Assembly of SBA-15 Derived Hybrid Heterogeneous Catalysts for Liquid Phase Cyclopentene Epoxidation

摘要

Three two-dimensional SBA-15-based hybrid materials, SBA-15-ImCl-PF6, SBA-15-NH(PO3H2), and SBA-15-N+, were synthesized employing a post-synthetic functionalization strategy, and peroxo-W and PW species were successfully immobilized on the surface of the corresponding organic moieties-modified SBA-15 via electrostatic interaction or covalent linking. The TEM and XRD results presented that the structure and morphology of SBA-15 were maintained after multiple transformations. The final catalysts SBA-15-ImCl-PF6-W, SBA-15-NH(PO3H2)-W, and SBA-15-N+(PW4O24)(3-) all showed considerable activity for the epoxidation of cyclopentene to cyclopentene oxide using H2O2 as the oxygen source without any co-solvent. It was noteworthy that SBA-15-ImCl-PF6-W catalyst with increased hydrophobicity via altering counteranions of imisazolium ions exhibited excellent cyclopentene oxide selectivity (99 ), but a good cycle performance (10 times) was achieved via SBA-15-NH(PO3H2)-W owing robust covalent bonds. Besides, the use of a low dose of heterogeneous catalyst (W=20 mu mol) and a green oxidant of H2O2, along with the absence of co-solvent or other additives make cyclopentene epoxidation reaction an environmenttally benign chemical process.