addition of polyethylene glycol can introduce the uniform mesoporous structure into the microspheres by phase separation. The as-prepared mesoporous silica microspheres possess a narrow particle size distribution, a mesopore size of 5.0 nm and a Brunauer-Emmett-Teller specific surface area as high as 230 m2·g-1. The resultant silica microspheres were used for packing chiral high-performance liquid chromatography (HPLC) columns, after activated by hydrochloric acid and modified by amylose-tris(3,5-dimethylphenylcarbamate), respectively. The flurbiprofen axetil as a typical chiral drug with two stereocenters can be successfully separated by the as-obtained chiral HPLC columns using different mobile phases.